Antenna device

Abstract

To improve cross-polarization characteristics at a specific one frequency in a vertical-horizontal polarization shared patch antenna in which a power feeding point and a power feeding terminal of a reflector plate are connected using a power feeding member.SOLUTION: One embodiment of the present invention relates to a vertical-horizontal polarization shared antenna device in which a first power feeding point for horizontal polarization and a second power feeding point for vertical polarization provided on a patch and a strip line are connected to a first power feeding terminal for horizontal polarization and a second power feeding terminal for vertical polarization provided on a reflector plate via a power feeding member, a first short circuit point is provided so as to have a prescribed positional relation with the first power feeding point on the patch, a second short circuit point is provided so as to have a prescribed positional relation with the second power feeding point on the patch, and the first short circuit point is connected to a grounding surface of the reflector plate and the second short circuit point is connected to the grounding surface of the reflector plate by a first short circuit member and a second short circuit member.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] One aspect of the present invention relates to an antenna device using a patch as an antenna element. [Background technology]

[0002] A patch antenna, which uses a metal piece called a patch as an antenna element, is known as one type of antenna device. Patch antennas have a simple antenna structure and can be easily made thin, so they are widely used in many devices, including small wireless devices such as wireless tags.

[0003] Incidentally, there is a patch antenna that is a dual-purpose vertically and horizontally polarized patch antenna that can transmit or receive two orthogonal polarized waves by feeding power from two directions to the patch. This type of patch antenna has the advantage that it can maintain a communicable state even if the polarization direction changes depending on the state of the other party's antenna, for example, by arbitrarily switching the polarization direction (see Patent Document 1, for example). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2005-39756 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the patch antenna described in Patent Document 1 has a structure in which a patch is arranged with a certain gap (when the gap between the patch and the reflector is 0.03λ or more) or a dielectric between the patch and the reflector on which a ground pattern is formed, and a feed pin connects the feed point of the patch and the feed terminal provided on the reflector. Therefore, there is a problem that the electric field distribution of the polarized wave between the patch and the reflector by one feed system is disturbed by the feed pin of the other feed system, which causes deterioration of the cross polarization characteristics.

[0006] This invention has been made in light of the above-mentioned circumstances, and aims to provide a technology that can improve the cross-polarization characteristics of a specific frequency between polarized waves in a vertically and horizontally polarized patch antenna in which the feed point and the feed terminal of the reflector are connected using a feed member. [Means for solving the problem]

[0007] In order to solve the above problems, one aspect of the antenna device of the present invention is an antenna device for both horizontal and vertical polarization, in which a first feeding point for horizontal polarization and a second feeding point for vertical polarization provided on a patch and a strip line are connected to a first feeding terminal for horizontal polarization and a second feeding terminal for vertical polarization provided on a reflector via respective feeding members, in which a first short-circuit point is arranged on the patch with a predetermined positional relationship with the first feeding point, and a second short-circuit point is arranged on the patch with a predetermined positional relationship with the second feeding point, and the first short-circuit point and the ground surface of the reflector are connected by a first short-circuit member and a second short-circuit member, respectively.

[0008] According to one aspect of the present invention, when transmitting and receiving vertically polarized waves and horizontally polarized waves, the disturbance in the electric field distribution generated between the patch and the reflector by the other power supply member is symmetrical, thereby improving the cross-polarization discrimination degree at a specific frequency between vertically polarized waves and horizontally polarized waves, thereby making it possible to improve the quality of the radio signals of each polarization. Effect of the Invention

[0009] In other words, according to one aspect of the present invention, a technology can be provided that can improve the cross-polarization characteristics of a specific frequency between polarizations in a vertically and horizontally polarized patch antenna in which a power feed point and a power feed terminal of a reflector are connected using a power feed member. [Brief description of the drawings]

[0010] [Figure 1]FIG. 1 is a plan view showing an example of the structure of an antenna portion of an antenna device according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view of the antenna device shown in FIG. 1 taken along the line AA. [Diagram 3] FIG. 3 is a diagram for explaining the positional relationship of a short-circuit pin with respect to a feed pin in the antenna device shown in FIG. [Figure 4] FIG. 4 is a diagram showing an example of horizontal plane directivity characteristics of vertically polarized waves by the antenna device shown in FIG. [Diagram 5] FIG. 5 is a plan view showing the structure of a conventional antenna device of the same type that does not have a shorting pin. [Figure 6] FIG. 6 is a diagram showing the horizontal plane directivity characteristics of vertically polarized waves from the antenna device shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0012] [One embodiment] (Configuration example) 1 and 2 show an example of the structure of an antenna portion of an antenna device according to an embodiment of the present invention, with FIG. 1 being a plan view and FIG. 2 being a cross-sectional view taken along the line AA in FIG.

[0013] The antenna device in one embodiment has a patch 1 and a reflector 2 arranged on the back side of the patch 1 facing each other with a predetermined gap therebetween. However, the distance between the patch 1 and the reflector 2 is set to 0.03λ or more. The patch 1 is made of, for example, a square metal piece. The reflector 2 is made of a substrate with a ground pattern formed on the entire surface. The shape of the patch may be a polygonal shape such as a hexagon, or a circular shape.

[0014] Patch 1 is provided with feed point 31a for horizontal polarization and strip line 3 at a point on the Y axis, and with feed point 31b for vertical polarization and strip line 4 at a point on the Z axis. Meanwhile, feed terminal 32a for horizontal polarization and feed terminal 32b for vertical polarization are disposed at positions on reflector 2 facing feed points 31a and 31b, respectively.

[0015] The horizontally polarized power feed point 31a and the power feed terminal 32a are connected by a horizontally polarized power feed pin 33a, and the vertically polarized power feed point 31b and the power feed terminal 32b are connected by a vertically polarized power feed pin. The power feed terminals 32a and 32b are connected to a power feed circuit (not shown).

[0016] Meanwhile, the antenna device in one embodiment includes the feed point 31a for the horizontally polarized wave of the patch 1, and short points 41a1 and 41a2. The antenna device also includes the feed point 31b for the vertically polarized wave of the patch 1, and short points 41b1 and 41b2. The short points 41a1, 41a2 and 41b1, 41b2 are connected to the ground pattern of the reflector 2 via short pins 43a1, 43a2 and 43b1, 43b2, respectively.

[0017] 3 shows a specific example of the positional relationship between each of the feed points 31a and 31b and the short points 41a1, 41b2 and 41b1, 41b2. As shown in the figure, the distance y2 between the short points 41a1, 41b2 and the coordinate center of the patch 1, and the distance y1 between the feed point 31a and the coordinate center of the patch 1 are set to individual lengths, and the distance z2 between the short points 41b1, 41b2 and the coordinate center of the patch 1, and the distance z1 between the feed point 31b and the coordinate center of the patch 1 are set to individual lengths.

[0018] (Example of operation) With this configuration, when power is supplied to the horizontally polarized power supply terminal 32a and the vertically polarized power supply terminal 32b, the current is supplied to the power supply points 31a and 31b of the patch 1 via the power supply pin 33a, respectively, thereby generating horizontally polarized and vertically polarized electromagnetic waves from the patch 1.

[0019] At this time, for the horizontally polarized wave and the vertically polarized wave, the disturbance in the electric field distribution generated between the patch 1 and the reflector 2 due to the vertically polarized wave feed pin and the horizontally polarized wave feed pin 33a, which are on the other side, becomes symmetrical due to the vertically polarized wave feed pin and the short-circuit pins 43b1, 43b2, and due to the horizontally polarized wave feed pin 33a and the short-circuit pins 43a1, 43a2, respectively.

[0020] As a result, the cross-polarization discrimination at a specific frequency between vertical and horizontal polarization is improved, making it possible to transmit vertically polarized radio signals with reduced influence from horizontal polarization, and similarly, to transmit horizontally polarized radio signals with reduced influence from vertical polarization.

[0021] 4 shows an example of the horizontal plane directivity characteristic of the vertically polarized wave among the above-mentioned polarized waves. As is clear from this directivity characteristic, the component of the horizontally polarized wave m2 that mixes as noise into the vertically polarized wave m1 is suppressed.

[0022] Incidentally, Fig. 6 shows the horizontal plane directivity characteristic of a vertically polarized wave by a patch antenna that does not have a short-circuit pin as exemplified in Fig. 5, that is, a patch antenna that has only a feed pin connecting feed points 31a, 31b and the feed terminal of reflector 2. As shown in Fig. 6, in a patch antenna that has only a feed pin, the component of horizontally polarized wave m2 that mixes as noise into vertically polarized wave m1 is relatively large.

[0023] (effect) As described above, in one embodiment, in a patch antenna of a type in which the feed points 31a, 31b of the patch 1 and the feed terminals 32a, 32b provided on the reflector 2 are connected via the feed pin 33a, the feed points 31a, 31b of the patch 1 and the short-circuit points 41a1, 41b2 and 41b1, 41b2 are provided, and these short-circuit points 41a1, 41b2 and 41b1, 41b2 are connected to the reflector 2 via the short-circuit pins 43a1, 43a2 and 43b1, 43b2, respectively. In addition, there are at least two or more short-circuit points.

[0024] Therefore, when transmitting and receiving vertically polarized waves and horizontally polarized waves, the disturbance in the electric field distribution generated between the patch 1 and the reflector 2 by the other power supply pin 33a is symmetrical, thereby improving the cross-polarization discrimination at a specific frequency between vertically polarized waves and horizontally polarized waves, and making it possible to improve the quality of each of the vertically polarized and horizontally polarized radio signals.

[0025] In particular, in one embodiment, patch 1 is square-shaped so that both horizontally and vertically polarized waves resonate at the same frequency, which makes it easy for interference between the polarized waves to occur. However, by providing feed pin 33a and short-circuit pins 43a1, 43a2 and 43b1, 43b2 as in one embodiment to improve the cross-polarization characteristics at a specific frequency between vertically polarized waves and horizontally polarized waves, a significant effect is achieved in improving the quality of each polarized wave at a specific frequency.

[0026] [Other embodiments] In the above embodiment, a patch antenna in which the patch 1 and the reflector 2 are arranged opposite each other with a gap (when the gap between the patch 1 and the reflector 2 is 0.03λ or more) between them is used as an example. However, the present invention can be similarly applied to a patch antenna in which the patch 1 and the reflector 2 are arranged opposite each other with a dielectric between them.

[0027] In the embodiment, the patch 1 is formed in a square shape, and the feed points 31a, 31b are arranged at positions perpendicular to each other, but the present invention is also applicable to a case where the patch is formed in a hexagonal shape and three feed points are provided at equal intervals on the patch. In this case, short-circuit points are arranged at positions between each feed point and the center of the patch coordinate system, and these short-circuit points are connected to the ground pattern of the reflector by short-circuit pins.

[0028] Additionally, the shapes and sizes of the patch and reflector, the configurations of the power supply member and short-circuit member, and the like can be modified in various ways without departing from the spirit and scope of the present invention.

[0029] Although the embodiment of the present invention has been described in detail above, the above description is merely an example of the present invention in every respect. It goes without saying that various improvements and modifications can be made without departing from the scope of the present invention. In other words, in implementing the present invention, specific configurations according to the embodiment may be appropriately adopted.

[0030] In short, this invention is not limited to the above-mentioned embodiment as it is, and in the implementation stage, the components can be modified and embodied without departing from the gist of the invention. In addition, various inventions can be formed by appropriately combining multiple components disclosed in the above-mentioned embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, components from different embodiments may be appropriately combined. [Explanation of symbols]

[0031] 1. Patch 2...Reflector 3,4…Strip line 31a, 31b…Power supply point 32a, 32b...Power supply terminals 33a…Power supply pin 41a, 41b...Short circuit point 43a, 43b...Short pins

Claims

1. A horizontally and vertically polarized antenna device in which a first feeding point for horizontal polarization and a second feeding point for vertical polarization, which are provided on a patch and a strip line, and a first feeding terminal for horizontal polarization and a second feeding terminal for vertical polarization, which are provided on a reflector, are connected via feeding members, respectively, a first short-circuit point disposed on the patch in a predetermined positional relationship with the first feed point; a second short point disposed on the patch in a predetermined positional relationship with the second feed point; a first short-circuit member connecting the first short-circuit point and a ground surface of the reflector; a second short-circuit member connecting the second short-circuit point and the ground surface of the reflector; An antenna device comprising:

2. 2. The antenna device according to claim 1, wherein the gap between the patch and the reflector is set to 0.03λ or more.

3. 2. The antenna device according to claim 1, wherein the patch is square-shaped, and the first feed point and the first short point, and the second feed point and the second short point are arranged at positions on the patch that are mutually orthogonal with respect to the coordinate center.

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