JP2002185247A - Array antenna device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an array antenna device for inhibiting the interference between adjacent antenna elements. SOLUTION: In the array antenna having a plurality of horn antennas 1a and 1b that are arranged in a specific arrangement, and an amplifier 3 for amplifying a reception signal by each of the horn antenna 1a and 1b, the plurality of horn antennas 1a and 1b are arranged while the polarization directions of the adjacent horn antennas 1a and 1b orthogonally cross each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an array antenna in which a plurality of antenna elements are arranged and used for an on-vehicle radar, an observation radar, and the like, and more particularly to suppression of interference between antenna elements.

[0002]

2. Description of the Related Art FIG. 5 is a schematic configuration diagram of a conventional array antenna device, and also shows an outline of characteristics of the array antenna. In this array antenna device 500, a plurality of antenna elements 501 are arranged according to a predetermined rule, and an amplifier 503 and a detector 505 are provided for each antenna element 501.
Is connected to Further, a signal processing device 507 is connected to each detector 505. The plurality of antenna elements 501 of the array antenna device 500 include radio wave sources A,
When receiving a plurality of radio waves from B,..., X, it has strong directivity in which a main lobe Rm is formed in each direction of the arriving radio waves, while the adjacent antenna element 5
It is configured not to receive the direct wave 01.

[0003]

However, in the above-described conventional array antenna apparatus 500, as shown in the figure, low-power side lobes Rs exist on both sides of the main lobe Rm, and the bias of each antenna element 501 is increased. Since the wave directions are all the same, the side lobes Rs are overlapped between adjacent antenna elements. Therefore, there is a problem that the reflected wave of one antenna element 501 is input to the other antenna element 501 between adjacent antenna elements due to the influence of the side lobe Rs, and interference occurs between the antenna elements. .

[0004] Further, a reflected wave from the amplifier 503 or the like connected to the adjacent antenna element 501 may be input to the other antenna element 501. In this case, interference occurs between adjacent antenna elements. There is a problem that each antenna element 501 cannot exhibit sufficient characteristics.

[0005] The present invention has been made in view of such a problem, and has as its main object to provide an array antenna device capable of suppressing interference between adjacent antenna elements.

[0006]

According to a first aspect of the present invention, there is provided an array antenna device having a plurality of antenna elements arranged in a predetermined arrangement. And the antenna elements are arranged so that the polarization directions of adjacent antenna elements are orthogonal to each other.

According to the first aspect of the present invention, since the antenna elements are arranged so that the polarization directions of adjacent antenna elements are orthogonal to each other, the side lobes of both antenna elements are formed in directions orthogonal to each other. . For this reason, even if a reflected wave or re-radiation occurs from one adjacent antenna element, such a reflected wave or re-radiation wave is not input to the other antenna element, and interference between adjacent antenna elements is prevented. You. Further, the antenna elements in the present invention only need to be arranged so that the polarization directions of adjacent antenna elements are orthogonal to each other, and a specific arrangement can be arbitrarily determined.

According to a second aspect of the present invention, in the array antenna device of the first aspect, a quarter wavelength plate is provided in front of the plurality of antenna elements. According to the first aspect of the present invention, since the polarization directions of adjacent antenna elements are orthogonal to each other, it is not possible to simultaneously receive vertically polarized radio waves in the same direction. Since the quarter wave plate is provided in front of the antenna element, the arriving radio wave passes through the quarter wave plate and changes its phase, so that the vertically polarized wave is converted into a circularly polarized wave. For this reason, it becomes possible to receive vertically polarized radio waves in the same direction with adjacent antenna elements.

According to a third aspect of the present invention, there is provided an array antenna including a plurality of antenna elements arranged in a predetermined arrangement and an amplifier for amplifying a signal received by each antenna element. And a non-reciprocal element for blocking a reflected wave from the amplifier toward the antenna element.

According to the third aspect of the invention, a non-reciprocal element is connected between the antenna element and the amplifier, and the non-reciprocal element blocks a reflected wave from the amplifier toward the antenna element. No input is made to the antenna element, and interference by an adjacent antenna element is prevented.

The nonreciprocal transmission element according to the present invention may be any element that blocks a reflected wave from an amplifier to such an extent that the reflected wave is not input to an adjacent antenna element, and it is necessary to completely block the reflected wave. Not. One example of such a non-reciprocal element is an isolator.

According to a fourth aspect of the present invention, there is provided an array antenna including a plurality of antenna elements arranged in a predetermined arrangement and an amplifier for amplifying a signal received by each antenna element. And an attenuation element for attenuating a reflected wave from the amplifier toward the antenna element.

According to the fourth aspect of the present invention, an attenuating element is connected between the antenna element and the amplifier, and the reflected wave from the amplifier to the antenna element is attenuated by the attenuating element. Is reduced, which leads to suppression of interference by adjacent antenna elements.

The attenuating element in the present invention may be any element that attenuates the reflected wave from the amplifier to such an extent that the reflected wave is not input to an adjacent antenna element, and is not necessarily required to completely block the reflected wave. An example of such an attenuation element is an attenuator.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of an array antenna device according to the present invention will be described below in detail with reference to the accompanying drawings.

The array antenna devices according to the first to fourth embodiments described below are effective for on-vehicle radar effective in the case of fog, observation radar through a fire flame, and using the spectrum of a specific molecule. Radio meters for observing global environment or weather, observing volcanoes emitting smoke, radar for monitoring the attitude of objects during assembly work, sensors for monitoring surroundings of nuclear power plants, etc., detecting plastic bombs under clothing And various fields such as plasma measurement.

(First Embodiment) FIG. 1 is a schematic diagram of an array antenna device according to a first embodiment. The array antenna device of the present embodiment has two horn antennas 1a, 1
b, an amplifier 3 connected to the output side of each of the horn antennas 1a and 1b, a detector 5 connected to each amplifier 3, and a signal processing device 7. still,
The horn antennas 1a and 1b of the present embodiment constitute an antenna element of the present invention.

The amplifier 3 amplifies the received signals of the horn antennas 1a and 1b, and the detector 5 detects the amplified received signal and outputs the detected signal to the signal processing device 7. Horn antenna 1
Reference numerals a and 1b denote antennas using electromagnetic horns, each of which receives a circularly polarized incoming radio wave. In the array antenna device of the present embodiment, two horn antennas 1a, 1b
Are arranged such that their polarization directions are orthogonal to each other. That is, the polarization direction of the horn antenna 1a is the upward direction in FIG. 1, and the polarization direction of the horn antenna 1b is the rear direction in FIG.

As described above, in the array antenna device of the present embodiment, since the two horn antennas 1a and 1b are arranged so that their polarization directions are orthogonal to each other, an incoming wave enters the horn antennas 1a and 1b. In this case, the reflected wave from one horn antenna 1a (and 1b) is not input to the other horn antenna 1b (and 1a), and interference between the adjacent horn antennas 1a and 1b can be prevented. Has become.

(Second Embodiment) FIG. 2 is a schematic diagram of an array antenna device according to a second embodiment. The array antenna device of the present embodiment differs from the device of the first embodiment only in that a quarter-wave plate 9 is provided. For this reason, components other than the quarter-wave plate 9 are denoted by the same reference numerals as in the first embodiment, and description thereof is omitted.

The quarter-wave plate 9 is arranged at a position in front of the horn nozzle (left position in FIG. 2) on the incident side of the incoming wave. The quarter-wave plate 9 converts a vertically polarized radio wave into a circularly polarized wave by giving a phase difference to the radio wave. First
In the array antenna device of the embodiment, since the two horn antennas 1a and 1b are arranged so that the polarization directions are orthogonal to each other, they cannot receive the vertically polarized radio waves in the same direction.

In the array antenna device of this embodiment, 4
The radio wave is guided to the horn antennas 1a and 1b after the vertically polarized wave is converted into the circularly polarized wave by the half-wave plate 9,
Even when vertically polarized radio waves arriving in the same direction arrive, the two horn antennas 1a and 1b can receive the radio waves and exhibit the characteristics of the array antenna.

(Third Embodiment) FIG. 3 is a schematic diagram of an array antenna device according to a third embodiment. The array antenna device of the present embodiment has a point that an isolator 11 is connected between the horn antennas 1c and 1d and the amplifier 3.
The arrangement of the horn antennas 1c and 1d is different from the array antenna device of the first embodiment. Therefore, the same components as those in the first embodiment are denoted by the same reference numerals as those in FIG.

In the array antenna device of this embodiment, 2
The horn antennas 1c and 1d are arranged so that the polarization directions are the same as in the conventional array antenna device. The isolator 11 constitutes the non-reciprocal transmission element of the present invention, and allows propagation of radio waves in a direction from the horn antenna side to the amplifier side, and blocks propagation from the amplifier side to the horn antenna side. . Note that the horn antennas 1c and 1d may be arranged so that their polarization directions are orthogonal to each other, as in the first and second embodiments.

As described above, in the array antenna device of the present embodiment, since the isolator 11 is provided, the reflected wave of the radio wave by the amplifier 3 is prevented from being transmitted back to the horn antennas 1c and 1d by the isolator 11. You. Therefore, the reflected waves from the amplifier 3 are not input to the adjacent horn antennas 1c and 1d, and the interference by the adjacent horn antennas 1c and 1d is prevented.

(Fourth Embodiment) FIG. 4 is a schematic diagram of an array antenna device according to a fourth embodiment. The array antenna device of the present embodiment differs from the array antenna device of the third embodiment in that an attenuator 13 is connected between the horn antennas 1c and 1d and the amplifier 3. Therefore, the same components as those in the third embodiment are denoted by the same reference numerals as those in FIG. 3 and the description is omitted.

In the array antenna device of the present embodiment, 2
The horn antennas 1c and 1d are arranged so that the polarization directions are the same as in the conventional array antenna device. Note that the horn antennas 1c and 1d may be arranged so that their polarization directions are orthogonal to each other, as in the first and second embodiments.

The attenuator 13 constitutes the attenuating element of the present invention, and loses energy when radio waves propagate from the amplifier to the horn antenna.

As described above, in the array antenna apparatus of the present embodiment, since the attenuator 13 is provided, the reflected wave of the radio wave by the amplifier 3 is attenuated by the attenuator 13 and transmitted back to the horn antennas 1c and 1d. Is reduced. Therefore, the adjacent horn antenna 1
Input of reflected waves from the amplifier 3 to c and 1d is reduced, and interference by the adjacent horn antennas 1c and 1d is suppressed.

In each of the array antenna devices of the first to fourth embodiments described above, two horn antennas are arranged. However, even if three or more horn antennas are arranged in an array, the present invention is not limited to this. The effects of the invention can be achieved. In the array antenna devices of the first to fourth embodiments, a horn antenna is used as an antenna element. In addition, a slot antenna and a patch antenna are arranged in an array to provide an array antenna device. It goes without saying that the effect of the present invention can be achieved even if it is configured.

[0031]

As described above, according to the first aspect of the present invention, even if a reflected wave or re-radiation from an adjacent antenna element occurs, such reflected wave or re-radiated wave is applied to the other antenna element. Is not input, and it is possible to suppress the interference by the adjacent antenna.

According to the second aspect of the present invention, it is possible to suppress the interference by the adjacent antenna and to receive the vertically polarized radio wave in the same direction by the adjacent antenna element.

According to the third and fourth aspects of the present invention, it is possible to prevent a reflected wave from an amplifier from being input to an antenna element, thereby suppressing interference by an adjacent antenna element. Play.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an array antenna device according to a first embodiment.

FIG. 2 is a schematic diagram of an array antenna device according to a second embodiment.

FIG. 3 is a schematic diagram of an array antenna device according to a third embodiment.

FIG. 4 is a schematic diagram of an array antenna device according to a fourth embodiment.

FIG. 5 is a schematic view of a conventional array antenna device.

[Explanation of symbols]

 1a, 1b, 1c, 1d: Horn antenna 3, 503: Amplifier 5, 505: Detector 7, 507: Signal processor 9: Quarter wave plate 11: Isolator 13: Attenuator 501: Antenna element

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5J021 AA07 AB07 FA11 FA25 FA26 GA08 HA05 5J045 AA27 DA01 FA02 HA01 5K059 CC05 DD35

Claims (4)

[Claims] 1. An array antenna device comprising a plurality of antenna elements arranged in a predetermined arrangement, wherein said plurality of antenna elements are arranged such that the polarization directions of adjacent antenna elements are orthogonal to each other. Characteristic array antenna device. 2. The array antenna device according to claim 1, wherein a quarter-wave plate is provided in front of said plurality of antenna elements. 3. An array antenna comprising: a plurality of antenna elements arranged in a predetermined arrangement; and an amplifier for amplifying a signal received by each antenna element, wherein the amplifier is connected between the antenna element and the amplifier. An irreversible element for blocking a reflected wave from the antenna element in the direction of the antenna element. 4. An array antenna comprising: a plurality of antenna elements arranged in a predetermined arrangement; and an amplifier for amplifying a signal received by each antenna element, wherein the amplifier is connected between the antenna element and the amplifier. An attenuating element for attenuating a reflected wave in a direction from the antenna element to the antenna element.