JP4610587B2 - BANDPASS FILTER, RADIO COMMUNICATION MODULE AND RADIO COMMUNICATION DEVICE USING THE SAME - Google Patents

Description

  The present invention relates to a bandpass filter, a wireless communication module and a wireless communication device using the same, and in particular, a bandpass filter having a very wide passband that can be suitably used for UWB (Ultra Wide Band) and the same. The present invention relates to a wireless communication module and a wireless communication device.

  In recent years, UWB has attracted attention as a new communication means. UWB realizes large-capacity data transfer using a wide frequency band over a short distance of about 10 m. For example, according to US FCC (Federal Communication Commission) regulations, a plan to use a frequency band of 3.1 to 10.6 GHz It has become. Thus, the feature of UWB is that it uses a very wide frequency band. In Japan and ITU-R, avoiding 5.3GHz used in IEEE802.11.a, a low band that uses a band of about 3.1 to 4.7 GHz and a high band that uses a band of about 6 GHz to 10.6 GHz ( Standards divided into “high band” have been drafted, and the filter for low band is required to have a characteristic of sharply attenuating at 2.5 GHz and 5.3 GHz.

  In recent years, research on ultra-wideband filters that can be used for UWB has been actively conducted. For example, a bandpass filter that applies the principle of a directional coupler has a passband width of a specific bandwidth (bandwidth / center). There is a report that a broadband characteristic exceeding 100% is obtained in (frequency) (for example, see Non-Patent Document 1).

  On the other hand, as a filter often used conventionally, there is known a band-pass filter configured by connecting a plurality of quarter-wavelength stripline resonators to each other (see, for example, Patent Document 1).

Also, a plurality of resonator internal conductors (¼ wavelength stripline resonators) arranged in an interdigital manner so that the short-circuited end and the open end are staggered are provided, and each resonator internal conductor is provided. A multilayer dielectric filter having a configuration in which a short-circuit end connection pattern that connects between outer resonator conductors in the vicinity of a short-circuit end of an adjacent resonator inner conductor is embedded in a layer different from the layer is known (for example, Patent Documents). 2).
“Ultra-wideband bandpass filter using microstrip-CPW broadside coupling structure” Proceedings of the March 2005 IEICE General Conference C-2-114 p.147 JP 2004-180032 A JP 11-88009 A

  However, each of the bandpass filters described above has problems, and is not suitable for a UWB bandpass filter.

  For example, the bandpass filter proposed in Non-Patent Document 1 has a problem that the passband width is too wide. That is, UWB finally uses a frequency band of 3.1 GHz to 10.6 GHz, but initially it is planned to use a frequency band of about 3.1 GHz to 4.7 GHz, and the specific band is about 40%. Therefore, the filter used for this is required to have a pass bandwidth of about 40% in a specific band. In addition, it is necessary to consider the influence with W-LAN (IEEE 802.11.a), and attenuation at 5.15 GHz is required. Therefore, the bandpass filter proposed in Non-Patent Document 1 having a characteristic such that the passband width exceeds 100% in the specific band cannot be used because the passband width is too wide.

  Further, the pass band width of a bandpass filter using a conventional quarter wavelength resonator is too narrow, and even if the pass band width of the band pass filter described in Patent Document 1 is intended to be wide, it is 10 It was less than%. Therefore, it cannot be used as a bandpass filter for UWB requiring a wide pass bandwidth corresponding to about 40% in the specific band.

  Furthermore, in the bandpass filter described in Patent Document 2, since only one attenuation pole can be generated on either the low band side or the high band side of the pass band, 2.5 GHz in the vicinity of both sides of the pass band. However, it was not usable as a low band filter for UWB that needs to be attenuated sharply at 5.3 GHz.

  The present invention has been devised in view of such problems in the prior art, and its purpose is to provide an ultra-wideband and appropriate passband that can be suitably used as a UWB Low Band bandpass filter. An object of the present invention is to provide a band-pass filter having a width and having attenuation poles in the vicinity of both sides of the pass band and having a sufficient amount of attenuation in the stop band, and a wireless communication module and a wireless communication device using the same.

  The band-pass filter of the present invention includes a laminated body in which a plurality of dielectric layers are laminated, a first ground electrode that is disposed on the lower surface of the laminated body and connected to a ground potential, and an upper surface of the laminated body And a second ground electrode connected to the ground potential and arranged side by side so as to be electromagnetically coupled to each other between one layer of the laminate, each having one end connected to the ground potential Four or more strip-shaped resonance electrodes functioning as a quarter-wave resonator, and a ring surrounding the periphery of the four or more resonance electrodes between the one layer, and the one of the four or more resonance electrodes A ring-shaped ground electrode connected to the ground potential with an end connected thereto, and an input-stage resonant electrode among the four or more resonant electrodes disposed between layers above the one layer of the laminate. Banded input coupling with electromagnetic coupling A strip-shaped output coupling electrode that is electromagnetically coupled to the pole and output stage resonance electrodes, and one end of the laminated body disposed below the one interlayer is adjacent to the first through conductor. Near the one end of the foremost resonance electrode constituting the resonance electrode group consisting of an even number of the four or more resonance electrodes, and connected to the ground potential at the other end via the first through conductor. An electromagnetic field is connected to the ground potential in the vicinity of the one end of the last-stage resonance electrode constituting the group, and the first-stage resonance electrode of the resonance electrode group and the last-stage resonance electrode of the resonance electrode group And a resonance electrode coupling conductor having a region facing each resonance electrode so as to be coupled, wherein the four or more resonance electrodes are alternately arranged at the one end and the other end. Has been The input coupling electrode is disposed so as to face a region extending over half the longitudinal direction of the resonance electrode of the input stage, and an electric signal input point to which an electric signal from an external circuit is input is the input stage. The side closer to the other end of the resonance electrode of the input stage than the center in the length direction at the portion facing the resonance electrode, and the output coupling electrode is half the length direction of the resonance electrode of the output stage The output stage is arranged so as to face the above-mentioned region and the electrical signal output point at which the electrical signal is output toward the external circuit is longer than the center in the length direction at the portion of the output stage facing the resonance electrode. The at least one of the input coupling electrode and the output coupling electrode is one end opposite to the electrical signal input point or the electrical signal output point in the length direction. Part It extends so as to face the annular ground electrode beyond the one end of the resonance electrode of the input stage or the resonance electrode of the output stage.

  The band-pass filter according to the present invention may have a configuration in which, in the above-described configuration, an interlayer positioned on a side opposite to the one interlayer with respect to an interlayer in which at least one of the input coupling electrode and the output coupling electrode of the laminate is disposed. And an auxiliary earth electrode arranged to face the one end of at least one of the input coupling electrode and the output coupling electrode.

  Furthermore, the band-pass filter of the present invention is the above-described configuration, wherein at least one of the input coupling electrode and the output coupling electrode has an end of the opposing resonance electrode of the input stage or the resonance electrode of the output stage. It extends so as to face the annular ground electrode beyond the one end, and is bent along the annular ground electrode.

  Still further, in the bandpass filter of the present invention, in the above configuration, the one end of the input coupling electrode and the output coupling electrode is the one end of the resonance electrode of the input stage or the resonance electrode of the output stage facing each other. It is extended so that it may oppose the said cyclic | annular earth electrode, and it is bent so that it may mutually distance.

  Furthermore, in the bandpass filter of the present invention, in each of the above configurations, an attenuation pole is generated on the higher frequency side than the passband in the pass characteristic of the bandpass filter due to the half-wave resonance of the input coupling electrode and the output coupling electrode. The resonance electrode coupling conductor has a resonance peak on the high frequency side of the passband in the pass characteristic of the bandpass filter due to the half-wave resonance of the resonance electrode coupling conductor, and the frequency at which the attenuation pole is generated is located at the resonance peak. It is characterized by being equal to or lower than the frequency.

  Furthermore, the band-pass filter of the present invention is arranged so as to have a region facing the annular ground electrode and a region facing the resonance electrode between layers different from the one layer in each of the above-described configurations, The four or more auxiliary resonant electrodes connected to the other end of the resonant electrode by a second through conductor penetrating the dielectric layer located between the resonant electrode and the resonant electrode. It is characterized by being arranged corresponding to each of the resonance electrodes.

  Furthermore, the band-pass filter of the present invention is the above-described configuration, wherein the resonance electrode of the input stage among the four or more auxiliary resonance electrodes is disposed between the one layer and a layer different from the layer where the auxiliary resonance electrode is disposed. The dielectric is disposed so as to have a region facing the auxiliary resonance electrode connected to the region and a region facing the input coupling electrode, and the region facing the input coupling electrode is located between the input coupling electrode and the dielectric An auxiliary input coupling electrode connected to a side closer to the other end of the resonance electrode of the input stage than a center in the length direction of the input coupling electrode by a third through conductor penetrating a layer; and the one interlayer and A region facing the auxiliary resonance electrode connected to the resonance electrode of the output stage among the four or more auxiliary resonance electrodes between layers different from the layer where the auxiliary resonance electrode is disposed and the output coupling A region facing the pole, and a region facing the output coupling electrode is formed by a fourth through conductor penetrating the dielectric layer located between the output coupling electrode and the output coupling electrode. And an auxiliary output coupling electrode connected to a side closer to the other end of the resonance electrode of the output stage than a center in the length direction.

  A wireless communication module according to the present invention includes the band-pass filter according to the present invention having any one of the above-described configurations.

  A wireless communication device of the present invention includes an RF unit including the bandpass filter of the present invention having any one of the above-described configurations, a baseband unit connected to the RF unit, and an antenna connected to the RF unit. It is characterized by this.

  In the band-pass filter of the present invention, four or more band-shaped resonance electrodes functioning as quarter-wave resonators with one end connected to the ground potential are electromagnetically coupled to each other between one layer of the laminate. The one end and the other end of each of the four or more resonant electrodes are arranged alternately in the horizontal direction. Since one end and the other end of each of the four or more resonant electrodes are alternately arranged, the interdigital coupling is used, so that the coupling by the magnetic field and the coupling by the electric field are added to form a combline coupling. A stronger bond occurs compared to. As a result, it is suitable as a bandpass filter for UWB, in which the frequency interval between the resonance frequencies in each resonance mode far exceeds the range that could be realized by a filter using a conventional quarter wavelength resonator. It can be made moderate to obtain a wide passband width of about 40% in a specific bandwidth.

  In addition, according to the band-pass filter of the present invention, the input coupling electrode extends over a half of the length direction of the resonance electrode in the input stage between the layers above the layer where the resonance electrodes of the multilayer body are arranged. The other side of the resonance electrode of the input stage is arranged so as to face the region and the electric signal input point to which the electric signal from the external circuit is input is longer than the center in the length direction at the portion facing the resonance electrode of the input stage The output coupling electrode faces the region over the half of the length direction of the resonance electrode of the output stage between the layers above the layer where the resonance electrode of the multilayer body is arranged. And an electric signal output point from which an electric signal is output toward an external circuit is closer to the other end of the resonance electrode of the output stage than the center in the length direction at the portion facing the resonance electrode of the output stage It is said that. With this configuration, the input coupling electrode and the input stage resonance electrode are broadside coupled and coupled to the interdigital type, and the output coupling electrode and the output stage resonant electrode are broadside coupled and coupled to the interdigital type. Because it is broadside coupling, it becomes stronger compared to edge coupling, and since it is interdigitally coupled, the coupling by magnetic field and coupling by electric field are added together as in the case of the resonance electrodes described above, resulting in strong coupling Therefore, very strong coupling occurs between the input coupling electrode and the input stage resonance electrode and between the output coupling electrode and the output stage resonance electrode. As a result, even at a wide passband far exceeding the range that could be realized by a filter using a conventional quarter wavelength resonator, insertion at a frequency located between the resonance frequencies of the respective resonance modes It is possible to obtain a bandpass filter having flat and low-loss pass characteristics over the entire wide passband with no significant increase in loss.

  In addition, according to the bandpass filter of the present invention, the annular ground electrode connected to the ground potential is formed in an annular shape surrounding the periphery of four or more resonant electrodes between one layer, and one end of the resonant electrode is connected. Since there is an electrode that is connected to the ground potential on both sides in the length direction of the resonant electrode, one end of each of the alternately arranged resonant electrodes can be easily connected to the ground potential. can do.

  The band-pass filter according to the present invention includes an even number of four or more even numbers, one end of which is disposed between the layers below the layer where the resonance electrode of the multilayer body is disposed, and one end of which is adjacent via the first through conductor. The resonance electrode of the last stage constituting the resonance electrode group which is connected to the ground potential in the vicinity of one end of the foremost resonance electrode constituting the resonance electrode group composed of the resonance electrodes and the other end via the first through conductor. A resonance connected to the ground potential near one end and having a region facing each resonance electrode so as to be electromagnetically coupled to the foremost resonance electrode of the resonance electrode group and the last resonance electrode of the resonance electrode group An electrode coupling conductor is provided. With this configuration, inductive coupling is generated by the resonant electrode coupling conductor between the frontmost resonance electrode and the last resonance electrode of the resonance electrode group including four or more adjacent resonance electrodes. Adjacent resonant electrodes are coupled in an interdigital manner, and are strongly coupled with the addition of magnetic field coupling and electric field coupling, but as a whole, capacitive coupling. For this reason, it is transmitted by the inductive coupling via the resonance electrode coupling conductor between the first resonance electrode and the last resonance electrode of the resonance electrode group composed of four or more adjacent resonance electrodes. A phase difference of 180 ° is generated between the signal and the signal transmitted by capacitive coupling between the adjacent resonance electrodes, thereby causing a phenomenon of canceling each other. Since this phenomenon can occur near both sides of the passband of the bandpass filter, an attenuation pole that hardly transmits a signal near both sides of the passband can be formed in the pass characteristics of the bandpass filter.

  Regarding the number of resonance electrodes that constitute a resonance electrode group that is composed of adjacent resonance electrodes and that generates inductive coupling between the foremost resonance electrode and the last resonance electrode via the resonance electrode coupling conductor. It is necessary for the effect of the present invention to be an even number of 4 or more.

  For example, if the number of resonance electrodes constituting the resonance electrode group is an odd number, even if inductive coupling is caused by the resonance electrode coupling conductor between the first resonance electrode and the last resonance electrode. Phenomenon in which a phase difference of 180 ° occurs between a signal transmitted by inductive coupling via a resonant electrode coupling conductor and a signal transmitted by capacitive coupling between adjacent resonant electrodes, thereby canceling each other Is generated only on the high frequency side of the pass band of the band pass filter, and therefore, attenuation poles cannot be formed near both sides of the pass band in the pass characteristic of the band pass filter.

  In addition, when the number of resonance electrodes constituting the resonance electrode group is two, even if the resonance electrodes are connected by a resonance electrode coupling conductor, LC caused by inductive coupling and capacitive coupling between the resonance electrodes Since only a parallel resonant circuit is formed, only one attenuation pole is formed, and no attenuation pole can be formed near both sides of the passband.

  Furthermore, according to the band-pass filter of the present invention, at least one of the input coupling electrode and the output coupling electrode has an input stage in which one end portion on the opposite side of the electrical signal input point or the electrical signal output point in the length direction is opposed. In addition to the effect of simply increasing the length, it is statically connected to the ground. Since the effect of forming the capacitance is added and the electrical length becomes very long, the resonant frequency when operating as a half-wave resonator is lowered. This makes it possible to form an attenuation pole due to 1/2 wavelength resonance of at least one of the input coupling electrode and the output coupling electrode in a frequency region closer to the high-frequency side pass band than the pass band. The amount of attenuation in the frequency region close to the high-frequency side passband can be increased.

  Further, according to the band-pass filter of the present invention, between the layers where at least one of the input coupling electrode and the output coupling electrode of the multilayer body is disposed, the layer located on the opposite side to the layer where the plurality of resonance electrodes are disposed. When an auxiliary earth electrode is provided so as to face at least one end of the input coupling electrode and the output coupling electrode, between at least one end of the input coupling electrode and the output coupling electrode and the ground Since the capacitance formed can be further increased, the electrical length of at least one of the input coupling electrode and the output coupling electrode can be further increased, and the resonance frequency of the half-wave resonance can be further lowered. it can. As a result, an attenuation pole due to 1/2 wavelength resonance of at least one of the input coupling electrode and the output coupling electrode is formed nearer the pass band on the high frequency side than the pass band, and the attenuation of the portion is increased. Can do.

  Furthermore, according to the band-pass filter of the present invention, at least one end of the input coupling electrode and the output coupling electrode is beyond the one end of the opposing input stage resonance electrode or output stage resonance electrode, and the annular ground electrode Since the dimension in the length direction of the resonance electrode of the band-pass filter can be reduced, the band-pass filter can be obtained in a small size. .

  Still further, according to the bandpass filter of the present invention, one end of the input coupling electrode and the output coupling electrode is opposed to the annular ground electrode across one end of the opposing input stage resonance electrode or the output stage resonance electrode. When this is extended and bent away from each other, the electromagnetic coupling between one end of the input coupling electrode and the output coupling electrode can be reduced, so one of the input coupling electrode and the output coupling electrode can be reduced. It is possible to prevent the attenuation amount outside the pass band from being lowered by the electromagnetic coupling between the ends.

  Furthermore, according to the bandpass filter of the present invention, an attenuation pole is generated on the high frequency side of the passband in the pass characteristic of the bandpass filter due to the half-wave resonance of the input coupling electrode and the output coupling electrode, and the resonance electrode Due to the 1/2 wavelength resonance of the coupling conductor, the pass characteristic of the bandpass filter has a resonance peak at a higher frequency than the passband, and the frequency at which the attenuation pole is generated is equal to or lower than the frequency at which the resonance peak is located. In some cases, the resonance peak generated at the higher frequency side than the pass band in the pass characteristic of the band pass filter can be eliminated by the half wavelength resonance of the resonant electrode coupling conductor, so that the resonance peak in the stop band at the higher frequency side than the pass band. It is possible to prevent a decrease in attenuation due to. Although the mechanism by which this phenomenon occurs has not been specified, the level of the resonance peak caused by the half-wave resonance of the resonant electrode coupled conductor does not decrease, but the resonance peak disappears completely. Resonance electrode coupling by matching or lowering the frequency at which the attenuation pole is generated by the half-wave resonance of the electrode and the output coupling electrode with the frequency at which the resonance peak due to the half-wave resonance of the resonant electrode coupling conductor is generated. It is presumed that the state of the phase at the frequency at which the resonance peak due to the 1/2 wavelength resonance of the conductor changes and the condition for generating the resonance peak is not satisfied.

  Still further, according to the bandpass filter of the present invention, the auxiliary resonant electrode arranged so as to have a region facing the annular ground electrode and connected to the resonant electrode by the second through conductor has four or more resonant electrodes. Since the electrostatic capacity is generated between the auxiliary resonant electrode and the annular ground electrode, the length of each resonant electrode can be shortened. A small bandpass filter can be obtained.

  Furthermore, according to the band-pass filter of the present invention, the auxiliary input coupling electrode connected to the input coupling electrode, arranged to have a region facing the auxiliary resonant electrode connected to the resonant electrode of the input stage, and the output An auxiliary output coupling electrode connected to the output coupling electrode and having an area opposed to the auxiliary resonance electrode connected to the stage resonance electrode, the auxiliary connected to the input stage resonance electrode. Electromagnetic field coupling occurs between the resonant electrode and the auxiliary input coupling electrode, which is added to the electromagnetic coupling between the resonant electrode and the input coupling electrode of the input stage, and similarly connected to the resonant electrode of the output stage. An electromagnetic field coupling occurs between the auxiliary resonance electrode and the auxiliary output coupling electrode, and is added to the electromagnetic field coupling between the resonance electrode and the output coupling electrode in the output stage. As a result, the electromagnetic coupling between the input coupling electrode and the resonance electrode of the input stage and the electromagnetic coupling between the output coupling electrode and the resonance electrode of the output stage are further strengthened. However, a bandpass filter having a flatter and lower-loss pass characteristic over a wide passband, in which an increase in insertion loss at a frequency located between the resonance frequencies of the respective resonance modes is further reduced. Obtainable.

  The auxiliary input coupling electrode is connected to the side closer to the other end of the resonance electrode in the input stage than the center in the length direction of the input coupling electrode by the third through conductor, and similarly, the auxiliary output coupling electrode is connected to the fourth output coupling electrode. By connecting the output coupling electrode closer to the other end of the resonance electrode of the output stage than the center in the length direction of the output coupling electrode by the through conductor, an electric signal input from the outside is input to the input coupling electrode via the auxiliary input coupling electrode. Even when an electrical signal that is supplied to the output coupling electrode and output from the output coupling electrode is output to an external circuit via the auxiliary output coupling electrode, the input coupling electrode and the resonance electrode of the input stage are coupled in an interdigital manner, and output coupling is performed. The electrode and the resonant electrode at the output stage are coupled in an interdigital manner, and a strong coupling obtained by adding the coupling by the magnetic field and the coupling by the electric field can be generated.

  According to the wireless communication module of the present invention and the wireless communication device of the present invention, by using the band-pass filter of the present invention with a small loss of the signal passing over the entire communication band for filtering the transmission signal and the reception signal, Since the attenuation of the reception signal and the transmission signal passing through the band pass filter is reduced, the reception sensitivity is improved, and the amplification degree of the transmission signal and the reception signal can be reduced, so that the power consumption in the amplifier circuit is reduced. Therefore, a high-performance wireless communication module and wireless communication device with high reception sensitivity and low power consumption can be obtained.

  Hereinafter, a bandpass filter of the present invention, a wireless communication module and a wireless communication device using the same will be described in detail with reference to the accompanying drawings.

(First example of embodiment)
FIG. 1 is a schematic exploded perspective view of a bandpass filter of the present invention.

  The band-pass filter of this example includes a laminated body in which a plurality of dielectric layers 11 are laminated, a first ground electrode 21 arranged on the lower surface of the laminated body, and a second electrode arranged on the upper surface of the laminated body. Around the ground electrode 22, the strip-shaped resonance electrodes 30a, 30b, 30c, 30d arranged side by side between one layer of the laminate, and the resonance electrodes 30a, 30b, 30c, 30d between one layer of the laminate. An annular ground electrode 23 formed in an annular shape and connected to one end of the resonance electrodes 30a, 30b, 30c, and 30d, and the resonance electrode 30a in the input stage between the layers above one layer of the laminate. The strip-shaped input coupling electrode 40a and the strip-shaped output coupling electrode 40b disposed so as to face the output-stage resonance electrode 30d, one end disposed between layers below one layer of the laminate, and The other end is connected to the annular ground electrode 23 via the first through conductor 51. A resonance electrode coupling conductor 32 having a region facing each resonance electrode so as to be electromagnetically coupled to the resonance electrode 30a of the input stage and the resonance electrode 30d of the output stage, and an input coupling disposed on the upper surface of the multilayer body The input terminal electrode 60a is connected to the electrode 40a, and the output terminal electrode 60b is connected to the output coupling electrode 40b.

  Although the first ground electrode 21 is hidden in the drawing, the first ground electrode 21 is disposed on the entire lower surface of the multilayer body (the back surface of the dielectric layer 11 on which the resonant electrode coupling conductor 32 is formed), and the second ground electrode 22 is laminated. It is arranged on almost the whole surface except for the periphery of the input terminal electrode 60a and the output terminal electrode 60b on the upper surface of the body, and both are connected to the ground potential, and the stripline resonator is formed together with the resonance electrodes 30a, 30b, 30c, 30d. It is composed.

  The strip-shaped resonance electrodes 30a, 30b, 30c, and 30d constitute a stripline resonator together with the first ground electrode 21 and the second ground electrode 22, and one end of each is connected to the annular ground electrode 23 to ground. By connecting to a potential, it functions as a quarter wavelength resonator.

  The resonance electrodes 30a, 30b, 30c, and 30d are arranged side by side between one layer of the multilayer body and are electromagnetically coupled to each other. Since the layers are arranged side by side between the same layers and are electromagnetically coupled, the coupling between the resonance electrodes 30a, 30b, 30c, and 30d is not broadside coupling but edge coupling. If the distance between the resonance electrodes 30a, 30b, 30c, and 30d is smaller, stronger coupling is obtained. However, if the distance is reduced, manufacturing becomes difficult, so the distance is set to about 0.05 to 0.5 mm, for example. Further, the resonance electrodes 30a, 30b, 30c, and 30d are arranged in such a manner that one end and the other end of each of the resonance electrodes 30a, 30b, 30c, and 30d are interdigitally coupled to each other. Compared to the combline type, the bond is stronger. In this way, the resonant electrodes 30a, 30b, 30c, and 30d are edge-coupled to each other and coupled in an interdigital manner, so that the frequency interval between the resonant frequencies in each resonant mode can be changed to the conventional 1/4 wavelength resonance. It is reasonable to obtain a wide passband width of about 40% in a specific band suitable as a bandpass filter for UWB, far exceeding the range that could be realized by a filter using a filter.

  Note that when the resonant electrodes 30a, 30b, 30c, and 30d are coupled in an interdigital manner and are broad-side coupled to each other, the coupling becomes too strong, so that a pass bandwidth of about 40% is achieved in the specific band. Has been found to be undesirable.

  In the band-pass filter of the present invention, the number of resonance electrodes may be four or more. However, as the number of resonance electrodes increases, the size of the band-pass filter and the loss in the passband increase. The number of resonant electrodes is often set to about 10 or less.

  The annular ground electrode 23 is formed in an annular shape surrounding the periphery of the resonance electrodes 30a, 30b, 30c, and 30d between one layer of the laminate, and is connected to one end of the resonance electrodes 30a, 30b, 30c, and 30d. . And it has a function which connects one end of resonance electrode 30a, 30b, 30c, 30d to earth potential by being connected to earth potential. By providing the annular ground electrode 23, one end of the resonance electrodes 30a, 30b, 30c, 30d arranged in an interdigital manner even when a band-pass filter is formed in a partial region in the module substrate. Can be easily connected to the ground potential. Further, since the annular ground electrode 23 surrounds the resonance electrodes 30a, 30b, 30c, and 30d in an annular shape, leakage of electromagnetic waves generated from the resonance electrodes 30a, 30b, 30c, and 30d to the surroundings can be reduced. This effect is particularly useful in preventing adverse effects on other areas of the module substrate when a bandpass filter is formed in a partial area of the module substrate.

  The band-shaped input coupling electrode 40a is disposed in a layer different from the layer in which the resonance electrodes 30a, 30b, 30c, and 30d are disposed (the layer above the layer in which the resonance electrodes 30a, 30b, 30c, and 30d are disposed). The whole is disposed so as to face the resonance electrode 30a of the input stage, and faces a region extending over half of the length direction of the resonance electrode 30a of the input stage. Therefore, the input coupling electrode 40a and the input stage resonance electrode 30a are broadside coupled, and are strongly coupled as compared to the edge coupling. Further, the strip-shaped input coupling electrode 40a is connected to the through conductor 50, and the electric signal input point 45a to which an electric signal from an external circuit is input is long at the portion of the input coupling electrode 40a facing the resonance electrode 30a at the input stage. It is located at the end closer to the other end of the input stage resonance electrode 30a than the center in the vertical direction, and the opposite end is an open end. An electric signal input from an external circuit is supplied from the electric signal input point 45a to the input coupling electrode 40a. As a result, the input coupling electrode 40a and the input stage resonance electrode 30a are coupled in an interdigital manner, and the coupling due to the magnetic field and the coupling due to the electric field are added and coupled in the combline type or simply capacitively coupled. The bond is stronger than in the case. Thus, the input coupling electrode 40a is broad-side coupled to the input stage resonance electrode 30a and is interdigitally coupled to the entire input coupling electrode 40a. Are connected. Similarly, the output coupling electrode 40b is broadside-coupled to the output-stage resonance electrode 30d and is also interdigitally coupled.

  In this way, the input coupling electrode 40a and the input stage resonance electrode 30a are very strongly coupled, and the output coupling electrode 40b and the output stage resonance electrode 30d are very strongly coupled. Even in a wide passband far exceeding the region that could be realized with a filter using a resonator, the insertion loss at frequencies located between the resonance frequencies of the respective resonance modes does not increase significantly. A bandpass filter having flat and low-loss pass characteristics over the entire wide passband can be obtained.

  In addition, the input coupling electrode 40a and the output coupling electrode 40b have one end on the opposite side to the electric signal input point 45a or the electric signal output point 45b in the length direction, and the resonance electrode 30a of the input stage or the resonance of the output stage facing each other. Since the electrode 30d extends beyond one end of the electrode 30d so as to face the annular ground electrode 23, a capacitance is formed between the electrode 30d and the ground in addition to the effect of simply increasing the length. Since the effect is added and the electrical length becomes very long, the resonance frequency when operating as a half-wave resonator is lowered. This makes it possible to form attenuation poles due to half-wave resonance of the input coupling electrode 40a and the output coupling electrode 40b in a frequency region closer to the high frequency side of the pass band than the pass band. The amount of attenuation in the frequency region close to the side passband can be increased.

  Further, one end portions of the input coupling electrode 40a and the output coupling electrode 40b are extended so as to face the annular ground electrode 23 beyond one end of the opposing input stage resonance electrode 30a or output stage resonance electrode 30d. Since it is bent along the annular ground electrode 23, the band-pass filter in the longitudinal direction of the band-like resonant electrodes 30a, 30b, 30c is compared with the case where the input coupling electrode 40a and the output coupling electrode 40b are not bent. Since the size can be reduced, a small bandpass filter can be obtained.

  Still further, one end of both the input coupling electrode 40a and the output coupling electrode 40b is opposed to the annular ground electrode 23 across one end of the opposing input stage resonance electrode 30a or output stage resonance electrode 30d. Since the electrical lengths of both the input coupling electrode 40a and the output coupling electrode 40b are increased because of the extension, resonance occurs when operating as a half-wave resonator of both the input coupling electrode 40a and the output coupling electrode 40b. The frequency is lowered. As a result, both the attenuation pole due to the 1/2 wavelength resonance of the input coupling electrode 40a and the attenuation pole due to the 1/2 wavelength resonance of the output coupling electrode 40b are formed in a frequency region closer to the pass band on the higher frequency side than the pass band. This makes it possible to further increase the amount of attenuation in the frequency region closer to the passband on the higher frequency side than the passband.

  It is preferable that the shape and dimensions of the input coupling electrode 40a and the output coupling electrode 40b are set to be approximately the same as those of the resonance electrode 30a at the input stage and the resonance electrode 30d at the output stage. If the distance between the input coupling electrode 40a and the input stage resonance electrode 30a and the distance between the output coupling electrode 40b and the output stage resonance electrode 30d are reduced, the coupling becomes stronger but difficult to manufacture. It is set to about 0.5 mm.

  The resonance electrode coupling conductor 32 is disposed in a layer different from the layer in which the resonance electrodes 30a, 30b, 30c, and 30d are disposed (a layer below the layer in which the resonance electrodes 30a, 30b, 30c, and 30d are disposed). ing. Then, one end is connected to the annular ground electrode 23 in the vicinity of one end of the input stage resonance electrode 30a through the first through conductor 51, and the other end is connected to the output stage resonance through the first through conductor 51. The electrode 30d is connected to the annular ground electrode 23 in the vicinity of one end thereof, and has an electromagnetic field coupling region opposite to the input stage resonant electrode 30a and the output stage resonant electrode 30d. According to this structure, the resonance electrode 30a at the input stage and the resonance electrode 30d at the output stage can be inductively coupled via the resonance electrode coupling conductor 32.

  Here, the resonance electrodes 30a, 30b, 30c, and 30d constitute a resonance electrode group including four adjacent resonance electrodes, and the resonance electrode 30a at the input stage is the foremost resonance electrode constituting the resonance electrode group. The output stage resonance electrode 30d is the last stage resonance electrode constituting the resonance electrode group. Therefore, between the resonance electrode 30a of the input stage which is the foremost stage resonance electrode of the resonance electrode group including four adjacent resonance electrodes and the resonance electrode 30d of the output stage which is the last resonance electrode of the resonance electrode group. Inductive coupling is generated by the resonance electrode coupling conductor 32. The adjacent resonance electrodes 30a, 30b, 30c, and 30d are coupled in an interdigital manner, and are strongly coupled by adding a coupling by a magnetic field and a coupling by an electric field. However, as a whole, the coupling is capacitive. It has become.

  For this reason, inductive properties via the resonance electrode coupling conductor 32 are provided between the first resonance electrode and the last resonance electrode of the resonance electrode group including the four adjacent resonance electrodes 30a, 30b, 30c, and 30d. A phase difference of 180 ° is generated between the signal transmitted by the coupling and the signal transmitted by the capacitive coupling between the adjacent resonance electrodes 30a, 30b, 30c, and 30d, thereby causing a phenomenon of canceling each other. Can do. Since this phenomenon can occur near both sides of the low-frequency side and high-frequency side of the pass band of the band-pass filter, an attenuation pole that hardly transmits a signal near both sides of the pass band in the pass characteristics of the band-pass filter. Can be formed.

  Here, a resonance peak occurs at a higher frequency than the passband in the pass characteristic of the bandpass filter due to the half-wave resonance of the resonance electrode coupling conductor 32, and therefore, a decrease in attenuation in the frequency region where the resonance peak exists is a problem. There is a case. At this time, the frequency of the attenuation pole generated on the higher frequency side than the pass band in the pass characteristics of the band pass filter due to the half wavelength resonance of the input coupling electrode 40a and the output coupling electrode 40b is set to 1/2 of that of the resonant electrode coupling conductor 32. By making the resonance peak caused by the wavelength resonance equal to or lower than the frequency at which the resonance peak is located, the resonance peak due to the 1/2 wavelength resonance of the resonant electrode coupling conductor 32 is extinguished to prevent a decrease in attenuation due to the resonance peak. can do. The frequency of the attenuation pole generated by the half-wave resonance of the input coupling electrode 40a and the output coupling electrode 40b can be arbitrarily adjusted by the electrical length of the input coupling electrode 40a and the output coupling electrode 40b. When the electrical lengths of the input coupling electrode 40a and the output coupling electrode 40b are increased, the frequency of the attenuation pole generated by the 1/2 wavelength resonance is lowered. When the electrical lengths of the input coupling electrode 40a and the output coupling electrode 40b are shortened, the 1/2 wavelength is obtained. The frequency of the attenuation pole generated by resonance increases.

  Further, the frequency of the attenuation pole generated by the 1/2 wavelength resonance of the input coupling electrode 40a and the output coupling electrode 40b is made equal to the frequency at which the resonance peak generated by the 1/2 wavelength resonance of the resonant electrode coupling conductor 32 is located, Alternatively, if the resonance peak due to the 1/2 wavelength resonance of the resonant electrode coupling conductor 32 is eliminated by lowering, the attenuation pole due to the 1/2 wavelength resonance of the input coupling electrode 40a and the output coupling electrode 40b also disappears. Even the frequency that exists is lost. At this time, in order to specify the frequency of the attenuation pole generated by the 1/2 wavelength resonance of the input coupling electrode 40a and the output coupling electrode 40b and the frequency of the resonance peak generated by the 1/2 wavelength resonance of the resonance electrode coupling conductor 32 The following is recommended.

First, the structure of the bandpass filter is analyzed, and the position and shape dimension of each electrode are specified. For the structural analysis of the bandpass filter, X-ray photography, a method of measuring the dimensions of each part while gradually grinding the bandpass filter from the surface, and the like can be used. (Step 1)
Next, the relative dielectric constant of the dielectric layer 11 constituting the band pass filter is specified. In order to specify the relative dielectric constant of the dielectric layer 11, an electromagnetic field analysis is performed using the structure of the bandpass filter specified above, and its electrical characteristics are simulated. At this time, an electromagnetic field analysis is performed by changing the relative dielectric constant of the dielectric layer 11, and the dielectric constant that constitutes the bandpass filter has a dielectric constant that substantially matches the measured electric characteristics of the bandpass filter. The relative dielectric constant of the layer 11 can be estimated. At this time, by performing the electromagnetic field analysis by setting the dielectric loss tangent of the dielectric layer 11 and the conductivity of each electrode, the simulation and the actual measurement value including the attenuation can be matched to some extent in the filter characteristics. However, since the frequency of the resonance peak and attenuation pole is desired to be obtained, the difference between the simulation value and the actual measurement value in the attenuation amount depending on the loss of the dielectric and the loss of the conductor can be ignored to some extent. (Step 2)
Next, an electromagnetic field analysis is performed using the structure obtained by removing only the resonant electrode coupling conductor 32 from the bandpass filter whose structure is specified in step 1 and the relative dielectric constant of the dielectric layer 11 specified in step 2 to perform bandpass. By simulating the electrical characteristics of the filter, the attenuation pole due to the half-wave resonance of the input coupling electrode 40a and the output coupling electrode 40b appears on the pass characteristic, so that the frequency at which the attenuation pole is located can be specified. (Step 3)
Next, an electromagnetic field analysis is performed using a structure in which the electrical lengths of the input coupling electrode 40a and the output coupling electrode 40b are slightly shortened from the structure specified in Step 1 and the relative dielectric constant of the dielectric layer 11 specified in Step 2. By simulating the electrical characteristics of the band-pass filter, the attenuation pole due to the 1/2 wavelength resonance of the input coupling electrode 40a and the output coupling electrode 40b moves to the high frequency side, and the 1/2 of the resonant electrode coupling conductor 32 on the pass characteristics. Since a resonance peak caused by two-wavelength resonance appears, the frequency at which the resonance peak is located can be specified. (Step 4)
By the above procedure, the frequency of the attenuation pole generated by the 1/2 wavelength resonance of the input coupling electrode 40a and the output coupling electrode 40b and the frequency of the resonance peak generated by the 1/2 wavelength resonance of the resonance electrode coupling conductor 32 are specified. Each frequency can be compared.

  In addition, as shown in FIG. 1, the resonant electrode coupling conductor 32 includes a front-side coupling region facing the input-stage resonant electrode 30a, a rear-stage coupling region facing the output-stage resonant electrode 30d, and a front-side coupling region. And a connecting region that connects the rear-side coupling region orthogonally to these regions, and has a so-called crank structure. Here, this resonant electrode coupling conductor 32 is point-symmetric about the point equidistant from one end and the other end of the resonant electrode coupling conductor 32 from the viewpoint of ensuring the structural and electrical symmetry of the bandpass filter. It is preferable to be formed in such a shape. Further, the resonance electrode coupling conductor 32 is shaped so that the connection region is orthogonal to the front-side coupling region and the rear-side coupling region arranged in parallel to the resonance electrodes 30a, 30b, 30c, and 30d. Since the electrodes 30a, 30b, 30c, 30d and the connection region are orthogonal to each other in plan view, deterioration of electrical characteristics due to unnecessary coupling between the resonance electrodes 30a, 30b, 30c, 30d and the connection region is prevented. be able to.

  Thus, according to the bandpass filter of this example, the region that can be suitably used as a UWB low band filter, which can be realized with a conventional filter using a quarter-wave resonator, is far greater. It has a flat and low-loss pass characteristic over the entire wide passband of 40% in the ratio band that exceeds it, and has attenuation poles near both sides of the passband, so that the attenuation in the stopband is sufficient It is possible to obtain a secured high performance band pass filter.

(Second example of embodiment)
FIG. 2 is an exploded perspective view schematically showing another example of the embodiment of the bandpass filter of the present invention. Note that in this example, only differences from the first example described above will be described, and the same components will be denoted by the same reference numerals, and redundant description will be omitted.

  The difference from the first example of the band-pass filter of this example is a six-stage band-pass filter comprising resonant electrodes 30a, 30b, 30c, 30d, 30e, and 30f, and the input coupling electrode 40a is resonant at the input stage. The electromagnetic coupling is performed opposite to the electrode 30a, and the output coupling electrode 40b is electromagnetically coupled opposite to the resonance electrode 30f of the output stage. The resonant electrode coupling conductor 32 has one end connected to the annular ground electrode 23 in the vicinity of one end of the input stage resonant electrode 30a via the first through conductor 51, and the other end connected to the first through conductor 51. Is connected to the annular ground electrode 23 in the vicinity of one end of the output stage resonant electrode 30f, and has an electromagnetic field coupling region facing the input stage resonant electrode 30a and the output stage resonant electrode 30f. is doing.

  Also in the band pass filter of this example, one end is connected to the annular ground electrode 23 in the vicinity of one end (short-circuit end) of the resonance electrode 30a of the input stage via the first through conductor 51 and the other end is the first end. A resonance electrode coupling conductor 32 connected to the annular ground electrode 23 in the vicinity of one end (short-circuit end) of the output stage resonance electrode 30f through one through conductor 51, and one end (short-circuit) of the input stage resonance electrode 30a. Resonant electrode composed of six adjacent resonant electrodes 30a, 30b, 30c, 30d, 30e, 30f by coupling the side close to the end) and the side close to one end (short-circuited end) of the output stage resonant electrode 30f. The resonance electrode 30a in the input stage, which is the foremost resonance electrode of the group, and the resonance electrode 30f in the output stage, which is the last resonance electrode in the resonance electrode group, are inductively coupled via the resonance electrode coupling conductor 32. As a result, the resonance electrode coupling conductor 32 is interposed between the first resonance electrode and the last resonance electrode of the resonance electrode group including the six adjacent resonance electrodes 30a, 30b, 30c, 30d, 30e, and 30f. There is a phase difference of 180 ° between the signal transmitted by the inductive coupling and the signal transmitted by the capacitive coupling between the adjacent resonance electrodes 30a, 30b, 30c, 30d, 30e, and 30f. Phenomenon that cancel each other can be generated. Since this phenomenon can occur near both sides of the passband of the bandpass filter, an attenuation pole that hardly transmits a signal near both sides of the passband can be formed in the pass characteristics of the bandpass filter. Thereby, it is possible to have a filter characteristic that attenuates sharply outside the passband.

  Since the band-pass filter of this example is a band-pass filter having a six-stage configuration including the resonance electrodes 30a, 30b, 30c, 30d, 30e, and 30f, a band having a four-stage configuration including the resonance electrodes 30a, 30b, 30c, and 30d. Compared with the bandpass filter of the first example of the embodiment which is a pass filter, a bandpass filter having a steeper pass characteristic can be obtained.

(Third example of embodiment)
FIG. 3 is an exploded perspective view schematically showing still another example of the embodiment of the bandpass filter of the present invention. In this example, only points different from the second example described above will be described, and the same components will be denoted by the same reference numerals, and redundant description will be omitted.

  The difference of the bandpass filter of this example from the second example described above is that the resonance electrode coupling conductor 32 is annular at one end near the one end of the input stage resonance electrode 30a via the first through conductor 51. The other end is connected to the annular ground electrode 23 in the vicinity of one end of the resonance electrode 30d via the first through conductor 51, and is connected to the resonance electrode 30a and the resonance electrode 30d in the input stage, respectively. It has the area | region which opposes an electromagnetic field coupling facing.

  Also in the band pass filter of this example, one end is connected to the annular ground electrode 23 in the vicinity of one end (short-circuit end) of the resonance electrode 30a of the input stage via the first through conductor 51 and the other end is the first end. The resonance electrode coupling conductor 32 connected to the annular ground electrode 23 in the vicinity of one end (short-circuit end) of the resonance electrode 30d through one through conductor 51 is connected to one end (short-circuit end) of the resonance electrode 30a in the input stage. By combining the near side and the side close to one end (short-circuit end) of the resonance electrode 30d, the input is the foremost resonance electrode of the resonance electrode group consisting of the four adjacent resonance electrodes 30a, 30b, 30c, 30d. The resonance electrode 30a of the stage and the resonance electrode 30d which is the last resonance electrode of the resonance electrode group are inductively coupled via the resonance electrode coupling conductor 32. As a result, the inductive property via the resonance electrode coupling conductor 32 is provided between the first resonance electrode and the last resonance electrode of the resonance electrode group including the four adjacent resonance electrodes 30a, 30b, 30c, and 30d. A phase difference of 180 ° is generated between the signal transmitted by the coupling and the signal transmitted by the capacitive coupling between the adjacent resonance electrodes 30a, 30b, 30c, and 30d, thereby causing a phenomenon of canceling each other. Can do. Since this phenomenon can occur near both sides of the passband of the bandpass filter, an attenuation pole that hardly transmits a signal near both sides of the passband can be formed in the pass characteristics of the bandpass filter. As described above, the resonance electrode group may be configured by a part of the plurality of resonance electrodes constituting the band pass filter.

(Fourth example of embodiment)
FIG. 4 is an exploded perspective view schematically showing still another example of the embodiment of the bandpass filter of the present invention. Note that in this example, only differences from the first example described above will be described, and the same components will be denoted by the same reference numerals, and redundant description will be omitted.

  The difference between the band pass filter of the present example and the first example described above is that the resonant electrodes 30a, 30b, 30c, and 30d are arranged with respect to the layer 10 in which the input coupling electrode 40a and the output coupling electrode 40b are arranged. The auxiliary ground electrode 24 is provided between the layers located on the opposite side of the formed interlayer so as to face one end of the input coupling electrode 40a and the output coupling electrode 40b.

  According to the bandpass filter of this example, a capacitance is formed between one end of the input coupling electrode 40a and the output coupling electrode 40b and the auxiliary earth electrode 24, and the input coupling electrode 40a and the output coupling electrode 40b On the other hand, since the electrostatic capacitance formed between the one end and the ground can be further increased, the electrical length of the input coupling electrode 40a and the output coupling electrode 40b can be further increased, and the input coupling electrode 40a and The frequency at which the half wavelength resonance of the output coupling electrode 40b occurs can be further reduced. As a result, attenuation poles due to half-wave resonance of the input coupling electrode 40a and the output coupling electrode 40b are formed nearer to the pass band on the high frequency side than the pass band, and the attenuation amount of the portion can be increased. it can.

  When the auxiliary earth electrode 24 is formed only in a region facing the annular earth electrode 23, an electric capacity is generated due to generation of unnecessary capacitance between the plurality of resonance electrodes 30a, 30b, 30c, 30d. The deterioration of characteristics can be suppressed. Further, when the auxiliary earth electrode 24 is connected to the annular earth electrode 23 via the sixth through conductor 56 penetrating the multilayer body 10, the auxiliary earth electrode 24 can be easily connected to the earth potential.

(Fifth example of embodiment)
FIG. 5 is an exploded perspective view schematically showing still another example of the embodiment of the bandpass filter of the present invention. In this example, only points different from the above-described fourth example will be described, and the same components will be denoted by the same reference numerals, and redundant description will be omitted.

  The difference of the bandpass filter of this example from the fourth example described above is that it is opposed to the annular ground electrode 23 between the layers above which the resonance electrodes 30a, 30b, 30c, 30d and the annular ground electrode 23 are arranged. Auxiliary resonance electrodes 31a, 31b, 31c, and 31d having regions that face the resonance electrodes 30a, 30b, 30c, and 30d are disposed, and the resonance electrodes 30a, 30b, 30c, and 30d and the annular ground electrode 23 are disposed. Auxiliary resonance electrodes 31a, 31b, 31c, and 30d each having a region facing the annular ground electrode 23 and a region facing the resonance electrodes 30a, 30b, 30c, and 30d are disposed between layers below the layer where the electrode is disposed. Has been. The resonant electrodes 30a, 30b, 30c, 30d and the auxiliary resonant electrodes 31a, 31b, 31c, 31d are connected by a second through conductor 52 that penetrates the dielectric layer 11. As a result, the capacitance between the auxiliary resonant electrodes 31a, 31b, 31c, 31d and the annular ground electrode 23 is added, so that the other ends (open ends) of the resonant electrodes 30a, 30b, 30c, 30d and the ground potential are added. And the length of the resonant electrodes 30a, 30b, 30c, and 30d can be shortened, so that a smaller bandpass filter can be obtained.

  Thus, according to the bandpass filter of this example, a smaller bandpass filter can be obtained as compared with the bandpass filter of the fourth example of the embodiment of the present invention described above.

  In the band-pass filter of this example shown in FIG. 5, the auxiliary resonant electrodes 31a, 31b, 31c, 31d are provided in a pair of upper and lower sides, but the lengths of the resonant electrodes 30a, 30b, 30c, 30d are shortened so much. When not necessary, the auxiliary resonant electrodes 31a, 31b, 31c, 31d are provided on either the upper side or the lower side between the layers where the resonant electrodes 30a, 30b, 30c, 30d and the annular ground electrode 23 are disposed. It may be.

  As the auxiliary resonance electrodes 31a and 31d are formed, the layers where the resonance electrodes 30a, 30b, 30c and 30d and the annular ground electrode 23 are arranged, the layers where the auxiliary resonance electrodes 31a, 31b, 31c and 31d are arranged, and the input An auxiliary input coupling electrode 41a is provided corresponding to the input coupling electrode 40a between layers different from the layer where the coupling electrode 40a and the output coupling electrode 40b are disposed, and the auxiliary output coupling electrode 41b corresponding to the output coupling electrode 40b. Is provided.

  As shown in FIG. 5, the auxiliary input coupling electrode 41a has a strip shape and is arranged to have a region facing the auxiliary resonance electrode 31a connected to the resonance electrode 30a in the input stage and a region facing the input coupling electrode 40a. The region facing the input coupling electrode 40a is connected to the input coupling electrode 40a by a third through conductor 53 that penetrates the dielectric layer 11 located between the input coupling electrode 40a. As a result, the auxiliary input coupling electrode 41a and the auxiliary resonant electrode 31a are broadside coupled, and this coupling is added to the coupling between the input coupling electrode 40a and the resonant electrode 30a of the input stage, so that the coupling is stronger as a whole. It becomes.

  Similarly, the auxiliary output coupling electrode 41b has a band shape, and is disposed so as to have a region facing the auxiliary resonant electrode 31d connected to the resonant electrode 30d in the output stage and a region facing the output coupling electrode 40b, and output coupling The region facing the electrode 40b is connected to the output coupling electrode 40b by a fourth through conductor 54 that penetrates the dielectric layer 11 located between the output coupling electrode 40b. As a result, the auxiliary output coupling electrode 41b and the auxiliary resonant electrode 31d are broadside coupled, and this coupling is added to the coupling between the output coupling electrode 40b and the resonant electrode 30d of the output stage, so that the coupling is stronger as a whole. It becomes.

  As described above, the joint of the input stage resonance electrode 30a and the auxiliary resonance electrode 31a connected thereto, and the input coupling electrode 40a and the joint of the auxiliary input coupling electrode 41a connected thereto are broad-side coupled. In addition, the coupling is very strong by coupling to the interdigital type, and similarly, a joined body of the resonance electrode 30d of the output stage and the auxiliary resonance electrode 31d connected thereto, the output coupling electrode 40b and the auxiliary connected thereto Since the joint of the output coupling electrode 41b is broad-side coupled as a whole and is very strongly coupled by interdigital coupling, the resonance frequency of each resonance mode can be achieved even in a very wide pass band. The insertion loss increase at frequencies located between is further reduced, and the flatter and lower loss pass characteristics across the wide passband. Can be obtained.

  Note that the widths of the auxiliary input coupling electrode 41a and the auxiliary output coupling electrode 41b are set to be approximately the same as the input coupling electrode 40a and the output coupling electrode 40b, for example, and the lengths of the auxiliary input coupling electrode 41a and the auxiliary output coupling electrode 41b are For example, it is set slightly longer than the length of the auxiliary resonance electrodes 31a and 31d. The smaller distances between the auxiliary input coupling electrode 41a and the auxiliary output coupling electrode 41b and the auxiliary resonance electrodes 31a and 31d are desirable in terms of causing strong coupling, but are difficult to manufacture. For example, 0.01 to 0.5 mm Set to degree.

(Sixth example of embodiment)
FIG. 6 is a block diagram showing a configuration example of the wireless communication module 80 and the wireless communication device 85 using the bandpass filter of the present invention.

  The wireless communication module 80 of the present invention includes, for example, a baseband unit 81 that processes baseband signals, and an RF unit 82 that is connected to the baseband unit 81 and processes RF signals after modulation and before demodulation of the baseband signals. And. The RF unit 82 includes the band-pass filter 821 of the present invention described above. The band-pass filter 821 attenuates signals other than the communication band in the RF signal obtained by modulating the baseband signal or the received RF signal. Yes.

  Specifically, a baseband IC 811 is disposed in the baseband unit 81, and an RF IC 822 is disposed between the bandpass filter 821 and the baseband unit 81 in the RF unit 82. Note that another circuit may be interposed between these circuits. Then, by connecting the antenna 84 to the bandpass filter 821 of the wireless communication module 80, the wireless communication device 85 of the present invention that transmits and receives RF signals is configured.

  According to the wireless communication module 80 and the wireless communication device 85 of the present invention having such a configuration, a transmission signal and a reception are received using the band-pass filter 821 of the present invention in which the loss of a signal passing through the entire communication band is small. Since the signal is filtered, the attenuation of the transmission signal and the reception signal passing through the bandpass filter 821 can be reduced over the entire communication band, so that the reception sensitivity is improved and the transmission signal and the reception signal are reduced. Since the amplification degree can be reduced, power consumption in the amplifier circuit is reduced. Therefore, a high-performance wireless communication module 80 and wireless communication device 85 with high reception sensitivity and low power consumption can be obtained.

In the band-pass filter of the present invention, as the material of the dielectric layer 11, for example, a resin such as an epoxy resin or a ceramic such as a dielectric ceramic can be used. For example, a dielectric ceramic material such as BaTiO ₃ , Pb ₄ Fe ₂ Nb ₂ O ₁₂ , or TiO ₂ and a glass material such as B ₂ O ₃ , SiO ₂ , Al ₂ O ₃ , or ZnO, and 800 to 1200 ° C. Glass-ceramic materials that can be fired at relatively low temperatures are preferably used. Further, the thickness of the dielectric layer 11 is set to about 0.05 to 0.1 mm, for example.

  Examples of the materials for the various electrodes and through conductors described above include conductive materials mainly composed of Ag alloys such as Ag, Ag-Pd, and Ag-Pt, Cu-based, W-based, Mo-based, and Pd-based conductive materials. Are preferably used. The thicknesses of the various electrodes are set to 0.001 to 0.05 mm, for example.

  The bandpass filter of the present invention can be manufactured, for example, as follows. First, an appropriate organic solvent or the like is added to and mixed with the ceramic raw material powder to form a slurry, and a ceramic green sheet is formed by a doctor blade method. Next, a through hole to be a through conductor is formed in the obtained ceramic green sheet using a punching machine or the like, and a through conductor is formed by filling a conductor paste such as Ag, Ag-Pd, Au, Cu or the like. Next, the various electrodes described above are formed on the ceramic green sheet using a printing method. Next, these are laminated, pressure-bonded using a hot press apparatus, and fired at a peak temperature of about 800 ° C. to 1050 ° C.

(Modification)
The present invention is not limited to the first to sixth examples of the embodiment described above, and various modifications and improvements can be made without departing from the gist of the present invention.

  For example, in the example of the above-described embodiment, an example in which the input terminal electrode 60a and the output terminal electrode 60b are provided is shown. However, when a band-pass filter is formed in one area in the module substrate, the input terminal electrode The 60a and the output terminal electrode 60b are not necessarily required.

  In the example of the embodiment described above, an example in which the input coupling electrode 40a, the output coupling electrode 40b, and the auxiliary resonance electrodes 31a, 31b, 31c, and 31d are arranged between the same layers of the stacked body is shown. The coupling electrode 40a, the output coupling electrode 40b, and the auxiliary resonance electrodes 31a, 31b, 31c, 31d may be arranged between different layers, and the input coupling electrode 40a and the output coupling electrode 40b are arranged between different layers. Alternatively, the auxiliary resonance electrodes 31a, 31b, 31c, and 31d may be arranged between different layers.

  Further, in the example of the embodiment described above, the example in which the auxiliary input coupling electrode 41a and the auxiliary output coupling electrode 41b are arranged between the same layers of the stacked body is shown, but they may be arranged between different layers. Absent.

  Furthermore, in the example of the above-described embodiment, the example in which the first ground electrode 21 is disposed on the lower surface of the multilayer body and the second ground electrode 22 is disposed on the upper surface of the multilayer body is illustrated. The dielectric layer 11 may be further disposed under the first ground electrode 21, or the dielectric layer 11 may be further disposed over the second ground electrode 22.

  Furthermore, in the example of the embodiment described above, an example in which the electrical lengths of the input coupling electrode 40a and the output coupling electrode 40b are equal is shown. However, the electrical length of the input coupling electrode 40a and the electrical length of the output coupling electrode 40b are shown. May be different. At this time, in the pass characteristic of the band-pass filter, two attenuation poles are formed, that is, an attenuation pole due to 1/2 wavelength resonance of the input coupling electrode 40a and an attenuation pole due to 1/2 wavelength resonance of the output coupling electrode 40b. The attenuation at the pole is slightly smaller. However, when it is desired to eliminate the resonance peak due to the 1/2 wavelength resonance of the resonance electrode coupling conductor 32, the frequency of the attenuation pole due to the 1/2 wavelength resonance of both the input coupling electrode 40a and the output coupling electrode 40b is set to the resonance electrode coupling. It is necessary to match the frequency of the resonance peak due to the 1/2 wavelength resonance of the conductor 32 or lower.

  Furthermore, although the band pass filter used for UWB has been described above as an example, it goes without saying that the band pass filter of the present invention is effective in other applications that require a wide band.

  Next, a specific example of the bandpass filter of the present invention will be described.

  The band-pass filter of the fifth example of the embodiment having the first structure shown in FIG. 5, the band-pass filter having the second structure obtained by removing all the auxiliary earth electrodes 24 from the first structure, and as a comparative example, In the band-pass filter of the second structure, one end of the input coupling electrode 40a and the output coupling electrode 40b in the length direction opposite to the electrical signal input point 45a or the electrical signal output point 45b is opposite to the resonant electrode 30a of the input stage facing the input stage. Alternatively, the electrical characteristics of the bandpass filter having the third structure not extended so as to face the annular ground electrode 23 beyond one end of the resonance electrode 30d at the output stage were simulated by electromagnetic field analysis using a finite element method. The calculation conditions were such that the dielectric constant of the dielectric layer 11 was 9.4. The resonance electrodes 30a, 30b, 30c, and 30d have a width of 0.4 mm and a length of 2.9 mm, and the distance between the resonance electrode 30a and the resonance electrode 30b and the distance between the resonance electrode 30c and the resonance electrode 30d are 0.17 mm. The distance from the resonance electrode 30c was 0.16 mm. The input terminal electrode 60a and the output terminal electrode 60b were square with sides of 0.3 mm. The input coupling electrode 40a and the output coupling electrode 40b have a width of 0.3 mm, a length in the first structure and the second structure is 3.3 mm (including a bent portion of 0.5 mm), and a length in the third structure is 2.3 mm. It was. The auxiliary earth electrode 24 in the first structure has a width of 0.5 mm and a length of 0.8 mm. The auxiliary input coupling electrode 41a and the auxiliary output coupling electrode 41b have a width of 0.3 mm and a length of 1.45 mm. The auxiliary resonant electrodes 31a, 31b, 31c, 31d are arranged in a location 0.4 mm wide and 0.37 mm long disposed 0.3 mm away from the other end of the resonant electrodes 30a, 30b, 30c, 30d, and then the resonant electrodes 30a, 30a, It was made into the shape which joined the rectangle of width 0.2mm and length 0.5mm toward 30b and 30c. The resonance electrode coupling conductor 32 has a width of 0.1 mm in each of the front-side coupling region, the rear-stage coupling region, and the connection region. The thickness of the entire bandpass filter was 0.98 mm, and the layer where the resonant electrodes 30a, 30b, 30c, 30d and the annular ground electrode 23 were arranged was located in the center in the thickness direction. The layers where the resonance electrodes 30a, 30b, 30c, 30d and the annular ground electrode 23 are arranged, the layers where the input coupling electrode 40a, the output coupling electrode 40b and the auxiliary resonance electrodes 31a, 31b, 31c, 31d are arranged, and the auxiliary resonance electrode 31a , 31b, 31c, and 31d are spaced apart from each other by 0.065 mm, and the input coupling electrode 40a, the output coupling electrode 40b, and the auxiliary resonance electrodes 31a, 31b, 31c, and 31d are disposed between the auxiliary layer and the auxiliary layer. The distance between the input coupling electrode 41a, the auxiliary output coupling electrode 41b and the layer where the auxiliary earth electrode 24 is disposed is 0.065 mm, and the layer where only the auxiliary resonance electrodes 31a, 31b, 31c and 31d are disposed and the resonant electrode coupling The distance between the layers where the conductors 32 are arranged was set to 0.065 mm.

  FIG. 7 is a graph showing the simulation results, where the horizontal axis represents the frequency and the vertical axis represents the pass characteristic (S21) of the bandpass filter. According to the graph shown in FIG. 7, the first structure has a low-loss characteristic with little attenuation in the entire passband that is much wider than the region realized by the filter using the conventional quarter wavelength resonator. It is obtained in all bandpass filters of the third structure.

  In the band-pass filter of the third structure shown as the comparative example, there is a resonance peak due to half-wave resonance of the resonant electrode coupling conductor 32 in the vicinity of 7.5 GHz, and the attenuation in that portion is reduced. Note that attenuation poles due to half-wave resonance of the input coupling electrode 40a and the output coupling electrode 40b are formed in the vicinity of 8.1 GHz.

  On the other hand, in the band-pass filter of the second structure, the attenuation pole due to the 1/2 wavelength resonance of the input coupling electrode 40a and the output coupling electrode 40b moves to the low frequency side to near 7.8 GHz, and 1 of the resonant electrode coupling conductor 32 is obtained. The resonance peak due to the / 2 wavelength resonance is approaching, and accordingly, the level of the resonance peak due to the 1/2 wavelength resonance of the resonance electrode coupling conductor 32 is lowered, and the attenuation near the resonance peak is slightly increased. I understand that.

  In the band-pass filter of the first structure, the resonance peak due to the 1/2 wavelength resonance of the resonance electrode coupling conductor 32 disappears, and the attenuation near the frequency where the resonance peak exists greatly increases. It can be seen that the attenuation characteristics are greatly improved. It should be noted that the attenuation pole due to the 1/2 wavelength resonance of the input coupling electrode 40a and the output coupling electrode 40b disappears together with the resonance peak due to the 1/2 wavelength resonance of the resonance electrode coupling conductor 32. The attenuation pole in the vicinity of 8.6 GHz is an attenuation pole that exists in the vicinity of 9.9 GHz in the pass characteristics of the second structure, and is considered to exist in the higher frequency side in the first structure.

  From the above results, according to the bandpass filter of the present invention, it is flat and low-loss over the entire wide passband, and has attenuation poles near both sides of the passband, so that sufficient attenuation in the stopband is achieved. As a result, it was found that an excellent passage characteristic with a sufficient value was obtained, and the effectiveness of the present invention was confirmed.

It is a disassembled perspective view which shows typically an example of embodiment of the band pass filter of this invention. It is a disassembled perspective view which shows typically the other example of embodiment of the band pass filter of this invention. It is a disassembled perspective view which shows typically the further another example of embodiment of the band pass filter of this invention. It is a disassembled perspective view which shows typically the further another example of embodiment of the band pass filter of this invention. It is a disassembled perspective view which shows typically the further another example of embodiment of the band pass filter of this invention. It is a block diagram which shows typically the structural example of the radio | wireless communication module and radio | wireless communication apparatus using the band pass filter of this invention. It is a figure which shows the simulation result of the pass characteristic of the band pass filter of this invention, and the band pass filter of a comparative example.

Explanation of symbols

11: Dielectric layer
21: First ground electrode
22: Second ground electrode
23: Ring earth electrode
24: Auxiliary earth electrode
30a, 30b, 30c, 30d, 30e, 30f: Resonant electrode
31a, 31b, 31c, 31d: auxiliary resonance electrodes
32: Resonant electrode coupling conductor
40a: Input coupling electrode
40b: Output coupling electrode
41a: Auxiliary input coupling electrode
41b: Auxiliary output coupling electrode
45a: Electric signal input point
45b: Electrical signal output point
50: Through conductor
51: First through conductor
52: Second through conductor
53: Third through conductor
54: Fourth through conductor
80: Wireless communication module
85: Wireless communication equipment

Claims (9)

A laminate in which a plurality of dielectric layers are laminated;
A first ground electrode disposed on the lower surface of the laminate and connected to a ground potential;
A second ground electrode disposed on the top surface of the laminate and connected to a ground potential;
Four or more band-shaped resonance electrodes arranged side by side so as to be electromagnetically coupled to each other in one layer of the laminate, each having one end connected to a ground potential and functioning as a quarter wavelength resonator; ,
An annular ground electrode connected to a ground potential, formed in an annular shape surrounding the periphery of the four or more resonant electrodes between the one layer, and connected to the one end of the four or more resonant electrodes;
Of the four or more resonance electrodes, the band-like input coupling electrode and the output stage resonance electrode, which are electromagnetically coupled to the resonance electrode of the input stage, and electromagnetic A strip-shaped output coupling electrode that is field coupled;
The resonance electrode group which is arranged between the layers below the one layer of the multilayer body and includes one or more even number of resonance electrodes adjacent to each other through the first through conductor. The first resonance electrode is connected to the ground potential near the one end, and the other end is connected to the ground potential near the one end of the last resonance electrode constituting the resonance electrode group via the first through conductor. A resonance electrode coupling conductor connected and having a region facing each resonance electrode so as to be electromagnetically coupled to the foremost resonance electrode of the resonance electrode group and the last resonance electrode of the resonance electrode group; A bandpass filter comprising:
The four or more resonant electrodes have their one end and the other end arranged alternately,
The input coupling electrode is disposed so as to face a region extending over half the longitudinal direction of the resonance electrode of the input stage, and an electric signal input point to which an electric signal from an external circuit is input is the input stage. The side closer to the other end of the resonance electrode of the input stage than the center in the length direction at the portion facing the resonance electrode,
The output coupling electrode is disposed so as to face a region extending over half of the length direction of the resonance electrode of the output stage, and an electrical signal output point at which an electrical signal is output to an external circuit is the output stage The side closer to the other end of the resonance electrode of the output stage than the center in the length direction in the portion facing the resonance electrode of
At least one of the input coupling electrode and the output coupling electrode has the one end on the opposite side to the electrical signal input point or the electrical signal output point in the length direction, the resonant electrode of the input stage or the output stage facing each other. A band-pass filter extending beyond the one end of the resonance electrode so as to face the annular ground electrode.   At least one of the input coupling electrode and the output coupling electrode is disposed between layers on the opposite side of the one layer with respect to the layer on which at least one of the input coupling electrode and the output coupling electrode is disposed. The band pass filter according to claim 1, further comprising an auxiliary earth electrode disposed so as to face the one end.   The one end portion of at least one of the input coupling electrode and the output coupling electrode is opposed to the annular ground electrode across the one end of the opposed resonance electrode of the input stage or the resonance electrode of the output stage. The band-pass filter according to claim 1 or 2, wherein the band-pass filter is extended and bent along the annular ground electrode.   The one end of the input coupling electrode and the output coupling electrode is extended so as to face the annular ground electrode across the one end of the opposing resonance electrode of the input stage or the resonance electrode of the output stage. The band-pass filter according to claim 3, wherein the band-pass filter is bent so as to be away from each other.   Attenuation poles are generated on the high-frequency side of the pass band in the pass characteristics of the bandpass filter due to the half-wave resonance of the input coupling electrode and the output coupling electrode, and the band is caused by the half-wave resonance of the resonant electrode coupling conductor 2. The pass filter has a resonance peak on a higher frequency side than a pass band, and a frequency at which the attenuation pole is generated is equal to or lower than a frequency at which the resonance peak is located. The band-pass filter according to claim 4.   It is arranged so as to have a region facing the annular ground electrode and a region facing the resonance electrode between layers different from the one layer, and the region facing the resonance electrode is located between the resonance electrode An auxiliary resonance electrode connected to the other end side of the resonance electrode by a second through conductor penetrating the dielectric layer is disposed corresponding to each of the four or more resonance electrodes. The band-pass filter according to any one of claims 1 to 5. A region facing the auxiliary resonance electrode connected to the resonance electrode of the input stage among the four or more auxiliary resonance electrodes between the one layer and a layer different from the layer where the auxiliary resonance electrode is disposed, and the input coupling A region facing the input coupling electrode, and a region facing the input coupling electrode is disposed between the input coupling electrode and a third through conductor passing through the dielectric layer. An auxiliary input coupling electrode connected to the side closer to the other end of the resonance electrode of the input stage than the center in the length direction;
A region facing the auxiliary resonant electrode connected to the resonant electrode of the output stage among the four or more auxiliary resonant electrodes between the one layer and a layer different from the layer where the auxiliary resonant electrode is disposed, and the output coupling A region facing the electrode, and a region facing the output coupling electrode is formed by a fourth through conductor penetrating the dielectric layer located between the output coupling electrode and the output coupling electrode. The band-pass filter according to claim 6, further comprising: an auxiliary output coupling electrode connected to a side closer to the other end of the resonance electrode of the output stage than a center in the length direction.   A wireless communication module comprising the bandpass filter according to claim 1.   An RF unit including the bandpass filter according to claim 1, a baseband unit connected to the RF unit, and an antenna connected to the RF unit. Wireless communication equipment.

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