JP2000269731A - Microstrip antenna and transmitter/receiver using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily switch a polarization plane by disposing a pair of magnets for a polarized wave switch on straight lines at symmetrical positions on both sides of the symmetry axis of a patch electrode, so that an acute angle formed by a straight line going through the center of the patch electrode and the symmetry axis, which passes a power feeding point, is within a range of a specified value. SOLUTION: A microstrip antenna 10 is constituted of a magnetic material substrate 11, a patch electrode 12 provided on one surface of this magnetic material substrate 11, a grounding electrode 13 provided on a side opposing to the side where the patch electrode 12 is provided, and a magnet for magnetic permeability control consisting of a pair of electromagnets 14a and 14b provided in the vicinity of the magnetic material substrate 11, and only one power feeding point is provided on the patch electrode 12. These electromagnets 14a and 14b are disposed, so that an acute angle formed by straight lines which are on both sides of a symmetry axis of the patch electrode 12 and pass the center of the patch electrode 12 and a symmetry axis which pass the power feeding point is in the range of 37 degrees and 57 degrees.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a microstrip antenna that is used for an AN (Local Area Network) or the like and that can switch the polarization plane, and a transmitting / receiving apparatus using the same.

[0002]

2. Description of the Related Art In the case of a wireless system used indoors such as an indoor wireless LAN, its base station is often installed on a ceiling, a wall, or the like. It is desirable to eliminate as much as possible. As for the terminal device, for example, when a personal computer is considered, use of a PC card having a small and thin antenna built therein can be considered. For these reasons, a planar antenna is considered desirable.

A microstrip antenna is known as one of the planar antennas. Microstrip antennas are used as antennas to be mounted on moving objects such as aircraft and vehicles.
Attention has also been focused on antennas for terminal devices and the like of worldwide mobile phone systems using low-Earth orbit satellites.

FIG. 10A is a perspective view showing a conventional microstrip antenna. In a conventional microstrip antenna 90, a square patch electrode 92 is provided on one surface of a dielectric substrate 91 sufficiently thinner than the wavelength, and a ground electrode 93 is provided on one surface opposite to the surface on which the patch electrode 92 is provided.
A feeding point 94 is provided at a predetermined position on the patch electrode 92, and the antenna is operated by giving a potential difference between these two electrodes.

[0005]

Generally, radio waves radiated from an antenna include not only direct waves propagating directly, but also those reflected, refracted, and scattered by objects such as buildings. Very complicated. In particular, considering the environment of a wireless system used indoors such as an indoor wireless LAN, radio waves radiated from an antenna are multiple-reflected by a wall surface or an object existing in a room, and thus many multiple reflected waves are present. A more complex multi-wave propagation environment.

When a radio wave is reflected or scattered by an object such as a wall surface, its polarization plane changes, and a cross-polarization component is generated. Therefore, for example, even if the base station radiates vertically polarized waves, the radio waves arriving at the antenna on the terminal side are not necessarily left as vertically polarized waves, and the horizontal polarized wave components, which are cross polarized waves, have a higher level. Can be reached at If the plane of polarization of the arriving radio wave and the plane of polarization of the receiving antenna do not match, this contributes to a loss and lowers the receiving sensitivity. Therefore, it is desirable to make the polarization planes coincide as much as possible. Although it is ideal that the polarization plane of the antenna and the polarization plane of the arriving radio wave completely coincide with each other, an improvement effect can be expected only by switching the polarization plane.

However, in the above-described conventional microstrip antenna, since the position of the feed point for determining the polarization plane is fixed, switching of the polarization plane is performed as shown in FIG. It was necessary to rotate itself and re-install. The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a microstrip antenna capable of easily switching a polarization plane.

[0008]

The microstrip antenna of the present invention has a regular 4N square shape (where N is an integer of 1 or more) or a circular shape for radiating or receiving radio waves on one surface of a magnetic substrate. A patch electrode is provided, a ground electrode is provided on the other surface of the substrate, a feed point for exciting the patch electrode is provided on the axis of symmetry of the patch electrode, and the linear direction is provided on a straight line at a symmetric position on both sides of the symmetry axis. A pair of polarization switching magnets for applying a magnetic field to the symmetrical axis, the acute angle between the straight line passing through the center of the patch electrode on both sides of the axis of symmetry and the axis of symmetry passing the feed point is 37 degrees to 53 degrees. And a means for switching the pair of magnets.

In the microstrip antenna having the above-described structure, the magnetic substrate is used as the substrate because the magnetic permeability in one of the two intersecting linear directions is changed to change the magnetic permeability in that linear direction. This is because a resonance electric field having a desired frequency can be generated. The means for switching the pair of magnets is provided on the magnetic substrate at a position distant from the patch electrode. When a resonance electric field is generated, a magnetic current serving as a wave source is generated at an end of the patch electrode in a direction perpendicular to or nearly perpendicular to the direction of resonance. The plane of polarization is formed in a direction perpendicular or nearly perpendicular to the direction of the magnetic current. That is, the polarization plane is formed in a direction in which resonance occurs. Therefore, it is possible to switch the polarization plane by switching the direction in which the resonance electric field is generated.

In that sense, the acute angle between the above-mentioned straight line and the axis of symmetry through which the feed point passes is in the range of 37 degrees to 53 degrees. Preferably, this angle is 4 for the following reasons:
5 degrees. In other words, the condition where the polarization in the middle direction between the two polarization switching directions is radiated / received is the worst condition, but the radiation / reception level of the polarization in the middle direction can be maximized. This is because the angle between two intersecting straight lines is 90 degrees. According to the microstrip antenna of the present invention, by adopting the above configuration,
The polarization plane can be switched without changing the position of the feeding point and without rotating the antenna itself.

In another microstrip antenna according to the present invention, a regular 4N square shape for radio wave radiation or radio wave reception (N is an integer of 1 or more) is provided on one surface of a magnetic substrate.
Alternatively, a circular patch electrode is provided, a ground electrode is provided on the other surface of the substrate, and one excitation feed point for exciting the patch electrode is provided on at least two symmetry axes of the patch electrode, respectively. A pair of polarization switching magnets that apply a magnetic field in the direction of a straight line on the straight line located at the symmetrical position on each side of the patch electrode, and a straight line passing through the center of the patch electrode on both sides of the symmetry axis and the feeding point Are arranged so that the acute angle formed by the axis of symmetry with which the laser beam passes is in the range of 37 degrees to 53 degrees, and means are provided for each of the polarization switching magnet pairs.

In the microstrip antenna having the above-described structure, the magnetic substrate is used as the substrate because one of two linear directions intersecting and intersecting with each other with respect to one symmetry axis. By changing the magnetic permeability, a resonance electric field having a desired frequency can be generated in the linear direction. The means for switching the magnet pair is provided on the magnetic substrate at a position distant from the patch electrode. When a resonance electric field is generated, a magnetic current serving as a wave source is generated at an end of the patch electrode in a direction perpendicular to or nearly perpendicular to the direction of resonance. The plane of polarization is formed in a direction perpendicular or nearly perpendicular to the direction of the magnetic current.
That is, the polarization plane is formed in a direction in which resonance occurs. Therefore, it is possible to switch the polarization plane by switching the direction in which resonance occurs.

In this sense, the acute angle formed by the straight lines located on both sides with respect to the above-mentioned two symmetry axes and the respective symmetry axes through which the feeding point passes is in the range of 37 degrees to 53 degrees. Desirably, this angle is 4 because the radiation / reception level of the polarization in the middle of the two worst-case polarization switching directions can be maximized.
5 degrees.

This microstrip antenna can switch the polarization more finely than the above-mentioned microstrip antenna in which a pair of polarization switching magnets are provided on both sides of one symmetric axis, and the radiation / reception level can be improved. Can be higher.

In the above-described microstrip antenna according to the present invention, the magnitude of the magnetic permeability of the magnetic substrate is changed by applying a DC magnetic field by a magnet provided near the magnetic substrate, and the direction of the polarization plane is changed. Can be switched. The position where this magnet is provided may be on the diagonal line of the patch electrode, between the apexes of the patch electrode, or on a straight line passing between the apexes. This magnet only has to be on these target straight lines. However, it is sufficient that a magnetic field necessary for switching the plane of polarization in these linear directions is provided. In particular, it is preferable that the magnet is formed of an electromagnet because the magnitude of the magnetic permeability of the magnetic substrate can be electrically changed, and thus the direction of the polarization plane can be electrically switched.

The material constituting the magnetic substrate used in the present invention can be used for high frequencies when the microstrip antenna of the present invention is provided in a radio apparatus used in a frequency band of several hundred MHz or less. It is not particularly limited as long as it is provided in a wireless device used in a high frequency band of several hundred MHz or more, in which a decrease in magnetic permeability at a high frequency and an increase in loss are suppressed, and a high frequency characteristic is excellent. It is preferable to use a high frequency composite material.

The high frequency composite material used here is A
-MD (where A represents at least one element selected from the group consisting of Fe, Co, and Ni or a mixture thereof, and M represents Hf, Zr, W, Ti, V, Nb, Mo, C
r, Mg, Mn, Al, Si, Ca, Sr, Ba, C
u, Ga, As, Se, Zn, Cd, In, Sn, S
b, Te, Pb, Bi, at least one element selected from the group of rare earth elements or a mixture thereof, and D represents at least one element selected from the group of O, C, N, B or a mixture thereof. ) Based soft magnetic alloy powder;
It is made of a synthetic resin such as polytetrafluoroethylene and has soft magnetism and dielectric properties.

In the microstrip antenna device according to the present invention, a regular 4N square (N is an integer of 1 or more) or circular patch electrode for emitting or receiving radio waves is provided on one surface of the magnetic substrate. A ground electrode is provided on the other surface of the substrate, a feeding point for exciting the patch electrode is provided on the axis of symmetry of the patch electrode, and a magnetic field is applied on a straight line at a symmetric position on both sides of the axis of symmetry in the linear direction. A pair of polarization switching magnets are arranged such that an acute angle between a straight line passing through the center of the patch electrode on both sides of the axis of symmetry and the axis of symmetry passing the feeding point is in a range of 37 degrees to 53 degrees. And a means for switching the pair of magnets.

In this antenna device, the means for switching the pair of magnets is desirably provided together on a circuit board on which the microstrip antenna is mounted. However, this installation location is not limited to this. The positions where the magnets are provided are the same as those described for the microstrip antenna described above.

According to the microstrip antenna device of the present invention, with the above-described configuration, the polarization plane can be switched without changing the position of the feed point and without rotating the antenna itself.

In another microstrip antenna device according to the present invention, a regular 4N square shape for radiating or receiving radio waves (where N is an integer of 1 or more) is provided on one surface of a magnetic substrate.
Alternatively, a circular patch electrode is provided, a ground electrode is provided on the other surface of the substrate, and one excitation feed point for exciting the patch electrode is provided on at least two symmetry axes of the patch electrode, respectively. A pair of polarization switching magnets that apply a magnetic field in the direction of a straight line on the straight line located at the symmetrical position on each side of the patch electrode, and a straight line passing through the center of the patch electrode on both sides of the axis of symmetry and the feeding point. A microstrip antenna arranged so that an acute angle formed by the axis of symmetry through which passes is in a range of 37 degrees to 53 degrees, and means for switching for each of the polarization switching magnet pairs. Things.

In this antenna device, it is desirable that means for switching for each magnet pair be provided together on a circuit board on which the microstrip antenna is mounted. However, this installation location is not limited to this.
The positions where the magnets are provided are the same as those described for the microstrip antenna described above.

According to such another microstrip antenna device of the present invention, with the above-described configuration, the polarization plane can be switched without changing the position of the feeding point and rotating the antenna itself. . It is preferable that the magnet is formed of an electromagnet because the magnitude of the magnetic permeability of the magnetic substrate can be electrically changed, and thus the direction of the polarization plane can be electrically switched.

[0024] A radio transmitting apparatus and / or receiving apparatus according to the present invention includes the microstrip antenna or the microstrip antenna apparatus according to the present invention. According to the wireless device of the present invention, by providing the microstrip antenna of the present invention,
Since radio waves of a desired polarization can be emitted / received at a higher level, more stable transmission / reception can be performed.

[0025]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a perspective view showing a microstrip antenna according to a first embodiment of the present invention, and FIG. 2 is a plan view thereof. Microstrip antenna 10 according to the first embodiment shown in FIGS. 1 and 2
A magnetic substrate 11, a patch electrode 12 provided on one surface of the magnetic substrate 11, a ground electrode 13 provided on a surface opposite to the surface on which the patch electrode 12 is provided, 11, a pair of electromagnets 14a provided near
A single feed point F is provided on the patch electrode 12 and is roughly constituted by the magnet 14 for controlling the magnetic permeability consisting of 14b.

The patch electrode 12 is a square whose one side is an electric length of λe / 2, and penetrates the magnetic substrate 11 and the ground electrode 13 at one feeding point F on one diagonal line of the patch electrode 12. It is excited via an internal conductor of the connector 15 which is electrically insulated from the connector 15. Where λ
e represents an effective wavelength inside the microstrip antenna. The feed point F is provided on a diagonal line at which the impedance matching with the feed line is good, and at a position slightly shifted from the center. FIG. 1 shows a pair of electromagnets 14.
Although a switching circuit for turning on and off a and b is omitted, this switching circuit is shown in FIG. This switching circuit is desirably provided on the magnetic substrate 11 using the switch 16 and away from the patch electrode 12.

As a specific example of the microstrip antenna according to the first embodiment shown in FIGS. 1 and 2, the size of the microstrip antenna 10 is 50 mm × 50 m.
It is about mx 3 mm. The dimensions of each part are as follows: the size of the patch electrode 12 is 30 mm × 30 mm; the position of the feeding point F is 5.5 mm in the + X-axis direction from the central part E of the patch electrode;
Further, this is a point offset by 5.5 mm in the −Y axis direction. The magnetic substrate 11 is made of the above high-frequency composite material, and has a size of 50 mm × 50 mm × 3 mm, a relative permittivity of 2.6 and a relative magnetic permeability of 2.0. Patch electrode 12 formed on the surface of magnetic substrate 11
The thickness of the ground electrode 13 is 100 μm. The operating frequency (resonance frequency) at this time is about 2 G
Hz.

Power is supplied, for example, through a connector 15 having an outer conductor provided outside the inner conductor via a dielectric. The internal conductor (not shown) of the connector 15 is insulated so as not to contact the ground electrode 13, passes through the magnetic substrate 11 and the ground electrode 13, and passes through the patch electrode 12.
The tip is electrically connected to the patch electrode 12 at the feeding point F by soldering or the like. Each of the pair of magnets 14a and 14b is an electromagnet formed by winding a conductive wire made of a good conductive metal such as Cu around a magnetic core made of a high magnetic permeability magnetic material such as ferrite. 14a is installed on the lower surface of the ground electrode 13 by bonding or the like in a state where the longitudinal direction thereof coincides with the X-axis direction. Similarly, the pair of magnets 14b is provided on the lower surface of the ground electrode 13 so that the longitudinal direction thereof coincides with the Y-axis direction. The ON / OFF switching of the pair of magnets 14a and the pair of magnets 14b constituted by electromagnets is performed, as shown in FIG. 3, by setting one of the pair of magnets 14a and the pair of magnets 14b to an electrically conductive state. This is performed by a switch 16 that sets the other to a cutoff state.

Next, the operation of switching the polarization of the microstrip antenna according to the first embodiment will be described. 1 and 2, a magnet 14a composed of an electromagnet provided so as to generate a magnetic flux in the X-axis direction is
When the magnet 14b formed of an electromagnet provided to generate a magnetic flux in the Y-axis direction is turned ON, the magnetic permeability in the X-axis direction of the magnetic substrate 11 does not change, but the magnetic permeability in the Y-axis direction is FF. As a result, a resonance electric field in the Y-axis direction is generated at a desired frequency, and a magnetic current in the X-axis direction is generated. Conversely, when the magnet 14a is turned on and the magnet 14b is turned off, the magnetic permeability in the Y-axis direction of the magnetic substrate 11 does not change, but the magnetic permeability in the X-axis direction changes. Is generated, and a magnetic current in the Y-axis direction is generated. As described above, since the resonance electric field is generated in the direction in which the magnetic permeability is changed between the X-axis direction and the Y-axis direction, the direction of the magnetic current generated by each resonance can be switched. Since the polarization plane is formed in a direction perpendicular to the direction of the magnetic current, as a result, the polarization plane is formed in the X-axis direction and the Y-axis direction in which the magnetic permeability is changed. .

According to the microstrip antenna of the first embodiment, with the above configuration, the polarization plane can be switched without switching the feeding point of the antenna and without rotating the antenna itself. Can be. Further, by providing a magnet near the magnetic substrate and applying a DC magnetic field, the magnitude of the magnetic permeability of the magnetic substrate can be changed and the plane of polarization can be switched. In particular,
When the magnet is formed of an electromagnet, the magnitude of the magnetic permeability of the magnetic substrate can be electrically changed, and therefore, the direction of the polarization plane can be electrically switched.

Next, a microstrip antenna according to a second embodiment of the present invention will be described with reference to FIG. The microstrip antenna according to the second embodiment differs from the microstrip antenna 10 according to the first embodiment shown in FIGS. 1 and 2 in that the shape of the patch electrode 12 is circular, and other than the patch electrode. Are the same, the same members as those shown in FIGS. 1 and 2 are denoted by the same reference numerals, and description thereof is omitted. In the microstrip antenna 40, the patch electrode 42 has a circular shape, and one diameter of the patch electrode 42 is regarded as an axis of symmetry, and the feeding point F is provided on this diameter. According to the microstrip antenna 40 of the second embodiment, with the above-described configuration, the same operation and effects as those of the first embodiment can be achieved.

A first embodiment of another microstrip antenna according to the present invention will be described with reference to FIGS. In the microstrip antenna of this embodiment, the patch electrode 12 of the microstrip antenna 10 shown in FIGS. 1 and 2 has a regular octagonal shape, a pair of magnets is provided near each vertex of the patch electrode, and a feeding point is provided. Since two members are provided and the other members except for the patch electrode, the magnet and the feeding point are the same, the same members as those shown in FIGS. 1 and 2 are denoted by the same reference numerals, and the description thereof is omitted. .

In the microstrip antenna 50, the patch electrode 52 has a regular octagonal shape. In the microstrip antenna of this embodiment, two adjacent
Feed points F1 and F2 are provided on two diagonal lines, respectively, and a pair of magnets 54a, 54b, 54c and 54d formed by electromagnets are provided near the apexes of the patch electrodes. The switching between the feeding points F1 and F2 can be performed by providing a switching circuit including a switch 66 as shown in FIG. F1 is a feeding point, and each pair of magnets 54a, 54b is operated by a switching circuit similar to that shown in FIG.
By turning one of them ON and the other OFF, the polarization plane can be switched in the X-axis direction and the Y-axis direction in the same manner as in the first embodiment of the microstrip antenna of the present invention. Further, F2 is used as a feeding point, and a pair of magnets 54c, 5c, 5c is used as a switching circuit similar to that shown in FIG.
By setting one of 4d to ON and the other to OFF, Fd
The polarization plane can be switched in a direction inclined by 45 ° from the polarization direction when 1 is set as the feeding point. According to the microstrip antenna of this embodiment, with the above-described configuration, it is possible to achieve the same functions and effects as those of the microstrip antenna of the first embodiment of the present invention.

In each of the above-described embodiments, the configuration in which the magnet for changing the magnetic permeability is provided on the lower surface of the ground electrode has been described. However, the position where the magnet is provided is not limited to the lower surface of the ground electrode. It may be on the side of the magnetic substrate. Furthermore, the shape of the patch electrode is square, regular octagon,
The shape is not limited to a circle but may be any shape as long as it is a regular 4N square or a circle.

Next, an embodiment of the microstrip antenna device of the present invention will be described. In one embodiment of the microstrip antenna device of the present invention, as shown in FIG. 7, a microstrip antenna 32, a switch 33, a connector (not shown) and the like are mounted on a circuit board 31 and electrically connected to each other. It was done. The microstrip antenna 32 is obtained by removing the switch switching circuit including the switch 16 from the magnetic substrate 11 of the microstrip antenna 10 described above, and the other members except for the switch switching circuit are the same. The same members as those shown are denoted by the same reference numerals, and description thereof will be omitted. Switch 33
Is the ON / O of a pair of magnets 14a and a pair of magnets 14b composed of electromagnets, similarly to the switch 16 shown in FIG.
The switching of the FFs is performed, and one of the pair of magnets 14a and the pair of magnets 14b is electrically connected and the other is shut off. This switching circuit is
Since the switch 16 of the switching circuit shown in FIG. 3 is simply replaced with the switch 33, the illustration is omitted.

According to the microstrip antenna device of this embodiment, the above-described configuration can provide the same operation and effects as those of the above-described first embodiment of the microstrip antenna of the present invention.

Next, an embodiment of a wireless device having the microstrip antenna of the present invention will be described.
FIG. 8 is a perspective view showing an embodiment in which the microstrip antenna according to the first embodiment of the present invention is applied to a wireless LAN transceiver. The wireless transmission / reception device 7 is schematically configured such that a circuit board 73 on which a microstrip antenna 70, a circuit unit 71, and a feeder line 72 connecting the circuit strip 71 are mounted is housed in a housing 74. FIG. 9 shows a wireless transmission / reception device 7.
FIG. 2 is a block diagram showing a basic configuration of the embodiment. In the figure, 81 is a transmission / reception separation unit, 82 is a low noise amplifier, 83 is a first mixer, 8
4 is a first band-pass filter, 85 is a demodulator, 86 is a power amplifier, 87 is a second mixer, 88 is a modulator, and 89 is an oscillator.

First, a series of operations at the time of reception of the transmitting / receiving device 7 of the embodiment will be described. At the time of reception, a reception signal received by the microstrip antenna 70 of the present invention reaches the low noise amplifier 82 via the transmission / reception separation unit 81 and is amplified to a desired level. And the low noise amplifier 82
The received signal amplified by the first mixer 83 is supplied to the oscillator 8
9 is frequency-converted using the output signal of the ninth embodiment. The signal frequency-converted by the first mixer 83 reaches a demodulation unit 85 via a first band-pass filter 84, and data is extracted.

Next, a series of operations at the time of transmission of the transmitting / receiving device 7 of the embodiment will be briefly described. At the time of transmission, the modulation unit 88 modulates the carrier with the input data. The signal modulated by the modulation unit 88 is frequency-converted by the second mixer 87 using the output signal of the oscillator 89, amplified to a desired level by the power amplifier 86, and then transmitted and received by the transmission / reception separation unit 81. Radiated from the microstrip antenna 70 of the present invention.

In the transmitting / receiving device 7 of the embodiment, the microstrip antenna 70 of the present invention is provided, so that the polarization plane is switched by the microstrip antenna 70 to emit / receive a radio wave of a desired polarization at a higher level. Since it is possible, there is an advantage that more stable communication becomes possible. In the above-described embodiment, the wireless device has been described as being configured to transmit and receive the microstrip antenna 70 of the present invention, but may be configured to be connected to each of the transmitting device and the receiving device.

[0041]

As described above, according to the microstrip antenna of the present invention, with the above-described structure, the magnitude of the magnetic permeability of the magnetic substrate can be changed without rotating the antenna itself. Polarization switching can be performed.

[Brief description of the drawings]

FIG. 1 shows a first example of a microstrip antenna according to the present invention.
It is a perspective view which shows embodiment.

FIG. 2 is a plan view of the microstrip antenna shown in FIG.

FIG. 3 is a switching circuit diagram of an electromagnet of the microstrip antenna shown in FIG.

FIG. 4 shows a second example of the microstrip antenna of the present invention.
It is a top view which shows embodiment.

FIG. 5 is a plan view showing a first embodiment of another microstrip antenna according to the present invention.

6 is a circuit diagram for switching a feed point of the microstrip antenna shown in FIG. 5;

FIG. 7 is a perspective view showing one embodiment of the microstrip antenna device of the present invention.

FIG. 8 is a perspective view illustrating an embodiment of a wireless device including the microstrip antenna illustrated in FIG.

FIG. 9 is a block diagram illustrating a configuration of the wireless device illustrated in FIG. 8;

10A and 10B are views showing a conventional microstrip antenna, FIG. 10A is a perspective view thereof, and FIG. 10B is a view in which the polarization plane of the microstrip antenna shown in FIG. FIG. 3 is a plan view showing a configuration.

[Explanation of symbols]

7 Radio transceiver 10, 32, 40, 50, 70 Microstrip antenna 11 Magnetic substrate 12, 42, 52 Patch electrode 13 Ground electrode 14, 14a, 14b, 54a, 54b, 54c, 54
d magnet 15 connector 16, 33, 66 switch 71 circuit unit 72 power supply line 31, 73 circuit board 74 housing 81 transmission / reception separation unit 82 low noise amplifier 83 first mixer 84 first band pass filter 85 demodulation unit 86 power Amplifier 87 Second mixer 88 Modulator 89 Oscillator F, F1, F2 Power supply extension

 ──────────────────────────────────────────────────続 き Continued on front page F term (reference) 5J021 AA01 AB06 CA03 DB04 FA20 FA26 FA31 FA32 HA05 HA10 JA05 5J045 AA11 AA12 AB01 AB05 AB06 CA02 CA03 DA10 EA07 HA03 LA01 MA07 NA01 5J046 AA04 AA19 AB10 AB13 PA07 5J047 AA13 AB FB11 FC06 FD01

Claims (8)

[Claims] 1. A regular 4N square (N is an integer of 1 or more) or circular patch electrode for radio wave radiation or radio wave reception provided on one surface of a magnetic substrate, and grounded on the other surface of the substrate. A pair of polarization switching magnets for providing an electrode, providing a feeding point for exciting the patch electrode on the symmetry axis of the patch electrode, and applying a magnetic field in a linear direction on a straight line at a symmetric position on both sides of the symmetry axis. Are arranged so that an acute angle between a straight line passing through the center of the patch electrode on both sides of the axis of symmetry and the axis of symmetry passing the feeding point is in a range of 37 degrees to 53 degrees. A microstrip antenna comprising means for switching the magnets. 2. A regular 4N square (where N is an integer of 1 or more) or circular patch electrode for radio wave radiation or radio wave reception is provided on one surface of a magnetic substrate, and grounded on the other surface of the substrate. An electrode is provided, and one excitation feeding point for exciting the patch electrode is provided on at least two symmetry axes of the patch electrode, and a magnetic field is applied in a straight line at a symmetric position on both sides of each of the symmetry axes in the linear direction. A pair of polarization switching magnets is provided, and an acute angle between a straight line passing through the center of the patch electrode on each side of the symmetry axis and the symmetry axis passing the feed point is 37 degrees to 53 degrees. A microstrip antenna, wherein the microstrip antenna is provided so as to fall within the range of (1) and (2) is provided with means for switching each of the polarization switching magnet pairs. 3. The microstrip antenna according to claim 1, wherein the magnet is an electromagnet. 4. A radio transmitting apparatus and / or receiving apparatus comprising the microstrip antenna according to claim 1. 5. A regular 4N square (N is an integer of 1 or more) or circular patch electrode for radio wave radiation or radio wave reception is provided on one surface of the magnetic substrate, and grounded on the other surface of the substrate. A pair of polarization switching magnets for providing an electrode, providing a feeding point for exciting the patch electrode on a symmetry axis of the patch electrode, and applying a magnetic field in a linear direction on a straight line at a symmetric position on both sides of the symmetry axis. Are arranged so that an acute angle between a straight line passing through the center of the patch electrode on both sides of the axis of symmetry and the axis of symmetry passing the feeding point is in the range of 37 to 53 degrees. A microstrip antenna device comprising: an antenna; and means for switching the pair of magnets. 6. A regular 4N square (N is an integer of 1 or more) or circular patch electrode for radio wave emission or radio wave reception is provided on one surface of a magnetic substrate, and grounded on the other surface of the substrate. An electrode is provided, and one excitation feeding point for exciting the patch electrode is provided on at least two symmetry axes of the patch electrode, and a magnetic field is applied in a straight line at a symmetric position on both sides of each of the symmetry axes in the linear direction. A pair of polarization switching magnets is provided, and an acute angle between a straight line passing through the center of the patch electrode on each side of the symmetry axis and the symmetry axis passing the feed point is 37 degrees to 53 degrees. A microstrip antenna device comprising: a microstrip antenna arranged so as to fall within the range; and means for switching for each of the polarization switching magnet pairs. 7. The microstrip antenna device according to claim 5, wherein the magnet is an electromagnet. 8. A wireless transmission device and / or reception device comprising the microstrip antenna device according to claim 5.