JP2011049864A - Polarization shared antenna - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polarization shared antenna which has the low profile shape with respect to an installation surface (especially a ceiling) and in which vertically polarized wave and horizontally polarized wave have approximately the same directive characteristics within a range of a direction required for transmission and reception. <P>SOLUTION: The polarization shared antenna includes: a conductor plate; a dipole antenna element arranged facing the conductor plate; and an U-shaped antenna element one end of which is directly and electrically connected to the conductor plate and the other end of which is electrically connected to the conductor plate via a feeding part. A conductor part facing the U-shaped antenna element is arranged to face the dipole antenna element and power is separately fed to each antenna element. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to an antenna having a vertical polarization component and a horizontal polarization component.

  For example, in indoor MIMO (Multiple-Input Multiple-Output) communication, it is known that the communication capacity can be improved by using an antenna having directivity in the angular direction of the side surface of a room. Further, as shown in Non-Patent Document 1, by using antennas having separate radiating elements for vertical polarization and horizontal polarization, the communication capacity can be secured regardless of the distance between the radiating elements. Is also known.

  An antenna disclosed in Patent Document 1 is a polarization sharing antenna having substantially the same directivity characteristics in a specific direction. This antenna is intended to be installed in an outdoor base station, and is a directional antenna having separate radiating elements that transmit and receive orthogonal polarized waves.

JP-A-9-98019

Uchida et al., “Optimum conditions for indoor MIMO systems with directional antennas at the access point”, IEICE Technical Report, AP2008-122, pp.61-66, 2008.

  However, the antenna of Patent Document 1 has the following problems when used in a base station installed on an indoor ceiling. When the reflector is opposed to the ceiling (when installed on the ceiling horizontally), the two dipole elements both transmit and receive horizontal polarization, and cannot transmit and receive vertical polarization. On the other hand, if the vertical polarization is transmitted / received by any of the dipole elements, the dipole element protrudes from the ceiling by the length of the dipole element (one half of the wavelength at one end). Therefore, there is a problem that it gets in the way or the landscape is damaged. Furthermore, when using for MIMO using a plurality of antennas, the problem becomes remarkable.

  An object of the present invention is a polarized wave having a low profile with respect to the installation surface (especially the ceiling) and having substantially the same directivity characteristics in a range of directions required for transmission and reception between vertical polarization and horizontal polarization. To provide a shared antenna.

  In order to solve the above-described problems, a dual-polarized antenna according to the present invention includes a conductor plate, a dipole antenna element arranged opposite to the conductor plate, one end directly and the other end electrically connected via a feeder. In particular, a U-shaped antenna element connected to the conductor plate. The conductive wire portion facing the conductor plate of the U-shaped antenna element is disposed so as to face the dipole antenna element, and power is supplied to each antenna element separately.

  With the antenna configuration of the present invention, the shape is low with respect to the installation surface (especially the ceiling), and the vertically polarized waves and the horizontally polarized waves have almost the same directivity characteristics in the range of directions required for transmission and reception. It is possible to design a polarization sharing antenna with

FIG. 1 is a front view of a polarization sharing antenna 100. FIG. (A) is a directional characteristic with respect to the vertical polarization of the U-shaped antenna element 130 in the zx plane, and (B) is a diagram showing the directional characteristic with respect to the horizontal polarization of the dipole antenna element 120. FIG. The front view of the polarization sharing antenna 200. FIG. (A) is a directional characteristic with respect to the vertical polarization of the U-shaped antenna element 130 in the zx plane, and (B) is a diagram showing the directional characteristic with respect to the horizontal polarization of the dipole antenna element 120. The figure which shows the perspective view of the polarized-wave common antenna 300. FIG. The figure which shows the perspective view of polarized-wave common antenna 300B. FIG. FIG. FIG. 10 illustrates a configuration example of a power feeding unit 440. The perspective view of the polarization sharing antenna 400B. FIG. 14 illustrates a configuration example of a power feeding unit 540. FIG. 10 illustrates a configuration example of a power feeding unit 640. FIG. 6 shows a configuration example of a power feeding unit 740.

  Hereinafter, embodiments of the present invention will be described in detail.

[Polarized antenna 100]
FIG. 1 is a perspective view of the dual-polarized antenna 100 according to the first embodiment, and FIG. 2 is a front view of the dual-polarized antenna 100. In addition, let the surface in which each antenna element of the conductor plate was provided be the front. The polarization sharing antenna according to the first embodiment will be described with reference to FIGS. 1 and 2.

  The dual-polarized antenna 100 includes a conductor plate 110, a dipole antenna element 120, and a U-shaped antenna element 130.

[Conductor plate 110]
One surface of the conductor plate 110 is arranged in parallel with an installation surface such as a ceiling, for example, and is in contact with the other surface, and a dipole antenna element 120 and a U-shaped antenna element 130 described later are provided on the other surface.

When the use center frequency of the polarization sharing antenna is λ ₀ , for example, the size of the conductor plate 110 is a square plate shape of 1.8λ ₀ × 1.8λ ₀ . The thickness, material, and the like of the conductor plate 110 may be any as long as they are deformed during movement, installation, or the like and have strengths that do not impair the function as an antenna. The same applies to a dipole antenna element and a U-shaped antenna element described later.

[Dipole antenna element 120]
Dipole antenna element 120 is disposed to face conductive plate 110. For example, the straight line formed by the dipole antenna element 120 and the plane formed by the conductor plate 110 are arranged in parallel. In the present invention, the term “opposite” means substantially parallel and facing to the extent that the function as an antenna is not impaired.

The length of the dipole antenna element 120 is approximately half wavelength (for example, 0.44λ ₀ ), and the distance between the dipole antenna element 120 and the conductor plate 110 is, for example, 0.14λ ₀ .

  The dipole antenna element 120 is connected to the conductor plate 110 via the feed line 121. For example, one of the dipole antenna elements 120R is connected to the conductor plate 110 through the feed line 121R, and the other 120L is connected to the signal terminal of the feed unit through the feed line 121L. The signal terminal of the power feeding unit is electrically connected to the inner conductor of the coaxial cable 10, and the conductor plate 110 is electrically connected to the outer conductor of the coaxial cable 10.

[U-shaped antenna element 130]
The U-shaped antenna element 130 has one end 130L directly connected to the conductor plate 110 and the other end 130R electrically connected to the conductor plate 110 via a power feeding unit. The other end 130 </ b> R is connected to the signal terminal of the power feeding unit, the signal terminal of the power feeding unit is electrically connected to the inner conductor of the coaxial cable 11, and the conductor plate 110 is electrically connected to the outer conductor of the coaxial cable 11.

For example, the size of the loop surface formed by the U-shaped antenna element is 0.32λ ₀ × 0.12λ ₀ , and the total length of the U-shaped antenna element is 0.56λ ₀ .

[Example of arrangement and operation]
The conductive wire portion 130 </ b> C facing the conductor plate 110 of the U-shaped antenna element 130 is arranged to face the dipole antenna element 120. For example, the straight line formed by the dipole antenna element 120 and the straight line formed by the conductive wire portion 130 </ b> C facing the conductor plate 110 of the U-shaped antenna element 120 are arranged in parallel. For example, the distance in the horizontal direction of the U-shaped antenna element 130 and the dipole antenna element 120 is arranged such that 0.19Ramuda ₀ or more.

  Further, for example, the conductor portion 130C and the dipole antenna element 120 may be arranged to be line symmetric with respect to a straight line A passing through the center of the conductor portion 130C and the center of the dipole antenna element 120 as an axis of symmetry.

  Power is supplied separately to the dipole antenna element 120 and the U-shaped antenna element 130. By feeding the dipole antenna element 120, an electric field parallel to the dipole antenna element 120 is generated and becomes a horizontally polarized wave component. On the other hand, when the U-shaped antenna element 130 is fed, an electric field in a direction orthogonal to the conductor plate 110 is generated and becomes a vertical component.

[effect]
3A shows the directivity characteristic with respect to the vertical polarization of the U-shaped antenna element 130 in the zx plane passing through each antenna element, and FIG. 3B shows the directivity characteristic with respect to the horizontal polarization of the dipole antenna element 120. .

To send and receive horizontally polarized, instead of the U-shaped antenna element 130, in the case of using the dipole antenna elements, 0.5 [lambda ₀ or more height is required, if the conductive plate using a monopole antenna element it is necessary to be 0.25 [lambda ₀ or more height when standing vertically on 110. On the other hand, in the present invention, the highest part, the height of the dipole antenna element 120 is 0.14λ _0. Therefore, if it is the structure of the antenna of this invention, the low-profile shape with respect to an installation surface is realizable.

  Further, as can be seen from FIG. 3, the dipole antenna element 120 has the maximum directivity characteristic in the 0 degree direction (the vertical direction when the polarization sharing antenna 100 is installed on the ceiling), and the direction of about 300 to 360 degrees. It has directivity characteristics in the direction of about 0 to 120 degrees. The U-shaped antenna element 130 does not have directivity characteristics with respect to the 0 degree direction, but has directivity characteristics with respect to directions of about 5 to 90 degrees and about 270 to 355 degrees. Therefore, it is possible to design a polarization-sharing antenna that can be used within a specific range in a direction required for transmission and reception of vertical polarization and horizontal polarization.

  In the present invention, the antenna element, the feed line, and the U-shaped antenna element may have a shape other than a linear shape (for example, a belt shape). Further, in the present invention, the size, position, orientation, and distance between each element (conductor plate, dipole antenna element, U-shaped antenna element) are examples, and the function as an antenna is not impaired. Can be set as appropriate. For example, when a plurality of antenna elements are arranged on the conductor plate 110, the antenna elements may be appropriately separated so as not to interfere with each other.

[Polarized antenna 200]
4 is a perspective view of the dual-polarized antenna 200 according to the second embodiment, and FIG. 5 is a front view of the dual-polarized antenna 200. The polarization sharing antenna according to the second embodiment will be described with reference to FIGS. 4 and 5. Only parts different from the first embodiment will be described.

  The dual-polarized antenna 200 includes a conductor plate 110, a dipole antenna element 120, a U-shaped antenna element 130, a dipole parasitic element 223, and a U-shaped parasitic element 235.

The conductor plate 110, the dipole antenna element 120, and the U-shaped antenna element 130 have the same configuration as in the first embodiment. However, in the examples and modifications described below, the size of the loop surface formed by the U-shaped antenna element is 0.27λ ₀ × 0.12λ ₀ and the total length of the U-shaped antenna element is 0.51λ _0. It is.

[Dipole-shaped parasitic element 223]
The dipole parasitic element 223 is disposed opposite to the dipole antenna element 120 and on the opposite side of the U-shaped antenna element 130, and is shorter than the dipole antenna element 223.

For example, the straight line formed by the dipole parasitic element 223 and the straight line formed by the dipole antenna element 120 are arranged substantially in parallel. For example, the length of the dipole parasitic element 223 is 0.41λ ₀ , and the distance between the dipole parasitic element 223 and the conductor plate 110 is 0.14λ ₀ . The dipole parasitic element 223 is directly connected to the conductor plate 110 via a feed line.

[U-shaped parasitic element 235]
The U-shaped parasitic element 235 is disposed opposite to the U-shaped antenna element 130 and on the opposite side of the dipole antenna element 120, and has a total length longer than that of the U-shaped antenna element 130.

For example, the size of the loop surface formed by the U-shaped parasitic element 235 is 0.32λ ₀ × 0.12λ ₀ , and the total length of the U-shaped parasitic element 235 is 0.56λ ₀ . In this case, the height is the same as the U-shaped antenna 130, the width is wider than the U-shaped antenna 130, and the total length of the U-shaped antenna 130 is longer. Both ends of the U-shaped parasitic element 235 are directly connected to the conductor plate 110.

[Example of arrangement and operation]
For example, the distance between the U-shaped parasitic element 235 and the U-shaped antenna element 130 is 0.2? _0, the distance between the dipole antenna element 120 and the dipole-shaped parasitic element 223 is 0.24Ramuda _0, co the distance between the shaped antenna element 130 and the dipole antenna element 120 is 0.19λ _0.

  Further, for example, each element may be arranged to be line symmetric with respect to a straight line passing through the center of each element as a symmetry axis.

  Power is supplied separately to the dipole antenna element 120 and the U-shaped antenna element 130. By feeding the dipole antenna element 120, an electric field parallel to the dipole antenna element 120 is generated and becomes a horizontally polarized wave component. At that time, the dipole parasitic element 223 functions as a director, and the dipole antenna element 120 exhibits directivity characteristics in the direction of the dipole parasitic element 223.

  On the other hand, when the U-shaped antenna element 130 is fed, an electric field in a direction orthogonal to the conductor plate 110 is generated and becomes a vertical component. At this time, the U-shaped parasitic element 235 functions as a reflector, and the U-shaped antenna element 130 has directivity in the direction opposite to the U-shaped parasitic element 130 (that is, the direction of the dipole antenna element 120). Show properties.

  Note that the U-shaped antenna element 130 has a resonance frequency that is changed by providing the U-shaped parasitic element 235. Therefore, the resonance frequency can be adjusted by appropriately adjusting the size of the loop surface formed by the U-shaped antenna element.

[effect]
6A shows the directivity characteristic with respect to the vertical polarization of the U-shaped antenna element 130 in the zx plane passing through each antenna element, and FIG. 6B shows the directivity characteristic with respect to the horizontal polarization of the dipole antenna element 120. .

  Similar to the first embodiment, a polarization-sharing antenna is designed that has a low profile with respect to the installation surface (especially the ceiling) and that has substantially the same directivity characteristics for vertical transmission and horizontal polarization for transmission and reception. it can. Further, as can be seen from FIG. 6, the main beam direction of the U-shaped antenna element is 56 degrees, and the main beam direction of the dipole antenna element is 53 degrees, thereby forming a unidirectional antenna having unidirectionality. can do.

  A plurality of antenna elements and parasitic elements may be arranged as shown in FIG.

[Polarized antenna 300]
FIG. 7 is a perspective view of the dual-polarized antenna 300 according to the third embodiment. The polarization sharing antenna according to the third embodiment will be described with reference to FIG. Only parts different from the first embodiment will be described.

  The polarization sharing antenna 300 includes a conductor plate 110, a dipole antenna element 120, a U-shaped antenna element 130, a dipole parasitic element 325, and a U-shaped parasitic element 333. The conductor plate 110, the dipole antenna element 120, and the U-shaped antenna element 130 have the same configuration as in the first embodiment.

[Dipole parasitic element 325]
The dipole parasitic element 325 is disposed opposite to the dipole antenna element 120 and on the opposite side of the U-shaped antenna element 130 and is longer than the dipole antenna element 223.

For example, the length of the dipole-shaped parasitic element 325 is 0.47Ramuda _0, the distance of the dipole-shaped parasitic element 325 and the conductor plate 110 is 0.14λ _0.

  The dipole parasitic element 325 is directly connected to the conductor plate 110 via a feed line.

[U-shaped parasitic element 333]
The U-shaped parasitic element 333 is disposed opposite to the U-shaped antenna element 130 and on the side opposite to the dipole antenna element 120, and has a total length shorter than that of the U-shaped antenna element 130.

For example, the size of the loop surface formed by the U-shaped parasitic element 333 is 0.22λ ₀ × 0.12λ ₀ , and the total length of the U-shaped parasitic element 333 is 0.46λ ₀ . Both ends of the U-shaped parasitic element 235 are directly connected to the conductor plate 110.

[Example of arrangement and operation]
For example, the distance between the U-shaped parasitic element 333 and the U-shaped antenna element 130 is 0.2? _0, the distance between the dipole antenna element 120 and the dipole-shaped parasitic element 325 is 0.24Ramuda _0, co the distance between the shaped antenna element 130 and the dipole antenna element 120 is 0.19λ _0. Further, for example, each element may be arranged to be line symmetric with respect to a straight line passing through the center of each element as a symmetry axis.

  Power is supplied separately to the dipole antenna element 120 and the U-shaped antenna element 130. By feeding the dipole antenna element 120, an electric field parallel to the dipole antenna element 120 is generated and becomes a horizontally polarized wave component. At this time, the dipole parasitic element 325 functions as a reflector, and the dipole antenna element 120 exhibits directivity characteristics in a direction opposite to the dipole parasitic element 335.

  On the other hand, when the U-shaped antenna element 130 is fed, an electric field in a direction orthogonal to the conductor plate 110 is generated and becomes a vertical component. At this time, the U-shaped parasitic element 333 functions as a director, and the U-shaped antenna element 130 exhibits directivity characteristics in the direction of the U-shaped parasitic element 130.

[effect]
With the above configuration, the same effects as those of the second embodiment are obtained. A plurality of antenna elements and parasitic elements may be arranged as shown in FIG.

[Modification 1]
[Polarized antenna 300B]
FIG. 8 is a perspective view of the dual-polarized antenna 300B of the first modification. The polarization sharing antenna according to the first modification will be described with reference to FIG. Only the parts different from the third embodiment will be described.

  In addition to the conductor plate 110, the dipole antenna element 120, the U-shaped antenna element 130, the dipole-shaped parasitic element 325, and the U-shaped parasitic element 333, the dual-polarized antenna 300B is similar to the second embodiment. A dipole parasitic element 223 and a U-shaped parasitic element 235 are provided.

[Example of arrangement and operation]
For example, a dipole parasitic element 223 (waveguide), a dipole antenna element 120, a dipole parasitic element 325 (reflector), a U-shaped parasitic element 333 (waveguide), a U-shape on the conductor plate 110. The antenna element 130 and the U-shaped parasitic element 235 (reflector) are arranged in this order. In other words, for each antenna element, a director is provided in a direction in which unidirectionality is desired and a reflector is provided on the opposite side. As described above, since the dipole antenna element 120 and the U-shaped antenna element 130 face each other and each antenna element and the parasitic element face each other, all the elements face each other.

For example, the distance between the U-shaped antenna element 130 and the U-shaped parasitic element 333 and 235 are respectively 0.2? _0, the distance between the dipole antenna element 120 and the dipole-shaped parasitic element 223 and 325 respectively 0. 24λ ₀ . The distance between the U-shaped parasitic element 333 and the dipole antenna shaped parasitic element 325 is 0.19λ _0. Further, for example, each element may be arranged to be line symmetric with respect to a straight line passing through the center of each element as a symmetry axis.

Note that a U-shaped parasitic element 333 (waveguide), a U-shaped antenna element 130, a U-shaped parasitic element 235 (reflector), and a dipole parasitic element 223 (waveguide) are formed on the conductor plate 110. The dipole antenna element 120 and the dipole parasitic element 325 (reflector) may be disposed in this order. At this time, the distance between the U-shaped parasitic element 235 and the dipole antenna shaped parasitic element 223 is set to 0.19λ _0.

[effect]
With the above configuration, the same effects as those of the third embodiment are obtained. Furthermore, it is possible to have higher unidirectionality by simultaneously using a director and a reflector for one antenna element.

[Polarized antenna 400]
FIG. 9 is a perspective view of the dual-polarized antenna 400 according to the fourth embodiment, and FIG. 10 is a front view of the dual-polarized antenna 400. The polarization sharing antenna according to the fourth embodiment will be described with reference to FIGS. 9 and 10. Only the parts different from the second embodiment will be described.

  The dual-polarized antenna 400 includes a conductor plate 110, dipole antenna elements 120a to 120d, U-shaped antenna elements 130a to 130d, dipole parasitic elements 223a to 223d, and U-shaped parasitic elements 235a to 235d. A power feeding unit 440 is provided. A dipole antenna element and a U-shaped antenna element having directivity characteristics in the same direction are set as a set of element groups. For example, the dipole antenna element 120a and the U-shaped antenna element 130a form a set of element groups.

  The conductor plate 110, the dipole antenna elements 120a to 120d, the U-shaped antenna elements 130a to 130d, the dipole-shaped parasitic elements 223a to 223d, and the U-shaped parasitic elements 235a to 235d Same as 2.

  The point which has a some element group and the point which has the electric power feeding part 440 differ from Example 2. FIG.

[Power supply unit 440]
The power feeding unit 440 includes switching means 441 for switching feeding of the arranged dipole antenna elements 120a to 120d and switching means 442 for switching feeding of the U-shaped antenna elements 130a to 130d. FIG. 11 shows a configuration example of the power feeding unit 440.

  For example, any of the power feeding terminals to the switching unit 441 and the dipole antenna elements 120a to 120d is electrically connected, and the switching unit 441 and the horizontal polarization terminal of the wireless device are connected. In addition, for example, the switching unit 442 and any one of the feeding terminals to the U-shaped antenna elements 130a to 130d are electrically connected, and the switching unit 442 and the vertical polarization terminal of the wireless device are connected. The switching means 441 and 442 are interlocked to connect a pair of antenna elements (for example, a dipole antenna element 120a and a U-shaped antenna element 130a) having directivity characteristics in the same direction.

[Example of arrangement and operation]
On one surface of the dual-polarized antenna 400, the element groups (130a and 120a, 130b and 120b, 130c and 120c, 130d and 120d) are arranged in a radial direction. The U-shaped antenna elements 130a to 130d are the center side. A power feeding unit 440 is provided on the other surface of the polarization sharing antenna 400.

  Each element group operates in the same manner as in the second embodiment. The power feeding unit 440 can change the main beam direction by switching the antenna element to be fed by the switching units 441 and 442.

[effect]
With the above configuration, the same effects as those of the second embodiment can be obtained, and a polarization-shared multi-beam antenna can be configured.

  In addition, when the dipole parasitic element 325 and the U-shaped parasitic element 333 used in Example 3 are used, the polarization-shared multi-beam antenna 400B can be configured similarly. FIG. 12 shows a perspective view of the dual-polarized antenna 400B. In this case, the dipole antenna element 120 side is arranged as the center side. The same applies to the following modifications.

  Moreover, you may arrange | position the element used by the modification 1 of Example 3 radially. In that case, the direction opposite to the direction of the directivity characteristic is arranged as the central direction. The same applies to the following modifications.

[Modification 1]
The configuration of the power feeding unit is different from that of the fourth embodiment. FIG. 13 illustrates a configuration example of the power feeding unit 540 according to the first modification of the fourth embodiment.

[Power feeding unit 540]
The power feeding unit 540 includes three-direction switching units 5411 to 5414 that switch the connection with the power feeding terminals to the dipole antenna elements 120a to 120d in three directions. Moreover, the three-way switching means 5421-5424 which switches the connection with the electric power feeding terminal to the U-shaped antenna elements 130a-130d in three directions is provided. Furthermore, combining means 5416 to 5419 for combining signals from adjacent dipole antenna elements 120a to 120d and combining means 5426 to 5429 for combining signals from adjacent U-shaped antenna elements 130a to 130d are provided. Each of the combining means 5416 to 5419 and 5426 to 5429 has an amplitude adjuster (not shown) for combining the signals of the two antenna elements with equal amplitude and a phase adjuster (not shown) for combining with the same phase. Also good. The power feeding unit 540 connects the 8-direction switching unit 541 that switches the connection with the horizontal polarization terminal of the wireless device to any one of the three-direction switching units 5411 to 5414 or the combining units 5416 to 5419 and the vertical polarization terminal of the wireless device. Is provided with an eight-direction switching unit 542 for switching between the three-way switching unit 5421 to 5424 and the combining unit 5426 to 5429. In transmission, the output signals from the eight-direction switching unit 541 and the eight-direction switching unit 542 may be distributed by the combining units 5416 to 5419 and 5426 to 5429.

[effect]
By adopting such a configuration, in addition to the effects of the fourth embodiment, it is possible to configure a polarization sharing antenna having directivity characteristics in the direction between adjacent element groups as well as the arrangement of element groups. Therefore, it is possible to configure a polarization sharing antenna capable of more flexible directivity selection. Further, by making it possible to arbitrarily set the combined amplitude and the combined phase of the combining units 6416 to 6419 and 6426 to 6429, more flexible directivity control can be performed.

  Note that the three-way switching means 5411 to 5414 and the three-way switching means 5421 to 5424 are changed to the two-way switching means, the output that does not pass through the synthesizing means is deleted, and directivity characteristics only in four directions between adjacent element groups. A dual-polarized antenna may be configured.

[Modification 2]
The configuration of the power feeding unit is different from that of the fourth embodiment. FIG. 14 illustrates a configuration example of the power feeding unit 640 according to the second modification of the fourth embodiment.

[Power supply unit 640]
The power feeding unit 640 includes phase shifters 645a to 645d that give a 90-degree phase difference and phase shifters 647a to 647d that give a -90-degree phase difference to signals from the U-shaped antenna elements 130a to 130d. The power feeding unit 640 includes combining units 643a to 643h that combine the signals from the dipole antenna elements 120a to 120d and the signals of the U-shaped antenna elements 130a to 130d that have passed through the phase shifters 645a to 645d or 647a to 647d. . Furthermore, the power feeding unit 640 includes switching means 641 for switching between terminals synthesized through phase shifters 645a to 645d that give a phase difference of 90 degrees and terminals synthesized through phase shifters 647a to 647d that give a phase difference of -90 degrees. Prepare. Therefore, the switching unit 641 has a function of switching feeding of a plurality of dipole antenna elements and a function of switching feeding of a plurality of U-shaped antenna elements.

  In transmission, the output signal from the switching unit 641 may be distributed by the combining units 643a to 643h.

  The phase difference between the signals from the U-shaped antenna elements 130a to 130d and the signals from the dipole antenna elements 120a to 120d is 90 degrees and -90 degrees. Therefore, it is not always necessary to use a phase shifter that gives a 90 degree phase difference, a phase shifter that gives a -90 degree phase difference, a phase shifter that gives a 45 degree phase difference, a phase shifter that gives a -45 degree phase difference, etc. The phase difference between both signals may be 90 degrees.

[effect]
By switching and selecting a right-handed circularly polarized wave terminal and a left-handed circularly polarized wave terminal through the switching means 641, it is possible to realize a dual-polarized antenna having circular polarization and orthogonal polarization characteristics.

  In addition, communication performance can be improved by performing communication using circularly polarized waves. For example, Nobumoto Kasahara, Toshiyuki Maeyama, TH Laksono, Fumio Ikegami, “Circularly polarized wave propagation in indoor transmission As described in "Characteristics" (IEICE Technical Report, AP93-140, February 1994), a low-polarization circularly polarized antenna can be constructed using this configuration. If both terminals are combined in the same phase and opposite phase, a dual-polarized antenna having a linear polarization characteristic of ± 45 degrees can be realized.

[Modification 3]
The configuration of the power feeding unit is different from that of the fourth embodiment. FIG. 15 illustrates a configuration example of the power feeding unit 740 according to the third modification of the fourth embodiment.

[Power supply unit 740]
The power feeding unit 740 includes circulators 742a to 742h, transmitting means 743a to 743h, and digital signals to analog signals for the power feeding terminals to the dipole antenna elements 120a to 120d and the power feeding terminals to the U-shaped antenna elements 130a to 130d, respectively. DA converters 744a to 744h, receiving means 745a to 745h, and AD converters 746a to 746h for converting an analog signal into a digital signal.

  Further, a digital signal processing device (switching / synthesizing means) 741 is provided as means for switching or synthesizing signals from the AD converters 746a to 746h. The digital signal processing device 741 sends signals to the DA converters 744a to 744h.

  An output signal from the digital signal processing device 741 is converted into an analog signal by, for example, a DA converter 744a, is input to the circulator 742a through the transmission unit 743a, and is output to a power feeding terminal connected to the dipole antenna element. The signal received by the dipole antenna element 120a is input to the circulator 742a via, for example, a power feeding terminal. The circulator 742a outputs the input signal to the receiving unit 745a. The analog signal that has passed through the receiving unit 745a is converted into a digital signal by the AD converter 746a and input to the digital signal processing device 741.

[effect]
By adopting such a configuration, it is possible to configure a polarization shared multi-beam antenna that has a low profile and realizes directivity, polarization switching, and synthesis. Directional direction selection, polarization selection, and the like can be flexibly performed by digital signal processing technology.

  In this embodiment, the circulator is provided between the transmission / reception means and the power supply terminal to the antenna element, but other configurations such as switching with a switch may be used.

100, 200, 300, 300B, 400, 400B, 500, 600, 700 Dual-polarized antenna 110 Conductor plate 120 Dipole antenna element 130 U-shaped antenna elements 223, 325 Dipole-shaped parasitic elements 235, 333 U-shaped parasitic power Elements 440, 540, 640, 740

Claims (6)

A conductor plate;
A dipole antenna element disposed facing the conductor plate;
A U-shaped antenna element having one end directly connected and the other end electrically connected to the conductor plate via a feeding portion;
The conductor portion of the U-shaped antenna element facing the conductor plate is disposed so as to face the dipole antenna element,
Feeding each antenna element separately,
A dual-polarized antenna characterized by that. The dual-polarized antenna according to claim 1,
Opposed to the dipole antenna element and opposite to the U-shaped antenna element, a dipole parasitic element shorter than the dipole antenna element, opposed to the U-shaped antenna element, and the It is arranged on the side opposite to the dipole antenna element, and comprises at least one of a U-shaped parasitic element having a total length longer than the U-shaped antenna element,
A dual-polarized antenna characterized by that. The dual-polarized antenna according to claim 1,
Opposed to the U-shaped antenna element and opposite to the dipole antenna element, the U-shaped parasitic element having a total length shorter than the U-shaped antenna element, and opposed to the dipole antenna element And at least one of a dipole parasitic element longer than the dipole antenna element, disposed on the opposite side of the U-shaped antenna element,
A dual-polarized antenna characterized by that. The dual-polarized antenna according to claim 1,
Opposing the dipole antenna element, a dipole parasitic element shorter than the dipole antenna element and a long dipole parasitic element,
Opposite to the U-shaped antenna element, comprising a U-shaped parasitic element having a shorter total length than the U-shaped antenna element and a long U-shaped parasitic element,
Placing each short parasitic element in a direction in which each antenna element is desired to have unidirectionality, and arranging each long parasitic element in the opposite direction;
A dual-polarized antenna characterized by that. The dual-polarized antenna according to claim 2,
A dipole antenna element and a U-shaped antenna element having directivity characteristics in the same direction as an element group,
From at least one of means for switching feeding to a plurality of dipole antenna elements and means for synthesizing signals from dipole antenna elements, from means for switching feeding of a plurality of U-shaped antenna elements, and from a U-shaped antenna element A power supply unit including at least one of means for combining the signals of
A plurality of element groups are arranged with the U-shaped antenna element side as the center side so that the arrangement direction of the element groups is radial,
A dual-polarized antenna characterized by that. The dual-polarized antenna according to claim 3,
A dipole antenna element and a U-shaped antenna element having directivity characteristics in the same direction as an element group,
At least one of means for switching feeding to a plurality of dipole antenna elements and means for combining signals from dipole antenna elements, means for switching feeding of a plurality of U-shaped antenna elements, and a U-shaped antenna A power supply unit comprising at least one of means for synthesizing signals from elements;
A plurality of element groups are arranged with the dipole antenna element side as the center side so that the arrangement direction of the element groups is radial,
A dual-polarized antenna characterized by that.

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