JPH0570003U - Dielectric resonator - Google Patents

Abstract

(57) [Abstract] [Purpose] To reduce the size of the dielectric resonator. [Structure] The dielectric block 1 has first to fourth through holes 5 to 8 in order to obtain two resonators. Inner conductor films 11 are formed on the wall surfaces of the first to fourth through holes 5 to 8, respectively. An outer conductor film 12 is formed on the side surface of the dielectric block 1. The second end surface 3 of the dielectric block 1 has a first
A first connecting conductor film for connecting the inner conductor film 11 of the through hole 5 and the inner conductor film 11 of the second through hole 6 is further provided. A second connecting conductor film for connecting the conductor film 11 and the inner conductor film 11 of the fourth through hole 8 is provided. The inner conductor film 11 of the second and fourth through holes 6 and 8 is connected to the outer conductor film 12 by the short-circuit conductor film 15 on the first end face 2. In order to lower the resonance frequency, the second and fourth through holes 6 and 8 have the first
And smaller than the third through holes 5 and 7.
The inner conductor film 11 of the first and third through holes 5 and 7 is connected to the first and second input / output terminals.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a dielectric resonator or dielectric filter used in cordless phones, mobile phones, car phones and the like.

[0002]

[Prior Art]

 A conventional typical quarter-wave dielectric filter has a plurality of resonance holes penetrating from one end face of the prismatic dielectric block to the other end face thereof, and the resonance holes are coupled to each other. A hole is provided, an inner conductor film is provided in the resonance hole, an outer conductor film is provided on a side surface of the dielectric block, and the inner conductor film and the outer conductor film are connected to one end face of the dielectric block ( It is configured by providing an end face conductor for short circuit).

[0003]

[Problems to be solved by the device]

 By the way, the length of the resonance hole is determined so as to correspond to the resonance wavelength. Therefore, when the resonance wavelength is long because the resonance frequency is low, the length of the resonance hole is inevitably long, which makes it difficult to reduce the size or thickness. In order to solve this kind of problem, the applicant of the present application proposed in Japanese Patent Application No. 3-28769 to construct a resonator by connecting the inner conductors of a plurality of through holes for resonance in series. According to this structure, the height of the dielectric block can be significantly reduced. However, it is required to further reduce the height of the dielectric block.

Therefore, an object of the present invention is to provide a dielectric resonator that can be downsized or have a low resonance frequency.

[0005]

[Means for Solving the Problems]

 The present invention for achieving the above object has an opening which has first and second end faces facing each other and a side face between them, and which penetrates from the first end face to the second end face. A dielectric block having a plurality of through-holes for resonance including an end-side resonance through-hole and a short-circuited end-side resonance through-hole; an inner conductor provided in each of the plurality of through-holes; An outer conductor provided on the side surface, a connecting conductor connecting the inner conductors of the plurality of through holes in series with each other, and one end of a series circuit of the inner conductors of the plurality of through holes are connected to the outer conductor. A short-circuit conductor connected to an electric body, wherein the short-circuit-side resonance through-hole in which the inner conductor connected adjacent to the short-circuit conductor is formed is more than the open-end-side resonance through-hole. Also relates to a dielectric resonator formed to be small. As described in claim 2, the third and fourth through holes may be provided to form a plurality of resonators in one dielectric block. Further, as described in claim 3, a coupling hole can be provided in either or both of the first and second through holes and the third and fourth through holes. Further, as described in claim 4, an inner conductor can be provided in at least one coupling hole. Further, it is possible to provide an arbitrary number of through holes of 2 or more in the dielectric block, dispose the internal conductor in each of the through holes, and connect these in series.

[0006]

[Action]

 According to the present invention, by providing a plurality of through holes and connecting these inner conductors in series, an equivalently long through hole can be obtained, and a dielectric resonator or a dielectric filter having a low resonance frequency can be obtained. . Further, when the resonance frequency is the same as the conventional one, the length (height) from the first end face to the second end face of the dielectric block can be reduced. Further, if the through-hole for resonance on the short-circuit end side is made smaller than the through-hole for resonance on the open end side, the resonance frequency is lowered.

[0007]

【Example】

 Next, a dielectric filter according to an embodiment of the present invention will be described with reference to FIGS. A prismatic dielectric block 1 made of a dielectric ceramic for constituting a dielectric filter has a first end face 2, a second end face 3 and four side faces 4a, 4b, 4c, 4d, and It has first, second, third and fourth resonance holes 5, 6, 7, 8 penetrating from the first end face 2 to the second end face 3 and further has first and second coupling holes. There are 9, 10.

Inner conductor films 11 are provided on the wall surfaces of the first, second, third, and fourth resonance holes 5, 6, 7, and 8 arranged in parallel with each other. An outer conductor film 12 is provided on the four side surfaces 4a to 4d. As shown in FIG. 3, the second end face 3 has a first connecting conductor film 13 for connecting the inner conductor films 11 of the first and second resonance holes 5 and 6 in series with each other, and And a second connection conductor film 14 that connects the inner conductor films 11 of the fourth resonance holes 7 and 8 to each other in series. As shown in FIG. 6, the first end face 2 is provided with a short-circuit conductor film 15 for connecting the second and fourth resonance holes 6 and 8 to the outer conductor film 12, respectively. Therefore, the first and third resonance holes 5 and 7 are through-holes for resonance at the open end side, and the second and fourth resonance holes 6 and 8 are through-holes for resonance at the short-circuit end side. The second and fourth resonance holes 6 and 8 on the short-circuited end side are formed smaller than the first and third resonance holes 5 and 7 on the open end side. That is, the inner diameters or the planar areas of the second and fourth resonance holes 6 and 8 are about 20% smaller than those of the first and third resonance holes 5 and 7.

A conductor film 16 is provided on the wall surface of the second coupling hole 10 in order to change the coupling strength and adjust the frequency characteristic, and is connected to the short-circuit conductor film 15.

When connecting the dielectric filter to the transmission line, the first and second terminals 17 and 18 are inserted into the first and third resonance holes 5 and 7, respectively, as shown in FIG. The outer conductor film 12 is connected to the body conductor 11, and the outer conductor film 12 is connected to the ground conductor. The first and second terminals 17 and 18 are connected in series to the signal transmission line via a coupling capacitor.

FIG. 7 shows an equivalent circuit of the dielectric filter. The first resonator consisting of the capacitor C1 and the inductance L1 is based on the first and second resonance holes 5 and 6, and the second resonator consisting of the capacitor C2 and the inductance L2 is the third and third. 4 is based on the resonance holes 7 and 8, and the coupling impedance Z is based on the coupling holes 9 and 10.

According to this embodiment, since the first and second resonance holes 5 and 6 and the third and fourth resonance holes 7 and 8 are connected in series, the length of one resonance hole is twice as long. The same effect as when a resonance hole of length is provided is produced. Therefore, when the resonance frequency is the same as that of the conventional case, the length of each of the resonance holes 5 to 8 can be reduced to about half that of the conventional case. Further, when the lengths of the resonance holes 5 to 8 are the same as in the conventional case, the resonance frequency can be lowered. Further, the resonance frequency can be lowered by reducing the diameters of the second and fourth resonance holes 6 and 8. Further, the resonance frequency and the frequency characteristic can be adjusted by scraping off the conductor film 16 provided in the coupling hole 10 or by scraping off one or both of the connecting conductor films 13 and 14.

[0013]

[Modification]

 The present invention is not limited to the above-mentioned embodiment, and the following modifications are possible, for example. (1) As shown in FIG. 8, a single resonator structure in which the second resonator is omitted from the dielectric filters of FIGS. 1 to 6 can be formed. That is, it is possible to form a resonator having a structure in which the dielectric block 1 is provided with the first and second resonance holes 5 and 6 and the inner conductor films 11 of these are connected in series. The sectional view taken along the line DD of FIG. 8 is the same as FIG. In FIG. 8 and in FIGS. 9 and 10 which will be described later, portions common to those in FIGS. (2) The resonance frequency may be adjusted by extending the short-circuit conductor film 15 between the first and third resonance holes 5 and 7 as shown in FIG. In addition, the resonance frequency can be adjusted by extending the outer conductor film 12 on the first end face 2 as shown in FIG. Moreover, the inner conductor film 11 can be extended on the first end face 2 so as to surround the resonance holes 5 and 7 in a ring shape, and the resonance frequency and the coupling amount can be adjusted. Further, in the end face 3 shown in FIG. 3, the inner conductor film 11 can be extended over the end face 3 so as to surround the resonance holes 5 to 8 in a ring shape, and the resonance frequency and the coupling amount can be adjusted. (3) The conductor film 16 can be provided on only one of the coupling holes 9 and 10 or a part of both wall surfaces. Further, it is possible to adopt a structure in which the conductor film 16 is not provided in the coupling hole 10. (4) Either or both of the coupling holes 9 and 10 can be omitted. In this case, the first resonator of the first and second resonance holes 5 and 6 and the second resonator of the third and fourth resonance holes 7 and 8 can be used independently. . Further, instead of omitting either or both of the coupling holes 9 and 10, or together with the coupling by the coupling holes 9 and 10, capacitive coupling between the first and third resonance holes 5 and 7 is performed by a capacitor, or The connection conductors 13 and 14 can be capacitively coupled to each other and can be used as a two-stage filter. (5) Instead of providing the coupling holes 9 and 10, a groove can be provided at the center of the side surfaces 4a and 4b. (6) More dielectric holes can be formed in the dielectric block 1 to form a dielectric filter having three or more stages. (7) A part of the input / output coupling capacitor can be inserted into the resonance holes 5 and 7 and connected to the inner conductor film 11. (8) Three or more resonance holes can be provided to form one resonator, and the inner conductor films of these can be connected in series. (9) To reduce the inner diameters or areas of the second and fourth resonance holes 6 and 8 in various ranges (for example, 1 to 80% range) than those of the first and third resonance holes 5 and 7. You can

[Effect of the device]

 As is clear from the above, according to the present invention, it is possible to downsize the dielectric resonator or lower the resonance frequency.

[Brief description of drawings]

FIG. 1 is a perspective view showing a dielectric filter of an example.

FIG. 2 is a plan view of the dielectric filter of FIG.

FIG. 3 is a bottom view of the dielectric filter of FIG.

4 is a cross-sectional view taken along the line AA of FIG.

5 is a sectional view taken along line BB of FIG.

6 is a cross-sectional view taken along the line CC of FIG.

FIG. 7 is an equivalent circuit diagram of the dielectric filter of FIG.

FIG. 8 is a plan view showing a dielectric resonator of a modified example.

FIG. 9 is a plan view showing a dielectric filter of a modified example.

FIG. 10 is a plan view showing a dielectric filter of another modification.

[Explanation of symbols]

 1 Dielectric Block 5 First Resonance Hole 6 Second Resonance Hole 7 Third Resonance Hole 8 Fourth Resonance Hole 11 Inner Conductor Film 12 Outer Conductor Film 13 First Connection Conductor Film 14 Second Connection conductor film 15 Short-circuit conductor film

Claims (4)

[Scope of utility model registration request] 1. An open-end resonance through-hole having first and second end faces facing each other and side faces between them and penetrating from the first end face to the second end face. A dielectric block having a plurality of through-holes for resonance including a through-hole for resonance at the short-circuit end side, an inner conductor provided in each of the plurality of through-holes, and an outer conductor provided on the side surface. A body, a connecting conductor that connects the inner conductors of the plurality of through holes to each other in series, and a short-circuit conductor that connects one end of a series circuit of the inner conductors of the plurality of through holes to the outer conductor. The short-circuit end side resonance through-hole in which the inner conductor connected adjacent to the short-circuit conductor is formed is smaller than the open-end side resonance through-hole. Dielectric resonator. 2. A first and a second end faces which are opposed to each other and a side face between them, and which are formed so as to penetrate from the first end face to the second end face. A dielectric block having a second through hole and third and fourth through holes arranged substantially in parallel therewith; and inside the first, second, third and fourth through holes. An inner conductor provided respectively, an outer conductor provided on the side surface, and an inner conductor of the first through hole and an inner conductor of the second through hole are connected at the second end face. A first connection conductor, a second connection conductor that connects the inner conductor of the third through hole and the inner conductor of the fourth through hole at the second end surface, and A short-circuit conductor connecting the inner conductors of the second and fourth through holes to the outer conductor at one end face, respectively, and Wherein the second and fourth through holes first and third
The dielectric resonator is characterized in that it is formed smaller than the through hole. 3. Further, any one of the first and second through holes and the third and fourth through holes that penetrates from the first end surface to the second end surface, respectively, or The dielectric resonator according to claim 2, wherein the dielectric resonator has coupling holes arranged on both sides. 4. A conductor connected to the outer conductor is provided inside at least one of the coupling holes arranged in one or both of the above. Dielectric resonator.