JPS623510A - Antenna system shaping multi-frequency band - Google Patents

Abstract

PURPOSE:To use one antenna at plural frequency bands having different frequency bands by providing the 1st transmission/reception section transmitting/receiving a radio wave at the frequency band reflected in a frequency selection reflecting plate and the 2nd transmission/reception section transmitting/receiving a radio wave of a frequency band transmitted through the frequency selection reflecting plate. CONSTITUTION:A radio wave at a low frequency band is irradiated toward the frequency selective reflecting plate 10 from an electromagnetic horn 11 as a spherical wave taking a focus F1 as a wave source. The sherical wave is converted into a plane wave by the frequency selective reflecting plate 10 and irradiated toward a sub reflection mirror 32. On the other hand, a radio wave at a high frequency band is irradiated from an electromagnetic horn 13 toward a dielectric focus lens 12 as a spherical wave taking a focus F2 as a wave source. The spherical wave is converted into a plane wave by a dielectric focus lens 12, transmits through the frequency selectivity reflecting plate 10 and is directed to the sub reflecting mirror 32. In this case, since the plate 10 does not almost give any frequency change, the sub reflection mirror is fed by a plane wave even to a radio wave at a high frequency band irradiated from the electromagnetic horn 3.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a microphone and a multi-frequency band common antenna device that can share two or more relatively distant frequency bands in a high frequency region of four or more waves.

(Prior art) In satellite communications that use frequencies higher than the microwave band, such as microwaves and sub-millimeter waves, upstream I! (uplink) and the downlink from the satellite to the earth station (downlink), for example, 6G
Hz band and 4 GHz band, and earth stations generally use antennas that can transmit and receive signals using a pair of frequency bands. By the way, in recent years, in order to cope with the increasing demand for communication, for example, the Intelsat 5 satellite is equipped with repeaters for the 6/4 GHz band and 14/IIGH2 band.
There is a trend toward increasing communication capacity by allowing each satellite to handle multiple frequency bands.

On the other hand, as the shared antenna, an antenna in which a sub-reflector is interposed between a main reflector and a primary radiator, such as a Cassegrain antenna, is widely used. This type of antenna is classified into a spherical wave feeding type and a plane wave feeding type, depending on the wave front through which the primary radiator feeds the sub-reflector.The plane wave feeding type antenna to which the present invention is directed has a configuration, for example, as shown in FIG. be done. FIG. 3 shows a Cassegrain antenna, which includes a main reflector 31, a sub-reflector 32 placed at the focal point of the main reflector 31, and a primary radiator placed on the back side of the main reflector 31. It consists of 33. The primary radiator 33 includes a focusing reflector 33a disposed near the apex of the main reflector 31, and an electromagnetic horn 33b for transmitting and receiving radio waves.
It consists of The focusing reflector 33a has its reflecting surface at point F.
The electromagnetic horn 33b forms a part of a paraboloid of revolution having a focal point F1, and the electromagnetic horn 33b is arranged so that the focal point F1 becomes its wave source.

In the antenna configured in this way, the electromagnetic horn 3
3b is a reflecting mirror 33a that focuses a spherical wave with a wave source at the focal point F1.
When the spherical wave is radiated toward , this spherical wave is converted into a plane wave by the focusing reflector 33 a and reflected in the direction of the sub-reflector 32 . The sub-reflector 32 converts the plane wave from the focusing reflector 33a into a spherical wave as if it were radiated from the focal point of the main reflector 31, and reflects it toward the main reflector 31. This spherical wave is converted into a plane wave again by the main reflecting mirror 31 and is reflected in the front direction from the aperture surface with the same phase.

In this way, in the plane wave feeding type antenna, the sub-reflector 32
In order to supply power by essentially a planar wavefront with a small spread of the wavefront, it is possible to obtain an illuminance distribution in which the power density sharply decreases around the sub-reflector 32 over a wide frequency band. It is possible to realize a good antenna with less deterioration of sidelobe characteristics due to leakage power.

(Problems to be Solved by the Invention) However, when trying to transmit and receive radio waves in multiple frequency bands with one antenna in order to deal with the above-mentioned tendency with such conventional plane wave feeding antennas, the electromagnetic horn becomes Since there is only one, it is necessary to separate and combine each paired frequency band in the power supply circuit that supplies power to the electromagnetic horn.

However, for example, 6/4GH2 band and 14/11GHz
In order to separate the 6/4 GHz band, the waveguide used is for the 6/4 GHz band, and if the 14/IIGH2 band electromagnetic waves are propagated through this waveguide, it will become oversized.
Numerous higher-order modes occur, 14/11 GHz
There is a problem in that the communication quality in the frequency band is significantly degraded.6 Therefore, in the past, it has been unavoidable to construct a dedicated antenna for each frequency band. However, if one earth station antenna is used for each frequency band, e.g.
If it can be used in common with 4GH2 and 14/11 GHz bands,
The cost of antenna equipment, including securing the site, can be significantly reduced, and there are also significant benefits in terms of operation and maintenance.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to enable a single antenna to be shared by multiple frequency bands with different frequency ranges without deteriorating its quality, thereby reducing antenna equipment costs and facilitating operation and maintenance. An object of the present invention is to provide a multi-frequency band antenna that can achieve the following.

(Means for Solving the Problems) In order to achieve the above object, the multi-frequency band antenna according to the present invention includes a main reflector and a sub-reflector that convert plane waves and spherical waves, and a plane wave that transmits and receives waves. In the antenna device, the primary radiator is located at a position where radio waves are transmitted and received between the main reflector and the primary radiator via a sub-reflector. a frequency-selective reflector that reflects a part of the frequency bands of the plurality of frequency bands of radio waves transmitted and received and transmits the radio waves of the remaining frequency bands; and a frequency-selective reflector that reflects the frequencies reflected by the frequency-selective reflector. a first wave transmitting/receiving unit that transmits and receives radio waves belonging to a frequency band to and from the sub-reflector through reflection by the reflector, and a radio wave belonging to a frequency band that transmits through the frequency selective reflector through the reflector; It is composed of the sub-reflector and a second wave transmitting/receiving section that transmits and receives waves.

(Function) According to this configuration, the radio waves received via the sub-reflector are sent to the first reflector by the frequency-selective reflector according to the frequency band of the radio waves.
and a second wave transmitting/receiving section. Also, the first
The radio waves of different frequency bands respectively transmitted from the wave transmitting/receiving section and the second wave transmitting/receiving section are combined by the frequency selective reflector and radiated from the main reflecting mirror via the sub-reflecting mirror.

For this reason, the power supply circuit that feeds the electromagnetic horn included in each wave transmitting/receiving unit can use a waveguide that matches the frequency band being handled, thereby preventing the occurrence of higher-order modes that cause deterioration in communication quality. will disappear. In this way, it becomes possible to share two or more frequency bands that are relatively separated.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. Incidentally, the same parts as those of the conventional example shown in FIG. 3 are given the same reference numerals, and the explanation thereof will be omitted.

FIG. 1 is a diagram showing the configuration of a multi-frequency band antenna according to a first embodiment of the present invention. The primary radiator 1 according to one embodiment of the present invention has a sub-reflector 3 near the apex of the main reflector 31.
2, an electromagnetic horn 11 whose aperture face faces the reflection surface of the frequency-selective reflector 10, and a sub-reflector for the frequency-selective reflector 10. It is composed of a dielectric focusing lens 12 and an electromagnetic horn 13 placed on the opposite side of the mirror 32.

The frequency-selective reflector 10 is made of, for example, a rectangular metal lattice plate with a large number of rectangular windows perforated in a thin metal plate, and in this embodiment, it reflects a low frequency band among a plurality of relatively distant frequency bands. However, we use a high-frequency transmission type that transmits high frequencies. The reflecting surface of this frequency selective reflecting plate 10 has a shape forming a part of a paraboloid of revolution, and is arranged so that the wave source of the electromagnetic horn 11 is located at its focal point F1.

t=y4 The electric concentrating lens 12 has a focal point F2, and is arranged so that the wave source of the electromagnetic horn 13 is located at this focal point F2.

In such a configuration, radio waves in a low frequency band are emitted from the electromagnetic horn 11 toward the frequency selective reflector 10 as a spherical wave with the focal point F1 as a wave source. This spherical wave is converted into a plane wave by the frequency selective reflector 10 and reflected toward the sub-reflector 32. On the other hand, high-frequency radio waves are emitted from the electromagnetic horn 13 toward the dielectric focusing lens 12 as a spherical wave with the focal point F2 as the wave source.

This spherical wave is converted into a plane wave by the dielectric focusing lens 12 and then passes through the frequency selective reflector 10 and heads towards the sub-reflector 32. At this time, since the frequency-selective reflector 10 gives almost no wavefront change to the transmitted waves, it is possible to feed the sub-reflector with plane waves even for high-frequency radio waves emitted from the electromagnetic horn 13. It will be possible.

Although the above is a description of the transmitted wave of the primary radiator, the wavefront conversion is performed in exactly the same way for the received wave, only the traveling direction of the radio wave is reversed.

Next, FIG. 2 is a diagram showing the configuration of a primary radiator in a multi-frequency band antenna according to a second embodiment of the present invention. Extracting and explaining the differences from the first embodiment,
In this primary radiator 2, the reflection surface of the frequency selective reflection plate 24 made of the rectangular metal lattice plate is formed into a flat plate shape, and a focusing reflection mirror is provided between the frequency selective reflection plate 24 and the electromagnetic horn 11. 25 is arranged, and this focusing reflector 25
The electromagnetic horn 11 is arranged so that the wave source is located at the focal point F. , and is emitted toward the sub-reflector 32. In other words, the sub-reflector is irradiated with a plane wave in exactly the same way as in the first embodiment.

The configuration of the primary radiator 2 according to the second embodiment is effective in the case of an antenna device in which there is no mechanical margin for the support structure in the antenna radial direction.

As is clear from each of the above embodiments, in the primary radiator according to the present invention, dedicated electromagnetic horns 11 and 13 are provided for two frequency bands that are relatively apart from each other. The horn 11 has a low frequency band (
For example, a dedicated power supply circuit (for example, 074 GHz), and a high frequency band (for example, 14/11 GHz) for the electromagnetic horn 13.
> Since dedicated feeder circuits can be connected to each, in other words, the optimum waveguide for each frequency band can be used, an antenna device with optimized performance for each frequency band can be obtained.

In each of the above embodiments, the frequency-selective reflector was explained as having high-frequency transmission characteristics using a rectangular metal lattice plate. A low-pass transmitting type reflector may be used; in this case, the frequency bands handled by the electromagnetic horns 11 and 13 are opposite to those in the above case.

Furthermore, although the dielectric focusing lens 12 has been described as being separated from the electromagnetic horn 13, it may be an integral structure in which the dielectric focusing lens 12 is attached to the opening of the electromagnetic horn 13.

Furthermore, although the antenna device has been described as a Cassegrain type in which the main reflector and the sub-reflector have an axially symmetrical mirror system, the present invention is not limited to this. Of course, the present invention can also be applied to a mirror-type antenna device that is axially asymmetric.

(Effects of the Invention) As detailed above, according to the multi-frequency band antenna device according to the present invention, the primary radiator communicates with the sub-reflector in a part of the plurality of frequency bands of radio waves transmitted and received. a frequency-selective reflector that reflects radio waves and transmits radio waves in the remaining frequency band; and transmits and receives radio waves belonging to the frequency band reflected by the reflector to and from the sub-reflector through reflection by the reflector. Since it is equipped with a first wave transmitting/receiving section and a second wave transmitting/receiving section that transmits a radio wave belonging to a frequency band that passes through the reflector and transmits and receives a wave with the sub-reflector, The power feeding circuit that feeds the electromagnetic horn provided in each wave transmitting/receiving section can use a waveguide that matches the frequency band being handled, without generating higher-order modes that degrade communication quality.
It becomes possible to share two or more frequency bands that are relatively separated. As a result, antenna equipment costs can be significantly reduced, and operation and maintenance can be made easier.

In addition, each transmitter/receiver section can be optimally designed according to the frequency band it handles, so performance can be optimized in multiple frequency bands while maintaining the good sidelobe characteristics that are characteristic of plane wave-fed antennas. .

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the multi-frequency band common antenna device of the present invention, FIG. 2 is a block diagram of a primary radiator of another embodiment of the multi-frequency band common antenna device of the present invention, and FIG. The figure is a configuration diagram of a conventional plane wave feeding type antenna device. 1.2...Primary radiator, 10.24...
...Frequency selective reflector, 11.13... Electromagnetic horn, 12... Dielectric focusing lens, F,
, F2... Focus, 25... Focusing reflector, 31... Main reflecting mirror 32... Sub-reflecting mirror. Agent Patent Attorney Yoshihiro YahataFl, F2-・Toma・Takata 5 skin a straw base antenna princess 1 1st Figure 24--Itshouran @ju se watagaratakari Fj, F2-1--Kyo North, 1st Kagemiya's SeA firing column, 2nd figure, 5th column, 3rd figure

Claims (5)

[Claims] (1) Equipped with a main reflector and a sub-reflector that convert between plane waves and spherical waves, and a primary radiator that transmits and receives plane waves, and transmits and receives radio waves between the main reflector and the primary radiator via the sub-reflector. In the antenna device, the primary radiator is disposed at a position to transmit and receive radio waves with the sub-reflector, and reflects radio waves in a part of the frequency bands of the radio waves to be transmitted and received. a frequency-selective reflector that transmits radio waves in the remaining frequency band; and a second frequency-selective reflector that transmits and receives radio waves belonging to the frequency band reflected by the frequency-selective reflector to and from the sub-reflector through reflection by the reflector. a second wave transmitting/receiving section for transmitting and receiving waves with the sub-reflector by transmitting radio waves belonging to a frequency band that transmits through the frequency selective reflector through the reflector; An antenna device that can be used for multiple frequency bands. (2) The frequency selective reflector has a reflecting surface formed in a parabolic shape, and the first wave transmitting/receiving section includes a first electromagnetic horn disposed at the focal point of the reflector. A multi-frequency band shared antenna device according to claim (1). (3) The frequency selective reflector has a planar reflecting surface, and the first wave transmitting/receiving section is a focusing reflector disposed at a position to receive the received radio waves reflected by the reflector. 2. The multi-frequency band antenna device according to claim 1, further comprising a first electromagnetic horn placed at the focal point of the focusing reflector. (4) The second wave transmitting/receiving unit includes a radio wave concentrator disposed at a position to receive the received radio waves transmitted through the frequency selective reflector, and a second electromagnetic wave concentrator disposed at a focal position of the radio wave concentrator. 2. The multi-frequency band antenna device according to claim 1, further comprising a horn. (5) The multi-frequency band antenna device according to claim 4, wherein the radio wave focusing body is a dielectric focusing lens.