JP2008205645A - Antenna device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To shorten the calibration time of a layered array antenna. <P>SOLUTION: An element selection part 153 selects one element antenna 111 from each of sub-array antennas 110. A phase shift amount changing part 154 changes a set phase shift amount with respect to a phase shifter 112 (selected phase shifter) connected to each of element antennas 111 selected by the element selection part 154. Each measuring circuit 140 measures the amplitude and phase of a calibrated signal output from each calibration circuit 130 when the phase shift amount changing part 154 changes the phase shift amounts. An optimum phase shift amount calculation part 155 calculates an optimum phase shift amount on the basis of amplitudes and phases of calibrated signals measured by respective measuring circuits. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a hierarchical array antenna. In particular, it relates to the calibration of hierarchical array antennas.

The hierarchical array antenna includes a plurality of subarray antennas, and each subarray antenna includes a plurality of element antennas.
In the hierarchical array antenna, each subarray antenna is synthesized after adjusting the amplitude and phase of the signal received by each element antenna, and is further synthesized after adjusting the amplitude and phase of the signal output from each subarray antenna. Thus, it is possible to perform arbitrary beam scanning and pattern formation.
A digital beamforming (DBF) antenna realizes this synthesis electronically by multiplying digital weights. A hierarchical DBF antenna is referred to as a subarray DBF antenna.

In the subarray DBF antenna, the signal received by the element antenna is combined after the phase shift by the variable phase shifter. The combined signal becomes the output of the subarray antenna. The output of the sub-array antenna is subjected to predetermined conversion such as frequency conversion, and then the amplitude and phase are adjusted by multiplication of digital weights and synthesized.
In order to perform arbitrary beam forming, it is necessary to calibrate the phase shift amount and digital weight of the phase shifter.
Calibration of the phase shift amount of the phase shifter is performed by selecting the phase shifters one by one, changing the phase shift amount of the selected phase shifter, and measuring the output change.
JP 2001-201526 A JP 60-89766 A

The subarray DBF antenna has a number of element antennas.
If the set phase of the phase shifter connected to each element antenna is changed one by one, the number of measurements increases in proportion to the increase in the number of bits of the element antenna and phase shifter, so it takes time to measure. However, there are problems that a transmitter or a receiver generates heat, a temperature around the measurement changes, or a measurement error increases due to a problem of time fluctuation of an operating power source.

  The present invention has been made, for example, in order to solve the above-described problems, and an object thereof is to shorten the measurement time required for calculating the calibration amount in the subarray DBF antenna.

An antenna device according to the present invention includes:
A plurality of subarray antennas, a plurality of receivers, a plurality of calibration circuits, a plurality of measurement circuits, and an arithmetic circuit;
Each subarray antenna of the plurality of subarray antennas includes a plurality of element antennas, a plurality of phase shifters, and a signal synthesis circuit.
Each of the element antennas of the plurality of element antennas receives a reference transmission signal transmitted by the transmission device and serves as a reception signal,
Each phase shifter of the plurality of phase shifters is connected to one of the plurality of element antennas, shifts the received signal received by the connected element antennas in accordance with the set phase shift amount, and shifts the phase. As a phase signal,
The signal synthesis circuit is connected to the plurality of phase shifters, synthesizes a plurality of phase-shifted signals each phase-shifted by the phase shifters of the plurality of phase shifters, and forms a synthesized signal,
Each receiver of the plurality of receivers is connected to one of the plurality of subarray antennas, converts a combined signal synthesized by the connected subarray antennas, and outputs an output signal,
Each calibration circuit of the plurality of calibration circuits is connected to one of the plurality of receivers, and the output signal converted by the connected receiver is calibrated according to a set calibration amount to be a calibrated signal,
Each measurement circuit of the plurality of measurement circuits is connected to one of the plurality of calibration circuits, and measures the amplitude of the calibrated signal calibrated by the connected calibration circuit,
The arithmetic circuit is connected to the plurality of phase shifters, the plurality of calibration circuits, and the plurality of measurement circuits respectively provided in the plurality of subarray antennas, and includes an element selection unit, a phase shift amount change unit, and an optimum A phase shift amount calculation unit, an optimum phase shift amount setting unit, and an optimum calibration amount calculation unit;
The element selection unit selects one element antenna for each subarray antenna from the plurality of element antennas respectively provided in the plurality of subarray antennas, and selects a plurality of phase shifters connected to the selected element antennas. A phase shifter,
The phase shift amount changing unit changes the phase shift amount set for each selected phase shifter of the plurality of selected phase shifters selected by the element selection unit,
The optimal phase shift amount calculation unit is based on a change in amplitude of a plurality of calibrated signals measured by each measurement circuit of the plurality of measurement circuits when the phase shift amount change unit changes the phase shift amount. Calculate the optimum amount of phase shift for each selected phase shifter of the plurality of selected phase shifters selected by the element selector,
The optimal phase shift amount setting unit sets the optimal phase shift amount calculated by the optimal phase shift amount calculation unit for each selected phase shifter of the plurality of selected phase shifters selected by the element selection unit,
The optimal calibration amount calculation unit is configured to output the plurality of calibration values based on amplitudes of a plurality of calibrated signals respectively measured by the measurement circuits of the plurality of measurement circuits when the optimal phase shift amount setting unit sets the optimal phase shift amount. An optimum calibration amount is calculated for each calibration circuit of the calibration circuit.

  According to the antenna apparatus according to the present invention, one phase shifter is selected from each subarray antenna, the phase shift amount of the selected phase shifter is changed, the amplitude of the calibrated signal is measured, and the optimum phase shift is determined. Since the amount is calculated, the time required for the calibration process can be shortened.

Embodiment 1 FIG.
The first embodiment will be described with reference to FIGS.

  FIG. 1 is a block configuration diagram showing an example of the overall configuration of the antenna device 100 according to this embodiment.

The antenna device 100 is an array antenna having a plurality of subarray antennas 110. Each subarray antenna 110 is also an array antenna including a plurality of element antennas 111.
For example, if there are n subarray antennas 110 and there are m element antennas 111 included in each subarray antenna 110, the antenna apparatus 100 includes mxn element antennas 111 in total.

Each subarray antenna 110 includes a plurality of phase shifters 112. The number of phase shifters 112 is the same as the number of element antennas 111, and each phase shifter 112 is connected to one element antenna 111.
The phase shifter 112 inputs a received signal received by the connected element antenna 111. The phase shifter 112 shifts the input received signal according to the set phase shift amount.
The amount of phase shift of the phase shifter 112 is variable and is set by the arithmetic circuit 150 described later. The set phase shift amount is stored in a storage device such as a latch circuit. The phase shift amount is, for example, a k-bit digital value. In this case, the phase shift amount can be changed to 2 to the power of k.
In addition, the phase shift amount of the phase shifter 112 can be set to a different value for each phase shifter 112.
The phase shifter 112 outputs a signal generated by shifting the phase of the received signal as a phase-shifted signal.

  Each subarray antenna 110 includes a signal synthesis circuit 113 (feeding circuit). The signal synthesis circuit 113 inputs the phase-shifted signals output from all the phase shifters 112 in the subarray antenna 110. The signal synthesis circuit 113 synthesizes all input phase-shifted signals. The signal synthesis circuit 113 outputs a signal generated by synthesizing the phase-shifted signal as a synthesized signal.

The antenna device 100 also includes a plurality of receivers 120. The number of receivers 120 is the same as the number of subarray antennas 110, and each receiver 120 is connected to one subarray antenna 110.
The receiver 120 receives the combined signal output from the connected subarray antenna 110 (the signal combining circuit 113 thereof). The receiver 120 converts the input composite signal. For example, the receiver 120 converts the frequency of the combined signal into an intermediate frequency, and decomposes it into an in-phase component and a quadrature component. The receiver 120 outputs a signal generated by converting the combined signal as an output signal.

The antenna device 100 also has a plurality of calibration circuits 130. The number of calibration circuits 130 is the same as the number of subarray antennas 110, and each is connected to one receiver 120.
The calibration circuit 130 inputs an output signal output from the connected receiver 120. The calibration circuit 130 calibrates the input output signal according to the set calibration amount. The calibration circuit 130 is, for example, a weight multiplication circuit, and calibrates the output signal by multiplying the complex vector of the output signal by a calibration amount (calibration weight) represented by a complex number. The calibration circuit 130 outputs a signal generated by calibrating the output signal as a calibrated signal.

The antenna device 100 also has a plurality of measurement circuits 140. The number of measurement circuits 140 is the same as the number of subarray antennas 110, and each is connected to one calibration circuit 130.
The measurement circuit 140 inputs the calibrated signal output from the connected calibration circuit 130. The measurement circuit 140 measures the amplitude and phase of the input calibrated signal. The measurement circuit 140 is, for example, an analog / digital conversion circuit. The measurement circuit 140 outputs a signal representing the amplitude and phase of the measured calibrated signal.

The antenna device 100 also has an arithmetic circuit 150. The arithmetic circuit 150 is connected to each phase shifter 112 included in each subarray antenna 110. The arithmetic circuit 150 sets the phase shift amount of each phase shifter 112. The arithmetic circuit 150 is connected to each calibration circuit 130. The arithmetic circuit 150 sets the calibration amount of each calibration circuit 130. The arithmetic circuit 150 is connected to each measurement circuit 140. The arithmetic circuit 150 inputs a signal representing the amplitude and phase of the calibrated signal measured by each measurement circuit 140.
The arithmetic circuit 150 calculates the optimum phase shift amount to be set in the phase shifter 112 and the optimum calibration amount to be set in the calibration circuit 130 based on the amplitude and phase of the calibrated signal measured by the measurement circuit 140. And set.
Details of the arithmetic circuit 150 will be described later.

The antenna device 100 also has a beam forming circuit 180. The beam forming circuit 180 is connected to each calibration circuit 130. The beam forming circuit 180 inputs the calibrated signal output from all the calibration circuits 130. The beam forming circuit 180 generates and outputs a signal having a desired directivity based on the input calibrated signal.
The beam forming circuit 180 receives information representing the amplitude and phase of the calibrated signal measured by the measurement circuit 140 instead of the calibrated signal output from the calibration circuit 130, and based on the amplitude and phase of the calibrated signal. Thus, a signal having a desired directivity may be generated.

  As described above, the antenna device 100 is a multi-stage adaptive array antenna having a plurality of subarray antennas 110 including a plurality of element antennas 111, and has a function of calibrating amplitude and phase by receiving a reference transmission signal. .

Next, details of the arithmetic circuit 150 will be described.
The arithmetic circuit 150 is, for example, a processing device such as a CPU (Central Processing Unit), and the detailed block of the arithmetic circuit 150 described below is executed by the arithmetic circuit 150 executing software such as a program. Realize.
Alternatively, the arithmetic circuit 150 may be realized by hardware such as a logic circuit, partly realized by software, and partly realized by hardware.

  The arithmetic circuit 150 includes an initial calibration amount setting unit 151, an initial phase shift amount setting unit 152, an element selection unit 153, a phase shift amount changing unit 154, an optimal phase shift amount calculating unit 155, and an optimal phase shift amount setting. A unit 156, an optimum calibration amount calculation unit 157, and an optimum calibration amount setting unit 158.

The initial calibration amount setting unit 151 sets an initial value of the calibration amount for each calibration circuit 130.
The initial value of the calibration amount is, for example, a complex number “1 + j0” (representing that the amplitude and phase are not calibrated and output as they are).

The initial phase shift amount setting unit 152 sets an initial value of the phase shift amount for each phase shifter 112.
The initial value of the amount of phase shift is, for example, “0 degree”.

  The element selection unit 153 selects one element antenna 111 for each subarray antenna 110 from among the plurality of element antennas 111 included in each subarray antenna 110. Therefore, the element selection unit 153 selects the same number of element antennas 111 as the number of subarray antennas 110. Hereinafter, the phase shifter 112 connected to the element antenna 111 selected by the element selection unit 153 is referred to as a selective phase shifter. Since one phase shifter 112 is connected to each element antenna 111, there is one selective phase shifter for each subarray antenna 110, and the number of selective phase shifters is also the same as that of the subarray antenna 110. It is the same number as the number.

The phase shift amount changing unit 154 changes the set phase shift amount for each selected phase shifter selected by the element selecting unit 153.
For example, if the phase shifter 112 is a phase shifter that can set the amount of phase shift in 2k steps, the minimum step size Δφ of the phase shift amount that can be set is Δφ = 360 ° / 2 ^k . The phase shift amount changing unit 154 first sets the phase shift amounts of all the selected phase shifters to Δφ. Next, the phase shift amount changing unit 154 sets the phase shift amount of all the selected phase shifters to 2Δφ. In this way, the phase shift amount changing unit 154 changes the phase shift amounts of all the selected phase shifters to (2 ^k −1) Δφ in increments of Δφ.

The optimum phase shift amount calculation unit 155 inputs and inputs the amplitude and phase of the calibrated signal measured by each measurement circuit 140 each time the phase shift amount change unit 154 changes the phase shift amount of the selected phase shifter. Based on the amplitude and phase of each calibrated signal, the optimum amount of phase shift to be set for each selected phase shifter is calculated.
The optimum amount of phase shift to be set for the selected phase shifter varies depending on the calibration method and purpose. For example, when the purpose is to maximize the amplitude of the synthesized signal, the amplitude of the synthesized signal is maximized. The amount of phase shift is the optimum amount of phase shift.

FIG. 2 is a diagram illustrating the principle by which the optimum phase shift amount calculation unit 155 calculates the optimum phase shift amount.
In this figure, the phase-shifted signal output from the phase shifter 112 and the combined signal output from the signal combining circuit 113 are represented by complex vectors.
For example, when the complex vector (electric field vector) of the phase-shifted signal output from the phase shifter 112 is represented by a thick solid line arrow, these are combined and the complex vector of the combined signal output from the signal combining circuit 113 The (combined electric field vector) is the sum of complex vectors of the phase-shifted signal, as represented by the thick broken line arrows.

  When the phase shift amount changing unit 154 changes the phase shift amount of the selected phase shifter, the phase of the phase-shifted signal changes, so the locus of the tip of the complex vector of the phase-shifted signal is a circle centered on the origin. Draw. Since there is one selective phase shifter for each subarray antenna 110, the locus of the tip of the complex vector of the composite signal also draws a circle with the same radius (however, the center of the circle is not the origin).

  If the receiver 120 has no error (the calibration of the error of the receiver 120 will be described later), the amplitude / phase of the output signal output from the receiver 120 is proportional to the amplitude / phase of the combined signal. Since the calibration amount of the calibration circuit 130 is set to 1, the amplitude / phase of the calibrated signal is equal to the amplitude / phase of the output signal. Therefore, if the amplitude / phase of the calibrated signal is measured, the relationship between the phase shift amount set in the selected phase shifter and the amplitude / phase of the phase-shifted signal can be calculated.

  The optimal phase shift amount calculation unit 155 calculates the relationship between the phase shift amount set in the selected phase shifter and the amplitude / phase of the phase-shifted signal as described above, and based on this, the desired result In order to obtain the optimum phase shift amount, the optimum phase shift amount is obtained.

If the selected phase shifters selected by the element selection unit 153 are different, the radius and center of the circle drawn by the locus of the tip of the complex vector of the combined signal are different.
Based on this, the optimal phase shift amount calculation unit 155 calculates the optimal phase shift amount of each phase shifter 112.

  Returning to FIG. 1, the detailed block diagram of the arithmetic circuit 150 will be continued.

  The optimum phase shift amount setting unit 156 sets the optimum phase shift amount calculated for each phase shifter 112 by the optimum phase shift amount calculation unit 155 in each phase shifter 112.

The optimum calibration amount calculation unit 157 inputs the amplitude and phase of the calibrated signal measured by each measurement circuit 140 after the optimum phase shift amount setting unit 156 sets the optimum phase shift amount. Based on the amplitude and phase, the optimum calibration amount to be set in each calibration circuit 130 is calculated.
The optimum calibration amount to be set in the calibration circuit 130 also varies depending on the calibration method and purpose. For example, when the purpose is to align the amplitude and phase of the calibrated signal, the optimum calibration amount calculation unit 157 includes the measurement circuit. A complex vector of the calibrated signal is calculated from the amplitude / phase of the calibrated signal measured by 140, and a conjugate complex number of the calculated complex vector is obtained to obtain an optimum calibration amount.
Alternatively, if the purpose is to form a beam with a low side lobe such as a Taylor distribution, the optimum calibration amount calculation unit 157 calculates the optimum calibration amount so as to obtain a desired amplitude level.

The optimum calibration amount setting unit 158 sets the optimum calibration amount calculated for each calibration circuit 130 by the optimum calibration amount calculation unit 157 in each calibration circuit 130.
Thereby, even when there is an error in the receiver 120, the error of the receiver 120 can be calibrated.

Next, the operation will be described.
FIG. 3 is a flowchart showing an example of the flow of calibration processing in which the antenna apparatus 100 according to this embodiment performs calibration.

  In the initial calibration amount setting step S11, the initial calibration amount setting unit 151 sets the calibration amounts of all the calibration circuits 130 to initial values.

  In the initial phase shift amount setting step S12, the initial phase shift amount setting unit 152 sets the phase shift amounts of all the phase shifters 112 included in all the subarray antennas 110 to initial values.

  In the reference signal transmission step S13, the antenna device 100 notifies the transmission device 200 that the calibration is ready, and the transmission device 200 starts transmitting the reference transmission signal.

In the initial measurement step S14, each measurement circuit 140 receives a calibrated signal output from each connected calibration circuit 130. Each measurement circuit 140 measures the amplitude and phase of each input calibrated signal. Each measurement circuit 140 outputs a signal representing the amplitude and phase of each measured calibrated signal.
The arithmetic circuit 150 receives the signal output from each measurement circuit 140 and stores the amplitude and phase of each calibrated signal measured by each measurement circuit 140 in a memory or the like.

  In the element selection step S <b> 15, the element selection unit 153 selects one element antenna 111 from each subarray antenna 110.

  In the phase shift amount changing step S16, the phase shift amount changing unit 154 has set each phase shifter 112 (selected phase shifter) connected to each element antenna 111 selected by the element selecting unit 153 in the element selecting step S15. Change the amount of phase shift all at once.

  In the first measurement step S17, each measurement circuit 140 inputs the calibrated signal output from each connected calibration circuit 130, and measures the amplitude and phase shift of each input calibrated signal. The arithmetic circuit 150 stores the amplitude and phase shift of each calibrated signal measured by each measurement circuit 140 in a memory or the like.

Thereafter, the processing of the phase shift amount changing step S16 to the first measurement step S17 is repeated for all the phase shift amounts that can be set in the selected phase shifter. For example, the phase shifter 112 is as long as phase shifters can set the phase shift amount ^{2 k} stages, and repeats the processing of the phase shift amount changing step S16~ first measurement step S17 ⁽² k -1) times.

  In the phase shift amount restoration step S18, the phase shift amount changing unit 154 returns the phase shift amount set in each selected phase shifter to the initial value.

  In the optimum phase shift amount calculation step S19, the optimum phase shift amount calculation unit 155 selects each selected shift based on the amplitude / phase of each calibrated signal measured by the measurement circuit 140 in the initial measurement step S14 and the first measurement step S17. Calculate the optimum amount of phase shift to be set in the phase shifter.

  Thereafter, in order to calculate the optimum phase shift amount for all the phase shifters 112 included in each subarray antenna 110, the element antenna 111 selected in the element selection step S15 is changed, and the element selection step S15 to the optimum phase shift amount calculation step S19. repeat. For example, if each subarray antenna 110 includes m element antennas 111, the processes from the element selection step S15 to the optimum phase shift amount calculation step S19 are repeated m times.

  The process of the optimum phase shift amount calculation step S19 may be performed outside this repetition, and the optimal phase shift amount for all the phase shifters 112 may be calculated after the repetition is completed.

  In the optimum phase shift amount setting step S20, the optimum phase shift amount setting unit 156 uses the optimum phase shift amount calculated by the optimum phase shift amount calculation unit 155 for each phase shifter 112 in the optimum phase shift amount calculation step S19. Set to phaser 112.

  In the second measurement step S21, each measurement circuit 140 inputs the calibrated signal output from each connected calibration circuit 130, and measures the amplitude and phase of each input calibrated signal. The arithmetic circuit 150 stores the amplitude and phase of each calibrated signal measured by each measurement circuit 140 in a memory or the like.

  In the optimum calibration amount calculation step S22, the optimum calibration amount calculation unit 157 determines the optimum value to be set in each calibration circuit 130 based on the amplitude and phase of each calibrated signal measured by each measurement circuit 140 in the second measurement step S21. Calculate the calibration amount.

  In the optimum calibration amount setting step S23, the optimum calibration amount setting unit 158 sets the optimum calibration amount calculated by the optimum calibration amount calculation unit 157 for each calibration circuit 130 in each calibration circuit 130 in the optimum calibration amount calculation step S22.

  This completes the calibration process.

Here, the number of times that the measurement circuit 140 measures the amplitude / phase of the calibrated signal is one in the initial measurement step S14, (2 ^k −1) × m in the first measurement step S17, and in the second measurement step S21. Since this is one time, the total is {(2 ^k −1) × m + 2} times.

  In this way, by selecting one element antenna 111 from each subarray antenna 110 and simultaneously changing the amount of phase shift of each phase shifter 112 (selected phase shifter) connected to each selected element antenna 111. Since the number of times the measurement circuit 140 measures the amplitude / phase of the calibrated signal can be reduced, the time required for the calibration process can be shortened.

Incidentally, if the number of element antennas 111 is not selected as many as the number of subarray antennas 110 but one by one, the number of times the measurement circuit 140 measures the amplitude / phase of the calibrated signal is {(2 ^k − 1) × m × n + 1} times (n is the number of subarray antennas 110).
Therefore, the number of measurements is reduced to {(2 ^k −1) × m + 2} / {(2 ^k −1) × m × n + 1} ≈1 / n.

In this example, the measurement circuit 140 measures the amplitude and phase of the calibrated signal output from the calibration circuit 130, but the measurement circuit 140 measures the amplitude and phase of the output signal output from the receiver 120. It is good to do.
In this example, the measurement circuit 140 measures both the amplitude and phase of the calibrated signal, but the measurement circuit 140 may measure only the amplitude of the calibrated signal (or output signal).

The antenna device 100 in this embodiment is
A plurality of subarray antennas 110, a plurality of receivers 120, a plurality of calibration circuits 130, a plurality of measurement circuits 140, and an arithmetic circuit 150 are provided.
Each subarray antenna 110 of the plurality of subarray antennas 110 includes a plurality of element antennas 111, a plurality of phase shifters 112, and a signal synthesis circuit 113.
Each element antenna 111 of the plurality of element antennas 111 receives the reference transmission signal transmitted by the transmission apparatus 200 and uses it as a reception signal.
Each phase shifter 112 of the plurality of phase shifters 112 is connected to one of the plurality of element antennas 111 and shifts the received signal received by the connected element antennas 111 in accordance with the set phase shift amount. The phase-shifted signal is used.
The signal synthesis circuit 113 is connected to the plurality of phase shifters 112, and synthesizes a plurality of phase-shifted signals that are respectively phase-shifted by the phase shifters 112 of the plurality of phase shifters 112 into a synthesized signal. Features.
Each receiver 120 of the plurality of receivers 120 is connected to one of the plurality of subarray antennas 110, and converts the combined signal synthesized by the connected subarray antennas 110 into an output signal.
Each calibration circuit 130 of the plurality of calibration circuits 130 is connected to one of the plurality of receivers 120, calibrates the output signal converted by the connected receiver 120 in accordance with the set calibration amount, and calibrated signals. It is characterized by.
Each measurement circuit 140 of the plurality of measurement circuits 140 is connected to one of the plurality of calibration circuits 130, and measures the amplitude of the calibrated signal calibrated by the connected calibration circuit 130.
The arithmetic circuit 150 is connected to the plurality of phase shifters 112, the plurality of calibration circuits 130, and the plurality of measurement circuits 140 respectively provided in the plurality of subarray antennas 110, the element selection unit 153, the amount of phase shift A change unit 154, an optimum phase shift amount calculation unit 155, an optimum phase shift amount setting unit 156, and an optimum calibration amount calculation unit 157 are provided.
The element selection unit 153 selects one element antenna 111 for each subarray antenna 110 from the plurality of element antennas 111 included in each of the plurality of subarray antennas 110, and a phase shifter connected to the selected element antenna 111. 112 is a plurality of selective phase shifters.
The phase shift amount changing unit 154 changes the phase shift amount set for each selected phase shifter of the plurality of selected phase shifters selected by the element selection unit 153.
The optimal phase shift amount calculation unit 155 is based on the change in amplitude of the plurality of calibrated signals respectively measured by the measurement circuits 140 of the plurality of measurement circuits 140 when the phase shift amount change unit 154 changes the phase shift amount. The optimum phase shift amount is calculated for each selected phase shifter of the plurality of selected phase shifters selected by the element selection unit 153.
The optimum phase shift amount setting unit 156 sets the optimum phase shift amount calculated by the optimum phase shift amount calculation unit 155 for each selected phase shifter of the plurality of selected phase shifters selected by the element selection unit 153. To do.
Based on the amplitudes of the plurality of calibrated signals respectively measured by the measurement circuits 140 of the plurality of measurement circuits 140 when the optimum phase shift amount setting unit 156 sets the optimum phase shift amount, the optimum calibration amount calculation unit 157 The optimum calibration amount is calculated for each calibration circuit 130 of the calibration circuit 130.

  According to the antenna device 100 in this embodiment, one phase shifter is selected from each subarray antenna 110, the phase shift amount of the selected phase shifter is changed, the amplitude of the calibrated signal is measured, Since the optimum phase shift amount is calculated, the time required for the calibration process can be shortened.

The antenna device 100 in this embodiment is also characterized by the following points.
The phase shift amount changing unit 154 is characterized by simultaneously changing the phase shift amount set for each selected phase shifter of the plurality of selected phase shifters selected by the element selection unit 153.

  According to the antenna device 100 in this embodiment, one phase shifter is selected from each subarray antenna 110, the phase shift amount of the selected phase shifter is changed simultaneously, and the amplitude of the calibrated signal is measured. Since the optimum phase shift amount is calculated, the time required for the calibration process can be shortened.

Each measurement circuit 140 of the plurality of measurement circuits 140 further measures the phase of the calibrated signal calibrated by the connected calibration circuit 130.
The optimum phase shift amount calculation unit 155 is based on changes in amplitude and phase of a plurality of calibrated signals respectively measured by the measurement circuits 140 of the plurality of measurement circuits 140 when the phase shift amount change unit 154 changes the phase shift amount. Thus, the optimum phase shift amount is calculated for each selected phase shifter of the plurality of selected phase shifters selected by the element selection unit 153.
The optimum calibration amount calculation unit 157 is based on the amplitudes and phases of a plurality of calibrated signals respectively measured by the measurement circuits 140 of the plurality of measurement circuits 140 when the optimum phase shift amount setting unit 156 sets the optimum phase shift amount. The optimum calibration amount is calculated for each calibration circuit 130 of the plurality of calibration circuits 130.

  According to the antenna device 100 in this embodiment, since the optimum phase shift amount is calculated by measuring the amplitude and phase of the calibrated signal, there is an effect that the accurate optimum phase shift amount can be calculated.

  Further, according to antenna apparatus 100 in this embodiment, a conjugate complex number is used as the optimum calibration amount (calibration weight), so that calibration can be performed with a precision finer than the minimum step size of the phase shift amount that can be set in phase shifter 112. There is an effect.

Embodiment 2. FIG.
The second embodiment will be described with reference to FIGS.

FIG. 4 is a block configuration diagram showing an example of the overall configuration of the antenna device 100 according to this embodiment.
Note that blocks common to the blocks of the antenna device 100 described in Embodiment 1 are denoted by the same reference numerals, and description thereof is omitted here.

  The antenna device 100 further includes a calibration signal generation circuit 190.

  The calibration signal generation circuit 190 generates a reference calibration signal that serves as a reference for calibrating the calibration circuit 130. The calibration signal generation circuit 190 outputs a reference calibration signal having the same amplitude and phase to each receiver 120.

  Based on the instruction from the arithmetic circuit 150, the receiver 120 inputs either the combined signal output from the connected subarray antenna 110 or the reference calibration signal output from the calibration signal generation circuit 190. The receiver 120 converts the input composite signal or reference calibration signal into an output signal.

  The arithmetic circuit 150 further includes a calibration instruction unit 161, a provisional calibration amount calculation unit 162, and a provisional calibration amount setting unit 163.

  The calibration instruction unit 161 instructs each receiver 120 to input a combined signal output from the subarray antenna 110 or a reference calibration signal output from the calibration signal generation circuit 190. Hereinafter, instructing the input of the reference calibration signal is referred to as “provisional calibration instruction”.

The provisional calibration amount calculation unit 162 inputs the amplitude and phase of the calibrated signal measured by each measurement circuit 140 after the calibration instruction unit 161 instructs provisional calibration, and is based on the amplitude and phase of each inputted calibrated signal. Thus, a provisional calibration amount (calibration weight) is calculated for each calibration circuit 130.
The provisional calibration amount is calculated in the same manner as the optimum calibration amount described in the first embodiment. For example, the provisional calibration amount calculation unit 162 obtains a complex vector of each calibrated signal based on the measured amplitude and phase of each calibrated signal, calculates the reciprocal thereof, and sets it as a provisional calibration amount.

  The provisional calibration amount setting unit 163 sets the provisional calibration amount calculated for each calibration circuit 130 by the provisional calibration amount calculation unit 162 in each calibration circuit 130.

  FIG. 5 is a detailed block diagram showing an example of the configuration of the internal blocks of the calibration signal generation circuit 190 and the receiver 120 in this embodiment.

The calibration signal generation circuit 190 includes an oscillator 191 and a distributor 192.
The oscillator 191 generates a signal having a predetermined frequency and a predetermined amplitude that is the basis of the reference calibration signal.
The distributor 192 receives the signal generated by the oscillator 191 and distributes it to a signal having the same amplitude and the same phase as a reference calibration signal. The reference calibration signal distributed by the distributor 192 is output to each receiver 120.

The receiver 120 includes a changeover switch 121 and a receiving circuit 122.
The change-over switch 121 is a switch that changes the input in accordance with a signal from the arithmetic circuit 150. The change-over switch 121 receives the combined signal output from the subarray antenna 110 and the reference calibration signal output from the calibration signal generation circuit 190, and selects and outputs one of them.
The reception circuit 122 is a circuit similar to the receiver 120 described in Embodiment 1, and converts an input signal and outputs it as an output signal.

FIG. 6 is a detailed block diagram showing another example of the internal block configuration of the calibration signal generating circuit 190 and the receiver 120 in this embodiment.
In addition, about the block which is common in the internal block demonstrated in FIG. 5, the same code | symbol is attached | subjected and description is abbreviate | omitted here.

The calibration signal generation circuit 190 includes an oscillator 191 and a distributor 192.
The oscillator 191 oscillates or stops oscillation according to instructions from the arithmetic circuit 150. The calibration signal generation circuit 190 generates a reference calibration signal when there is an instruction from the arithmetic circuit 150.

The receiver 120 includes a coupler 123 and a receiving circuit 122.
The coupler 123 (input coupler) inputs the combined signal output from the subarray antenna 110 and the reference calibration signal output from the calibration signal generation circuit 190, combines the input combined signal and the reference calibration signal, and combines them. Output the signal.

When instructing provisional calibration, the arithmetic circuit 150 instructs the calibration signal generation circuit 190 to generate a reference calibration signal, and instructs the transmission apparatus 200 to stop transmission of the reference transmission signal. As a result, the coupler 123 receives the reference calibration signal, but the amplitude of the combined signal becomes 0, so the receiving circuit 122 inputs the reference calibration signal.
Conversely, when canceling the provisional calibration instruction (instructing the input of the composite signal), the arithmetic circuit 150 instructs the calibration signal generation circuit 190 to stop the generation of the reference calibration signal, and the transmission apparatus 200. To start transmission of the reference transmission signal. As a result, the combiner 123 inputs the combined signal, but the amplitude of the reference calibration signal becomes 0, so that the receiving circuit 122 inputs the combined signal.

Next, the operation will be described.
FIG. 7 is a flowchart showing an example of the flow of calibration processing in which the antenna apparatus 100 according to this embodiment performs calibration.
Note that the calibration processing of the antenna device 100 in this embodiment is performed between the initial calibration amount setting step S11 and the initial phase shift amount setting step S12 of the calibration processing described in the first embodiment and the temporary calibration instruction steps S31 to S31. Since the process of the provisional calibration instruction canceling step S35 is added, the description of the subsequent processes is omitted.

  In the provisional calibration instruction step S31, the calibration instruction unit 161 instructs all receivers 120 to perform provisional calibration. Thereby, each receiver 120 generates an output signal obtained by converting the reference calibration signal.

  In the provisional measurement step S32, each measurement circuit 140 inputs the calibrated signal output from each connected calibration circuit 130, and measures the amplitude and phase of each input calibrated signal. The arithmetic circuit 150 stores the amplitude and phase of each calibrated signal measured by each measurement circuit 140 in a memory or the like.

  In the provisional calibration amount calculation step S33, the provisional calibration amount calculation unit 162 sets the provisional calibration amount to be set in each calibration circuit 130 based on the amplitude and phase of each calibrated signal measured by each measurement circuit 140 in the provisional measurement step S32. Is calculated.

In the provisional calibration amount setting step S34, the provisional calibration amount setting unit 163 sets the provisional calibration amount calculated for each calibration circuit 130 by the provisional calibration amount calculation unit 162 in the provisional calibration amount calculation step S33 in each calibration circuit 130.
As a result, a calibration amount considering the error of each receiver 120 is set in each calibration circuit 130.

  In the provisional calibration instruction canceling step S35, the calibration instruction unit 161 cancels the provisional calibration instruction for all the receivers 120. Thereby, each receiver 120 generates an output signal obtained by converting the combined signal.

  The subsequent processing is the same as that described in the first embodiment, but only one point is different, so that point will be mentioned.

In the second measurement step S21, a temporary calibration amount is set as the calibration amount of the calibration circuit 130 instead of the initial value. The measurement circuit 140 measures the amplitude and phase of the calibrated signal calibrated according to the provisional calibration amount, not the output signal output from the receiver 120 as it is.
Therefore, in the optimum calibration amount calculation step S22, when the optimum calibration amount calculation unit 157 calculates the optimum calibration amount, it is necessary to correct the provisional calibration amount.
For example, the optimum calibration amount calculation unit 157 calculates the optimum calibration amount in the same manner as described in the first embodiment, and then divides the optimum calibration amount by the provisional calibration amount (optimum calibration amount) / (temporary calibration amount). ), And this is the optimum calibration amount in this embodiment.

  Thus, first, the provisional calibration amount is calculated based on the reference calibration signal, and the provisional calibration amount is set in the calibration circuit 130. Therefore, the influence of the error of the receiver 120 is eliminated, and accurate calibration can be performed.

The antenna device 100 in this embodiment further includes a calibration signal generation circuit 190.
The calibration signal generation circuit 190 generates a reference calibration signal that serves as a calibration reference.
Each receiver 120 of the plurality of receivers 120 is further connected to the calibration signal generation circuit 190, and converts the reference calibration signal generated by the calibration signal generation circuit 190 instead of the synthesized signal when provisional calibration is instructed. Thus, the output signal is used.
The arithmetic circuit 150 further includes a calibration instruction unit 161, a provisional calibration amount calculation unit 162, and a provisional calibration amount setting unit 163.
The calibration instruction unit 161 instructs each receiver 120 of the plurality of receivers 120 to perform temporary calibration.
The provisional calibration amount calculation unit 162 is configured to perform the calibration of the plurality of calibration circuits 130 based on the amplitudes of the plurality of calibrated signals respectively measured by the measurement circuits 140 of the plurality of measurement circuits 140 when the calibration instruction unit 161 instructs provisional calibration. A provisional calibration amount is calculated for each calibration circuit 130.
The provisional calibration amount setting unit 163 sets the provisional calibration amount calculated by the provisional calibration amount calculation unit 162 for each calibration circuit 130 of the plurality of calibration circuits 130.

  According to the antenna device 100 in this embodiment, the provisional calibration amount is first calculated based on the reference calibration signal, and the provisional calibration amount is set in the calibration circuit 130. The effect is that calibration can be performed.

FIG. 2 is a block configuration diagram illustrating an example of an overall configuration of the antenna device 100 according to Embodiment 1. The figure which shows the principle by which the optimal phase shift amount calculation part 155 calculates the optimal phase shift amount. FIG. 3 is a flowchart showing an example of a calibration process flow in which the antenna apparatus 100 according to Embodiment 1 performs calibration. FIG. 6 is a block configuration diagram illustrating an example of an overall configuration of an antenna device 100 according to Embodiment 2. FIG. 4 is a detailed block diagram illustrating an example of the configuration of internal blocks of a calibration signal generation circuit 190 and a receiver 120 in Embodiment 2. FIG. 6 is a detailed block diagram illustrating another example of the configuration of internal blocks of the calibration signal generation circuit 190 and the receiver 120 in the second embodiment. The flowchart figure which shows an example of the flow of the calibration process which the antenna apparatus 100 in Embodiment 2 calibrates.

Explanation of symbols

  100 antenna device, 110 subarray antenna, 111 element antenna, 112 phase shifter, 113 signal synthesis circuit, 120 receiver, 121 changeover switch, 122 reception circuit, 123 coupler, 130 calibration circuit, 140 measurement circuit, 150 arithmetic circuit, 151 Initial calibration amount setting unit, 152 Initial phase shift amount setting unit, 153 Element selection unit, 154 Phase shift amount changing unit, 155 Optimal phase shift amount calculating unit, 156 Optimal phase shift amount setting unit, 157 Optimal calibration amount calculating unit, 158 Optimal calibration amount setting unit, 161 Calibration instruction unit, 162 Provisional calibration amount calculation unit, 163 Provisional calibration amount setting unit, 180 Beam forming circuit, 190 Calibration signal generation circuit, 191 Oscillator, 192 Distributor, 200 Transmitting device.

Claims (4)

A plurality of subarray antennas, a plurality of receivers, a plurality of calibration circuits, a plurality of measurement circuits, and an arithmetic circuit;
Each subarray antenna of the plurality of subarray antennas includes a plurality of element antennas, a plurality of phase shifters, and a signal synthesis circuit.
Each of the element antennas of the plurality of element antennas receives a reference transmission signal transmitted by the transmission device and serves as a reception signal,
Each phase shifter of the plurality of phase shifters is connected to one of the plurality of element antennas, shifts the received signal received by the connected element antennas in accordance with the set phase shift amount, and shifts the phase. As a phase signal,
The signal synthesis circuit is connected to the plurality of phase shifters, synthesizes a plurality of phase-shifted signals each phase-shifted by the phase shifters of the plurality of phase shifters, and forms a synthesized signal,
Each receiver of the plurality of receivers is connected to one of the plurality of subarray antennas, converts a combined signal synthesized by the connected subarray antennas, and outputs an output signal,
Each calibration circuit of the plurality of calibration circuits is connected to one of the plurality of receivers, and the output signal converted by the connected receiver is calibrated according to a set calibration amount to be a calibrated signal,
Each measurement circuit of the plurality of measurement circuits is connected to one of the plurality of calibration circuits, and measures the amplitude of the calibrated signal calibrated by the connected calibration circuit,
The arithmetic circuit is connected to the plurality of phase shifters, the plurality of calibration circuits, and the plurality of measurement circuits respectively provided in the plurality of subarray antennas, and includes an element selection unit, a phase shift amount change unit, and an optimum A phase shift amount calculation unit, an optimum phase shift amount setting unit, and an optimum calibration amount calculation unit;
The element selection unit selects one element antenna for each subarray antenna from the plurality of element antennas respectively provided in the plurality of subarray antennas, and selects a plurality of phase shifters connected to the selected element antennas. A phase shifter,
The phase shift amount changing unit changes the phase shift amount set for each selected phase shifter of the plurality of selected phase shifters selected by the element selection unit,
The optimal phase shift amount calculation unit is based on a change in amplitude of a plurality of calibrated signals measured by each measurement circuit of the plurality of measurement circuits when the phase shift amount change unit changes the phase shift amount. Calculate the optimum amount of phase shift for each selected phase shifter of the plurality of selected phase shifters selected by the element selector,
The optimal phase shift amount setting unit sets the optimal phase shift amount calculated by the optimal phase shift amount calculation unit for each selected phase shifter of the plurality of selected phase shifters selected by the element selection unit,
The optimal calibration amount calculation unit is configured to output the plurality of calibration values based on amplitudes of a plurality of calibrated signals respectively measured by the measurement circuits of the plurality of measurement circuits when the optimal phase shift amount setting unit sets the optimal phase shift amount. An antenna device characterized in that an optimum calibration amount is calculated for each calibration circuit of the calibration circuit. 2. The antenna device according to claim 1, wherein the phase shift amount changing unit simultaneously changes a phase shift amount set for each selected phase shifter of the plurality of selected phase shifters selected by the element selection unit. . The antenna device further includes a calibration signal generation circuit,
The calibration signal generation circuit generates a reference calibration signal that serves as a calibration reference,
Each receiver of the plurality of receivers is further connected to the calibration signal generation circuit, and converts the reference calibration signal generated by the calibration signal generation circuit instead of the synthesized signal when instructed to perform provisional calibration. As an output signal,
The arithmetic circuit further includes a calibration instruction unit, a provisional calibration amount calculation unit, and a provisional calibration amount setting unit,
The calibration instruction unit instructs provisional calibration to each receiver of the plurality of receivers,
The provisional calibration amount calculation unit is configured to determine each of the plurality of calibration circuits based on the amplitudes of the plurality of calibrated signals respectively measured by the measurement circuits of the plurality of measurement circuits when the calibration instruction unit instructs provisional calibration. Calculate the provisional calibration amount for the calibration circuit,
The antenna apparatus according to claim 1, wherein the temporary calibration amount setting unit sets the temporary calibration amount calculated by the temporary calibration amount calculation unit for each calibration circuit of the plurality of calibration circuits. Each measurement circuit of the plurality of measurement circuits further measures the phase of the calibrated signal calibrated by the connected calibration circuit,
The optimum phase shift amount calculation unit is based on changes in amplitude and phase of a plurality of calibrated signals respectively measured by the measurement circuits of the plurality of measurement circuits when the phase shift amount change unit changes the phase shift amount. , The optimal phase shift amount is calculated for each selected phase shifter of the plurality of selected phase shifters selected by the element selection unit,
The optimum calibration amount calculation unit is based on the amplitude and phase of a plurality of calibrated signals respectively measured by the measurement circuits of the plurality of measurement circuits when the optimum phase shift amount setting unit sets the optimum phase shift amount. The antenna apparatus according to claim 1, wherein an optimum calibration amount is calculated for each calibration circuit of the plurality of calibration circuits.

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