JP2001068928A - Polarized wave diversity antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To adopt a configuration possible for miniaturization for a polarized wave diversity antenna even when it is designed for a low frequency. SOLUTION: A horizontally polarized wave use H type element 10 consists of a 1st H type element 11a and a 2nd H type element 11b of an H shape where linear vertical elements 12a, 12b (12c, 12d) are provided at both ends of a linear feeding element 13a (13b) placed horizontally. Since the 1st H type element 11a and the 2nd H type element 11b are placed within a horizontal plane at an angle difference of about 90 degrees and receive power at a phase difference of about 90 degrees, the polarized wave diversity antenna is omnidirectional within the horizontal plane. A linear vertically polarized wave use dipole element 20 is placed in the vicinity of the horizontally polarized wave use H type element 10 to configure the polarized wave diversity antenna 1 smaller in size.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a simplified polarization diversity antenna used for mobile communication.

[0002]

2. Description of the Related Art In general, the quality of communication in mobile communication may be degraded by fading accompanying movement of a mobile body. Diversity reception is performed to reduce the adverse effect of this fading. Space diversity obtains a diversity branch by placing antennas spatially separated. In order to obtain a sufficient diversity effect, the antenna should be spatially separated at a distance of at least 5 wavelengths in the case of horizontal separation and 2.5 wavelengths in the case of vertical separation. As described above, it is necessary to install antennas apart from space diversity.Therefore, due to its structure, the physical size of the antenna configuration increases as the frequency used decreases, and it is hardly used below the 400 MHz band. It is. On the other hand, as a method for reducing the size of a diversity antenna, there is polarization diversity for obtaining a diversity branch using horizontal polarization and vertical polarization, and is being studied for public mobile communication applications. (Arai, Fujimori, Homma,
"Bidirectional Polarized Diversity Antenna for PHS", IEICE Spring Institute of Technology B-1-117 1998, Naga, Usawazawa, Kiya, Hori, "Polarized Dual-Phase Height Diversity Antenna with Bidirectional Direction" IEICE Tech. P95-111 199
6)

[0003]

In the polarization diversity reception which can improve the communication quality, the horizontal polarization element and the vertical polarization element can be arranged close to each other.
The polarization diversity antenna has a feature that can be configured to be smaller than the space diversity antenna. However, VH of 400 MHz band or less used for business communication
At low frequencies such as the F band, a dipole antenna is usually used as the antenna element for horizontal polarization, so that the polarization diversity antenna becomes large, making it difficult to easily configure the antenna element for each polarization. There was a problem of becoming.

Accordingly, it is an object of the present invention to provide a polarization diversity antenna which can be downsized even for low frequencies.

[0005]

In order to achieve the above object, a polarization diversity antenna according to the present invention has an H-shape in which linear vertical elements are provided at both ends of a linearly arranged linear feed element. A horizontal polarization H-type element comprising a first H-type element and a second H-type element, wherein the first H-type element and the second H-type element are arranged with an angle difference of about 90 degrees in a horizontal plane with each other;
A linearly polarized vertically arranged element for vertical polarization, and a phase difference of about 90 degrees between a substantially center of the feeding element in the first H-type element and a substantially center of the feeding element of the second H-type element. Power is being supplied.

In the polarization diversity antenna according to the present invention, the vertical polarization element may be any one of a dipole pole antenna, a brown antenna, a sleeve antenna, and a collinear antenna. In the above-mentioned polarization diversity antenna according to the present invention, two short-circuit bars for impedance matching that short-circuit between the vertical elements are provided in parallel with the feed element of the first H-type element and the second H-type element interposed therebetween. It may be. In the polarization diversity antenna of the present invention, the vertical polarization element may be arranged inside a circumcircle of the horizontal polarization H-shaped element.

According to the present invention, two H-shaped H-shaped elements in which linear vertical elements are provided at both ends of a horizontally arranged linear feed element are arranged so as to be orthogonal to each other in a horizontal plane. Since the horizontal polarization H-type element is configured by the above, the occupied area of the horizontal polarization H-type element in the horizontal plane can be reduced. As a result, the size of the polarization diversity antenna can be reduced. In addition, since the H-type element for horizontal polarization and the dipole element for vertical polarization are configured by linear elements, the configuration of the polarization diversity antenna can be simplified and the wind receiving area can be reduced. You can also. Furthermore, since the two H-type elements arranged orthogonally in the horizontal plane are fed with a phase difference of about 90 degrees, the directivity of the horizontally polarized H-type element can be made non-directional in the horizontal plane. it can.

As described above, the simplified and inexpensive polarization diversity antenna makes it possible to improve the deterioration of communication quality due to fading of mobile communication. Furthermore, the size of the polarization diversity antenna for diversity reception at a low frequency such as the VHF band used in business communication can be reduced, so that a polarization diversity antenna suitable for a low frequency can be obtained.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1 and 2 show a configuration example of a polarization diversity antenna according to an embodiment of the present invention. FIG. 1A is a perspective view of a polarization diversity antenna of the present invention, and FIG.
FIG. 2 (a) is a front view of FIG.
(B) is a top view thereof. As shown in FIGS. 1 and 2, a polarization diversity antenna 1 according to the present invention includes a horizontal polarization H-type element 10 for transmitting and receiving horizontal polarization, and a vertical polarization dipole element 2 for transmitting and receiving vertical polarization.
0. H-type element for horizontal polarization 10
Comprises a first H-type element 11a formed in an H-shape,
The second H having the same configuration as the first H-type element 11a
The mold element 11b is disposed so as to be substantially orthogonal to the horizontal plane. That is, the first H
The mold element 11a and the second H-type element 11b
They are arranged with an angle difference of about 90 degrees in a horizontal plane.

The first H-type element 11a is formed as shown in FIG.
As shown in the enlarged view of the portion A in FIG. 2B, two vertically arranged vertical elements 12a and 12b are provided at both ends of a short horizontally arranged feeding element 13a. However, in FIG. 1B, the dipole element 20 for vertical polarization is omitted. The element lengths of the vertical element 12a and the vertical element 12b are substantially equal. The two short bars 14 for impedance matching are substantially parallel to each other so as to sandwich the feed element 13a and are substantially equidistant from the feed element 13a.
a and 14b are provided to short-circuit the vertical element 12a and the vertical element 12b. Similarly, in the second H-type element 11b, two vertically arranged vertical elements 12c and 12d are provided at both ends of a horizontally arranged short feeding element 13b. The element lengths of the vertical element 12c and the vertical element 12d are substantially equal. And the feed element 13
b, and two short bars 14c and 14d for impedance matching at substantially the same distance from the feed element 13b are connected to the vertical element 12c.
It is provided to short-circuit the vertical element 12d. Note that the first H-type element 11a and the second H-type element 11b are both feed elements 13a and 13b.
The configuration is devised so that the short bars 14a to 14d do not electrically contact each other.

In the vicinity of the H-type element 10 for horizontal polarization, a dipole element 20 for vertical polarization has vertical elements 12a to 12d of the H-type element 10 for horizontal polarization.
Are arranged substantially parallel to each other. In the examples shown in FIGS. 1 and 2, the vertically polarized dipole element 20 is
It is arranged inside the circumscribed circle B of the H-type element for horizontal polarization 10 shown in FIG. 2B, and the area occupied by the polarization diversity antenna 1 in the horizontal plane is extremely small.

The first H-type element 11a and the second H-type element 1 constituting the H-type element 10 for horizontal polarization
The power supply elements 13a and 13b in 1b are supplied with power almost at the center thereof, but the power supply points are omitted in FIGS. 1 and 2. And the feed element 1
Power is supplied between the power supply element 3a and the power supply element 13b with a phase difference of about 90 degrees. That is, the first H-type element 11a and the second H-type element 11b constitute a turn style antenna. Thereby, the directivity in the horizontal plane of the H-type element 10 for horizontal polarization can be made non-directional. Therefore, it is possible to provide an omnidirectional horizontal polarization antenna in a horizontal plane required as the polarization diversity antenna 1.

The vertical polarization dipole element 20 arranged inside the circumcircle B of the horizontal polarization H-type element 10 is fed centrally, and in principle the directivity in the vertical plane is omnidirectional. And sex. The H-type element for horizontal polarization 10 can be composed of a conductive rod or pipe, and the dipole element 20 for vertical polarization can also be composed of a conductive rod or pipe. That is,
Since the H-type element 10 for horizontal polarization and the dipole element 20 for vertical polarization can be a wire antenna, the configuration of each element can be simplified and reduced in cost. Furthermore, since it is a wire system and is miniaturized as described above, the cross sectional area of wind of the polarization diversity antenna 1 is reduced, so that when the polarization diversity antenna 1 is fixed to a tower or a pole. Sufficient mechanical strength can be obtained even if the mounting structure is simple. In addition, H for horizontal polarization
First H-type element 11a constituting the mold element 10
The second H-type element 11b is provided with, for example, a 90 ° phase shifter and a hybrid circuit in a power supply system, and supplies power to the first H-type element 11a and the second H-type element 11b with a phase difference of 90 degrees.

Next, the configuration of the H-type element 10 for horizontal polarization according to the present invention will be described. Since the first H-type element 11a and the second H-type element 11b have the same configuration, the first H-type element 11a is representatively the first H-type element 11a. FIG. 3 shows the configuration of the mold element 11a. However, FIG. 3 is a plan view thereof. The first H-type element 11a has long vertical elements 12a at both ends of a short horizontally arranged power supply element 13a in order to reduce the area occupied in the horizontal plane and to reduce the size.
a and 12b are provided. A feeding point 15a is provided substantially at the center of the feeding element 13a.
A is connected to a coaxial cable. Vertical element 12
The dimension L2 from the connection point of the feed element 13a to the tip of the feed elements 13a and 12b is approximately 0.225λ, where λ is the wavelength of the center frequency of the operating frequency band. The allowable range of the dimension L2 is about ± 10%. The vertical element 12a (12
The dimension L1 from the connection point b) to the feeding point 15a is approximately 0.0125λ. The tolerance of this dimension L1 is ±
It is about 10%.

Further, in order to match the impedance of the first H-type element 11a with the coaxial cable connected to the feed point 15a and to improve the characteristics of the H-type element 10 for horizontal polarization, the first H-type element 11a has The short bars 14a, 14b are almost
Are provided in parallel with each other. At this time, the dimension L3 between the short bar 14a or the short bar 14b and the feed element 13a is substantially equal, and the dimension L3 is approximately 0.025λ. At this time, the antenna impedance of the first H-type element 11a is about 50Ω.
Becomes Therefore, impedance matching is achieved with a coaxial cable having a general characteristic impedance of 50Ω.
Note that the dimension L3 is not limited to 0.025λ, and the short bars 14a, 14b
By adjusting the dimension L3 between a, various matching impedances can be obtained. At this time, when the short bars 14a, 14b are separated from the feed element 13a to increase the dimension L3, the matching impedance increases, and the short bars 14a, 14b are connected to the feed element 13a.
When the dimension L3 is reduced close to a, the matching impedance is reduced.

The second H-type element 11b has the same configuration as the first H-type element 11a. The first H-type element 11a and the second H-type element 11b are arranged at an angle difference of about 90 degrees in a horizontal plane. By using a turn-style antenna configuration in which power is supplied with a phase difference of about 90 degrees, the H-type element 10 for horizontal polarization can be made non-directional in a horizontal plane. FIG. 6 shows an example of directivity in the horizontal plane of the H-type element for horizontal polarization 10 configured as described above. At this time, the frequency is set to 150 MHz which is a VHF band, and it can be seen that the directivity in the horizontal plane, which is almost circular, is good.

The dipole element 20 for vertical polarization is
Although the half-wavelength dipole antenna is vertically arranged, an antenna type such as a brown antenna, a sleeve antenna, and a collinear antenna may be used instead of the half-wavelength dipole antenna. In addition, the wire diameter of the H-type element 10 for horizontal polarization and the dipole element 20 for vertical polarization is, for example, about 1 mm, but is not limited thereto.

Next, another configuration example of the polarization diversity antenna 1 according to the present invention is shown in FIG. The polarization diversity antenna 1 shown in FIG.
When the zero feed elements 13a and 13b are arranged in the XY plane, the vertical polarization dipole element 20 is arranged outside the horizontal polarization H-type element 10 so as to be separated in the XY plane. . Thus, the horizontal polarization H-type element 10 and the vertical polarization dipole element 20
By arranging them apart in the XY plane, it is possible to further reduce the coupling between the two elements and prevent deterioration of characteristics.

FIG. 5 shows still another configuration example of the polarization diversity antenna 1 according to the present invention. The polarization diversity antenna 1 shown in FIG. 5 includes a vertical polarization dipole element 20 when the feed elements 13a and 13b of the horizontal polarization H-type element 10 are arranged in the XY plane.
Are spaced apart from the H-type element 10 for horizontal polarization on the Z-axis. Thus, H for horizontal polarization
Mold element 10 and dipole element 2 for vertical polarization
By disposing 0 at a distance on the Z axis, it is possible to further reduce the coupling between the two elements and prevent deterioration of characteristics. In the polarization diversity antenna 1 according to the present invention, when the feed elements 13a and 13b of the H-type element 10 for horizontal polarization are arranged in the XY plane, the dipole element 20 for vertical polarization is A composite arrangement in which the H-shaped elements 10 are separated in the XY plane and also separated in the Z-axis direction may be adopted.

[0020]

As described above, according to the present invention, two H-shaped H-shaped elements in which linear vertical elements are provided at both ends of a linearly arranged linear power supply element are arranged so as to be orthogonal to each other in a horizontal plane. Since the H-shaped elements for horizontal polarization are arranged to form the H-shaped elements for horizontal polarization, the occupied area of the H-type elements for horizontal polarization in the horizontal plane can be reduced.
As a result, the size of the polarization diversity antenna can be reduced. In addition, since the H-type element for horizontal polarization and the dipole element for vertical polarization are configured by linear elements, the configuration of the polarization diversity antenna can be simplified and the wind receiving area can be reduced. You can also. Furthermore, since the two H-type elements arranged orthogonally in the horizontal plane are fed with a phase difference of about 90 degrees, the directivity of the horizontally polarized H-type element can be made non-directional in the horizontal plane. it can.

As described above, the simplified and inexpensive polarization diversity antenna can improve the deterioration of communication quality due to fading of mobile communication. Furthermore, the size of the polarization diversity antenna for diversity reception at a low frequency such as the VHF band used in business communication can be reduced, so that a polarization diversity antenna suitable for a low frequency can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view and a partially enlarged view showing a configuration of a polarization diversity antenna according to an embodiment of the present invention.

2A and 2B are a plan view and a top view showing a configuration of a polarization diversity antenna according to an embodiment of the present invention.

FIG. 3 is a diagram showing a configuration of a first H-type element according to the polarization diversity antenna according to the present invention.

FIG. 4 is a perspective view showing another configuration example of the polarization diversity antenna according to the present invention.

FIG. 5 is a perspective view showing still another configuration example of the polarization diversity antenna according to the present invention.

FIG. 6 is a diagram showing directivity in a horizontal plane of an H-shaped element for horizontal polarization of the polarization diversity antenna according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Polarization diversity antenna 10 H element for horizontal polarization 11a 1st H element 11b 2nd H element 12a-12d Vertical element 13a, 13b Feed element 14a-14d Short bar 15a Feed point 20 Dipole element for vertical polarization

Continued on the front page F term (reference) 5J021 AA02 AB02 AB03 CA04 DB03 GA07 GA08 HA05 HA06 HA10 JA05 JA07

Claims (4)

[Claims] 1. An H-shaped first H in which linear vertical elements are provided at both ends of a linearly arranged linear power supply element.
And a second H-type element.
An H-type element for horizontal polarization, in which the mold element and the second H-type element are arranged with an angle difference of about 90 degrees in a horizontal plane, and a vertically-polarized element, linearly arranged, in a horizontal plane. A polarization diversity antenna, wherein power is supplied to a substantially center of a feed element of the first H-type element and a substantially center of a feed element of the second H-type element with a phase difference of about 90 degrees. 2. The polarization diversity antenna according to claim 1, wherein the vertical polarization element is any one of a dipole pole antenna, a brown antenna, a sleeve antenna, and a collinear antenna. . 3. The first H-type element and the second H-type element.
In parallel with the feed element of the H-shaped element,
2. The polarization diversity antenna according to claim 1, wherein two short bars for impedance matching that short-circuit between the vertical elements are provided. 3. 4. The polarization diversity antenna according to claim 1, wherein the vertical polarization element is arranged inside a circumscribed circle of the horizontal polarization H-shaped element.