JP2009194475A - Phased array antenna - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a phased array antenna which outputs a multibeam while switching the direction for forming the multibeam instantaneously and selectively by a DBF method. <P>SOLUTION: Signals received by antenna elements arranged in two-dimensional matrix in the directions of the elevation angle and the azimuth angle are divided into two for distribution, and RF electric power synthesis is performed for each column (longitudinal direction, or the direction of the elevation angle) and each row (lateral direction, or the direction of the azimuth angle). One direction for RF electric power synthesis is selected at a two-dimensional antenna aperture by selecting any one of signals combined for each column or row, and beam formation processing is performed by DBF method using a selected composite signal thus forming a multibeam in another direction. Signals composed for each column or row are selected switchedly, and thus switching its direction electronically and instantaneously is performed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a phased array antenna, and more particularly to a phased array antenna that forms a multi-beam in a predetermined direction by DBF (Digital Beam Forming).

  2. Description of the Related Art Conventionally, a phased array antenna that performs phase control by arranging a plurality of antenna elements has been realized as a radar antenna used for detecting and tracking a target such as an aircraft or a flying object. Also, in receiving a radar echo signal, a DBF technique is adopted in which a received signal from each arrayed antenna element is converted into a digital signal and a beam is formed by calculation. Since the DBF technology has a relatively high degree of freedom in beam forming and beam scanning, it contributes to multi-purpose and multi-functionalization of the radar system by forming multi-beams in particular.

  In such a phased array antenna using DBF, when antenna elements are arranged two-dimensionally, for example, corresponding to the azimuth direction and the elevation angle direction, the received signals from all the antenna elements are converted into digital signals, and the azimuth and Forming multi-beams using DBF technology in both directions of elevation is heavy in many aspects, including fabrication and cost. In consideration of the operating environment of the radar system and the like, an antenna device using a one-dimensional DBF method is disclosed in which any one of azimuth and elevation is RF-combined and the other is multi-beam formed by DBF technology ( For example, see Patent Document 1.)

In the case disclosed in this patent document, a receiving one-dimensional DBF phased array antenna that forms a one-dimensional multi-beam in the horizontal direction is disclosed.
JP 2001-185934 A (6th page, FIG. 4)

  By the way, in the radar system, in order to cope more appropriately with targets such as flying aircraft and flying objects, multi-functions are made by using antennas that form multi-beams in consideration of various other system operation requirements. Or, it may be devised to realize a plurality of operation modes. At this time, for a plurality of operation modes, it is necessary to form a multi-beam having a more appropriate shape for each mode. That is, as an example, when searching for a target flying from a distance in the search mode and monitoring in the tracking mode after detection, in the search mode, the multi-beam formed in a relatively low elevation range is rotated in the azimuth direction, and the target After the target is detected, tracking and monitoring are performed while forming a multi-beam in an appropriate direction according to the movement of the target while limiting the angle range.

  However, when the above-described one-dimensional DBF type phased array antenna is used, multi-beam formation by DBF can be performed only in one of the azimuth direction and the elevation angle direction. Therefore, in order to efficiently perform multi-beam formation in accordance with the target movement direction, the degree of freedom in that direction has not been sufficient. In addition, the direction in which the multi-beam is formed can be set to a desired direction by mechanically rotating the entire antenna. However, in this case, for example, the polarization plane may be changed, so that the expected rotation may occur. There was a risk that the performance of the radar system could not be obtained.

  The present invention has been made in consideration of the above-described circumstances, and an object of the present invention is to provide a phased array antenna that instantaneously switches and selects a direction in which a multi-beam is formed by a DBF.

  In order to achieve the above object, a phased array antenna according to a first aspect of the present invention is a phased array antenna that forms a multi-beam on a two-dimensional aperture surface, and a plurality of antenna elements arranged two-dimensionally in the row direction and the column direction. A plurality of phase shifters that are provided for each of the antenna elements and give a predetermined phase shift amount to a received signal received by the antenna elements, and are provided for each of the phase shifters and after the phase shift by the phase shifter A plurality of distributors that divide and output the received signal in two, and a first plurality that outputs one distributed output of the distributor for each column of the antenna elements as a first combined received signal A combiner, a second plurality of combiners that combine the power of the other distributed output of the distributor for each row of the antenna elements and output as a second combined received signal, and the first combined received signal, or Said second synthesis A plurality of selectors that select and output one of the reception signals in correspondence with the multi-beam forming direction, and a combined reception signal that is provided corresponding to the plurality of selectors and selected by the selector A plurality of reception processors for processing and converting into digital signals; and a beam former for forming the multi-beams in a predetermined direction based on the digital signals converted by the plurality of reception processors. .

  A phased array antenna according to a second aspect of the present invention is a phased array antenna that forms a multi-beam on a two-dimensional aperture, and includes a plurality of antenna elements arranged two-dimensionally in a row direction and a column direction, and each antenna element. A plurality of phase shifters for providing a predetermined amount of phase shift to a received signal received by the antenna element; and a phase shifter provided for each of the phase shifters. A plurality of switches that switch-output in one of two directions corresponding to the beam forming direction, and one switch output of the switch is power-combined for each column of the antenna elements as a first combined received signal A first plurality of combiners for outputting; a second plurality of combiners for combining the power of the other switching output of the switch for each row of the antenna elements and outputting as a second combined received signal; Synthesis of 1 A plurality of selectors for selecting and outputting either a reception signal or the second combined reception signal in correspondence with a forming direction of the multi-beam, and a selector corresponding to the plurality of selectors. A plurality of reception processors for receiving and processing the combined reception signal selected in step (b) and converting them into digital signals; and a beam former for forming a multi-beam in a predetermined direction based on the digital signals converted by the plurality of reception processors. It is characterized by having.

  According to the present invention, it is possible to obtain a phased array antenna capable of instantaneously switching and selecting a direction in which a multi-beam is formed by DBF.

  The best mode for carrying out the phased array antenna according to the present invention will be described below with reference to FIGS.

  FIG. 1 is a block diagram showing a first embodiment of a phased array antenna according to the present invention. In this embodiment, a case where n antenna elements are arranged two-dimensionally in the elevation angle direction and the azimuth angle direction is illustrated. Further, since the antenna has reversibility in transmission and reception, the following description will focus on the case of receiving a radar signal.

  As shown in FIG. 1, this phased array antenna includes n × n antenna elements 11 (# 11 to #nn) arranged in a matrix of n pieces each in the elevation direction and the azimuth direction. N × n number of phase shifters 12 (# 11 to #nn) provided corresponding to the antenna elements, and n × n number of distributors 13 (# 11 to # 11) similarly provided in the subsequent stage of these phase shifters. #Nn), n vertical power combiners 14 (# 1 to #n) that combine the outputs of the two divided by the distributor 13 in the elevation direction for each column, and the other outputs of the distributor 13 Is composed of n horizontal power combiners 15 (# 1 to #n) that combine power in the azimuth direction for each row.

  In addition, n signal selectors 16 (# 1 to #n) that select and pass one of the combined signals after the n vertical power combiners 14 and the horizontal power combiners 15, respectively. DBF direction controller 17 for supplying selection signals to n signal selectors 16, n receivers 18 (# 1 to #n) provided corresponding to n signal selectors 16, and n The A / D converter 19 (# 1 to #n) and a beam former 20 that forms a predetermined beam based on the converted signal are included.

  Each of the n × n antenna elements 11 receives a signal and sends it to the phase shifter 12 at the subsequent stage. These antenna elements 11 (# 11 to #nn) are arranged in a matrix of n two-dimensionally in the elevation direction (vertical direction) and the azimuth direction (lateral direction), and form an aperture surface as an array antenna. ing. The array arrangement surface serving as the opening surface may be a flat surface or a curved surface. The phase shifter 12 is provided corresponding to each of the n × n antenna elements 11, and the phase shift necessary for synthesizing a signal received by each antenna element 11 with a predetermined synthesis phase in the subsequent stage. A quantity is given for each signal. Subsequent to these phase shifters 12, n × n distributors 13 (# 11 to #nn) are provided corresponding to the antenna elements 11 and the phase shifters 12, respectively. Each of these n × n distributors 13 is a two distributor that equally divides the input signal, and distributes and transmits the signal from the corresponding phase shifter 12 in two.

  The n vertical power combiners 14 (# 1 to #n) are provided corresponding to the columns in which the antenna elements 11 are arrayed in a matrix, and each of the signals distributed in two by the distributor 13 is supplied to each column. The power is combined for each column (vertical direction) and sent to the corresponding signal selector 16. Similarly, n horizontal power combiners 15 (# 1 to #n) are provided corresponding to the respective rows of the array arrangement, and the other of the signals after the two distributions by the distributor 13 is performed in the respective rows (horizontal direction). Are combined with each other and sent to the corresponding signal selector 16. The n signal selectors 16 (# 1 to #n) are provided corresponding to the n vertical power synthesizers 14 and the horizontal power synthesizers 15, respectively, and are used as control signals from the DBF direction controller 17. Based on this, one of the combined signals sent from the vertical power combiner 14 and the horizontal power combiner 15 is selected and sent to the subsequent stage. The DBF direction controller 17 generates and sends control signals for these n signal selectors 16. In signal selection control, all n signal selectors 16 are controlled to select the same side.

  In the subsequent stage of the n signal selectors 16, n receivers 18 (# 1 to #n) and A / D converters 19 (# 1 to #n) are provided correspondingly. The receiver 18 performs reception processing such as low noise amplification, filtering, frequency conversion, and detection on the signal from the corresponding signal selector 16, and the A / D converter 19 converts the signal after reception processing into a digital signal. Converted and sent to the beamformer 20. The beam former 20 performs desired beam forming processing including multi-beam formation from the digital signals from the n A / D converters 19 using the DBF technique, and sends the reception result of the formed beam to the subsequent stage. .

  Next, the operation of the phased array antenna according to the present embodiment configured as described above will be described with reference to FIG. 1 and the explanatory diagrams of FIGS. First, in FIG. 1, received signals received by n × n antenna elements 11 arrayed in a matrix form are subjected to a predetermined phase shift by a phase shifter 12 provided corresponding to each antenna element. The quantity is given and sent to n × n corresponding distributors 13. Each distributor 13 divides the received signal from these phase shifters 12 into two, and sends the distributed signals to one of n vertical power combiners 14 and horizontal power combiners 15 provided. . At this time, the vertical power combiner 14 serving as a transmission destination from each distributor is one vertical power combiner provided corresponding to the array array column of each distributor 13 among n vertical power combiners. The horizontal power combiner 15 that is a power combiner and is a destination is one horizontal power combiner provided corresponding to the array array row of each distributor 13 itself among the n horizontal power combiners. It is a power combiner. The vertical power combiner 14 outputs a reception signal synthesized with RF power in the elevation direction for each column, and the horizontal power combiner 15 outputs a reception signal synthesized with RF power in the azimuth direction for each row. Are sent to the corresponding n signal selectors 16.

  In the n signal selectors 16, either one of the n received signals from the vertical power combiner 14 or the horizontal signal combiner 15 is selected based on the control signal from the DBF direction controller 17. At this time, all the n signal selectors 16 are controlled to select the same side. That is, either all signal selectors 16 select n signals from the vertical power combiner 14 or all signal selectors 16 select n signals from the horizontal power combiner 15. It is controlled. These controls are performed by the DBF direction controller 17. The selected received signal is sent to n receivers 18 provided corresponding to the respective signal selectors 16. Each of them is subjected to reception processing by the receiver 18, further converted into a digital signal by the A / D converter 19, and then sent to the beam former 20. In the beamformer 20, a desired beam forming process such as multi-beam is performed from the digital signals from the n A / D converters 19 using the DBF technique, and a received signal by the formed beam is obtained as a result of the process. Is output to the subsequent stage.

  An example of a conceptual diagram of a beam formed by the phased array antenna of this embodiment is shown in FIGS. 2 and 3 in association with the control by the DBF direction controller 17 and the beam forming process by the beam former 20. Each of these shows an example applied to reception of a radar device. In the example of FIG. 2, the DBF direction controller 17 selects a composite signal from the vertical power combiner 14 for the signal selector 16. In this example, the control signal is transmitted and the beam former 20 forms a multi-beam by the DBF method using these selected signals. That is, in this case, RF power is combined in the elevation direction with respect to a two-dimensional antenna opening surface in which the antenna elements 11 are arranged in the elevation direction and the azimuth direction, and beam forming processing by the DBF method is performed in the azimuth direction. Since the desired multi-beam is obtained by performing the above, it is suitable, for example, for an operation scene in which multi-beams are simultaneously formed in the azimuth direction and a wide azimuth range is searched.

  On the other hand, in the case of FIG. 3, the signal selector 16 selects the combined signal from the lateral power combiner 15 and the beamformer 20 performs multi-beam forming. That is, RF power is combined in the azimuth direction and multi-beam formation is performed in the elevation direction by the DBF method. For example, multi-beams are simultaneously formed in the elevation direction to compare multiple target targets after detection. It is suitable for operational situations where collective tracking is performed within a narrow azimuth angle range. As described above, one-dimensional DBF processing is performed in the azimuth direction in the example of FIG. 2 and in the elevation direction in the example of FIG. 3. The direction is selected by a control signal from the DBF direction controller 17. The electronic switch is selected electronically.

  As described above, in this embodiment, the signals received by the antenna elements arranged in a two-dimensional matrix in the elevation angle direction and the azimuth angle direction are divided into two, and each column (vertical direction, that is, the elevation angle direction) is divided. , And for each row (lateral direction, that is, azimuth angle direction), RF power synthesis is performed. Then, by selecting one of the signals synthesized for each column or each row, one direction for synthesizing the RF power in the two-dimensional antenna aperture is selected, and the DBF method is performed using the selected synthesized signal. The multi-beam is formed in the other direction. Then, the direction is electronically and instantaneously switched by switching the selection of the signal synthesized for each column or each row. Thereby, it is possible to obtain a phased array antenna capable of instantaneously switching and selecting the direction in which the multi-beam is formed by the DBF.

  Accordingly, since it has a degree of freedom with respect to the direction in which a multi-beam is formed by the DBF method, for example, if a phased array antenna as in this embodiment is applied to a radar system or the like, as illustrated in FIG. 2 and FIG. It is possible to efficiently concentrate resources by efficiently limiting the space to be oriented according to the operation scene and the target situation.

  FIG. 4 is a block diagram showing a second embodiment of the phased array antenna according to the present invention. In the second embodiment, the same parts as those in the first embodiment shown in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted. The second embodiment is different from the first embodiment in that signals received by a plurality of array antennas arranged in a matrix are column by column with respect to the elevation angle direction and row by row with respect to the azimuth angle direction. In the first embodiment, the received signal from each antenna element 11 is divided into two by the distributor 13 in the first embodiment, whereas in the second embodiment, this is converted from the DBF direction controller 17. The switch 21 that switches the output direction of the received signal to one of the two directions according to the selection signal is used, and the received signal output from the switch 21 is used. Hereinafter, only the differences will be described with reference to FIGS. 1 to 3 and FIG.

  As illustrated in FIG. 4, this phased array antenna includes n × n antenna elements 11 (# 11 to #nn) arranged in a matrix of n pieces each in the elevation direction and the azimuth direction. N × n phase shifters 12 (# 11 to #nn) provided corresponding to the antenna elements, and n × n two-way switchers 21 provided similarly in the subsequent stage of these phase shifters. (# 11 to #nn), n vertical power combiners 14 (# 1 to #n) that combine one of the two-way switching outputs of the switch 21 in the elevation direction for each column, and the switch 21 The other switching output is composed of n transverse power combiners 15 (# 1 to #n) that combine power in the azimuth direction for each row.

  In addition, n signal selectors 16 (# 1 to #n) that select and pass one of the combined signals at the subsequent stage of the n vertical power combiners 14 and the horizontal power combiners 15, respectively, n A DBF direction controller 17 for supplying a selection signal so as to link both the n number of two-way switches 21 and the n signal selectors 16 and the n signal selectors 16 are provided. N receivers 18 (# 1 to #n), n A / D converters 19 (# 1 to #n), and a beam former 20 that forms a predetermined beam based on the converted signal. It is configured.

  The switchers 21 (# 11 to #nn) are provided corresponding to the antenna elements 11 (# 11 to #nn) and the phase shifters 12 (# 11 to #nn), respectively. Switch to either one and output. In the present embodiment, based on the selection signal from the DBF direction controller 17, the received signal from the phase shifter 12 is converted to the vertical power combiner 14 (# 1 to #n) of the corresponding column or the horizontal of the corresponding row. The output is switched to one of the power combiners 15 (# 1 to #n). The DBF direction selector 17 switches the output destination of the switch 21 to either the vertical power combiner 14 or the horizontal power combiner 15 based on the direction in which the multi-beam is formed by the DBF technique. In conjunction with the switching, the signal selector 16 generates a selection signal for allowing either the vertical power synthesizer 14 or the horizontal power synthesizer 15 to pass the reception signal combined, and the switch 21 (# 11 To #nn) and the signal selector 16 (# 1 to #n).

  Next, referring to FIG. 4 and the explanatory diagrams of FIGS. 2 and 3, the operation of the phased array antenna of the present embodiment configured as described above is different from the first embodiment. The explanation will be focused on. First, in FIG. 4, the received signal is sent to the corresponding switch 21 via each antenna element 11 and the phase shifter 12. In each switcher 21, these received signals are switched and output to one of the corresponding vertical power combiner 14 or horizontal power combiner 15 based on the selection signal from the DBF direction controller 17 for power synthesis. In the signal selector 16, either the vertical power synthesizer 14 or the horizontal power synthesizer 15 receives the power-combined received signal based on the selection signal from the DBF direction controller 17. One of the combined outputs is selected and sent to the receiver 18 at the subsequent stage.

  The selection signal sent from the DBF direction controller 17 to the switch 21 and the signal selector 16 is generated based on the direction in which the multi-beam is formed by the DBF method. That is, if a multi-beam is formed in the azimuth direction as illustrated in FIG. 2, the selection signal is sent from the switch 21 so that the vertical power combiner 14 combines the received signal with RF power in the elevation direction. The signal selector 16 is controlled so as to select the combined signal from the vertical power combiner 14 so as to be switched and interlocked therewith. On the other hand, if a multi-beam is formed in the elevation direction as illustrated in FIG. 3, the selection signal is output to the switch 21 so that the received signal is output to the lateral power combiner 15 and the signal is selected. Each of the units 16 is controlled to select a combined signal from the lateral power combiner 15.

  The combined signal selected by the signal selector 16 is subjected to signal processing by the receiver 18 and the A / D converter 19, and a desired multi-beam is formed by the DBF technique in the beam former 20.

  As described above, also in this embodiment, the RF power is synthesized in one direction of two dimensions on the aperture plane in which the antenna elements are arranged in a two-dimensional matrix in the elevation direction and the azimuth direction, and the synthesis is performed. The multi-beam forming process by the DBF method is performed in the other direction using the later signal, and the direction of combining the RF power and the direction of forming the multi-beam by the DBF method are electronically and instantaneously switched by the selection signal. Therefore, an effect equivalent to that of the first embodiment can be obtained. In addition, since the signal loss corresponding to the distribution loss due to the distributor can be reduced by using the switching device, it is more advantageous particularly in the noise figure at the time of reception signal processing in the subsequent stage.

  Note that the present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the above-described embodiments. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

1 is a block diagram showing a first embodiment of a phased array antenna according to the present invention. Explanatory drawing which shows an example at the time of forming a multi-beam in an azimuth angle direction. Explanatory drawing which shows an example at the time of forming a multi-beam in an elevation angle direction. The block diagram which shows the 2nd Example of the phased array antenna which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Antenna element 12 Phase shifter 13 Divider 14 Vertical power combiner 15 Horizontal power combiner 16 Signal selector 17 DBF direction controller 18 Receiver 19 A / D converter 20 Beam former 21 Switcher

Claims (2)

In a phased array antenna that forms a multi-beam on a two-dimensional aperture,
A plurality of antenna elements arranged two-dimensionally in a row direction and a column direction;
A plurality of phase shifters that are provided for each antenna element and give a predetermined phase shift amount to a received signal received by the antenna element;
A plurality of distributors that are provided for each of the phase shifters and that distribute and output the received signal after the phase shift by the phase shifter;
A plurality of first combiners that combine the power of one distribution output of the distributor for each column of the antenna elements and output as a first combined received signal;
A second plurality of combiners that combine the power of the other distributed output of the distributor for each row of the antenna elements and output as a second combined received signal;
A plurality of selectors for selecting and outputting either the first combined received signal or the second combined received signal in correspondence with the multi-beam forming direction;
A plurality of reception processors which are provided corresponding to the plurality of selectors, receive the combined reception signals selected by the selectors, and convert them into digital signals;
A phased array antenna, comprising: a beam former that forms the multi-beams in a predetermined direction based on digital signals converted by the plurality of reception processors. In a phased array antenna that forms a multi-beam on a two-dimensional aperture,
A plurality of antenna elements arranged two-dimensionally in a row direction and a column direction;
A plurality of phase shifters that are provided for each antenna element and give a predetermined phase shift amount to a received signal received by the antenna element;
A plurality of switches that are provided for each phase shifter, and that switch-output the received signal after the phase shift by the phase shifter in either of two directions corresponding to the formation direction of the multi-beam;
A plurality of first combiners that combine the power of one switching output of the switch for each column of the antenna elements and output as a first combined received signal;
A second plurality of combiners that combine the power of the other switching output of the switch for each row of the antenna elements and output as a second combined received signal;
A plurality of selectors for selecting and outputting either the first combined received signal or the second combined received signal in correspondence with the multi-beam forming direction;
A plurality of reception processors which are provided corresponding to the plurality of selectors, receive the combined reception signals selected by the selectors, and convert them into digital signals;
A phased array antenna comprising: a beam former that forms a multi-beam in a predetermined direction based on digital signals converted by the plurality of reception processors.

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