JP2012207992A - Radar device and array antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radar device and an array antenna, of which the phase control is easy even though the phase to be given to an antenna element arranged on a same coordinate at an original point and around the original point is complicated.SOLUTION: The radar device is equipped with the array antenna, a transmission section, a receiving section, a phase control section and a signal processing section. The array antenna includes a plurality of first and second sub-antennas which consist of the antenna element and transmitting/receiving modules aligned in the preset numbers, and the first and second sub-arrays are confusedly arranged in the neighborhood of a center line of an antenna opening. The transmission section creates a transmission signal to output it to the array antenna. The receiving section performs a reception process with respect to the reception signal received by the array antenna. The phase control section controls transmitting/receiving modules in such a way that the first sub-array and the second sub-array are in reverse phases and that an amplitude distribution of a Δ signal at the antenna opening becomes small in the neighborhood of the center line of the antenna opening. The signal processing section performs a process to acquire a desired signal from the reception signal.

Description

  Embodiments described herein relate generally to an array antenna including a plurality of antenna elements and a radar apparatus including the array antenna.

  In general, in a radar device, for example, when a ΔEL signal that is a difference signal in the vertical direction (elevation direction, hereinafter referred to as an EL direction) is to be received, the antenna elements in the upper half of the antenna opening of the array antenna are used. The phase is set to 0 degree, and the phase of the lower half antenna element is set to 180 degrees. However, setting the phase of the antenna element in this way makes the amplitude distribution of the entire antenna aperture uniform and increases the side lobe level.

  Therefore, in order to reduce the side lobe level of the ΔEL signal, the phase of the antenna element is controlled so that the phase of the antenna element arranged on the same coordinate in the EL direction in the vicinity of the origin and the origin is confused and has an opposite phase. Technology has been proposed. As a result, the amplitude of the antenna element on the same coordinate in the EL direction near the origin and the origin is canceled, and the side lobe level of the ΔEL signal is reduced.

  However, there is a problem that the phase control becomes more difficult as the phase applied to the antenna element arranged on the same coordinate in the EL direction near the origin and the origin is more complicated. This problem also occurs when a ΔAZ signal that is a difference signal in the horizontal direction (azimuth direction, hereinafter referred to as AZ direction) is received.

JP 2006-332840 A

  As described above, in the conventional radar apparatus, the phase of the antenna element is controlled so that the phase of the antenna element arranged on the same coordinate near the origin and the origin is confused and becomes the opposite phase. There is a problem that phase control becomes more difficult as the applied phase becomes more complex.

  Therefore, an object is to provide a radar device that can easily control the phase even if the phase given to the antenna element arranged on the same coordinate near the origin and the origin is complex, and an array antenna used in this radar device. It is in.

  According to the embodiment, the radar apparatus includes an array antenna, a transmission unit, a reception unit, a phase control unit, and a signal processing unit. The array antenna includes first and second antenna elements, and a transmission signal transmitted from the antenna element and a transmission / reception module for controlling a phase of a reception signal received by the antenna element in a predetermined number. A plurality of two subarray antennas are provided, and the first and second subarray antennas are confusedly arranged in the centerline of the antenna opening formed by the plurality of first and second subarray antennas and in the vicinity of the centerline. The transmission unit generates a transmission signal, converts the transmission signal into a radio frequency band, and outputs the radio signal to the array antenna. The reception unit performs reception processing on the reception signal received by the array antenna. The phase control unit is configured such that the phase of the transmission / reception module of the first sub-array antenna is opposite to the phase of the transmission / reception module of the second sub-array antenna, and the amplitude distribution of the Δ signal at the antenna opening is the center of the antenna opening. The amount of phase to be controlled in the plurality of transmission / reception modules is determined so as to be smaller in the vicinity of the line and the center line. The signal processing unit instructs generation timing of the transmission signal generated by the transmission unit, and performs processing for acquiring a desired signal from the reception signal after reception processing by the reception unit.

It is a block diagram which shows the function structure of the radar apparatus which concerns on this embodiment. FIG. 2 is a diagram illustrating an example of arrangement of subarray antennas in the array antenna of FIG. 1 and an example of phase setting of the subarray antenna for a ΔEL signal. It is a figure which shows the example of amplitude distribution of an antenna opening.

  Hereinafter, embodiments will be described with reference to the drawings.

  FIG. 1 is a block diagram showing a functional configuration of the radar apparatus according to the present embodiment. The radar apparatus shown in FIG. 1 includes an array antenna 10, a receiving unit 20, a transmitting unit 30, a phase control unit 40, a signal processing unit 50, and an instruction unit 60.

  The array antenna 10 includes a plurality of subarray antennas 11 and a distribution / synthesis unit 12.

  The subarray antenna 11 includes antenna elements 111-1 to 111-3 and transmission / reception modules 112-1 to 112-3. The antenna elements in the array antenna 10 are arranged in units of subarray antennas 11, and the antenna elements are thinned out in units of subarray antennas. In this embodiment, the case where the subarray antenna 11 includes three antenna elements and three transmission / reception modules will be described as an example, but the present invention is not limited to this. For example, the subarray antenna 11 may include five antenna elements and five transmission / reception modules.

  The antenna elements 111-1 to 111-3 are connected to the transmission / reception modules 112-1 to 112-3, respectively. The antenna elements 111-1 to 111-3 form an antenna opening.

  The transmission / reception module 112-1 includes a circulator 1121, a transmission amplifier 1122, a reception amplifier 1123, a switch 1124, a first phase shifter 1125, and a second phase shifter 1126. Since the transmission / reception modules 112-2 and 112-3 have the same configuration as the transmission / reception module 112-1, the transmission / reception module 112-1 will be described here.

  The circulator 1121 outputs a transmission signal transmitted from the transmission amplifier 1122 to the antenna element 111-1 connected to the antenna end, or receives a reception signal transmitted from the antenna element 111-1 via the antenna end. Whether to output to the receiving amplifier 1123 is switched.

  The transmission amplifier 1122 amplifies the transmission signal sent from the switch 1124 and outputs it to the circulator 1121.

  The reception amplifier 1123 amplifies the reception signal supplied from the circulator 1121 with low noise and outputs the amplified signal to the switch 1124 and the second phase shifter 1126.

  The switch 1124 switches whether to output the transmission signal supplied from the first phase shifter 1125 to the transmission amplifier 1122 or to output the reception signal supplied from the reception amplifier 1123 to the first phase shifter 1125.

  The first phase shifter 1125 changes the phase of the transmission signal supplied from the distribution / synthesis unit 12 according to a control signal from the phase control unit 40 by a predetermined amount. The first phase shifter 1125 outputs the phase-controlled transmission signal to the transmission amplifier 1122 via the switch 1124.

  Further, the first phase shifter 1125 changes the phase of the reception signal supplied from the reception amplifier 1123 via the switch 1124 according to a control signal from the phase control unit 40 to change the phase by a predetermined amount. The first phase shifter 1125 outputs the phase-controlled signal to the distribution / synthesis unit 12 as the reception signal RS1.

  The second phase shifter 1126 changes the phase of the reception signal supplied from the reception amplifier 1123 by a predetermined amount by controlling according to the control signal from the phase control unit 40. The second phase shifter 1126 outputs the phase-controlled signal to the distribution / synthesis unit 12 as the reception signal RS2.

  Distribution / combination section 12 distributes the power of the transmission signal supplied from transmission section 30 and outputs it to transmission / reception modules 112-1 to 112-3 of a plurality of connected subarray antennas 11.

  Further, the distribution / synthesis unit 12 synthesizes the reception signal RS1 from the first phase shifter 1125 to generate a ΔEL signal that is a difference signal in the vertical direction (elevation direction, hereinafter referred to as EL direction). . In addition, the distribution / synthesis unit 12 combines the received signal RS2 from the second phase shifter 1126, so that the sum signal is a Σ signal and a difference signal in the lateral direction (azimuth direction, hereinafter referred to as AZ direction). A certain ΔAZ signal is generated. The distribution / synthesis unit 12 outputs the generated ΔEL signal, Σ signal, and ΔAZ signal to the reception unit 20.

  The receiving unit 20 receives the Σ signal, the ΔEL signal, and the ΔAZ signal from the distribution / synthesis unit 12, and converts the frequency of these signals into a baseband. Then, the receiving unit 20 amplifies the frequency-converted signal, performs analog-digital conversion, and then outputs the signal to the signal processing unit 50.

  The transmission unit 30 generates a transmission signal in accordance with the timing and modulation scheme instructed by the signal processing unit 50. The transmission unit 30 amplifies the frequency of the generated transmission signal after converting it to a radio frequency band. The transmission unit 30 outputs the transmission signal subjected to the transmission process to the distribution / combination unit 12.

  The phase controller 40 generates a control signal that specifies the amount of phase to be changed by the first phase shifter 1125 and the second phase shifter 1126, and outputs the control signal to the first phase shifter 1125 and the second phase shifter 1126. . At this time, the phase control unit 40 outputs a control signal to the first phase shifter 1125 and the second phase shifter 1126 for each subarray.

  The signal processing unit 50 receives the Σ signal, ΔEL signal, and ΔAZ signal received and processed by the receiving unit 20, and performs signal processing for acquiring a desired signal therefrom. In addition, the signal processing unit 50 instructs the transmission unit 30 to generate a transmission signal, a modulation method, and the like.

  The instruction unit 60 instructs the reception unit 20 and the transmission unit 30 to switch between the reception operation and the transmission operation of the array antenna 10.

  Next, the operation of the array antenna 10 in the radar apparatus configured as described above will be described. FIG. 2 is a diagram illustrating an arrangement example of the subarray antenna 11 in the array antenna 10 of the radar apparatus according to the present embodiment and an example of the phase setting of the subarray antenna 11 with respect to the ΔEL signal.

  In the array antenna 10 shown in FIG. 2, antenna elements are arranged in units of subarray antennas 11. In the array antenna 10, the antenna elements are thinned out in units of subarray antennas so that the ΔEL signal can be received and the side lobe level of the ΔEL signal is reduced.

  In FIG. 2, sub-array antennas 11 having different phases set are mixedly arranged on the same coordinate in the EL direction at the origin in the EL direction and in the vicinity of the origin. The phase of each subarray antenna 11 is controlled by the first phase shifter 1125 and the second phase shifter 1126 in accordance with the control signal from the phase control unit 40.

  By appropriately changing the mixing ratio of the antenna elements in which different phases are set in the EL direction in the origin and in the vicinity of the origin, the amplitude distribution of the entire antenna aperture is lowered in the vicinity of the origin and the origin. As a result, the amplitude distribution of the antenna aperture is as shown in FIG. In FIG. 3, the solid line is the amplitude distribution acquired by the radar apparatus according to the present embodiment, and the broken line is the amplitude distribution acquired by the conventional radar apparatus that divides the antenna aperture surface into upper and lower halves to give a phase difference. According to FIG. 3, it can be seen that the radar apparatus according to the present embodiment can receive the ΔEL signal and reduce the side lobe level of the ΔEL signal.

  In FIG. 2, the case where the ΔEL signal is received has been described as an example. However, the ΔAZ signal can be received by a similar method.

  As described above, in this embodiment, the sub-array antenna 11 is formed by the three antenna elements and the three transmission / reception modules, and is arranged on the array antenna 10. The phase control unit 40 controls the phase of the antenna element in units of the subarray antenna 11. This eliminates the need to connect the antenna elements one by one, thereby reducing the labor for manufacturing the array antenna. In addition, since it is not necessary to control the phase of each antenna element one by one, even if the phase applied to the antenna element arranged on the same coordinate in the EL direction near the origin and the origin is complex, the phase control effort is reduced. Is done.

  In the present embodiment, the antenna elements are thinned out in units of the subarray antenna 11. As shown in FIG. 3, even if the antenna elements are thinned out in units of the subarray antenna 11, the ΔEL signal can be received and the side lobe level of the ΔEL signal can be reduced. This eliminates the need to consider one antenna element at a time for thinning and reduces the thinning effort.

  Therefore, according to the radar apparatus according to the present embodiment, even if the phase given to the antenna element arranged on the same coordinate near the origin and the origin is complicated, the phase control becomes easy.

  In the above embodiment, the sub-array antenna 11 is described as an example in which the antenna element and the transmission / reception module are aligned in one direction. However, the present invention is not limited to this. For example, even when aligned in an L shape, the present invention can be similarly implemented.

  Although the embodiment has been described, this embodiment is presented as an example and is not intended to limit the scope of the invention. This embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. This embodiment and its modifications are included in the scope of the present invention and the gist thereof, and are also included in the invention described in the claims and the equivalent scope thereof.

DESCRIPTION OF SYMBOLS 10 ... Array antenna 11 ... Subarray antenna 12 ... Distribution / combination part 111-1 to 111-3 ... Antenna element 112-1 to 112-3 ... Transmission / reception module 1121 ... Circulator 1122 ... Transmission amplifier 1123 ... Reception amplifier 1124 ... Switch 1125 ... 1st phase shifter 1126 ... 2nd phase shifter 20 ... receiving part 30 ... transmitting part 40 ... phase control part 50 ... signal processing part 60 ... instruction | indication part

Claims (3)

First and second subarray antennas in which an antenna element and a transmission / reception module for controlling the phase of a transmission signal transmitted from the antenna element and a reception signal received by the antenna element are aligned in a preset number. An array antenna in which the first and second subarray antennas are confusedly arranged in the centerline of the antenna opening formed by the plurality of first and second subarray antennas and in the vicinity of the centerline; and
A transmission unit that generates a transmission signal, converts the transmission signal into a radio frequency band, and outputs the radio signal to the array antenna;
A receiving unit that performs a receiving process on the received signal received by the array antenna;
The phase of the transmission / reception module of the first subarray antenna is opposite to the phase of the transmission / reception module of the second subarray antenna, and the amplitude distribution of the Δ signal at the antenna opening is the centerline of the antenna opening and the vicinity of the centerline A phase control unit that determines an amount of phase to be controlled in the plurality of transmission and reception modules,
A signal processing unit that instructs generation timing of the transmission signal generated by the transmission unit and performs processing for obtaining a desired signal from the reception signal after reception processing by the reception unit; Radar device.   2. The radar apparatus according to claim 1, wherein antenna elements are thinned out in units of the first and second subarray antennas. A plurality of first and second antenna elements, and a plurality of first and second antennas that are arranged in a preset number of transmission / reception modules that control the phases of transmission signals transmitted from the antenna elements and reception signals received by the antenna elements. A sub-array antenna,
An array antenna comprising: a distribution / combining unit that distributes a supplied transmission signal, outputs the transmission signal to the sub-array antenna, and combines a reception signal from the sub-array antenna to generate a Δ signal.

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