JPS58101509A - Antenna device - Google Patents

Abstract

PURPOSE:To eliminate the need for the adjustment of amplitude and phase, feeding lines and to improve the broad band characteristic, by using a reflection type phased antenna. CONSTITUTION:A subarray antenna 12a has the characteristics which passes through electromagnetic waves of a frequency band and reflects the most parts of the waves, the antenna is inserted to a notch provided in a part of a mirror surface to be almost the same plane as the mirror surface, and a phase shifter 12b, an attenuator 12c, and a short-circuit plane 12d are fitted on the antenna 12a at the rear side of the reflecting mirror as layers. Electromagnetic waves incident to the antenna 12a are reflected other than the waves of one frequency band to be transmitted for the formation of a main beam. The transmitted waves of the frequency band pass through the phase shifter 12a and the attenuator 12c and are reflected on the short-circuit plane 12d, and pass through the attenuator and phase shifter again and are reflected to the outside through the antenna 12a. Further, the phase shifter and the attenuator are controlled to provide the required phase shift and attenuation for the electromagnetic waves, allowing to obtain a desired directivity.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an antenna that can control the antenna's wave rope in a rounded manner to reduce interference from a particular direction. More specifically, the present invention relates to an antenna that uses one reflecting mirror and shares two or more frequency bands, and can lower the side rope in a certain direction.

Taking the case of a receiving antenna as an example of a conventional so-called O antenna, as shown in Fig. 1, in addition to the main antenna, a sub antenna is provided with the main radiation direction facing the interference wave source, and the main antenna and the sub antenna are connected to each other. By combining the interference waves received by the antenna so that they cancel each other out, the side lobe in the direction of the interference wave source of the main antenna is apparently lowered.

That is, in Fig. 111, the interference wave received by the sub-antenna (2) whose main radiation direction is directed toward the interference wave source is transmitted through a variable attenuator (3) and a variable phase shifter (4), and is then processed by a combining circuit (
5), the side lobe in the direction of the interference wave source of the main antenna (1) is combined with the received interference wave. At this time, 1 synthesis circuit (
If the variable attenuator (3) and variable phase shifter (4) are adjusted so that the interference wave output becomes zero at the output (6) of 5), there will be no interference wave output and only the desired wave will be output ( 6) Hail to you.

However, in the configuration shown in FIG. 1, if the main antenna (1) is a multi-frequency band antenna of two or more, the sub antenna (2) and the variable attenuator (3) are used.

Either a variable phase shifter (4) and a combining circuit (5) are provided for each frequency band, or the sub antenna (2) is also connected to the main antenna (1).
As a multi-frequency band common antenna, after splitting into each frequency band with a demultiplexer, a variable attenuator (3) and a variable phase shifter (4) are used.
Since it is necessary to provide a synthesis circuit for each frequency band, the structure becomes complicated and economically expensive. Furthermore, it is almost impossible to match the electrical lengths between the main antenna 111 and the combining circuit (5) and between the auxiliary antenna (2) and the combining circuit (5) over a wide band, and only narrow band performance can be obtained. Furthermore, if the direction of the interference wave source changes, it is necessary to change the direction of the sub antenna (2) and readjust the variable attenuator (3) and variable phase shifter (4) for each frequency band. There were drawbacks.

This invention aims to solve these shortcomings.

The secondary antenna is configured as a reflective phased array antenna, and its aperture is installed so that it coincides with a part of the inner surface of the reflector of the main antenna. By installing a frequency-selective element that passes only radio waves and reflects radio waves in other frequency bands, a part of the radio waves in the target frequency band is used from the radiation waves from the primary radiator of the main antenna. This eliminates the need for a synthesis circuit, and by controlling the phase shifter and attenuator in the phased array antenna, it is possible to respond to changes in the direction of the interference wave source without moving the antenna. The drawings will be described in detail below.

FIG. 2 shows an embodiment of the present invention, in which the main antenna is a horn reflector antenna and the side ropes are controlled in one frequency band. In the figure, QQ is a water induction horn with a multi-frequency band, 1 parabolic reflector is a parabolic reflector, and (12m) is a sub-play antenna with a reflective 7-aided array antenna configuration. It is a frequency-selective element that reflects most of the radio waves in the band, and is installed by fitting it into a cut-out part of a mirror surface, so that it is flush with the mirror surface. (12b) is a phase shifter.

(12c) is an attenuator, (12dl is a short-circuit surface for reflection, and is mounted in a layered manner on the selective element on the back side of the reflecting mirror. Figure 3 is the same as that in Figure 2. It is a front view.

In the figure, most of the multi-frequency radio waves emitted from the -order horn member are reflected by a parabolic reflector I and have the same phase at the aperture surface, forming a main beam in the front direction. On the other hand 9
The radio waves incident on the frequency selective element (12a) are reflected by this surface, except for the radio waves in one frequency band that pass therethrough, to form the main beam. ), passes through the attenuator (12c), and passes through the short-circuit surface (1
2d) and is reflected at the attenuator (12c) and phase shifter (12c) again.
12b) and is reflected to the outside through one frequency selective element (12m). The light phase generator (12b) and the attenuator (1
2c) t- By electronically controlling from the outside and giving the necessary phase shift and attenuation to one wave, it is possible to obtain the desired radiation directivity as the 1LAL array antenna Qa. In addition, if the array antenna also changes only the direction of the radiation directivity of the hot water, the attenuator (L2c) may be set in advance and a fixed attenuator may be used, or it may not be used.

Therefore, in the frequency band where the side lobes are controlled, if you want to lower the side lobes in a certain characteristic direction in the radiation directivity from the parabolic reflecting mirror surface 6 theory other than the sub-play antenna aJ to avoid interference, the AT array antenna It is possible to direct the four-directional main beam in the direction of the side ropes, match the amplitudes, and make one phase out of phase. The size of the auxiliary play antenna I is determined by the direction and level of the side ropes of the main antenna to be rounded and lowered to avoid interference waves. In a normal horn reflector antenna, the side rope level is approximately -20 dB or less, so the parabolic reflector 01)K
On the other hand, the size of the sub-array antenna function can be made considerably small, and there is no problem in terms of configuration or structure.

FIG. 4 shows another embodiment of the present invention, in which the main antenna is a horn reflector antenna and there are two frequency bands for controlling the side ropes. In the figure, I is an array antenna for controlling the sub-array antenna ring and the side rope of another frequency band, and its structure and function are the same as the array antenna I.

FIG. 6 is a front view of FIG. 4.

Therefore, in this case, in the radiation directivity of the main antenna in this frequency band, the side ropes in one direction or in different directions can be lowered to avoid interference waves.

As explained above, according to the present invention, a round antenna that conventionally requires a sub-antenna installed in addition to the main antenna, and a circuit that adjusts and synthesizes the amplitude and phase of the interference waves between both antennas, Even in the case of a multi-frequency antenna, the amplitude can be improved by providing a sub-array antenna in a part of the parabolic reflector surface, using a frequency-selective element in its aperture, and making this sub-array antenna a reflective phased array antenna. This eliminates the need for a circuit that adjusts and synthesizes the phase, making it possible to lower the side lobe in the direction of the interference wave source in the frequency band corresponding to the 9-frequency & number-selective element, and when changing the direction in which you want to lower the side lobe. This has the advantage that it is only necessary to electronically control the phase shifter and attenuator in the sub-array antenna from the outside, and there is no need to change the installation direction of the antenna. In addition, even if the number of frequency bands to control the side lobe increases, since the sub-play antenna is provided through one frequency-selective element, a sub-array antenna can be provided for each frequency band without affecting other frequency bands. Another advantage is that the side ropes can be lowered in different directions for each frequency band.

Furthermore, the frequency selective element of each sub-play antenna is in y-coincidence with the parabolic reflecting mirror surface, which serves as the aperture of the sub-play antenna.

By eliminating the need for a feed line and shortening the length of the phase shifter and attenuator, the frequency characteristics of the radiation waves from the sub-array antenna can be made close to that of the main antenna, resulting in broadband characteristics. It has the advantage of being able to

Note that although the above explanations have been given for examples of horn reflector antennas, the same results can be applied to other types of antennas that use a single reflector, such as parabolic antennas, Cassegrain antennas, offset antennas, etc. Effects can be obtained.

In this way, the antenna device according to the present invention that can reduce interference waves has multiple frequency bands, can easily change the direction in which the side rope is desired to be lowered, and can obtain broadband characteristics, making it practical for practical use. is of great value.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing a conventional antenna device. FIG. 2 is a sectional view showing one embodiment of the antenna device according to the present invention, FIG. 8 is a front view of the antenna device intended for stripes, and FIG.
The figure is a sectional view showing another embodiment of the present invention, and FIG. S is a front view of FIG. 4. (1)...Main antenna, +2)...Sub antenna, (
3)...variable attenuator, (4)...variable phase shifter, a
ll...-next horn, Gichin...parabolic reflector, a2
．． a3...Sub array antenna, (12m) (1
3m) - frequency selective element, (12b) (tab) -.
・Phase shifter, f12c) (13e) -Attenuator,
(12d) (13d)...Short-circuit surface Note that the same or corresponding parts in each figure are designated by the same reference numerals. Agent Shin Kuzuno −

Claims (1)

[Scope of Claims] 0) A partial horn that transmits or receives radio waves, a reflecting mirror that reflects radio waves facing this secondary horn, and a portion of this reflecting mirror surface that is substantially uniform with the mirror surface. A frequency-selective element provided in the top and a phase shifter in which the selective element is layered*. 1. An antenna device comprising a plurality of reflective array elements each including an attenuator and a short circuit surface. (2) Equipped with a plurality of reflective array elements for each of two or more different frequency bands (one frequency selective element, phase shifter, attenuator, shorting surface, etc.) for each of two or more different frequency bands. The antenna device according to claim II (1), characterized in that: