JP2006311478A - Circular polarizing microstrip antenna and circular polarizing microstrip antenna apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small-sized circular polarizing microstrip antenna of which axial ratio characteristics are excellent in a wide band. <P>SOLUTION: In a circular polarizing microstrip antenna 1 of the present embodiment, a 90° phase difference line 7 and a Wilkinson distributor 8 are further provided on the surface of a dielectric substrate 2 whereon a patch conductor 3 of a two-feed-point system is formed. The 90° phase difference line 7 and the Wilkinson distributor 8 are connected to a first power feeding part 4 and a second power feeding part 5 and form a power feeding circuit 9 for feeding power to the patch conductor 3. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to an antenna that is mounted on a moving body such as an automobile and transmits / receives information using circularly polarized radio waves, and an antenna device including a high-frequency circuit connected to the antenna.

2. Description of the Related Art In recent years, with the introduction of automobile IT, there has been a remarkable spread of in-vehicle information terminals represented by car navigation. In particular, communication means using radio waves and light capable of exchanging information in a non-contact manner with respect to automobiles that are moving bodies have been mounted in various forms.

FIG. 5 shows a configuration of a typical in-vehicle information terminal. As antennas, there are a GPS antenna unit 41, a VICS antenna unit 42, and an ETC / DSRC antenna unit 43, and each receiver or transceiver is provided on the information terminal main body 44 side. In addition to this, a VICS light projecting / receiving unit for receiving an optical signal from the optical beacon is also provided.

In the configuration shown in FIG. 5, the GPS antenna unit 41 and the ETC / DSRC antenna unit 43 are stored in separate housings and connected to the information terminal main body 44 side using dedicated coaxial cables 46 and 48, respectively. .

However, instead of the method of connecting via a coaxial cable in view of the recent demand for weight reduction of automobiles, miniaturization of parts, and diversification / high performance of wireless communication devices, as shown in FIG. In addition, there is a strong demand for a form in which an antenna unit and a part or all of a receiver or a transceiver are integrated and incorporated in one housing.

In FIG. 4, the antenna unit 31 is directly connected to a circuit board 32 on which part or all of the high-frequency circuit unit and the transceiver are mounted, and is stored in the same housing 33.

On the other hand, since some systems used for in-vehicle information terminals, such as GPS and ETC / DSRC, use circularly polarized signals, it is necessary to use circularly polarized antennas as information terminal side antennas. There is.

There are various types of circularly polarized antennas. As a widely used antenna, there is a microstrip antenna (MSA) formed on a dielectric substrate. An example of a microstrip antenna is shown in FIG. As a method of realizing a circularly polarized antenna using a microstrip antenna, two methods are known: a one-point feeding method shown in FIG. 6A and a two-point feeding method shown in FIG. 6B. Yes.

In the microstrip antenna 51 using the one-point power feeding method shown in FIG. 6A, a circularly polarized wave is generated by providing the radiating patch 52 with a structure for giving asymmetry called, for example, a degenerate separation element 53. I am doing so. In the one-point feeding method, only one feeding point 54 is provided.

On the other hand, in the microstrip antenna 56 using the two-point feeding system shown in FIG. 6B, power is fed through signal transmission lines 58 and 59 called feeding lines from two directions almost orthogonal to each other when viewed from the center of the radiating patch 57. By doing so, circularly polarized waves are generated. The high-frequency signals supplied to the two power supply lines 58 and 59 are generally two signals having equal amplitude and a phase difference of 90 °.

FIG. 7 shows a power supply circuit that supplies a high-frequency signal with an equal amplitude and a phase difference of 90 ° to a two-point power supply microstrip antenna.

FIGS. 7A, 7B, and 7C are systems called a T-type branch + 90 ° phase difference line, a branch line divider, and a Wilkinson divider + 90 ° phase difference line, respectively. In particular, when a power supply circuit having the configuration shown in FIG. 7B or FIG. 7C is used, a characteristic value indicating the circularity of circular polarization called an axial ratio realizes an excellent antenna over a wide band. There is a feature that can be done.

In each power supply circuit shown in FIG. 7, one high-frequency signal is branched and output to two lines, and a difference in electrical length corresponding to a quarter wavelength of the used frequency is provided between the two lines. Thus, a 90 ° phase difference is realized. That is, if the wavelength of the used frequency is λ, a line having an electrical length corresponding to at least λ / 4 is required, and a corresponding installation space is required.

For example, if it is going to implement | achieve the electric power feeding circuit of the antenna for GPS (usage frequency: 1.57542GHz) with the branch line divider | distributor shown in FIG.7 (b), a glass epoxy board | substrate (FR-4 etc .: ratio: thickness 0.8mm) A line having an electric length λ / 4 formed on the dielectric constant 4.3) has a pattern width of about 1.5 mm and a pattern length of about 30 mm. If this line is formed in a ring shape to form the branch line distributor, the feeding circuit occupies a considerable area of the high-frequency circuit board, and there is a problem that it cannot coexist with the circuit of the transceiver. It was.

Therefore, in order to make the installation space of the power feeding circuit as small as possible, a high frequency circuit board is formed on the back surface side of the ground electrode of the antenna element as described in Patent Document 1, for example, and the high frequency circuit In many cases, the feeder circuit is formed on a substrate using a pattern.
JP 2004-56204 A

However, as described in Patent Document 1, if a power feeding circuit is formed on the same high frequency circuit board as that of the high frequency circuit / transmitter / receiver, antenna characteristics including the power feeding circuit cannot be evaluated. There was a problem.

In addition, in the above configuration, it is difficult to finely adjust a part of the feed circuit in order to optimize the radiation characteristics of the antenna. Will occur.

Thus, for example, as shown in FIG. 8, an example in which a feeder circuit including a branch line distributor 73 shown in FIG. 7B is formed on the radiation surface 72 where the patch conductor 71 is formed has been reported.

However, in the configuration as shown in FIG. 8, not only the radiation surface 72 becomes large, but also the shape of the radiation surface 72 has a shape that is greatly symmetric with respect to the center of the patch conductor 71. There was also a problem that the axial ratio characteristics of the antenna deteriorated due to the influence of coupling and the like.

The present invention has been made to solve these problems, and an object of the present invention is to provide a small circularly polarized microstrip antenna having a wide bandwidth and good axial ratio characteristics of the antenna.

According to a first aspect of the circularly polarized microstrip antenna of the present invention, a dielectric substrate in which a dielectric material is formed to a predetermined thickness, a patch conductor disposed on one surface of the dielectric substrate, and the dielectric A grounding conductor disposed on the other surface of the substrate; a first feeding portion disposed in a first direction as viewed from the center of the patch conductor; and feeding the patch conductor; and the first conductor as viewed from the center of the patch conductor. A second power feeding unit that is disposed in a second direction orthogonal to the direction of 1 and feeds power to the patch conductor, and the first power feeding unit and the second power feeding unit have substantially the same amplitude and a phase difference of about 90 °. A circularly polarized microstrip antenna capable of exciting circularly polarized waves by feeding with a 90 ° phase difference line on one output side of the Wilkinson divider on the same plane as the patch conductor. Equipped with a feeding circuit formed in front The circularly polarized microstrip antenna is characterized in that a high-frequency signal is supplied to the patch conductor by connecting the first feeding unit and the second feeding unit to two output ends of the feeding circuit.

According to a second aspect, the feeding circuit includes a symmetry axis in the first direction as viewed from the center of the dielectric substrate, a symmetry axis in the second direction as viewed from the center of the dielectric substrate, A circularly polarized microstrip antenna formed in a region surrounded by an end portion of a dielectric substrate.

A third aspect is a circularly polarized microstrip antenna characterized in that the area of the ground conductor is nine times or smaller than the area of the patch conductor.

A fourth aspect is a circularly polarized microstrip antenna, wherein the dielectric substrate has a thickness of 0.4 mm or more.

According to a fifth aspect, the 90 ° phase difference line and the Wilkinson divider determine the amplitude component of each of the two high-frequency signals output from the power supply circuit and the phase difference between the two components, A1, A2, and Δθ, respectively. And when
A1 ≠ A2, Δθ ≠ 90 °
The circularly polarized microstrip antenna is characterized by being configured as follows.

A sixth aspect is characterized in that the first power feeding unit is connected to an output end of the Wilkinson distributor, and the second power feeding unit is connected to an output end of the 90 ° phase difference line. This is a circularly polarized microstrip antenna.

A seventh aspect is characterized in that the first power feeding unit is connected to an output end of the 90 ° phase difference line, and the second power feeding unit is connected to an output end of the Wilkinson distributor. It is a circularly polarized microstrip antenna.

An eighth aspect includes the circularly polarized microstrip antenna according to any one of the first aspect to the seventh aspect, further comprising another dielectric substrate laminated on the open-side surface of the ground conductor, A high frequency circuit unit including a transceiver is disposed on the open side surface of another dielectric substrate, and the high frequency circuit unit and the input end of the Wilkinson distributor are connected via a through hole. This is a polarized microstrip antenna device.

As described above, according to the present invention, it is possible to provide a circularly polarized microstrip antenna in which a feeding circuit including a 90 ° phase difference line and a Wilkinson divider is formed on the antenna radiation surface.

By forming the feeding circuit on the antenna radiation surface, it is possible to evaluate the antenna characteristics including the feeding circuit, and it is easy to adjust the feeding circuit and optimize the antenna radiation characteristics.

In addition, since the shape of the dielectric substrate can be made almost symmetrical with respect to the center of the patch conductor, a good axial ratio can be obtained over a wide band.

Furthermore, according to the present invention, it is possible to provide a circularly polarized microstrip antenna and an antenna device suitable for ETC and DSRC using the 5.8 GHz band, GPS using the 1.575 GHz band, and the like.

A configuration of a circularly polarized microstrip antenna according to a preferred embodiment of the present invention will be described in detail with reference to the drawings. In addition, about each component which has the same function, the same code | symbol is attached | subjected and shown for simplification of illustration and description.

FIG. 1 is a block diagram showing a schematic configuration of a circularly polarized microstrip antenna according to an embodiment of the present invention. In the circularly polarized microstrip antenna 1 of this embodiment, a patch conductor 3 is formed on the surface of a dielectric substrate 2 in which a dielectric material is formed to a predetermined thickness. A ground conductor (not shown) is formed on the back surface of the dielectric substrate 2.

The patch conductor 3 is a two-point feeding type patch antenna having two feeding parts, a first feeding part 4 and a second feeding part 5. The first power feeding portion 4 is provided in the vertical direction in the drawing as viewed from the center 6 of the patch conductor 3, and the second power feeding portion 5 is provided in the horizontal direction in the drawing as viewed from the center 6 of the patch conductor 3. It has been. That is, the first power feeding unit 4 and the second power feeding unit 5 are provided in directions different by 90 °.

The circularly polarized microstrip antenna 1 of the present embodiment further includes a 90 ° phase difference line 7 and a Wilkinson distributor 8 on the surface of the dielectric substrate 2 on which the patch conductor 3 is formed. The 90 ° phase difference line 7 and the Wilkinson distributor 8 are connected to the first feeding unit 4 and the second feeding unit 5 to form a feeding circuit 9 that feeds the patch conductor 3.

That is, the first power feeding unit 4 and one output terminal of the Wilkinson distributor 8 are connected, the other output terminal of the Wilkinson distributor 8 and the input terminal of the 90 ° phase difference line 7 are connected, and about 90 °. The output end of the phase difference line 7 and the second power feeding unit 5 are connected.

When the 90 ° phase difference line 7 and the Wilkinson distributor 8 shown in FIG. 7C are used as the power feeding circuit 9, at least one λ is compared with the branch line distributor shown in FIG. / 4 line can be omitted. As a result, even if the feeder circuit 9 is formed on the same plane as the patch conductor 3, the antenna can be arranged so as not to greatly impair the symmetry of the antenna.

That is, the dielectric substrate is formed so that the shape of the dielectric substrate 2 is substantially symmetric with respect to the center 6 of the patch conductor 3 by forming the feeder circuit 9 with the 90 ° phase difference line 7 and the Wilkinson distributor 8. It is possible to dispose the power supply circuit 9 on 2.

In FIG. 1, of the two symmetry axes 10 and 11 of the dielectric substrate 2, the symmetry axis 11 in the vertical direction passes through the center 6 of the patch conductor 3, but the symmetry axis 10 in the horizontal direction is the patch conductor 3. Is shifted from the center 6. However, since the deviation between the horizontal symmetry axis 10 and the center 6 of the patch conductor 3 is slight, the symmetry of the dielectric substrate 2 with respect to the center 6 of the patch conductor 3 is substantially maintained.

In FIG. 1, a power feeding circuit 9 including a 90 ° phase difference line 7 and a Wilkinson distributor 8 is disposed at the lower left of the dielectric substrate 2. That is, the feeder circuit 9 is arranged in a region surrounded by the two symmetry axes 10 and 11 and the end portions of the dielectric substrate 2.

As described above, the feeder circuit 9 is disposed in any one of the four regions divided by the two symmetry axes 10 and 11 of the dielectric substrate 2, By preventing the feeding circuit 9 from being arranged, it is possible to reduce the influence of the feeding circuit 9 on the radiation pattern of the antenna.

The characteristics of the circularly polarized microstrip antenna 1 of the present invention configured as shown in FIG. 1 will be described with reference to FIG. FIG. 2 is a graph showing an axial ratio that is one of the characteristics of circularly polarized waves. FIG. 2A is a graph showing the axial ratio characteristics of a one-point feeding type patch antenna as shown in FIG. 6A, and FIG. 2B is an axis of the circularly polarized microstrip antenna 1 of the present invention. It is a graph which shows a ratio characteristic.

The axial ratio of the circularly polarized antenna is preferably 6 dB or less, for example, in a predetermined frequency band, and more preferably has a wide bandwidth of 6 dB or less around the predetermined frequency. As shown in FIG. 2 (a), the axial ratio of the one-point feeding type patch antenna has a very narrow band of 6 dB or less. On the other hand, the axial ratio of the circularly polarized microstrip antenna 1 of the present invention is greatly expanded in the band of 6 dB or less as shown in FIG.

As shown in FIG. 1, a circularly polarized microstrip antenna 1 according to the present invention includes a feed circuit 9 including a 90 ° phase difference line 7 and a Wilkinson distributor 8 in the lower left region on the same plane as the patch conductor 3. Is arranged. On the other hand, in the antenna described in Patent Document 1, the 90 ° phase difference line 7 and the Wilkinson distributor 8 are disposed on the surface (back surface) opposite to the patch conductor 3 with respect to the dielectric substrate 2.

How the axial ratio of the antenna changes according to the arrangement positions of the 90 ° phase difference line 7 and the Wilkinson distributor 8 will be described with reference to FIG. FIG. 3 is a graph schematically showing changes in the axial ratio depending on the installation position of the feeder circuit 9 including the 90 ° phase difference line 7 and the Wilkinson distributor 8.

Similarly to Patent Document 1, when the 90 ° phase difference line 7 and the Wilkinson distributor 8 are arranged on the surface (back surface) opposite to the patch conductor 3 with respect to the dielectric substrate 2, the axial ratio is as shown in FIG. As shown in the graph 21 shown in FIG.

On the other hand, for example, similarly to the conventional antenna shown in FIG. 8, if the 90 ° phase difference line 7 and the Wilkinson distributor 8 are arranged on the same plane as the patch conductor 3, the axial ratio is shown in the graph 22 of FIG. Thus, the band centered at a frequency of about 5.8 GHz is significantly narrowed. This is because the antenna radiation surface has a shape in which the objectivity is greatly collapsed with respect to the center 6 of the patch conductor 3.

In FIG. 8, the branch line distributor is used as the power supply circuit. However, the graph 22 in FIG. 3 shows the axial ratio when the 90 ° phase difference line 7 and the Wilkinson distributor 8 are used instead of the branch line distributor. Is shown.

Further, even when the 90 ° phase difference line 7 and the Wilkinson distributor 8 are arranged on the same plane as the patch conductor 3, it is symmetric as in the circularly polarized microstrip antenna 1 of the present invention shown in FIG. When the 90 ° phase difference line 7 and the Wilkinson distributor 8 are arranged in a region surrounded by the axes 10 and 11 and the end of the dielectric substrate 2, the axial ratio is again as shown in the graph 21 to obtain a wide band. Is realized.

As described above, the circularly polarized microstrip antenna 1 of the present invention can be applied to the patch conductor even if the 90 ° phase difference line 7 and the Wilkinson distributor 8 constituting the feeder circuit 9 are arranged on the same plane as the patch conductor 3. As a result, it is possible to realize the same wide bandwidth as when the power feeding circuit 9 is arranged on the surface (back surface) opposite to the surface 3.

On the other hand, when the power feeding circuit 9 is provided on the surface (back surface) opposite to the patch conductor 3, the characteristics of the antenna element (patch conductor 3) including the power feeding circuit 9 cannot be evaluated. For this reason, in order to optimize the radiation characteristics of the antenna, it is difficult to finely adjust a part of the power feeding circuit 9, and it is necessary to re-manufacture including the transmitter / receiver every time the power feeding circuit 9 is finely adjusted. End up.

On the other hand, in the circularly polarized microstrip antenna 1 according to the present invention, the 90 ° phase difference line 7 and the Wilkinson distributor 8 constituting the feed circuit are arranged on the same plane as the patch conductor 3. 3 and the power feeding circuit 9 can be evaluated integrally. Therefore, it is possible to optimize the radiation characteristics of the antenna using only the patch conductor 3 and the feeding circuit 9.

In the circularly polarized microstrip antenna 1 of the present invention, even if the area of the ground conductor formed on the back surface of the dielectric substrate 2 is 9 times or less than the area of the patch conductor 3, it is a wideband antenna. The characteristics can be realized. In the microstrip patch antenna, generally, the ground conductor having an area sufficiently larger than the area of the patch conductor 3 is desirable. However, there has been a report of an example designed using a grounding conductor having one side that is about one wavelength or less of the operating frequency of the antenna due to a demand for miniaturization of the antenna.

In this way, when a grounding conductor having a finite area is used for the patch conductor, when a feeding circuit using a branch line distributor is formed on the antenna radiation surface, the symmetry of the antenna is obtained as shown in FIG. Is greatly impaired, and the axial ratio characteristics deteriorate. Furthermore, when it is difficult to form a branch line distributor in which the area of the ground conductor is 9 times or less that of the patch conductor, it is difficult to ensure a wide-band axial ratio characteristic. On the other hand, in the circularly polarized microstrip antenna 1 of the present invention, even when the area of the ground conductor is 9 times or less than the area of the patch conductor 3, it is possible to realize a wide band antenna characteristic.

Further, in the circularly polarized microstrip antenna 1 of the present invention, the thickness of the dielectric substrate 2 is preferably 0.4 mm or more. As the thickness of the dielectric substrate 2 increases, the characteristics of gain, VSWR, and axial ratio can be broadened. Conventionally, the thickness is 1.6 mm or more, for example.

On the other hand, in the circularly polarized microstrip antenna 1 of the present invention, the thickness of the dielectric substrate 2 can be set to 1.6 mm or less, for example. realizable.

Like the circularly polarized microstrip antenna 1 of the present invention, the feeder circuit 9 including the 90 ° phase difference line 7 and the Wilkinson distributor 8 is disposed on the same plane as the patch conductor 3 (on the antenna radiation plane). In some cases, the antenna radiation pattern may not be able to ensure symmetry with respect to the center 6 of the patch conductor 3. In this case, interference occurs between the resonance modes excited from the first feeding unit and the second feeding unit, and the axial ratio characteristic as a circularly polarized antenna is deteriorated.

Therefore, in the circularly polarized microstrip antenna 1 of the present invention, even when the symmetry of the antenna radiation pattern cannot be ensured, the line width of the 90 ° phase difference line 7 (characteristic impedance changes) and the line length (propagation phase delay are Change) and the distribution ratio of the Wilkinson distributor 8 can be adjusted to obtain a circularly polarized antenna having a good axial ratio characteristic over a wide band.

As described above, by making the 90 ° phase difference line 7 and the Wilkinson distributor 8 asymmetrical, the two high-frequency signals output from the power feeding circuit 9 are signals having the following characteristics. That is, when the amplitude of each of the two high-frequency signals and the phase difference between the two are A1, A2, and Δθ, respectively,
A1 ≠ A2, Δθ ≠ 90 °
Becomes a high-frequency signal. By adjusting the feeding circuit 9 to obtain two high-frequency signals satisfying the above formula, a preferable axial ratio characteristic can be obtained.

Furthermore, the circularly polarized microstrip antenna 1 of the present invention has an advantage that the antenna radiation characteristic and the feeding characteristic can be easily optimized by providing the feeding circuit 9 on the same plane as the patch conductor 3. .

An embodiment of the circularly polarized microstrip antenna device of the present invention will be described below with reference to FIG. FIG. 4 shows an antenna device in which an antenna unit and a part or all of a receiver or a transmitter / receiver are integrated into one housing. The circularly polarized microstrip antenna device of the present invention is configured using the circularly polarized microstrip antenna 1 of the present invention in the antenna section.

In the circularly polarized microstrip antenna device of the present invention shown in FIG. 4, another dielectric substrate 37 is laminated on the open surface of the ground conductor 36 formed on the back surface of the dielectric substrate 35. A circuit board 32 on which a part of or all of the high-frequency circuit unit and the transceiver is mounted is provided on the surface opposite to the ground conductor 36. Further, the high frequency circuit section and the input end of the Wilkinson distributor 8 are connected through a through hole.

Since the circularly polarized microstrip antenna 1 of the present invention has a small and wide band characteristic as described above, an integrated antenna device as shown in FIG. 4 can be obtained without impairing the wide band characteristic. Is possible.

FIG. 1 is a diagram for explaining the configuration of a circularly polarized microstrip antenna of the present invention. FIG. 2 is a diagram for explaining the axial ratio characteristics of the circularly polarized antenna. (A) is a figure explaining the circularly polarized-axis axial ratio of the conventional antenna by a 1 point feeding system, (b) is a circularly-polarized-axis ratio of the circularly polarized microstrip antenna of this invention, respectively. FIG. 3 is a graph schematically showing changes in the axial ratio depending on the installation position of the feeder circuit 9 including the 90 ° phase difference line 7 and the Wilkinson distributor 8. FIG. 4 is a diagram illustrating a configuration of an antenna device in which an antenna unit and a receiver or a transceiver are partially or entirely integrated. FIG. 5 is a diagram for explaining the configuration of a typical in-vehicle information terminal. FIG. 6 is a diagram for explaining an embodiment of a microstrip antenna. (A) is a figure explaining 1 point electric power feeding system, (b) is a 2 point electric power feeding system, respectively. FIG. 7 is a diagram illustrating the configuration of a power feeding circuit that generates a high-frequency signal. (A) is a diagram illustrating a T-type dispersion + 90 ° phase difference line, (b) is a branch line distributor, and (c) is a diagram illustrating a 90 ° phase difference line + Wilkinson type distributor. FIG. 8 is a diagram illustrating the configuration of an antenna in which a power feeding circuit is formed on the same plane as a radiating patch.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Circularly polarized microstrip antenna 2, 55, 62 ... Dielectric substrate 3 ... Patch conductor 4 ... 1st electric power feeding part 5 ... 2nd electric power feeding part 6 ... Patch conductor 3 The center of the substrate 7 ... 90 ° phase difference line 8 ... Wilkinson type distributor 9 ... feed circuit 10 ... horizontal symmetry axis 11 of the dielectric substrate 2 ... vertical direction of the dielectric substrate 2 Axis of symmetry 21, 22 ... Circular polarization axis ratio 31 ... Antenna 32 ... Circuit board 33 ... Housing 33
34 ... Shield case 35, 37 ... Dielectric substrate 36 ... Grounding conductor 41 ... GPS antenna part 42 ... VICS antenna part 43 ... ETC / DSRC antenna part 44 ... Information terminal Main body 45... VICS light projecting and receiving parts 46, 47 and 48... Coaxial cable 51... Single-strip type microstrip antenna 52 and 57... Radiating patch 53. 61 ... Feed point 56 ... Two-point feed type microstrip antenna 58, 59 ... Signal transmission line 71 ... Patch conductor 72 ... Radiation surface 73 ... Branch line distributor

Claims (8)

A dielectric substrate formed with a predetermined thickness of a dielectric material, a patch conductor disposed on one surface of the dielectric substrate, a ground conductor disposed on the other surface of the dielectric substrate, and the patch conductor A first feeding portion that is arranged in a first direction as viewed from the center of the patch and feeds the patch conductor; and a patch conductor that is arranged in a second direction perpendicular to the first direction as seen from the center of the patch conductor. A circularly polarized wave that is capable of exciting a circularly polarized wave by feeding the first and second feeding parts with substantially the same amplitude and a phase difference of about 90 °. A microstrip antenna,
Provided with a feeding circuit formed on the same plane as the patch conductor by connecting a 90 ° phase difference line to one output side of the Wilkinson distributor,
A circularly polarized microstrip antenna that supplies a high-frequency signal to the patch conductor by connecting the first feeding unit and the second feeding unit to two output ends of the feeding circuit. The feeding circuit is
A region surrounded by an axis of symmetry in the first direction as viewed from the center of the dielectric substrate, an axis of symmetry in the second direction as viewed from the center of the dielectric substrate, and an end of the dielectric substrate. The circularly polarized microstrip antenna according to claim 1, wherein the circularly polarized microstrip antenna is formed inside. The area of the ground conductor is
The circularly polarized microstrip antenna according to claim 1 or 2, wherein the area of the patch conductor is nine times or smaller. The circularly polarized microstrip antenna according to any one of claims 1 to 3, wherein the dielectric substrate has a thickness of 0.4 mm or more. The 90 ° phase difference line and the Wilkinson divider are:
When the amplitude component of each of the two high-frequency signals output from the power feeding circuit and the phase difference between the two are A1, A2, and Δθ, respectively,
A1 ≠ A2, Δθ ≠ 90 °
5. The circularly polarized microstrip antenna according to claim 1, wherein the circularly polarized microstrip antenna is configured as follows. The said 1st electric power feeding part is connected to the output end of the said Wilkinson type | mold divider | distributor, and the said 2nd electric power feeding part is connected to the output end of the said 90 degree phase difference track | line. Circular polarized microstrip antenna. The said 1st electric power feeding part is connected to the output end of the said 90 degree phase difference line, and the said 2nd electric power feeding part is connected to the output end of the said Wilkinson type | mold divider | distributor. Circularly polarized microstrip antenna. A circularly polarized microstrip antenna according to any one of claims 1 to 7,
Laminating another dielectric substrate on the open-side surface of the ground conductor,
A high frequency circuit unit including a transceiver is disposed on the open side surface of the another dielectric substrate,
A circularly polarized microstrip antenna device, wherein the high-frequency circuit unit and the input end of the Wilkinson distributor are connected through a through hole.

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