JPS63121302A - Circular polarized wave line shape antenna - Google Patents

Abstract

PURPOSE:To electrically insulate spots where four dipole antenna elements of lambda/2 intersect each other and to thin the thickness of the antenna so as to obtain the antenna which is suitable for mobile communication by arranging the above-mentioned elements in parallel crosses. CONSTITUTION:The dipole antenna elements 10, 11, 12 and 13 whose lengths are lambda/2 (lambda wavelength) are arranged in parallel crosses and the respective antenna elements, for which a piano wire, etc., having a specific diameter is used and which is plated with gold, respectively intersect each other. The intersecting points are set as the points of 0.1875lambda from the center of the respective antenna elements 10-13 and the gaps of 1.0X10<-4>lambda are provided so as to obtain a state electrically insulated each other. And feeding to the respective antenna elements 10-13 is made in order that their phases are different from each other about ninety degrees, so that a circular polarized wave line shape antenna whose half-power angle is approximately 120-130 degrees and whose axis ratio (less than 3dB) is approximately 130 degrees can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a circularly polarized linear antenna, and can be used, for example, for satellite communications.

(Prior art) For example, communication with fixed stations or satellite stations for mobile communications, television broadcast reception, radio broadcast reception, self-location recognition, etc. generally uses very weak radio waves, so high A gain with sharp directivity is used. These antennas include, for example, end-fire helical antennas or cross-dipole antennas.

These antennas with sharp directivity, ie, antennas with narrow beam widths, have sharp directivity, but have poor wide-angle axial ratios.

Therefore, when using these antennas, it is important to control the attitude of the antenna because communication becomes impossible if the direction of the antenna (the direction in which the main lobe points = the attitude of the antenna) deviates from the radio wave source. Therefore, conventionally, an attitude control mechanism such as an azimuth/elevation method, an X-Y method, or a Burdeck method is used.

(Problems to be Solved by the Invention) However, in these antenna attitude control methods, it is necessary to set and arrange another drive axis on one drive axis.

That is, the height of the antenna increases. This is a vehicle,
This has been an obstacle to miniaturizing the antenna when it is placed on a moving object (hereinafter referred to as a moving object) such as a ship or an aircraft.

In addition, since the attitude of the antenna itself changes as the moving body moves, it has been desired to improve the frequency and accuracy of attitude control.

Therefore, a first object of the present invention is to provide an antenna that does not require attitude control by widening the beam. A second object is to make the antenna thinner and to reduce the area occupied by the antenna so that it can be easily placed on a moving body.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, the present invention arranges at least four λ/2 (λ is one wavelength) dipole antenna elements in a grid pattern to form a circularly polarized linear antenna. do.

(Function) According to this, by arranging the four Guypol anti-f@ elements in a cross-shaped pattern, it is possible to transmit and receive circularly polarized waves while maintaining the symmetry of the antenna. In addition, as will be described later, its half-power angle is approximately 120 to 130 degrees, and its axial ratio (3 dB or less) is approximately 1.
30 degrees, which is an improvement over conventional cross dipole antennas. Furthermore, since it is sufficient to simply arrange the antenna elements in a grid pattern, the thickness of the antenna can be reduced, and the occupied area can be reduced.

(Example) An example of the present invention will be described below. FIG. 1 shows a plan view of the circularly polarized linear antenna of the present invention. Dipole antenna elements 10, 11, 12° 13 having a length of λ/2 are arranged in a grid pattern. The wire of the antenna element is composed of a piano wire with a diameter of 0.3 mm and plated with 25 μm of gold.

Each antenna element crosses each other. This intersection is a point 0.1875λ from the center of each antenna element. A gap of 1.0×10""λ is provided at the intersection so that the antenna elements are electrically insulated from each other (see FIG. 2).

Further, power is fed to each antenna element so that the antenna elements are out of phase by 90 degrees.

Next, the characteristics of the antenna with the above configuration are shown in Table 1, Table 2, and Figures 3 and 4. (Y plane)
Table 2 and Figure 4 show the Y-2 plane of the antenna (Y-2 plane in Figure 1).
-2 side) characteristics are shown.

Further, in Tables 1 and 2, H (0 degrees) indicates the characteristics of horizontal polarization, and H [90 degrees] indicates the characteristics of vertical polarization.The unit is dB.

(Margins below) Table 1 (X-Y plane) Table 2 (Y-Z plane) The half-value angle determined from FIGS. 3 and 4 is approximately 130 degrees. Also, when finding the point where the axial ratio is 3 dB or less, it is approximately 1
The temperature ranges from 20 to 130 degrees.

As described above, in the present invention, it is only necessary to arrange four antenna elements in a grid pattern. Therefore, it can be easily mounted at any position on the moving body. As for the mounting location, it can be mounted on an external material or glass that faces toward the air. If the moving object is a car, it is advantageous to integrate it into the ceiling or glass.

[Effects of the Invention] As described above, according to the present invention, by configuring the dipole antenna element in a cross-shaped shape, the half-power angle can be approximately 120 to 13.
The antenna can have an angle of 0 degrees and an axial ratio (3 dB or less) of approximately 130 degrees. This is improved compared to the half-value angle of a conventional cross dipole antenna, which is about 60 to 70 degrees. The wide-angle axial ratio has also been improved. Therefore, a wide range can be covered without having to control the attitude of the antenna. Furthermore, since there is no need to control the attitude of the antenna, an attitude control device is also not required, making it easy to mount the antenna on a moving body. In addition, since the antenna element only needs to be configured in a cross-shaped structure, the antenna can be thin and occupy a small area. Therefore, mounting on a moving object can be made easier.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing one embodiment of the antenna of the present invention, FIG. 2 is a side view showing one embodiment of the antenna of the present invention, and FIG.
4 and 4 are diagrams showing the characteristics of an embodiment of the antenna of the present invention.

Claims (5)

[Claims] (1) A circularly polarized linear antenna in which at least four λ/2 (λ is one wavelength) dipole antenna elements are arranged in a parallel grid pattern. (2) The circularly polarized linear antenna according to claim 1, wherein portions of the antenna elements that intersect with each other are electrically insulated. (3) The circularly polarized linear antenna according to claim 2, wherein the electrical insulation is configured by arranging a gap between each antenna element. (4) The circularly polarized linear antenna according to claim 3, wherein the point where the antenna elements intersect is at a position 0.1875λ from the center of each antenna element. (5) The circularly polarized linear antenna according to claim 1, wherein the phases of power feeding to the antenna elements are different by 90 degrees.