JP2006180218A - Array antenna device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an array antenna device capable of reducing side lobes even when using a complex unit having uniform amplitude distribution. <P>SOLUTION: An antenna opening face is formed by arraying a plurality of the complex units 3 having the uniform amplitude distribution in feeder circuits 33, 34 for controlling a plurality of antenna elements arrayed in a row in the array antenna device. The antenna opening face is formed into a pseudo-circular shape by a plurality of the complex units 3 arrayed in one direction, and a plurality of the complex units 3 arrayed in the crossing direction of crossing with the one direction. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an array antenna apparatus in which a plurality of antenna elements are arranged, and more particularly to a technique for reducing the level of side lobes.

  2. Description of the Related Art Conventionally, an array antenna apparatus in which a plurality of transmission / reception modules and phase shifters are arranged is known. In such an array antenna apparatus, in order to reduce costs, a plurality of transmission / reception modules and phase shifters are combined to form a composite unit, and an antenna opening surface is formed by arranging a plurality of such composite units. . Each composite unit is configured to have a uniform amplitude distribution in order to reduce the cost by using it in common.

  By the way, in order to enlarge the antenna opening surface, it is necessary to arrange a plurality of composite units in multiple stages. In this case, for example, as shown in FIG. 11B, it is common to arrange a plurality of composite units uniformly in a rectangular shape.

  However, if the amplitude distribution of each composite unit is uniform, as shown in FIG. 11 (a), the amplitude distribution of the entire antenna opening surface is also uniform, so that the directivity gain can be increased. There is a problem that the level of the side lobe becomes high (see Non-Patent Document 1).

  Further, when a plurality of composite units are arranged in multiple stages, a gap may be formed between the composite units due to the shape of the housing of the composite unit. In this case, there is a step in the amplitude distribution, and there is a problem that the side lobe level becomes higher.

Further, in the conventional array antenna apparatus, as shown in FIG. 12, the antenna aperture surface is divided into an aperture A and an aperture B, and a Σ beam is obtained by the sum of the outputs of aperture A and aperture B, and aperture A Δ beam is formed by the difference between the output of the aperture B and the aperture B. According to this configuration, only one type of phase shifter may be used, but the phase shifter is limited to a case where the antenna opening surface can be divided into two. When the complex unit is an odd number (or odd number), the antenna aperture cannot be divided into two, so that the sum and difference beams cannot be formed, and there is a problem that the monopulse beam by the Σ beam and the Δ beam cannot be formed.
Supervised by Takashi Yoshida, “Revised Radar Technology”, first edition, The Institute of Electronics, Information and Communication Engineers, February 15, 2003, p99

  As described above, the conventional array antenna apparatus has a problem that the side lobe becomes high when complex units having a uniform amplitude distribution are arranged in multiple stages. Further, when the composite units are arranged in an odd number (or odd number), there is a problem that a monopulse beam using a Σ beam and a Δ beam cannot be formed.

  The present invention has been made to solve such problems, and the problem is that even when a composite unit having a uniform amplitude distribution is used, side lobes can be reduced. An object of the present invention is to provide an array antenna apparatus capable of forming a monopulse beam by a Σ beam and a Δ beam even when complex units having a uniform amplitude distribution are arranged in odd stages.

  In order to achieve the above object, an array antenna apparatus according to a first aspect of the present invention provides an antenna aperture by arranging a plurality of composite units having a uniform amplitude distribution in a power feeding circuit that controls a plurality of antenna elements arranged in a row. In the array antenna device having a surface, the antenna opening surface is formed into a pseudo circle by a plurality of composite units arranged in one direction and a plurality of composite units arranged in a crossing direction intersecting the one direction. It is formed.

  An array antenna device according to a second invention is the array antenna device according to the first invention, wherein the plurality of composite units arranged in one direction are alternately arranged in the intersecting direction so as to fill a gap generated in the intersecting direction. It is arranged by shifting the position.

  The array antenna apparatus according to a third aspect of the present invention is the array antenna apparatus according to the first or second aspect of the present invention, wherein each of the plurality of composite units in at least one direction of the one direction and the intersecting direction has an amplitude distribution on the antenna opening surface. It is characterized in that the amplitude distribution in the power feeding circuit is corrected so as to change smoothly.

  The array antenna apparatus according to a fourth aspect of the present invention is the array antenna apparatus according to the first aspect of the present invention, wherein each of the plurality of composite units includes two types of phase shifters that independently control the phase of the received signal from the antenna element. A mono-pulse beam by controlling the phase of one of the two types of phase shifters to form a Σ beam and controlling the phase of the other phase shifter to form a Δ beam. It is characterized by forming.

  According to the array antenna device of the first invention, the antenna opening surface is formed in a pseudo-circular shape by the plurality of composite units arranged in one direction and the plurality of composite units arranged in the intersecting direction intersecting the one direction. Therefore, the amplitude distribution on the antenna opening surface has a taper. Therefore, even when a composite unit having a uniform amplitude distribution is used, the side lobe level is reduced.

  According to the array antenna apparatus according to the second aspect of the invention, the plurality of composite units arranged in one direction are arranged so as to be alternately shifted in the intersecting direction so as to fill a gap generated in the intersecting direction. The unevenness of the amplitude distribution is reduced and smoothed, and the side lobe level can be further reduced.

  According to the array antenna apparatus of the third invention, each of the plurality of composite units in at least one direction of the one direction and the crossing direction has an amplitude distribution in the feed circuit so that the amplitude distribution on the antenna opening surface changes smoothly. Therefore, the amplitude distribution on the antenna opening surface becomes smooth, and the side lobe level can be reduced.

  According to the array antenna apparatus of the fourth invention, the mono-pulse is formed by controlling the phase of one phase shifter to form a Σ beam and controlling the phase of the other phase shifter to form a Δ beam. Since the beam is configured to be formed, the monopulse beam can be formed when the monopulse beam of the Σ beam and the Δ beam is necessary by using an odd-numbered (or odd-numbered) complex unit having a uniform amplitude distribution.

  Hereinafter, an array antenna apparatus according to an embodiment of the present invention will be described in detail with reference to the drawings.

  In the following description, one direction of the present invention will be described as “horizontal direction”, and an intersecting direction intersecting one direction will be described as “vertical direction”. However, one direction is defined as “vertical direction”, and an intersecting direction intersecting one direction is represented by “ It can also be “lateral”.

  FIG. 1 is a diagram illustrating a configuration of an array antenna apparatus according to Embodiment 1 of the present invention. This array antenna apparatus includes a horizontal distribution synthesizer 1, a plurality of vertical distribution synthesizers 2, a plurality of composite units 3, a plurality of vertical synthesizers 4, a horizontal synthesizer 5, and a circulator 6.

  The circulator 6 sends a transmission signal Tx sent from a transmitter (not shown) to the horizontal distribution synthesizer 1 or a vertical direction (elevation direction, hereinafter referred to as “EL direction”) sent from the horizontal synthesizer 5. The difference signal ΔEL is switched to a receiver not shown.

  The horizontal distribution synthesizer 1 distributes the power of the transmission signal Tx sent from the transmitter via the circulator 6 and sends it to the vertical distribution synthesizer 2 and the composite unit 3 (the signal path is a broken line in FIG. 1). Is shown). Further, the horizontal distribution synthesizer 1 synthesizes the reception signal Rxb2 included in the reception signal Rxa sent directly from the composite unit 3 and from the composite unit 3 via the vertical distribution synthesizer 2. A vertical difference signal ΔEL is generated and sent to the receiver via the circulator 6.

  The vertical distribution combiners 2 are provided in a number corresponding to the number of columns of the plurality of composite units 3 that form the antenna opening surface. Each vertical distribution synthesizer 2 further distributes the power of the transmission signal sent from the horizontal distribution synthesizer 1 and sends it to the composite unit 3 as a transmission signal Txa. The vertical distribution synthesizer 2 synthesizes the reception signal Rxb2 included in the reception signal Rxa transmitted from the composite unit 3 and sends it to the horizontal distribution synthesizer 1.

  A plurality of composite units 3 are provided so as to form an antenna opening surface of the array antenna device. The plurality of composite units 3 are arranged in a pseudo circle (details of the arrangement will be described later). Details of the configuration and operation of each composite unit 3 will be described later.

  The vertical synthesizers 4 are provided in a number corresponding to the number of columns of the plurality of composite units 3 that form the antenna opening surface. Each vertical direction synthesizer 4 synthesizes the reception signal Rxb1 included in the reception signal Rxa from the composite unit 3 and sends it to the horizontal direction synthesizer 5.

  The horizontal direction synthesizer 5 is based on the received signal Rxb1 included in the received signal Rxa transmitted directly from the composite unit 3 and via the vertical direction synthesizer 4, and the sum signal Σ and the horizontal direction (azimuth direction, The difference signal ΔAZ (hereinafter referred to as “AZ direction”) is generated and sent to a receiver (not shown).

  FIG. 2 is a block diagram showing a detailed configuration of the composite unit 3. The composite unit 3 includes a plurality of transmission / reception modules 32, a distributor 33, and a combiner 34. The distributor 33 and the combiner 34 are collectively referred to as a power feeding circuit.

  A plurality of antenna elements 31 arranged in a row are respectively connected to the plurality of transmission / reception modules 32 (see FIGS. 5 and 7). As shown in FIG. 3, each transmission / reception module 32 includes a circulator 321, a transmission amplifier 322, a reception amplifier 323, a switch 324, a first phase shifter 325, and a second phase shifter 326.

  The circulator 321 sends a transmission signal sent from the transmission amplifier 322 to the antenna element 31 connected to the antenna end, or sends a reception signal sent from the antenna element 31 via the antenna end to the reception amplifier 323. Switch between.

  The transmission amplifier 322 amplifies the transmission signal sent from the switch 324 and sends it to the circulator 321. The reception amplifier 323 amplifies the reception signal sent from the circulator 321 with low noise, and sends the amplified signal to the switch 324 and the second phase shifter 326.

  The switch 324 switches between transmitting a transmission signal transmitted from the first phase shifter 325 to the transmission amplifier 322 and transmitting a reception signal transmitted from the reception amplifier 323 to the first phase shifter 325. The first phase shifter 325 controls the phase of the transmission signal Txb sent from the distributor 33 and sends it to the switch 324, and also changes the phase of the reception signal sent from the reception amplifier 323 via the switch 324. And send it to the combiner 34 as a received signal Rxb2. The second phase shifter 326 controls the phase of the received signal sent from the receiving amplifier 323 and sends it to the combiner 34 as the received signal Rxb1.

  In the transmission / reception module 32 configured as described above, the transmission signal Txb transmitted from the distributor 33 is subjected to predetermined phase control by the first phase shifter 325 and then transmitted via the switch 324 to the transmission amplifier 322. Sent to. The transmission signal amplified by the transmission amplifier 322 is transmitted from the antenna element 31 via the circulator 321.

  On the other hand, the reception signal received by the antenna element 31 is sent to the reception amplifier 323 via the circulator 321. The received signal amplified by the reception amplifier 323 with low noise is sent to the first phase shifter 325 via the switch 324 and to the second phase shifter 326. The received signal whose phase is controlled by the first phase shifter 325 is sent to the combiner 34 as the received signal Rxb2. Further, the received signal whose phase is controlled by the second phase shifter 326 is sent to the combiner 34 as the received signal Rxb1.

  The distributor 33 of the composite unit 3 distributes the power of the transmission signal Txa sent from the horizontal distribution synthesizer 1 or the vertical distribution synthesizer 2 and sends it to the plurality of transmission / reception modules 32 as the transmission signal Txb. Each of the plurality of transmission / reception modules 32 controls the phase of the transmission signal Txb from the distributor 33 and then amplifies it and sends it to the antenna element 31.

  The synthesizer 34 of the composite unit 3 synthesizes the reception signal Rxb1 sent from the transmission / reception module 32 and sends it to the vertical direction synthesizer 4 or the horizontal direction synthesizer 5 in the reception signal Rxa. The vertical direction synthesizer 4 synthesizes the reception signal Rxa sent from the composite unit 3 and sends it to the horizontal direction synthesizer 5.

  The horizontal synthesizer 5 synthesizes the sum by monopulse synthesis that takes the difference between the sum and difference of the aperture-divided signals based on the received signal Rxb1 included in the received signal Rxa sent from the vertical synthesizer 4 and the composite unit 3. A signal Σ and a lateral difference signal ΔAZ are generated.

  The synthesizer 34 of the composite unit 3 synthesizes the reception signal Rxb2 sent from the transmission / reception module 32 and sends it to the vertical direction distribution synthesizer 2 or the horizontal direction distribution synthesizer 1 in the reception signal Rxa. The vertical distribution synthesizer 2 synthesizes the reception signal Rxa sent from the composite unit 3 and sends it to the horizontal distribution synthesizer 1. The horizontal distribution synthesizer 1 generates a vertical difference signal ΔEL based on the reception signal Rxb 2 included in the reception signal Rxa sent from the vertical direction synthesizer 4 and the composite unit 3, and outputs it via the circulator 6. To do.

  Next, the arrangement of the composite units 3 forming the antenna opening surface of the array antenna apparatus according to the first embodiment configured as described above will be described.

  FIG. 4 is a diagram showing the arrangement of the composite units 3 constituting the antenna opening surface. The antenna opening surface is composed of a plurality of composite unit blocks 7, and each composite unit block 7 is configured by arranging a plurality of composite units 3 in the AZ direction as shown in FIG.

  As shown in FIG. 4B, the antenna opening surface has a three-stage composite unit block 7 arranged in the EL direction at the center thereof, and a two-stage composite unit block 7 arranged in the EL direction on both sides thereof. The composite unit block 7 is arranged at the outermost side in the EL direction, and the composite units 3 are arranged in a pseudo circle as a whole.

  Due to the quasi-circular arrangement of the composite units 3 as described above, the AZ direction on the antenna opening surface has an amplitude distribution as shown in FIG. 4A, and the EL direction has an amplitude as shown in FIG. Distribution. As a result, the amplitude distribution of the entire antenna opening surface becomes close to a cosine distribution or a cosine square distribution, so that the sidelobe level can be reduced.

  As described above, according to the array antenna device according to the first embodiment of the present invention, since the antenna opening surface is formed by arranging the composite units in a pseudo circle shape, the amplitude distribution of the entire antenna opening surface has a taper. It becomes close to a cosine distribution or a cosine square distribution, and the sidelobe level can be reduced.

  In the case where a plurality of composite unit blocks 7 are arranged in a pseudo circle shape, gaps 8 may be generated between the plurality of composite unit blocks 7 as shown in FIG. When such a gap 8 occurs, for example, as shown in FIG. 4A, unevenness occurs in the amplitude distribution in the EL direction, and the reduction of the side lobe level is hindered.

  In order to solve this problem, the array antenna apparatus according to the first embodiment can be modified as follows. That is, in the array antenna apparatus according to the modification, as shown in FIG. 7, the composite units 3a constituting each composite unit block 7a are arranged with their positions in the EL direction being alternately shifted.

  According to this configuration, as shown in FIG. 6 (b), the gap 8a between the plurality of composite unit blocks 7a is filled, so the amplitude distribution in the AZ direction on the antenna opening surface is shown in FIG. 6 (a). Thus, it becomes smooth as compared with the case shown in FIG. Therefore, the side lobe level can be further reduced.

  In the above-described first embodiment and its modifications, the array antenna device having both the transmission function and the reception function has been described. However, the present invention is applied to, for example, an array antenna device having only the reception function or only the transmission function. can do.

  Further, in the above-described first embodiment and the modification thereof, the configuration is such that two phase shifters are provided in the transmission / reception module 32. However, the configuration is made up of one phase shifter that is used for both transmission and reception. You can also.

  Next, an array antenna apparatus according to Embodiment 2 of the present invention will be described. In the array antenna apparatus according to the first embodiment described above, for example, when it is desired to give a Taylor distribution as shown in FIG. 9A as the amplitude distribution in the AZ direction of the antenna opening surface, as shown in FIG. It is possible to correct the amplitude distribution obtained by arranging the complex units 3 in multiple stages.

  This correction can be realized by giving an amplitude distribution Wc (n) (n = 1 to N) as shown in FIG. 9C to the lateral synthesizer 5 of the composite unit 3. The amplitude distribution Wc can be obtained by the following equation (1).

Wc (n) = Wt (n) / Wd (n) (1)
Here, Wc (n) is the amplitude distribution (n = 1 to N) in the horizontal synthesizer 5, N is the number of synthesis, Wt (n) is the amplitude distribution (for example, Taylor distribution) to be set, and Wd (n). Represents an amplitude distribution obtained by arranging in multiple stages.

  As described above, according to the array antenna apparatus according to the second embodiment of the present invention, the amplitude distribution in the antenna opening surface can be smoothed, so that the side lobes can be reduced. The above configuration is applicable not only to the amplitude distribution in the AZ direction but also to the amplitude distribution in the EL direction.

  Next, an array antenna apparatus according to Embodiment 3 of the present invention will be described. When the number of stages of the composite unit 3 is three (odd number) as in the array antenna device according to the first embodiment described above, the antenna opening surface has an opening A, as shown in FIG. It is divided into an opening B and an opening C.

  The first phase shifter 325 included in the transmission / reception module 32 of the composite unit 3 corresponding to the aperture A controls the phase of the received signal and outputs a sum signal ΣA having a phase of 0 °. The second phase shifter 326 The phase of the received signal is controlled to output a difference signal ΔA having a phase of 0 °.

  The first phase shifter 325 included in the transmission / reception module 32 of the composite unit 3 corresponding to the opening B controls the phase of the received signal and outputs a sum signal ΣB having a phase of 0 °, and is half of the second phase shifter 326. Controls the phase of the received signal and outputs a phase difference signal ΔB of 0 °, and the other half of the second phase shifter 326 controls the phase of the received signal and outputs the phase difference signal ΔB of 180 °. To do.

  The first phase shifter 325 included in the transmission / reception module 32 of the composite unit 3 corresponding to the opening C outputs a sum signal ΣC having a phase of 0 ° by controlling the phase of the received signal, and the second phase shifter 326 The phase of the received signal is controlled to output a difference signal ΔC having a phase of 180 °.

  The horizontal direction synthesizer 5 adds the sum signal ΣA from the opening A, the sum signal ΣB from the opening B, and the sum signal ΣC from the opening C, as shown in FIG. ) Is generated. The horizontal synthesizer 5 adds the difference signal ΔA from the opening A, the difference signal ΔB from the opening B, and the difference signal ΔC from the opening C to generate a difference signal ΔAZ (Δ beam). Similarly, the lateral distribution synthesizer 1 adds the difference signal ΔA from the opening A, the difference signal ΔB from the opening B, and the difference signal ΔC from the opening C to generate a difference signal ΔEL (Δ beam).

  As described above, according to the array antenna apparatus according to the third embodiment, two types of phase shifters such as the first phase shifter 325 and the second phase shifter 326 are provided, one for the Σ beam and the other for the Σ beam. Since the phase control is made so as to correspond to the sum and difference when the antenna aperture is divided into two for the Δ beam, an odd-numbered (or odd-numbered) complex unit having a uniform amplitude distribution is used. When a monopulse beam by Σ beam and Δ beam is required, a monopulse beam can be formed.

  The present invention is applicable to an array antenna apparatus in which a plurality of transmission / reception modules and phase shifters are arranged.

It is a figure which shows the structure of the array antenna apparatus which concerns on Example 1 of this invention. It is a block diagram which shows the detailed structure of the composite unit shown in FIG. It is a figure which shows the detailed structure of the transmission / reception module shown in FIG. It is a figure which shows the arrangement | sequence of the composite unit which comprises the antenna opening surface of the array antenna apparatus which concerns on Example 1 of this invention. It is a figure which shows the arrangement | sequence of the composite unit which comprises the composite unit block shown in FIG. It is a figure which shows the arrangement | sequence of the composite unit block which comprises the antenna opening surface of the array antenna apparatus which concerns on the modification of Example 1 of this invention. It is a figure which shows the arrangement | sequence of the composite unit which comprises the composite unit block shown in FIG. It is a figure which shows the amplitude distribution of the AZ direction in the antenna opening surface of the array antenna apparatus which concerns on Example 1 of this invention. It is a figure for demonstrating correction | amendment of the amplitude distribution in the antenna opening surface of the array antenna apparatus which concerns on Example 2 of this invention. It is a figure for demonstrating formation of the monopulse beam in the array antenna apparatus which concerns on Example 3 of this invention. It is a figure for demonstrating the structure of the antenna opening surface of the conventional array antenna apparatus. It is a figure for demonstrating formation of the monopulse beam in the conventional array antenna apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Horizontal distribution synthesizer 2 Vertical distribution synthesizer 3 Composite unit 4 Vertical synthesizer 5 Horizontal synthesizer 6 Circulator 31 Antenna element 32 Transmission / reception module 33 Divider 34 Synthesizer 321 Circulator 322 Transmit amplifier 323 Receive amplifier 324 Switch 325 First phase shifter 326 Second phase shifter

Claims (4)

An array antenna device in which an antenna opening surface is formed by arranging a plurality of composite units having a uniform amplitude distribution in a power feeding circuit that controls a plurality of antenna elements arranged in a row,
The antenna opening surface is formed in a pseudo circle by a plurality of composite units arranged in one direction and a plurality of composite units arranged in a crossing direction intersecting the one direction. apparatus.   2. The array antenna according to claim 1, wherein the plurality of composite units arranged in one direction are arranged so as to be alternately shifted in the intersecting direction so as to fill a gap generated in the intersecting direction. apparatus.   Each of the plurality of composite units in at least one of the one direction and the intersecting direction corrects the amplitude distribution in the power feeding circuit so that the amplitude distribution of the antenna opening surface changes smoothly. The array antenna apparatus according to claim 1 or 2. Each of the plurality of composite units includes two types of phase shifters that independently control the phase of a received signal from the antenna element,
Control the phase of one of the two types of phase shifters to form a Σ beam, and control the phase of the other phase shifter to form a Δ beam to form a monopulse beam The array antenna apparatus according to claim 1, wherein:

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