JP3854211B2 - Antenna device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an antenna device used in a base station such as a mobile communication system, for example, which uses a horizontally polarized wave and a vertically polarized wave and has a horizontal plane directivity that is non-directional.
[0002]
[Prior art]
An omnidirectional antenna device may be selected as one form of a base station antenna device in a land mobile communication system. This is generally the case when a zone is formed in a place where the subscriber capacity is small.
Conventionally, in this type of antenna device, for example, an antenna device using vertically polarized waves, such as a collinear antenna, in which a horizontal plane is omnidirectional and a vertical plane has a narrow beam width, is often used.
With the increase in subscribers due to the spread of mobile communication in recent years, further improvement in communication quality is required. For this reason, a diversity reception system is employed in order to increase radio wave reception efficiency.
While space diversity requires the same two antennas to be installed at a distance, in the case of polarization diversity, there is no need to install the two antennas at a distance, as shown in FIG. The antenna for horizontal polarization and the antenna for vertical polarization can be stacked on the upper stage and the lower stage and housed in one radome to form one antenna device.
[0003]
However, the method of combining separate antennas for horizontal polarization and vertical polarization into one on the upper and lower stages doubles the length of the antenna, so the length of each individual antenna is actually sufficient. The length could not be increased, and therefore the gain could not be increased.
Further, in a horizontal omnidirectional antenna device represented by a collinear antenna or the like, the feeding to each antenna element arranged in the vertical direction is a so-called series feeding, and it is known that it has VSWR and directivity frequency characteristics. It has been.
In addition, since it is difficult to arbitrarily give power distribution to each antenna element due to series feeding, it is difficult to perform beam shaping with directivity related to the zone configuration.
Further, the tilt angle of the vertical plane directivity is fixed, and it is impossible to reconstruct the zone by changing the tilt angle of the vertical plane directivity after the antenna is installed.
In order to control the tilt angle, if the collinear antennas are forcibly blocked and the cables that feed power to each block are connected, the cables pass near the antenna elements in the lower block. It will be disturbed.
[0004]
[Problems to be solved by the invention]
As described above, in the conventional method in which the horizontally polarized antenna and the vertically polarized antenna are overlapped on the upper and lower stages, it is difficult to obtain a high gain because the antenna length cannot be increased.
In addition, since a conventional horizontal omnidirectional antenna device such as a collinear antenna is a series feeding method, it has a frequency characteristic of VSWR and directivity, and it is difficult to perform beam shaping of vertical plane directivity.
Furthermore, the tilt angle of the vertical surface directivity is fixed, and it is impossible to reconstruct the zone by changing the vertical surface tilt angle after installation.
The present invention has been made in view of the above points, and the object of the present invention is to eliminate the above-mentioned problems, enable high gain and vertical plane directivity beam shaping and tilt angle change, and block feed cable for variable tilt. An object of the present invention is to provide a horizontal and vertical polarization horizontal plane omnidirectional antenna device that eliminates the influence of the presence on the horizontal plane omnidirectionality.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, an antenna device according to the present invention includes a substantially rectangular prism-shaped cylindrical reflector having a vertical direction as a longitudinal direction and a plurality of dielectrics arranged on the cylindrical reflector. An element substrate, and a feeder circuit is formed on the cylindrical reflector. The plurality of dielectric element substrates are attached perpendicular to four side surfaces of the cylindrical reflector, and each includes a branch circuit and a horizontal bias. A dielectric having a plurality of wave elements or vertically polarized elements arranged to surround the cylindrical reflector, connected to the feeder circuit on the cylindrical reflector, and having the horizontally polarized elements The element substrate for horizontal polarization which is an element substrate and the element substrate for vertical polarization which is a dielectric element substrate provided with the element for vertical polarization are alternately arranged in the vertical direction.
The antenna device according to the present invention further includes a portion having one or a plurality of sets of the horizontal polarization element substrate and the vertical polarization element substrate as one block, and a plurality of the blocks are vertically stacked in the vertical direction. Structure.
The antenna device according to the present invention further has a structure in which a power feeding cable that is connected to the power feeding circuit of each block and feeds power is arranged inside the cylindrical reflector. Further, the power supply cable for supplying power to another block arranged above or below the block is accommodated inside the cylindrical reflector.
The antenna device according to the present invention further has a vertical plane directivity by collecting power supply cables to each block at one place, connecting a phase shifter to the power supply cable, and controlling power supplied to each block. The beam tilt control is performed.
[0006]
As described above, according to the present invention, of the horizontal and vertical polarization element substrates, the same polarization substrates are arranged at equal element intervals of a single polarization antenna, and different polarization element substrates are alternately arranged. Thus, an equivalent gain can be obtained with the same length as that of the single polarization antenna.
In addition, since the power supply circuit to the element substrate can be formed on the cylindrical reflector within a certain area, a parallel power supply system can be formed instead of a series power supply system, and thus VSWR and directivity can be formed. Frequency characteristics can be suppressed.
Furthermore, the parallel power feeding method allows the power distribution to each antenna element to be freely set due to the ease of designing the power feeding circuit, so that the vertical plane directivity can be formed. Also, several sets of horizontal and vertical polarization elements are made into one block, and a high gain can be obtained by multi-stage this, and the power supply cable to each block is passed through the cavity of the cylindrical reflector. Thus, the influence of the feeding cable on the directivity can be eliminated.
In addition, it is possible to control the tilt angle of the vertical plane directivity by collecting the feeding cables at the lowest stage and connecting a phase shifter.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 and FIG. 2 are views showing an embodiment of the horizontal and vertical polarization antenna apparatus of the present invention.
FIG. 1 shows a configuration example of one block in which two horizontal polarization element substrates and two vertical polarization element substrates are alternately arranged, and FIG. 2 is a cross-sectional view showing a horizontal polarization element portion. is there.
There are two pairs of feeding circuits arranged on a cylindrical reflector with four sides. Each pair corresponds to horizontal polarization and vertical polarization, and the two sets face each other. Is arranged in. The power supply circuit on the cylindrical reflector is formed of a microstrip line, and serves to supply power to the upper and lower element substrates by the two distribution circuits.
Electric power is supplied to the element substrate from the intersection of the end of the cylindrical reflector and the element substrate, where it is connected to a balanced strip line formed on the element substrate.
This strip line is branched into two at this connection point, and is connected to two dipole elements.
Four dipole elements are formed on the element substrate, two of which are fed from the aforementioned microstrip feeding circuit on one of the cylindrical reflectors, and the other two dipole elements are the other. Power is supplied from the microstrip power supply circuit on the cylindrical reflector.
The shapes of the microstrip feeding circuit and the element substrate on the cylindrical feeding reflector are point-symmetric with respect to the central axis of the cylindrical reflector.
The dipole elements are arranged in the horizontal direction in the case of horizontal polarization, and in the vertical direction in the case of vertical polarization.
The dipole elements on the element substrate are arranged so as to surround the cylindrical reflector, and furthermore, since these dipole elements are fed with the same amplitude and phase, the combined directivity of the dipole elements is horizontal. Becomes omnidirectional.
[0008]
FIG. 3 shows measured values of horizontal plane directivity of horizontal and vertical polarization.
In both polarizations, omnidirectionality with little deviation is obtained.
A power supply cable is connected to the microstrip power supply circuit on each cylindrical reflecting plate through the cavity of the cylindrical reflecting plate, and the paired power supply cables are collected by a distributor.
This can be made into one block and can be multi-staged.
In the case of multiple stages, as shown in FIG. 4, the feeding cable of each block can be extended to the lowest stage through the hollow of the cylindrical reflector of the lower block, and a phase shifter can be connected there. .
[0009]
In the above example, the number of element substrate groups in one block is two, but the number of element substrate groups in one block can be arbitrarily set in accordance with the design of the vertical plane directivity.
In the above example, four dipole elements are arranged on the element substrate. However, when the size of the cylindrical reflector is smaller than the wavelength, two plane dipole elements can be used to obtain horizontal plane omnidirectionality. it can.
In addition, the technology of the present invention is not limited to the technology in the above-described embodiment, and may be based on the technology of another aspect that performs the same function, and the technology of the present invention may be various within the scope of the above configuration. Changes and additions are possible.
[0010]
【The invention's effect】
As is clear from the above description, according to the horizontal and vertical polarization horizontal plane omnidirectional antenna apparatus of the present invention, the same polarization substrate among the horizontal and vertical polarization element substrates is connected to the single polarization antenna. By alternately disposing different polarization element substrates in the vertical direction at equal element intervals, it is possible to obtain an equal gain with the same length as that of a single polarization antenna.
In addition, since the power supply circuit to the element substrate can be formed on the cylindrical reflector within a certain area, a parallel power supply system can be formed instead of a series power supply system, and thus VSWR and directivity can be formed. Frequency characteristics can be suppressed.
Furthermore, the parallel power feeding method allows the power distribution to each antenna element to be freely set due to the ease of designing the power feeding circuit, so that the vertical plane directivity can be formed. Moreover, several sets of horizontal and vertical polarization elements are made into one block, and by aiming at high gain by making this multi-stage, by passing the feeding cable to each block through the cavity of the cylindrical reflector, The influence of the feeding cable on the directivity can be eliminated.
Further, by gathering the power supply cables at the lowest stage and connecting a phase shifter, there is an excellent effect that the tilt angle of the vertical plane directivity can be controlled.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of one block of an antenna device of the present invention.
FIG. 2 is a cross-sectional view of the antenna device of the present invention.
FIG. 3 is a diagram showing horizontal plane directivity of the antenna device of the present invention.
FIG. 4 is a diagram showing a configuration of an antenna device in which the antenna device of the present invention is multistaged and a phase shifter is connected.
FIG. 5 is a diagram showing a configuration of a conventional polarization-shared horizontal plane omnidirectional antenna.

Claims (5)

The vertical direction is the longitudinal direction, and includes a substantially rectangular prism-shaped cylindrical reflector having four side surfaces, and a plurality of dielectric element substrates arranged in the vertical direction on the cylindrical reflector,
Forming a feeding circuit composed of a microstrip line on the cylindrical reflector;
The plurality of dielectric element substrates are attached perpendicular to the four side surfaces of the cylindrical reflector,
One of the plurality of dielectric element substrates branches a horizontal polarization element parallel to the short sides of the four side surfaces of the cylindrical reflector on the substrate and a feed signal from the feed circuit to the horizontal polarization element. It is an element substrate for horizontal polarization in which a branch circuit is formed,
The other one of the plurality of dielectric element substrates is provided with a vertical polarization element parallel to a vertical direction facing each of the four side surfaces of the cylindrical reflector on the substrate and a feed signal from the feed circuit. It is a vertically polarized element substrate in which a branch circuit that branches to a vertically polarized element is formed,
The horizontal polarization element substrate and the vertical polarization element substrate are alternately arranged vertically in the vertical direction,
The branch circuit is configured by a balanced strip line, and feeds power to each polarization element facing both side surfaces constituting the corner, with the corners on the diagonals of the four side surfaces as branch points, respectively.
Between the adjacent horizontal polarization element substrates, a pair of branch points on the one diagonal line of the branch circuit on one substrate, and a pair of branch points on the other diagonal line of the branch circuit on the other substrate, Are respectively formed on one opposing side surface of the four side surfaces, and each configured as a distribution circuit,
Between the adjacent vertical polarization element substrates, a pair of branch points on the one diagonal of the branch circuit on one substrate, and a pair of branch points on the other diagonal of the branch circuit on the other substrate, Are respectively formed on the other opposing side surface of the four side surfaces, and each is configured as a distribution circuit. An antenna device according to claim 1, wherein the antenna device according to claim 1 is used as one block, and a plurality of the blocks are vertically stacked in the vertical direction. The antenna device according to claim 2, wherein
An antenna device, wherein a power supply cable connected to the power supply circuit of each block for supplying power is disposed inside the cylindrical reflector. The antenna device according to claim 3, wherein
An antenna device characterized in that the feeding cable for feeding power to another block arranged above or below the block is housed inside the cylindrical reflector. In the antenna device according to claim 3 or 4,
Collecting the power supply cables to each block in one place, connecting a phase shifter to the power supply cable, and controlling the power supplied to each block to perform beam tilt control of the vertical plane directional beam A feature antenna device.

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