JP2004215245A - Flat antenna - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To also obtain freedom in the form design of a radiator while maintaining the excellent antenna characteristics. <P>SOLUTION: In the flat antenna wherein a dielectric plate 12 is interposed between a radiator 11 and a ground conductor plate 13, the antenna is equipped with a power feeder conductor plate 15 which is provided outside the ground conductor plate 13 and wherein the current distribution similar to the current distribution of respective radiators formed on the radiator 11 is present, and a plurality of conduction parts 16 for connecting the power feeder conductor plate 15 and the radiator 11 corresponding thereto, and a feeder line 17 is connected to an impedance matching point on the power feeder conductor plate 15. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to a planar antenna that is a microstrip antenna having a dielectric plate interposed between a radiating element and a ground conductor plate, and more particularly to a planar antenna that can reliably ensure impedance matching of a feeder line.

  2. Description of the Related Art Conventionally, a planar antenna such as a microstrip antenna has been used as a vehicle-mounted antenna because of its small size and light weight. FIG. 24-1 and FIG. 24-2 are diagrams showing a schematic configuration of a conventional planar antenna. FIG. 24-1 is a plan view of the flat antenna 100, and FIG. 24-2 is a cross-sectional view of the flat antenna 100.

  24A and 24B, the planar antenna has a structure in which a dielectric plate 112 is sandwiched between a radiating element 111 and a grounding conductor plate 113. Are arranged substantially in parallel. In the radiating element 111, when a power supply line 117 that supplies power is connected to a certain power supply point, there is a specific location that matches the impedance of the power supply line 117, a so-called impedance matching point. In addition, the impedance of the radiating element 111 tends to increase as the feeding point moves away from the center and approaches the end. For example, when the characteristic impedance of the feed line 117 is 50Ω and the position PP1 is a matching point of 50Ω, impedance matching is performed when the feed line 117 is connected to the position PP1, and the characteristic impedance of the feed line 117 is 300Ω and the position PP2. Is a matching point of 300Ω, impedance matching is performed when the feeder 117 is connected to this position PP2. Here, when the feed line 117 is 50Ω, the inner conductor 117a of the feed line 117 is connected to the position PP1, and the outer conductor 117b is connected to the ground conductor plate 113 and grounded.

JP-A-5-102721 JP-A-11-289216 JP 2000-134028 A Japanese Utility Model Publication No. 5-68108 JP-A-11-220325

  However, in the above-described conventional planar antenna, since the impedance matching point with respect to the feed line is only at a specific position, the matching position becomes inconsistent as the feed position of the feed line becomes farther from the matching point, and efficient feeding cannot be performed. Of course, there is a problem that the degree of freedom in shape design of the radiating element is limited.

  For example, as shown in FIG. 25, when a rectangular hole is formed in the center of the radiating element 211 and an impedance matching point exists inside the hole, power cannot be supplied to the hole. Therefore, the feeding point cannot be matched with the matching point, and is provided on the radiating element near the matching point. In FIG. 25A, power is supplied from the power supply point PP3 that has moved outside the matching point due to the presence of the hole 211a. In the radiating element 212 of FIG. 25B, power is supplied from the feeding point PP4 further moved outside the matching point due to the presence of the hole 212a larger than the hole 211a. Here, a simulation of the relationship between the hole size, the feeding point position, and the impedance is as shown in the Smith chart shown in FIG.

  For example, the outer dimensions of the radiating elements 211 and 212 are L × L, and the length of one side of the square holes 211a and 212a is changed from 0.15L → 0.2L → 0.25L → 0.3L. When the distance from the center of the radiating element to the feeding point positions PP3 and PP4 is sequentially changed from 0.1L to 0.125L to 0.15L to 0.175L, the real component of the impedance is 65Ω to 165Ω to 260Ω to 390Ω. This is a large value. In such a case, if a 50 Ω feed line is used, matching becomes impossible. Even if an impedance matching circuit is provided near the feed point, conversion to extremely high impedance requires a high matching line. Processing accuracy is required, and there is a practical limit in terms of cost. Here, the fact that matched power supply cannot be performed means that return loss increases and it is difficult to obtain practical antenna characteristics.

  The present invention has been made in view of the above, and an object of the present invention is to provide a planar antenna that can obtain a degree of freedom in shape design of a radiating element while maintaining good antenna characteristics.

  In order to achieve the above object, the planar antenna according to claim 1, wherein one or more radiating elements, a ground conductor plate provided via the radiating element and a dielectric plate, and the radiating element sandwiching the ground conductor plate. One or more power supply conductor plates, which are provided on the opposite side of the element and are insulated from the ground conductor plate and are electrically connected to the radiating element by two or more conductive portions, and a power supply line connected to the power supply conductor plate; It is characterized by having.

  A planar antenna according to a second aspect of the present invention is a planar antenna in which a dielectric plate is interposed between one or more radiating elements and a ground conductor plate. And one or more feeding conductor plates having a current distribution similar to the current distribution of each radiating element present on the one or more radiating elements, and between the feeding feeding plate and the corresponding radiating element. And a plurality of conducting portions for connection, wherein a feeder line is connected to an impedance matching point on the feeder conductor plate.

  According to the first and second aspects of the present invention, a feed conductor plate provided outside the ground conductor plate and having a current distribution similar to the current distribution of each radiating element existing on one or more radiating elements; And a radiating element corresponding to the power supply conductor plate, and a power supply line is connected to an impedance matching point on the power supply conductor plate. Therefore, it is possible to supply power so as to maintain good antenna characteristics without maintaining a good antenna characteristic and without providing a feed point that coincides with a matching point on the radiating element. improves. Also, attachment and change of the power supply line are facilitated.

  According to a third aspect of the present invention, in the planar antenna according to the above invention, a dielectric plate is interposed between the ground conductor plate and the feed conductor plate.

  According to the third aspect of the present invention, the dielectric plate is interposed between the ground conductor plate and the power supply conductor plate so as to have mechanical strength.

  According to a fourth aspect of the present invention, in the above-mentioned invention, at least two of the conductive portions have one ends sandwiching an impedance matching point on the radiating element when power is directly supplied to the radiating element. And the power supply conductor plate is formed in a band shape connecting at least two other ends of at least two of the conductive portions.

  According to the fourth aspect of the present invention, at least two ends of the conducting portion are connected to two places including an impedance matching point on the radiating element when power is directly supplied to the radiating element. The conductor plate is formed so as to form a band connecting at least two ends of at least two of the conductive portions so that a feed point where impedance is matched can be easily found.

  According to a fifth aspect of the present invention, in the above-mentioned invention, at least one of the radiating elements is a frame-shaped radiating element.

  According to the fifth aspect of the present invention, the radiating element is formed as a frame-shaped radiating element having a hole at the center thereof. Can be reliably found above.

  Further, in the planar antenna according to claim 6, in the above invention, the one or more radiating elements are a frame-shaped first radiating element and a second radiating element provided in a frame of the first radiating element. A radiating element.

  According to the sixth aspect of the present invention, the second radiating element is provided in the frame of the first radiating element, the hole of the first radiating element is effectively used, and a plurality of antennas having different characteristics are arranged in a small space. Can be implemented.

  A planar antenna according to a seventh aspect is characterized in that, in the above invention, the second radiating element is directly fed with power by the feeder line.

  Further, in the planar antenna according to claim 8, in the above invention, the conducting portions for conducting the at least one radiating element and the feeder conductor plate are provided at four locations on the radiating element that are substantially 90 degrees rotationally symmetric, Two points on the power supply conductor plate are fed with a phase difference of 90 degrees.

  A ninth aspect of the present invention is the planar antenna according to the above invention, wherein the at least one radiation conductor has a rotationally symmetric shape of approximately 90 degrees.

  According to a tenth aspect of the present invention, in the above-mentioned invention, the at least one feed conductor plate has a rotationally symmetric shape of about 90 degrees.

  According to these inventions, impedance matching is possible even when transmitting and receiving circularly polarized waves.

  Further, a planar antenna according to claim 11 is characterized in that, in the above invention, a feeder line connection pattern is provided on the at least one feeder conductor plate.

  According to the present invention, power can be easily supplied to the power supply conductor plate.

  According to a twelfth aspect of the present invention, in the above-described invention, a notch is provided on a periphery of at least one of the radiating elements.

  A planar antenna according to a thirteenth aspect is characterized in that, in the above invention, the notch is a cross-shaped notch.

  According to these inventions, the notch is provided at the periphery of at least one of the radiating elements, thereby reducing the size of the entire antenna. In these planar antennas, the resonance frequency is determined by the electrical length of the radiating element. However, if the conductor width of the radiating element is narrow, the gain may be deteriorated and stable transmission and reception may be difficult. Therefore, when a notch is provided around the second radiating element provided in the frame as in the present invention and the electrical length is extended to reduce the size to a predetermined resonance frequency, a frame is formed. The space for installation of the first radiating element can be given a margin, and the width of the conductor can be increased to improve the gain. Further, when the size of the first radiating element on the frame determined by the electrical length is large and the size of the second radiating element in the frame is small, the first radiating element is reduced in size to reduce the entire antenna. It can be configured efficiently.

  A planar antenna according to claim 14 is characterized in that at least one radiating element is provided with a through hole.

  Extending the electrical length of the radiating element without changing the outer dimensions of these planar antennas can be realized by providing a notch around the radiating element as described above or by providing a through hole in the radiating element.

  An antenna module according to a fifteenth aspect includes the planar antenna according to the invention.

  According to the present invention, an antenna module can be configured using a suitable planar antenna. In particular, it is possible to suitably configure an integrated antenna module corresponding to a plurality of wireless systems.

  A wireless information terminal according to a sixteenth aspect is provided with the antenna module according to the invention.

  According to the present invention, a wireless information terminal can be configured using a suitable antenna module. In particular, when an integrated antenna module corresponding to a plurality of wireless systems is used, a multifunctional wireless information terminal can be suitably configured.

  An automobile according to a seventeenth aspect is characterized in that the wireless information terminal according to the above invention is mounted.

  According to the present invention, a high-performance automobile can be configured by mounting a suitable wireless information terminal.

  According to this invention, the power supply conductor plate provided on the opposite side to the radiating element with the ground conductor plate side interposed therebetween is connected to each of the one or more radiating elements by two or more conductive portions, and Since the feeder is connected to the impedance matching point of the above, it is possible to obtain the degree of freedom in the design of the radiating element while maintaining good antenna characteristics, and it is easy to attach and change the feeder. Play.

  Further, according to the present invention, at least two ends of the conductive portion are connected to two places sandwiching an impedance matching point on the radiating element when directly feeding the radiating element, and the power supply conductor plate is It is formed so as to form a band connecting at least two ends of at least two of the conductive portions, and it is possible to easily find a feed point where impedance is matched.

  Further, according to the present invention, the radiating element is provided as a frame-shaped radiating element with a hole in the center, but even in this case, a feed point that matches the impedance on the feed conductor plate is reliably found. It has the effect of being able to.

  Further, according to the present invention, the second radiating element is provided in the frame of the first radiating element, and the hole of the first radiating element can be effectively used, and the size of the entire antenna can be reduced. Play.

  Further, according to the present invention, a notch or a through-hole is provided in a peripheral edge of at least one of the radiating elements, whereby an effect of promoting miniaturization of the entire antenna can be achieved.

  Hereinafter, preferred embodiments of a planar antenna according to the present invention will be described in detail with reference to the accompanying drawings. In the schematic diagram of the planar antenna shown below, the dimensional ratio between the length and width of the radiating element, that is, the aspect ratio is shown as 1. However, it is necessary to appropriately change the aspect ratio in accordance with desired characteristics from the spirit of the present invention. There is no deviation.

(Embodiment 1)
FIG. 1 is a perspective view showing a schematic configuration of the planar antenna according to the first embodiment of the present invention. FIG. 2 is a sectional view of the planar antenna shown in FIG. FIG. 3 is a bottom view of the planar antenna shown in FIG. 1 to 3, the planar antenna 1 has a feed conductor plate 15, a dielectric plate 14, a ground conductor plate 13, a dielectric plate 12, and a radiating element 11 sequentially laminated. At least, a substantially parallel positional relationship is maintained between the radiating element 11 and the ground conductor plate 13. The radiating element 11 is a rectangular flat plate or a conductor pattern, and transmits and receives linearly polarized radio waves.

  The two conducting portions 16 are formed in a pin shape, connect the radiating element 11 and the feeding conductor plate 15 in a conductive manner, and connect two connecting points 16a and 16b sandwiching an impedance matching point when the radiating element 11 is directly supplied with power. Connected. Here, the insulated state is maintained between the ground conductor plate 13 and the conduction portion 16. In FIG. 2, a through hole for the conduction portion 16 is provided in the ground conductor plate 13 to maintain an insulated state.

  The dielectric plate 12 is formed of a material having a relative dielectric constant εr of 5 or more, and may be realized by, for example, ceramics. Since the wavelength shortening rate of the antenna is proportional to the square root of the relative permittivity εr, the larger the relative permittivity εr, the smaller the radiating element 11 can be realized. On the other hand, the dielectric plate 14 is formed of a dielectric material such as a glass epoxy resin having a smaller relative dielectric constant εr than the dielectric plate 12. It should be noted that, for example, air may be used instead of the dielectric plate 14, but in that case, it is necessary to secure the strength of the planar antenna 1 by some other means.

  The power supply conductor plate 15 is a band-shaped pattern, and both ends of the power supply conductor plate 15 are connected to connection points 16c and 16d of the conduction portion 16, respectively. Therefore, a strip-shaped continuous conductor is formed between the two points 16c and 16d sandwiching the impedance matching point, and the current distribution on the radiating element 11 is formed between the two points 16c and 16d on the feed conductor plate 15. Will be reproduced.

  As a result, a matching point P1 that matches the impedance of the feeder line 17 can always be found on the feeder conductor plate 15. By connecting the inner conductor 17a of the feeder line 17 to this matching point P1, a return loss is reduced. Impedance matching can be performed.

  On the other hand, the outer conductor 17b of the feed line 17 is connected to the ground conductor plate 13 and grounded.

  In addition, as shown in FIG. 4, the ground conductor plate 13, the dielectric plate 14, the power supply conductor plate 15, and the second ground conductor plate 18 can be formed by a multilayer substrate. In this case, the inner conductor 17a of the feed line 17 may be connected to the feed conductor plate 15 at the matching point P1, and the outer conductor 17b may be connected to the second ground conductor plate 18. The second ground conductor plate 18 is connected to the ground conductor plate 13 via a through hole or a pin (not shown).

  By the way, since the impedance matching point can be obtained on the feed conductor plate 15 without depending on the shape of the radiating element, for example, as shown in FIGS. , The impedance matching can be performed even if the true impedance matching point for the radiating element 21 is within the hole 22. That is, even when there is an impedance matching point where the power supply line 17 matches inside the hole 22, the impedance matching can be reliably performed on the power supply conductor plate 15.

  In the first embodiment, as described above, impedance matching can always be performed irrespective of the shapes of the radiating elements 11 and 21, so that the degree of freedom in the shape design of the radiating elements can be significantly improved. At the same time, the degree of freedom in selecting the feeder line 17 that can perform impedance matching can be increased. Further, since the impedance matching point is provided so as to be exposed on the outer surface, the impedance matching can be easily adjusted.

(Embodiment 2)
Next, a second embodiment of the present invention will be described. In the planar antenna 2 described in the first embodiment described above, the hole 22 is provided inside the radiating element 21. In the second embodiment, the hole 22 is actively used, and A planar antenna capable of transmitting and receiving radio waves in a frequency band different from that of the radiating element 21 is formed.

  FIG. 7 is a perspective view showing a schematic configuration of the planar antenna according to the second embodiment of the present invention. FIG. 8 is a sectional view of the planar antenna shown in FIG. 9A and 9B are diagrams showing the feed conductor plates 15a and 15b of the planar antenna shown in FIG. In FIG. 7, FIG. 8, FIG. 9A, and FIG. 9B, this planar antenna 3 is inserted into the hole 21 at the center of the radiating element 21 of the planar antenna 2 shown in FIG. The radiating element 31 for transmitting and receiving a frequency band having a higher frequency than the frequency band is provided. The radiating element 21 covers, for example, a GPS frequency band (1.6 GHz), and the radiating element 31 covers, for example, a VICS transmitting / receiving frequency band (2.5 GHz). In this way, by mounting antennas having different characteristics required for a vehicle in a small size, it is possible to contribute to the enhancement of functions of the vehicle.

  This radiating element 31 is connected at connection points 16e and 16f to a conduction portion 16Q that penetrates through dielectric plate 12, ground conductor plate 13 and dielectric plate 14, and conduction portion 16Q is connected to power supply circuit at connection points 16g and 16h. 15b. On the other hand, the internal conductor 19a of the power supply line 19 is connected to the power supply circuit 15b, and the external conductor 19b is grounded to the ground conductor plate 13b. Note that this connection can also be realized using a multilayer substrate as described above. Further, the connection points 16e and 16f are located at positions sandwiching the impedance matching point when the power is directly supplied to the radiating element 31.

  According to the second embodiment, transmission and reception in a plurality of frequency bands can be performed in a space-saving manner by effectively utilizing hole 22 at the center of radiating element 21 having the shape shown in the first embodiment.

(Embodiment 3)
Next, a third embodiment of the present invention will be described. In Embodiments 1 and 2 described above, both are planar antennas for transmitting and receiving linearly polarized radio waves. In Embodiment 3, transmission and reception of circularly polarized radio waves are performed in a configuration corresponding to Embodiment 1. To realize a planar antenna.

  FIG. 10 is a bottom view showing the configuration of the planar antenna according to the third embodiment of the present invention. In FIG. 10, the planar antenna is provided with conducting portions 41a and 41b and conducting portions 42a and 42b corresponding to the conducting portion 16 shown in FIGS. The conductive portions 41a, 41b, 42a, and 42b are provided at locations that are rotationally symmetrical by 90 degrees. In addition, one power supply conductor plate 41, 42 corresponding to the power supply conductor plate 15 shown in FIGS.

  One implementation method for transmitting and receiving circularly polarized waves is a two-point feeding method. This forms two current distributions on the radiating element 11 that resonate orthogonally to each other. By making the current distribution have a phase difference of 90 degrees, transmission and reception of circularly polarized waves are realized. Note that one side of the radiating element is approximately 波長 wavelength. Here, the high-frequency signal delayed by 90 degrees by the 90-degree phase shifter 43 is input to a point P4 which is an impedance matching point, and the high-frequency signal without delay is input to a point P3 which is an impedance matching point. As a result, circularly polarized waves that have turned to the right toward the bottom of the page of FIG. 10, that is, right-handed polarized waves, can be transmitted and received. In FIG. 10, impedance conversion is performed so that reflection does not occur at the branch of the power supply line.

  By the way, the plane antenna shown in FIG. 10 has a 90-degree phase shifter provided outside. However, as shown in FIG. 11, a 90-degree hybrid circuit 44 may be provided to delay by 90 degrees.

  In addition, as shown in FIG. 12, a feeder line connection pattern 45 having a phase difference of 90 degrees can be provided in an empty space on the same plane as the feeder conductor plate. Thereby, circular polarization can be driven only by connecting one feeder line 17. Incidentally, a Wilkinson distributor may be used for the power supply connection pattern.

  In the third embodiment, a circularly polarized wave can be obtained by two-point power supply by forming a power supply conductor plate having a shape corresponding to the excitation state. Also in this case, as in the first embodiment, impedance matching can always be performed irrespective of the shape of the radiating element 11, so that the degree of freedom in designing the shape of the radiating element can be significantly improved, and In addition, it is possible to increase the degree of freedom in selecting a feed line that can perform impedance matching. Further, since the impedance matching point is provided outside the radiation element, the impedance matching can be easily adjusted.

(Embodiment 4)
Next, a fourth embodiment of the present invention will be described. In the above-described third embodiment, transmission and reception of circularly polarized waves are realized according to the first embodiment. However, in the fourth embodiment, the outer radiating element 21 corresponding to the second embodiment is realized. Can realize transmission and reception of circularly polarized waves.

  FIG. 13 is a bottom view showing the configuration of the planar antenna according to the fourth embodiment of the present invention. This planar antenna forms a conductor pattern having a hole 46 near the center of the planar antenna shown in FIG. Then, power is supplied to the radiating element 31 from the area of the hole 46.

  Thus, transmission and reception of circularly polarized waves with respect to radiating element 21 and transmission and reception of linearly polarized waves with respect to radiating element 31 are enabled. The shape of the power supply conductor plate is realized by having a rotational symmetry of 90 degrees.

  Therefore, the power supply conductor plate may be formed diagonally as shown in FIG. This also makes it possible for the radiating element 21 to transmit and receive circularly polarized waves. The feeding point for the radiating element 31 is located at a position shifted from the center.

(Embodiment 5)
Next, a fifth embodiment of the present invention will be described. In the fifth embodiment, the radiating element is a slit-loaded antenna, and the planar antennas described in the first to fourth embodiments are to be further miniaturized.

  15-1 and 15-2 are plan views showing the configuration of the planar antenna according to the fifth embodiment of the present invention. In FIG. 15A, in this planar antenna, a notch 62a is provided in the inner radiating element 60, thereby increasing the perimeter and promoting the miniaturization of the radiating element 60 itself. Due to the downsizing of the inner radiating element 60, the width d of the outer radiating element 61 can be increased, and the antenna characteristics can be maintained. Also, as shown in FIG. 15B, the same effect can be obtained by providing the through hole 62b.

  Further, as shown in FIG. 16, a notch 66 is provided in the outer radiating element 64 to promote the miniaturization of the entire antenna, and in addition, a cross-shaped notch 65 is provided in the inner radiating element 63, The radiating element 63 is miniaturized by increasing the peripheral length of the radiating element 63. As a result, sufficient antenna characteristics of the radiating element 64 can be obtained, and miniaturization of the entire antenna can be further promoted. Also in this case, the same effect can be obtained by providing a through hole instead of the notches 65 and 66.

(Embodiment 6)
Next, a sixth embodiment of the present invention will be described. Although the above-described circular polarization is mainly realized by the two-point feeding method, the present invention is not limited to this, and the circular polarization can also be realized by the one-point feeding method using a notch as a perturbation element. FIG. 17 shows a rectangular radiating element with diagonal corners cut off. As a result, a difference is provided in the electrical length in the diagonal direction, and transmission and reception of circularly polarized waves can be realized using the difference in the resonance frequency. FIG. 18 shows normalized frequency characteristics of return loss and axial ratio as characteristics when the planar antenna shown in FIG. 17 is operated. f is the measurement frequency, f0 is the frequency at which the axial ratio is minimum, and is normalized by f0. As another example, as shown in FIG. 19, a slit 91 facing a circular radiating element is provided, and thereby, circular polarization can be realized. Similarly to the first embodiment, the radiating element shown in FIG. 20 is formed into a frame shape by using the feeder conductor plate 15 connected by the conducting portion 16 also to the planar antenna shown in FIGS. The degree of freedom in shape design, such as performing, can be obtained.

(Example)
21-1 to 21-3 are diagrams showing a configuration of a planar antenna according to an embodiment of the present invention, FIG. 21-1 is a plan view thereof, and FIG. 21-2 is a right side view thereof. FIG. 21C is a bottom view of FIG. In addition, each entry dimension shows an example of design conditions when the radiating element 71 is adjusted to resonate in the GPS band when the effective wavelength in each of the dielectric plates 72 and 74 is λg1 and λg2, respectively. It is a thing. This planar antenna has a feed conductor plate 75 formed in a cross shape with a conductor width of 0.01λg2, a dielectric plate 74 having a thickness of 0.02λg2 and a relative permittivity εr2, a ground conductor plate 73, and 0.63λg1 × 0.63λg1. A dielectric plate 72 having a thickness of 0.09λg1 and a relative dielectric constant εr1, a radiating element 71 having an outer dimension of 0.50λg1 × 0.50λg1 and an inner dimension of 0.27λg1 × 0.27λg1 are sequentially laminated. Assuming that the resonance wavelength in vacuum is λ, effective wavelengths λg1 and λg2 are obtained by using εr1 for the relative permittivity of the dielectric plate 72 and εr2 for the relative permittivity of the dielectric plate 74.
λg1 = λ / √ (εr1)
λg2 = λ / √ (εr2)
Is represented by The resonance wavelength λ, the radiating element 71 and the feeding conductor plate 75 were conducted through conduction portions 76a to 76d provided at four locations which were rotationally symmetrical by 90 degrees. A high-frequency signal without delay was input to the matching point P71 on the power supply conductor plate 75, and a high-frequency signal delayed by 90 degrees by the 90-degree phase shifter 76 was input to the matching point P72. FIG. 22 shows the directivity at this time. As shown in FIG. 22, the gain of the right-handed polarized wave on the paper surface of FIG. 22, that is, in the zenith direction is about 4 dB, and functions sufficiently as a circularly polarized plane antenna.

  23-1 to 23-4 show an example of a manufacturing process of the planar antenna according to the first embodiment of the present invention. The member shown in FIG. 23A is obtained by integrally forming the radiating element 11 and the conducting portion 16 on the dielectric 12, and there are various methods for forming the same depending on the material of the dielectric 12. For example, a hole large enough to allow the conduction portion 16 to be inserted into the dielectric 12 is formed in advance, the conduction portion 16 is inserted into the hole, and then connected to the radiating element 11 at 16a and 16b. Is fixed to the dielectric 12 using, for example, an adhesive. In this case, it is desirable that the gap between the conductive portion 16 and the dielectric 12 is small. In addition, a circuit board having a power supply conductor plate 15 formed on one surface and a ground conductor plate 13 formed on the other surface is used as the dielectric 14, and the inner surface of a hole through which the conductive portion 16 penetrates the dielectric 14 is used. Metal is also provided to form a so-called through hole, and by filling the through hole with solder 20, the conductive portion 16 is fixed to the dielectric 14, and the conductive portion 16 and the power supply conductor plate 15 are connected. Make it conductive.

1 is a perspective view illustrating a schematic configuration of a planar antenna according to a first embodiment of the present invention. It is sectional drawing of the planar antenna shown in FIG. FIG. 2 is a bottom view of the planar antenna illustrated in FIG. 1. FIG. 4 is a cross-sectional view illustrating a schematic configuration of a planar antenna that is a modification of the first embodiment of the present invention. FIG. 3 is a perspective view showing a schematic configuration of a planar antenna which is a modification of the first embodiment of the present invention. FIG. 6 is a plan view of the planar antenna illustrated in FIG. 5. FIG. 9 is a perspective view illustrating a schematic configuration of a planar antenna according to a second embodiment of the present invention. It is sectional drawing of the planar antenna shown in FIG. FIG. 9 is a diagram illustrating a feed conductor plate 15a of the planar antenna illustrated in FIG. 8. FIG. 9 is a diagram illustrating a feed conductor plate 15b of the planar antenna illustrated in FIG. 8. FIG. 9 is a bottom view illustrating a schematic configuration of a planar antenna according to a third embodiment of the present invention. FIG. 21 is a bottom view showing a schematic configuration of a planar antenna which is a modification of the third embodiment of the present invention. FIG. 21 is a bottom view showing a schematic configuration of a planar antenna which is a modification of the third embodiment of the present invention. FIG. 13 is a bottom view illustrating a schematic configuration of a planar antenna according to a fourth embodiment of the present invention. FIG. 21 is a bottom view showing a schematic configuration of a planar antenna which is a modification of the fourth embodiment of the present invention. It is a top view which shows the schematic structure of the planar antenna which is Embodiment 5 of this invention. FIG. 21 is a plan view showing another schematic configuration of the planar antenna according to the fifth embodiment of the present invention. FIG. 21 is a plan view showing a schematic configuration of a planar antenna which is a modification of the fifth embodiment of the present invention. FIG. 16 is a plan view showing a schematic configuration of a planar antenna according to a sixth embodiment of the present invention. FIG. 18 is a diagram illustrating an example of operation characteristics of the planar antenna illustrated in FIG. 17. FIG. 21 is a plan view showing a schematic configuration of a planar antenna which is a modification of the sixth embodiment of the present invention. FIG. 21 is a plan view showing a schematic configuration of a planar antenna which is a modification of the sixth embodiment of the present invention. 1 is a plan view of a planar antenna according to an embodiment of the present invention. 1 is a right side view of a planar antenna according to an embodiment of the present invention. 1 is a bottom view of a planar antenna according to an embodiment of the present invention. FIG. 21 is a diagram showing the antenna directivity of the planar antenna shown in FIG. 20. FIG. 5 is a diagram illustrating an example of a manufacturing process of the planar antenna according to the first embodiment of the present invention (part 1). FIG. 7 is a diagram illustrating an example of a manufacturing process of the planar antenna according to the first embodiment of the present invention (part 2). FIG. 5 is a diagram illustrating an example of a manufacturing process of the planar antenna according to the first embodiment of the present invention (part 3). FIG. 4 is a diagram illustrating an example of a manufacturing process of the planar antenna according to the first embodiment of the present invention (part 4). It is a top view of the conventional planar antenna. It is sectional drawing of the conventional planar antenna. It is a figure showing an example of a radiating element provided with a hole in the center. It is a Smith chart which shows the change of the magnitude | size of the hole of the center part provided in the radiation element, a feeding position, and impedance.

Explanation of reference numerals

1,2,3 Planar antenna 11,21,31,60,61,63,64,71 Radiating element 12,14,14a, 14b, 14c, 72,74 Dielectric plate 13,13a, 13b, 73 Ground conductor plate 15, 15a, 15b, 41, 42, 75 Feeding conductor plate 16, 16P, 16Q, 41a, 41b, 42a, 42b, 76a to 76d Conducting part 17, 19 Feeding line 17a, 19a Feeding line inner conductor 17b, 19b Outer conductor of electric wire 18 Second ground conductor plate 20 Solder 22, 46 hole 43 90-degree phase shifter 44 90-degree hybrid circuit 45 Power supply line connection pattern 62a, 65, 66 Notch 62b Through hole

Claims (17)

One or more radiating elements;
A ground conductor plate provided via the radiating element and the dielectric plate,
One or more feeder conductor plates provided on the opposite side to the radiating element with the grounding conductor plate interposed therebetween, insulated from the grounding conductor plate, and conducted by two or more conducting portions for each of the radiating elements;
A power supply line connected to the power supply conductor plate,
A planar antenna comprising: In a planar antenna having a dielectric plate interposed between one or more radiating elements and a ground conductor plate,
One or more power supply conductor plates provided on the opposite side to the radiating element with the ground conductor plate therebetween and having a current distribution similar to the current distribution of each radiating element present on the one or more radiating elements,
A plurality of conductive portions connecting between the power supply conductor plate and the corresponding radiating element,
And a feed line is connected to an impedance matching point on the feed conductor plate.   The planar antenna according to claim 1, wherein a dielectric plate is interposed between the ground conductor plate and the feed conductor plate. At least two of the conducting portions are connected at one end to two places sandwiching an impedance matching point on the radiating element when the radiating element is directly supplied with power,
The planar antenna according to any one of claims 1 to 3, wherein the power supply conductor plate has a band shape connecting at least the other ends of the conductive portions.   The planar antenna according to any one of claims 1 to 4, wherein at least one of the radiating elements is a frame-shaped radiating element. The one or more radiating elements include:
A frame-shaped first radiating element;
A second radiating element provided in the frame of the first radiating element;
The planar antenna according to any one of claims 1 to 5, further comprising:   The planar antenna according to claim 6, wherein the second radiating element is directly fed by the feed line.   The conducting portions for conducting the at least one radiating element and the feeding conductor plate are provided at four positions on the radiating element which are substantially 90-degree rotationally symmetric, and two points on the feeding conductor plate are fed with a phase difference of 90 degrees. The planar antenna according to claim 1, wherein:   The planar antenna according to claim 8, wherein the at least one radiation conductor has a rotationally symmetric shape of about 90 degrees.   The planar antenna according to claim 8, wherein the at least one feed conductor plate has a rotationally symmetric shape of approximately 90 degrees.   The planar antenna according to any one of claims 1 to 10, wherein a power supply line connection pattern is provided on the at least one power supply conductor plate.   The planar antenna according to any one of claims 1 to 11, wherein a notch is provided at a periphery of at least one of the radiation elements.   The planar antenna according to claim 12, wherein the notch is a cross-shaped notch.   The planar antenna according to any one of claims 1 to 13, wherein a through hole is provided in at least one of the radiation elements.   An antenna module comprising the planar antenna according to any one of claims 1 to 14.   A wireless information terminal comprising the antenna module according to claim 15.   An automobile equipped with the wireless information terminal according to claim 16.

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