JP3983604B2 - Antenna device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an antenna device using a planar antenna for microwave transmission / reception mainly used for communication, radar and the like.
[0002]
[Prior art]
FIG. 6 is a perspective view of an antenna apparatus using a conventional two-point feed type microstrip antenna disclosed in, for example, Japanese Patent Laid-Open Nos. 2000-312112 and 06-232626.
[0003]
In FIG. 6, the antenna device has a first feeding terminal 4 for radiating horizontal polarization, which is linearly polarized, on a dielectric substrate 3 having a ground conductor 2 formed on the back surface, and is orthogonal to the horizontal polarization. A feed patch (conductor patch) 1 made of a plate-like conductor having a second feed terminal 5 for radiating vertically polarized waves is formed.
[0004]
The first power supply terminal 4 exists on the X axis of the XY plane with the center of the dielectric substrate 3 as the origin, and the second power supply terminal 5 exists on the Y axis.
[0005]
The power distribution / combination circuit 20 connected to the first power supply terminal 4 and the second power supply terminal 5 has the amplitude of each radio signal (power supply signal) supplied to the first power supply terminal 4 and the second power supply terminal 5. Control is made to change at least one of the phases, and the radiation areas of radio waves having a linear polarization in the excitation direction parallel to the X axis and radio waves having a linear polarization in the excitation direction parallel to the Y axis are different. It is
[0006]
[Problems to be solved by the invention]
As described above, the conventional antenna device has a problem that when one of the feed terminals is excited, mutual coupling occurs between the feed terminals, and unnecessary cross-polarized waves are generated from the other feed terminal.
[0007]
In addition, the dielectric substrate 3 may be formed by injection or the like, but in this case, the dielectric constant has directionality, so that degenerative separation occurs and unnecessary cross polarization occurs.
[0008]
The present invention has been made to solve the above-described problems, and cancels the cross-polarized wave component generated by the mutual coupling between the feeding terminals and the cross-polarized wave component generated by the anisotropy of the dielectric constant, An object of the present invention is to obtain an antenna device capable of suppressing the generation of cross polarization.
[0009]
[Means for Solving the Problems]
An antenna device according to the present invention includes a ground conductor composed of a plate-shaped conductor and an anisotropic dielectric substrate formed on the top surface of the ground conductor and having a different dielectric constant depending on a difference in axial direction on a surface in contact with the top surface of the ground conductor. And first and second power supply terminals for radiating the first linearly polarized wave and the second linearly polarized wave orthogonal to the first linearly polarized wave formed on the upper surface of the dielectric substrate. , A power supply patch made of a plate-like conductor, and a power supply means for supplying a first power supply signal to the first power supply terminal and supplying a second power supply signal to the second power supply terminal. The two power supply terminals are disposed at positions symmetrical to each other with respect to an axis passing through the center on the plane of the power supply patch and having a minimum dielectric constant.
[0010]
The antenna device according to the present invention includes a ground conductor made of a plate-like conductor, a first dielectric substrate formed on the top surface of the ground conductor, and a top surface of the first dielectric substrate. A power supply patch having first and second power supply terminals for radiating a linearly polarized wave and a second linearly polarized wave orthogonal to the first linearly polarized wave, and a plate-shaped conductor; A second dielectric substrate formed on the upper surface of the substrate, a non-feeding patch made of a plate-like conductor formed on the upper surface of the second dielectric substrate, and a first feeding signal fed to the first feeding terminal And at least one of the first and second dielectric substrates has a different dielectric constant depending on a difference in the direction of the axis on the plane. The first and second feeding terminals pass through the center on the plane of the feeding patch. With respect to the direction of the axis conductivity is minimized, in which are disposed at mutually symmetrical positions.
[0011]
Further, the power feeding means of the antenna device according to the present invention outputs the first and second power feeding signals for setting the phase difference between the first linearly polarized wave and the second linearly polarized wave to 90 degrees.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1 FIG.
Hereinafter, the first embodiment of the present invention will be described in detail with reference to the drawings.
[0013]
FIG. 1 is a perspective view showing an antenna apparatus using a planar antenna according to Embodiment 1 of the present invention. In FIG. 1, the same components as those described above (see FIG. 6) are denoted by the same reference numerals, and detailed description thereof is omitted.
[0014]
FIG. 1 is a diagram showing an antenna apparatus according to Embodiment 1 of the present invention. In FIG. 1, the antenna device has a feeding patch 1 formed on the top surface of a dielectric substrate 3, and a ground conductor 2 made of a plate-like conductor is formed on the back surface of the dielectric substrate 3. The ground conductor 2 is laminated via a dielectric substrate 3.
[0015]
For example, the power supply patch 1 is formed so that the center of the power supply patch 1 is located at the origin of the XY plane on the XY plane having the origin at the center of the dielectric substrate 3.
[0016]
The dielectric substrate 3 is an anisotropic dielectric substrate having a dielectric anisotropy depending on the direction of each axis on the substrate surface. This anisotropic dielectric substrate 3 has a different dielectric constant depending on, for example, the X-axis direction and the Y-axis direction of the XY plane of the dielectric substrate 3, and the dielectric constant in the X-axis direction is higher than the dielectric constant in the Y-axis direction. The value is low.
[0017]
Further, the power supply patch 1 is formed with a first power supply terminal 4 and a second power supply terminal 5 for supplying power, and the first power supply terminal 4 and the second power supply terminal 5 are connected to the power supply patch 1. They are arranged symmetrically with respect to an axis 6 that passes through the center and is parallel to an axis (for example, the X axis) having a minimum dielectric constant among the axes in the XY plane.
[0018]
The first power supply terminal 4 and the second power supply terminal 5 are connected to a power distribution / combination circuit (power supply means) 20, respectively. A horizontally polarized wave that is a wave and a vertically polarized wave that is a linearly polarized wave orthogonal to the horizontally polarized wave are radiated.
[0019]
Here, the first power supply terminal 4 and the second power supply terminal 5 show a structure in which the conductor wire is connected to the power supply patch 1, but in addition to the direct power supply by the connection of the coaxial line and the strip line, the strip line Power may be supplied by electromagnetic coupling using a slot, a cross slot, or the like.
[0020]
In addition, the power supply patch 1 is circular here, but a shape capable of emitting orthogonal two linearly polarized waves such as a square, a rhombus, and an ellipse may be used.
[0021]
A mixture of liquid crystal polymer, glass fiber, synthetic resin, or the like may be used as the dielectric having dielectric anisotropy.
[0022]
Next, the operation according to the first embodiment of the present invention will be described. FIG. 2 is an explanatory diagram showing an operation according to the first embodiment of the present invention. The same parts as those described above (see FIG. 1) are denoted by the same reference numerals and will not be described in detail.
[0023]
In FIG. 1, when the power distribution / combination circuit 20 supplies power to the first power supply terminal 4, a current (main polarization current) 7 flows as shown in FIG. 2A, and a corresponding linearly polarized wave is generated.
[0024]
When power is supplied to the first power supply terminal 4, a current (cross-polarized current due to mutual coupling) 8 flows due to mutual coupling between the power supply terminals due to the presence of the second power supply terminal 5. Polarization occurs.
[0025]
Next, the influence of the dielectric having anisotropy will be described. In FIG. 2, when the dielectric constants are different between the X-axis direction and the Y-axis direction, degenerate separation occurs because the resonance frequencies in the X-axis direction and the Y-axis direction are different on the power supply patch 1. As a result, a current component (cross-polarized current due to dielectric anisotropy) 9 that is orthogonal to the current direction excited from the first power supply terminal 4 is generated.
[0026]
Here, when the first feeding terminal 4 and the second feeding terminal 5 are arranged symmetrically with respect to the axis 6 as shown in FIG. The cross polarization current 9 due to the anisotropy of the dielectric material cancels out, and as a result, the generation of cross polarization can be suppressed.
[0027]
On the other hand, even when power is supplied to the second power supply terminal 5, similarly, the cross-polarized current generated by mutual coupling between the power supply terminals due to the presence of the first power supply terminal 4 and the anisotropy of the dielectric And the cross-polarized current generated by each other cancel each other, and the generation of the cross-polarized light can be suppressed (see FIG. 2C).
[0028]
Further, since the first power supply terminal 4 and the second power supply terminal 5 are arranged at positions symmetrical to each other with respect to the axis having the minimum dielectric constant (for example, the axis 6), the generation of AC polarization is prevented. Further suppression can be achieved.
[0029]
FIG. 3 is a characteristic diagram showing antenna characteristics according to the configuration of the first embodiment of the present invention and the prior art.
[0030]
In FIG. 3, the cross-polarization current (see FIG. 3B) suppressed by the cancellation of the cross-polarization current due to mutual coupling and the cross-polarization current due to the dielectric anisotropy is generated by the conventional configuration. Compared with the cross polarization (refer to FIG. 3A), it is greatly suppressed.
[0031]
In this way, the anisotropic dielectric substrate 3 having a different dielectric constant depending on the direction of each axis is formed between the power supply patch 1 and the ground conductor 2, and the first power supply terminal 4 and the second power supply terminal 5. Are arranged at positions symmetrical to each other with respect to the axis of the minimum dielectric constant, and without providing a special mechanism, cross polarization of linearly polarized waves radiated by feeding to the first feeding terminal 4; Both the linearly polarized wave and the cross polarized wave radiated by feeding to the second feeding terminal 5 can be suppressed.
[0032]
Embodiment 2. FIG.
In the first embodiment, the dielectric substrate formed between the feeding patch and the ground conductor is an anisotropic dielectric, but the dielectric substrate is also formed between the feeding patch and the non-feeding patch. At least one of the dielectric substrates may be an anisotropic dielectric substrate.
[0033]
FIG. 4 is a perspective view showing an antenna apparatus using a planar antenna according to Embodiment 2 of the present invention. 4, the same components as those described above (FIGS. 1 and 6) are denoted by the same reference numerals, and detailed description thereof is omitted.
[0034]
In FIG. 4, in the antenna device, a parasitic patch 10 is formed on the upper surface of the feeding patch 1 via a dielectric substrate 11.
[0035]
Although the non-feeding patch 10 is circular, a shape capable of radiating orthogonal two linearly polarized waves, such as a square, a rhombus, and an ellipse, may be used similarly to the feeding patch 1.
[0036]
The dielectric substrate 3 is an anisotropic dielectric substrate having a dielectric constant anisotropy depending on the direction of each axis on the substrate surface. This anisotropic dielectric substrate 3 has a different dielectric constant depending on, for example, the X-axis direction and the Y-axis direction of the XY plane of the dielectric substrate 3, and the dielectric constant in the X-axis direction is higher than the dielectric constant in the Y-axis direction. The value is low.
[0037]
Further, the first power supply terminal 4 and the second power supply terminal 5 pass through the center of the power supply patch 1 and are parallel to an axis (for example, the X axis) having a minimum dielectric constant among the axes in the XY plane. They are arranged at symmetrical positions with respect to the axis 6.
[0038]
The first power supply terminal 4 and the second power supply terminal 5 are each connected to a power distribution / combination circuit 20.
[0039]
Even in the antenna device configured as described above, by feeding power to the first and second feeding terminals, the cross-polarized current due to mutual coupling between the feed terminals and the cross-polarized current due to dielectric anisotropy Since these cancel each other, cross polarization can be suppressed without providing a special mechanism.
[0040]
Although the dielectric substrate (first dielectric substrate) 3 formed between the power supply patch 1 and the ground conductor 2 is an anisotropic dielectric substrate, the power supply patch 1 is used instead of the dielectric substrate 3. The dielectric substrate (second dielectric substrate) 11 formed between the power supply patch 10 and the parasitic patch 10 may be an anisotropic dielectric substrate having dielectric anisotropy. Further, both dielectric substrates may be anisotropic dielectric substrates having dielectric anisotropy.
[0041]
Embodiment 3 FIG.
FIG. 5 is a perspective view showing an antenna apparatus using a planar antenna according to Embodiment 3 of the present invention. In FIG. 5, the same components as those described above (FIGS. 1, 4, and 6) are denoted by the same reference numerals, and detailed description thereof is omitted.
[0042]
In FIG. 5, the antenna apparatus includes a circularly polarized wave generating circuit (feeding means) 21 that outputs a feeding signal with equal amplitude and a phase difference between two linearly polarized waves of 90 degrees. The terminal 4 and the second power supply terminal 5 are connected to each other.
[0043]
The circularly polarized wave generating circuit 21 controls the first and second power supply signals so that the phase difference is 90 degrees with equal amplitude, and supplies power to the first power supply terminal 4 and the second power supply terminal 5, respectively.
[0044]
By this feeding, the linearly polarized waves generated by feeding to the respective feeding terminals are combined, and the antenna device radiates a circularly polarized wave or an elliptically polarized wave with a low axial ratio.
[0045]
In this way, by feeding a feed signal for generating a radio wave having an equal amplitude and a phase difference of 90 degrees to the first feed terminal 4 and the second feed terminal 5, the antenna device is arranged in a circular manner with a low axial ratio. It can be a wave radiation antenna.
[0046]
【The invention's effect】
As described above, according to the present invention, the anisotropy varies in dielectric constant depending on the difference in the axial direction between the ground conductor made of a plate-like conductor and the surface of the ground conductor that is in contact with the top surface of the ground conductor. A first and second power supply terminals for radiating a first linearly polarized wave and a second linearly polarized wave orthogonal to the first linearly polarized wave formed on the upper surface of the dielectric substrate and the dielectric substrate A feeding patch comprising a plate-like conductor, and a feeding means for feeding the first feeding signal to the first feeding terminal and feeding the second feeding signal to the second feeding terminal, The first and second feeding terminals are arranged at positions symmetrical to each other with respect to the axis in the direction in which the dielectric constant is minimum through the center on the plane of the feeding patch. There is an effect that an antenna device capable of suppressing waves can be obtained.
[0047]
According to the present invention, the ground conductor made of a plate-shaped conductor, the first dielectric substrate formed on the top surface of the ground conductor, and the first straight line formed on the top surface of the first dielectric substrate. A power supply patch having first and second power supply terminals for radiating polarized waves and a second linearly polarized wave orthogonal to the first linearly polarized wave, and made of a plate-like conductor, and an upper surface of the power supply patch A second dielectric substrate formed on the second dielectric substrate, a parasitic patch made of a plate-like conductor formed on the upper surface of the second dielectric substrate, and a first feeding signal to the first feeding terminal, Power supply means for supplying a second power supply signal to the second power supply terminal, and at least one of the first and second dielectric substrates has an anisotropy having a different dielectric constant depending on a difference in an axial direction on a plane. It is a dielectric substrate, and the first and second feeding terminals pass through the center on the plane of the feeding patch and have a minimum dielectric constant. Relative becomes the direction of the axis, so arranged in mutually symmetrical positions, the effect of obtaining an antenna device capable of suppressing the cross-polarization without providing a special mechanism.
[0048]
Furthermore, according to the present invention, the power feeding means outputs the first and second power feeding signals that make the phase difference between the first linearly polarized wave and the second linearly polarized wave 90 degrees. There is an effect that an antenna device using a circularly polarized radiation antenna can be obtained.
[Brief description of the drawings]
FIG. 1 is a perspective view showing Embodiment 1 of the present invention.
FIG. 2 is an explanatory diagram showing an operation according to the first embodiment of the present invention.
FIG. 3 is a characteristic diagram showing antenna characteristics according to the first embodiment of the present invention.
FIG. 4 is a perspective view showing Embodiment 2 of the present invention.
FIG. 5 is a perspective view showing Embodiment 3 of the present invention.
FIG. 6 is a perspective view showing a conventional antenna device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Feeding patch (conductor patch), 2 Ground conductor, 3 Derivative board, 4 1st feeding terminal, 5 2nd feeding terminal, 6 Axis parallel to X axis, 7 main polarization current, 8 Cross-polarization current generated by mutual coupling, 9 Cross-polarization current generated by dielectric anisotropy, 10 Parasitic patch, 11 Dielectric substrate, 20 Power distribution / combination circuit, 21 Circular polarization generation circuit.

Claims (3)

A ground conductor made of a plate-like conductor;
An anisotropic dielectric substrate formed on the top surface of the ground conductor and having a different dielectric constant due to a difference in axial direction on a surface in contact with the top surface of the ground conductor;
First and second power supply terminals are formed on the top surface of the dielectric substrate and radiate a first linearly polarized wave and a second linearly polarized wave orthogonal to the first linearly polarized wave. A feeding patch made of a plate-shaped conductor;
Power supply means for supplying a first power supply signal to the first power supply terminal and supplying a second power supply signal to the second power supply terminal;
The first and second power supply terminals are
An antenna device, wherein the antenna device is disposed symmetrically with respect to an axis passing through a center on a plane of the feeding patch and having a minimum dielectric constant. A ground conductor made of a plate-like conductor;
A first dielectric substrate formed on the top surface of the ground conductor;
First and second power supply terminals formed on the upper surface of the first dielectric substrate for radiating a first linearly polarized wave and a second linearly polarized wave orthogonal to the first linearly polarized wave A power supply patch made of a plate-shaped conductor,
A second dielectric substrate formed on the upper surface of the power supply patch;
A parasitic patch made of a plate-like conductor formed on the upper surface of the second dielectric substrate;
Power supply means for supplying a first power supply signal to the first power supply terminal and supplying a second power supply signal to the second power supply terminal;
At least one of the first and second dielectric substrates is an anisotropic dielectric substrate having a different dielectric constant due to a difference in axial direction on a plane,
The first and second power supply terminals are
An antenna device, wherein the antenna device is disposed symmetrically with respect to an axis passing through a center on a plane of the feeding patch and having a minimum dielectric constant. The power supply means is
3. The first and second power feeding signals that output a phase difference of 90 degrees between the first linearly polarized wave and the second linearly polarized wave are output. Antenna device.

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