JP6223244B2 - Antenna device and antenna excitation method - Google Patents

Description

  The present invention relates to an antenna apparatus and an antenna excitation method for realizing low side lobe by adjusting excitation phases of a plurality of element antennas constituting a phased array antenna.

A phased array antenna composed of multiple element antennas can form an antenna radiation pattern that is difficult to achieve with a single antenna by controlling the excitation distribution (excitation amplitude phase) of the multiple element antennas. it can.
In a phased array antenna, the antenna radiation pattern can be controlled electronically by controlling the amount of phase shift of a phase shifter connected to multiple element antennas. Widely used.

The above-described phase shifter includes an analog phase shifter that continuously varies the amount of phase shift and a digital phase shifter that switches the amount of phase shift to a discrete value.
Since analog phase shifters are difficult to control with high accuracy, generally, digital phase shifters that are advantageous in terms of control are often used.
When a digital phase shifter is used, the phase shift amount to be switched is a discrete value corresponding to the number of quantization bits, and therefore, between the ideal phase shift amount and the phase shift amount achievable with the digital phase shifter. Quantization phase error occurs in In addition, in the digital phase shifter, the amount of phase shift is switched by a semiconductor switch such as a diode or a transistor, so that a pass amplitude error and a pass phase error are generated due to a difference in characteristics of each semiconductor switch. The antenna characteristics are deteriorated due to the influence of the error.

In Patent Document 1 below, in order to reduce the influence of the above error, the power when the received signal S1 of the main antenna and the distribution signals S2 and S3 of the received signal of the sub antenna are combined is minimized. Discloses an antenna device for controlling the excitation amplitude phase of an element antenna.
However, it is not easy to freely control the excitation amplitude in the phased array antenna.
In addition, in order to control the excitation amplitude phase of the element antenna, it is necessary to add hardware such as a variable attenuator to the phased array antenna, which increases the manufacturing cost.
Patent Document 2 below discloses a time-modulated array antenna that uses the concept of time weighting so that the excitation amplitude of a phased array antenna can be freely controlled.
This is to obtain the same radiation pattern as a state in which a predetermined amplitude distribution is equivalently given by averaging the signals received or transmitted at a plurality of excitation phases.
(For example, see Patent Document 1).

JP2013-118613A (FIG. 1) JP 2013-219742 A (FIG. 1)

  Since the conventional antenna device is configured as described above, in the case of Patent Document 2, the excitation amplitude of the phased array antenna can be freely controlled. However, the amplitude error or the quantization error of the digital phase shifter can be controlled. There is a problem that a means for reducing the phase error is not provided and the side lobe level is deteriorated.

  The present invention has been made to solve the above-described problems, and reduces the quantization error of the phase shifter without adding hardware such as a variable attenuator to the phased array antenna, thereby reducing the low side lobe. An object of the present invention is to obtain an antenna device and an antenna excitation method capable of realizing the above.

  An antenna device according to the present invention includes a plurality of element antennas constituting a phased array antenna, a plurality of phase shifters for adjusting the phase of a signal received by the element antenna, an excitation distribution of the element antennas, and an excitation of the phase shifter From the setting means for setting the number of switching times to switch the phase in time division and the excitation phases that can be set for the phase shifter, select multiple combinations of excitation phases for the number of switching times, and switch for each combination of excitation phases. A combined vector calculation means for calculating a combined vector of phase vectors indicated by the number of excitation phases, and an excitation vector indicating an excitation distribution set by the setting means from the combined vectors calculated for each combination by the combined vector calculation means A combined vector selecting means for selecting a combined vector correlated with the combination vector selected by the combined vector selecting means. A phase shift amount control means for controlling the phase shift amount of the phase shifter according to the excitation phase indicated by the vector, and a synthesis means for synthesizing the signals whose phases are adjusted by the plurality of phase shifters; The time average of the signals synthesized by the synthesizing means is calculated.

  According to the present invention, a plurality of combinations of excitation phases corresponding to the number of times of switching are selected from the excitation phases that can be set for the phase shifter, and the phase vector indicated by the excitation phase corresponding to the number of times of switching is selected for each combination of the excitation phases. A combined vector calculating means for calculating the combined vector and a combined vector calculated for each combination by the combined vector calculating means and selecting a combined vector correlated with the excitation vector indicating the excitation distribution set by the setting means The phase shift amount control means is configured to control the phase shift amount of the phase shifter according to the excitation phase indicated by the composite vector selected by the composite vector selection means. Reduce the side lobe by reducing the quantization error of the phase shifter without adding hardware such as a phase detector There is an effect that can be current.

It is a block diagram which shows the antenna apparatus by Embodiment 1 of this invention. It is a flowchart which shows the processing content (antenna excitation method) of the antenna apparatus by Embodiment 1 of this invention. It is an explanatory view showing a synthetic vector which is the most correlated with the excitation vector V _d. It is explanatory drawing which shows that the reduction precision of a quantization error improves by increasing the frequency | count M of switching. It is a block diagram which shows the antenna apparatus by Embodiment 2 of this invention. It is a flowchart which shows the processing content (antenna excitation method) of the antenna device by Embodiment 2 of this invention. It is a block diagram which shows the antenna apparatus by Embodiment 3 of this invention. It is a conceptual diagram which shows the relationship of Formula (3).

Embodiment 1 FIG.
In the first embodiment, description will be made assuming that the antenna apparatus includes N element antennas and operates as a receiving antenna.
1 is a block diagram showing an antenna apparatus according to Embodiment 1 of the present invention.
In FIG. 1, reference numerals 1-1 to 1-N denote N element antennas that form antenna openings.
The phase shifters 2-1 to 2-N adjust the phase of the signals received by the element antennas 1-1 to 1-N under the control of the phase shifter control device 5.
The power combiner 3 combines signals whose phases have been adjusted by the phase shifters 2-1 to 2 -N, and outputs the combined signal to the receiver 11.
The phased array antenna 4 is configured by the element antennas 1-1 to 1-N, the phase shifters 2-1 to 2-N, and the power combiner 3.

The phase shifter control device 5 is composed of, for example, a semiconductor integrated circuit mounted with a CPU or a one-chip microcomputer, and is a device that controls the amount of phase shift of the phase shifters 2-1 to 2-N. .
The excitation distribution setting unit 6 of the phase shifter control device 5 is a setting unit that sets an excitation amplitude phase that is an ideal excitation distribution of the element antennas 1-1 to 1-N in order to realize a desired radiation pattern. .
The phase switching number setting unit 7 is a setting unit that sets a switching number M for switching the excitation phases of the phase shifters 2-1 to 2 -N in a time division manner.
The excitation distribution setting unit 6 and the phase switching number setting unit 7 constitute setting means.

The combined vector calculation unit 8 is an excitation phase that can be set for the phase shifters 2-1 to 2-N (all excitation phases determined from the number of quantization bits of the phase shifters 2-1 to 2-N. If the number of conversion bits is 5 bits, the number of excitation phases that can be set is 32), and combinations of excitation phases β _{m, k} (phase shift states) corresponding to the number of switching times (M) are selected. For each combination of excitation phases β _{m, k} , a plurality of selections are performed, and a process of calculating a combined vector v _k of the phase vectors indicated by the excitation phases β _{m, k for the} number of times of switching is performed. The combined vector calculation unit 8 constitutes a combined vector calculation unit.

The vector comparison unit 9 is a composite vector correlated with the excitation vector V _d indicating the excitation amplitude phase set by the excitation distribution setting unit 6 out of the composite vectors v _k calculated for each combination by the composite vector calculation unit 8. A process of selecting v _k is performed. For example, the Euclidean distance between the combined vector v _k calculated for each combination by the combined vector calculating unit 8 and the excitation vector V _d set by the excitation distribution setting unit 6 is calculated, and the combined vector having the smallest Euclidean distance is calculated. select. The vector comparison unit 9 constitutes a combined vector selection unit.
The phase shifter control signal output unit 10 outputs the excitation phase indicated by the combined vector v _k selected by the vector comparison unit 9 during the excitation time set by the excitation time setting unit 12 to the phase shifters 2-1 to 2-N. To set the phase shifter 2-1 to 2-N to control the amount of phase shift. The phase shifter control signal output unit 10 constitutes a phase shift amount control means.

The receiver 11 detects the combined signal output from the power combiner 3, converts the combined signal into digital data, and outputs the digital data to the time average processing unit 13.
The excitation time setting unit 12 is a setting unit that sets the excitation time.
The time average processing unit 13 is composed of, for example, a semiconductor integrated circuit on which a CPU is mounted, a one-chip microcomputer, or the like, and performs a process of calculating a time average of digital data output from the receiver 11. The time average processing unit 13 constitutes a time average processing means.
The signal processing unit 14 performs, for example, processing for detecting a desired signal from the time average calculation result by the time average processing unit 13.
In each embodiment of the present invention, data to be processed is processed as digital data. However, the data is not limited to digital data, and may be processed as analog data.

In the example of FIG. 1, each of the phased array antenna 4, the phase shifter control device 5, the receiver 11, the excitation time setting unit 12, the time average processing unit 13, and the signal processing unit 14 that are components of the antenna device is dedicated. Although what is comprised with the hardware was shown, for example, components other than the phased array antenna 4 and the receiver 11 may be comprised with the computer.
When the components other than the phased array antenna 4 and the receiver 11 are configured by a computer, the processing contents of the phase shifter control device 5, the excitation time setting unit 12, the time average processing unit 13, and the signal processing unit 14 are described. The program may be stored in the memory of the computer, and the CPU of the computer may execute the program stored in the memory.
FIG. 2 is a flowchart showing the processing contents (antenna excitation method) of the antenna device according to Embodiment 1 of the present invention.

Next, the operation will be described.
In the first embodiment, an example in which N element antennas 1-1 to 1-N are linear array antennas arranged at equal intervals will be described.
First, the excitation distribution setting unit 6 of the phase shifter control device 5 provides an excitation amplitude phase _An (n) that is an ideal excitation distribution of the element antennas 1-1 to 1-N in order to realize a desired radiation pattern. = 1, 2,..., N) is set (step ST1 in FIG. 2).
For example, if the number of element antennas 1 is 8, eight excitation amplitude phases _An are set for each element antenna 1.

Next, the phase switching number setting unit 7 sets the switching number M for switching the excitation phases of the phase shifters 2-1 to 2-N in a time division manner (step ST2).
The excitation time setting unit 12 sets the excitation time of the excitation phase that is switched in a time division manner (step ST3). The excitation times of the excitation phases that are switched in time division may be different times, but may be all equal times.

When the phase switching number setting unit 7 sets the switching number M, the composite vector calculation unit 8 sets the number of switching times (for M) from the excitation phases that can be set for the phase shifters 2-1 to 2-N. A combination of excitation phases β _{m, k} is obtained. Here, m = 1, 2,..., M, k = 1, 2,..., K, and K is the number of combinations of excitation phases.
Here, the excitation phases that can be set for the phase shifters 2-1 to 2-N are all excitation phases determined from the number of quantization bits of the phase shifters 2-1 to 2-N. If the number is 5 bits, the number of settable excitation phases is 32, and if the number of quantization bits is 6 bits, the number of settable excitation phases is 64.

式（２）のＶ_kは、合成ベクトル算出部８により算出されたＫ個の合成ベクトルｖ_kを表している。 When the combined vector calculation unit 8 obtains a combination of K excitation phases β _{m, k} , for each combination of the excitation phases β _{m, k} , M associated with the combination is obtained as shown in the following equation (1). A combined vector v _k of phase vectors (M phase vectors) indicated by the excitation phases β _{m, k} is calculated (step ST4).

V _{k in} Equation (2) represents K composite vectors v _k calculated by the composite vector calculator 8.

When the combined vector calculation unit 8 calculates K combined vectors v _k , the vector comparison unit 9 calculates an excitation vector indicating the excitation amplitude phase set by the excitation distribution setting unit 6 from the K combined vectors v _k. A composite vector most correlated with V _d is selected (step ST5).
Here, FIG. 3 is an explanatory view showing the synthetic vector which is the most correlated with the excitation vector V _d.
Hereinafter, the processing contents of the combined vector calculation unit 8 and the vector comparison unit 9 will be specifically described with reference to FIG.

The horizontal axis in FIG. 3 represents the real axis Re of the excitation phase in one phase shifter 2, and the vertical axis represents the imaginary axis Im of the excitation phase.
FIG. 3 shows an example in which the excitation phase switching frequency M is 2 (M = 2) for the sake of simplicity.
If the number of quantization bits of the phase shifter 2 is 5, as described above _, the number of excitation phases β _{m, k that} can be set is 32, but in order to simplify the drawing, FIG. Only three excitation phases β _i−1 , β _i , β _{i + 1} are representatively shown.
3, 20 is the excitation vector V _d showing the excitation amplitude and phase A _n set by the excitation distribution setting unit 6 (vector of angle is phi ₀ and the real axis Re), the excitation amplitude and phase A _n is Since this is an ideal excitation distribution for realizing a desired antenna radiation pattern, the length of the excitation vector V _d matches the radius of the circle shown in FIG.

The phase vector 21 is a vector indicating the excitation phase β _i (vector whose angle with the real axis Re is φ ₁ ), and since the phase vector 21 has a quantization error, the vector length is longer than the radius of the circle. . Further, the angle φ ₁ formed is also different from the angle formed when there is no quantization error.
The phase vector 22 is a vector indicating the excitation phase β _{i + 1} (a vector having an angle of φ ₂ with the real axis Re). Since the phase vector 22 has a quantization error, the vector length is shorter than the radius of the circle. ing. Further, the angle φ ₂ formed is also different from the angle formed when there is no quantization error.
The phase vector 23 is a vector indicating the excitation phase β _i-1 (a vector whose angle with the real axis Re is φ ₃ ), and the phase vector 23 has a quantization error, so that the vector length becomes longer than the radius of the circle. ing. Further, the angle φ ₃ formed is also different from the angle formed when there is no quantization error.

Synthetic vector calculation unit 8, when switching circuits the number M of the excitation phase is twice (M = 2), Synthesis and phase vector 21 indicating the excitation phase beta _i, and phase vector 22 indicating the excitation phase beta _{i + 1} Then, after calculating the composite vector 24, the composite vector 25 is calculated by averaging the composite vector 24 with the number of switching times M (= 2).
The synthesized vector calculation unit 8 synthesizes the phase vector 21 indicating the excitation phase β _i and the phase vector 23 indicating the excitation phase β _i−1 , calculates the synthesized vector 26, and then combines the synthesized vector 26. Is averaged by the number of times of switching M (= 2) to calculate the composite vector 27.
Note that the synthesized vector calculation unit 8 synthesizes the phase vector 22 indicating the excitation phase β _{i + 1} and the phase vector 23 indicating the excitation phase β _i−1 to generate a synthesized corresponding to the synthesized vector 25 and the synthesized vector 27. Although a vector is also calculated, this composite vector is not shown in FIG. 3 for simplification of the drawing and explanation.

When the combined vector calculation unit 8 calculates the combined vectors 25 and 27, the vector comparison unit 9 calculates the Euclidean distance L ₁ between the combined vector 25 and the excitation vector V _d (vector 20), and the combined vector 27 and the excitation vector V. _d Calculate the Euclidean distance L ₂ of (vector 20).
When the vector comparison unit 9 calculates the Euclidean distances L ₁ and L ₂ , the vector comparison unit 9 compares the Euclidean distance L ₁ and the Euclidean distance L ₂ , and the combined vector most correlated with the excitation vector V _d has the smallest Euclidean distance. Select a composite vector.
In the example of FIG. 3, since L ₁ <L ₂ , the combined vector 25 is selected as the combined vector most correlated with the excitation vector V _d .
In this way, the composite vector most correlated with the excitation vector V _d indicating the excitation amplitude phase set by the excitation distribution setting unit 6 is selected from the plurality of composite vectors v _k calculated by the composite vector calculation unit 8. Therefore, the amplitude error and phase error, which are quantization errors of the phase shifter 2, are reduced.

The phase shifter control signal output unit 10 is set by the excitation time setting unit 12 when the vector comparison unit 9 selects a combined vector (the combined vector 25 in the example of FIG. 3) most correlated with the excitation vector V _d . During the excitation time, the excitation phase β indicated by the composite vector selected by the vector comparison unit 9 (the vector length of the composite vector selected by the vector comparison unit 9 and the angle formed by the composite vector and the real number axis Re are shown. (Phase information) is set in the phase shifters 2-1 to 2-N (step ST6).

When the element antennas 1-1 to 1 -N receive signals, the phase shifters 2-1 to 2 -N receive the element antennas by the amount of phase shift indicated by the excitation phase set by the phase shifter control signal output unit 10. The phase of the signal received by 1-1 to 1-N is adjusted (step ST7).
The power combiner 3 combines the signals whose phases are adjusted by the phase shifters 2-1 to 2 -N and outputs the combined signal to the receiver 11.
The receiver 11 detects the combined signal output from the power combiner 3, performs A / D conversion on the combined signal, and converts the combined signal (hereinafter referred to as “digital data”) into a time average processing unit 13. Output to.
When receiving the digital data from the time average processing unit 13, the time average processing unit 13 accumulates the digital data (step ST8).

The excitation phase β set in the phase shifters 2-1 to 2 -N is switched by the phase shifter control signal output unit 10 every time the excitation time set by the excitation time setting unit 12 elapses. Until the number of switching times β reaches M times, the processes of steps ST7 to ST8 are repeatedly executed. When the number of switching of the excitation phase β _{m, k} reaches M times, M digital data are accumulated in the time average processing unit 13, and the process proceeds to step ST10 (step ST9).
When the time average processing unit 13 accumulates M pieces of digital data, it calculates an average value (time integration value) of the M pieces of digital data (step ST10).
When the signal processing unit 14 receives the average value of the M pieces of digital data from the time average processing unit 13, the signal processing unit 14 performs, for example, processing for detecting a desired signal from the average value of the digital data.

In the first embodiment, the example in which the excitation phase switching frequency M is 2 times (M = 2) is shown. However, the switching frequency M can be arbitrarily set. The accuracy of reducing the quantization error of the phase shifter 2 can be increased.
FIG. 4 is an explanatory view showing that the accuracy of reducing the quantization error is improved by increasing the number M of switching times.
4, 20, as in the case of FIG. 3, a excitation vector V _d showing the excitation amplitude and phase A _n set by the excitation distribution setting unit 6 (the ideal vector).
The phase vectors 31, 32, and 33 are vectors indicating the respective excitation phases.

The combined vector 34 is a vector obtained by combining the phase vector 31 and the phase vector 32 (a combined vector averaged by the number of times of switching “2”), and a plurality of times when the number of times of switching M is 2 (M = 2). Among these composite vectors, the composite vector has the minimum Euclidean distance from the excitation vector V _d (ideal vector).
The combined vector 35 is a vector obtained by combining the phase vector 31, the phase vector 32, and the phase vector 33 (a combined vector averaged by the number of times of switching “3”), and the number of times of switching M is 3 (M = 3). Among a plurality of composite vectors at a certain time, the composite vector has the minimum Euclidean distance from the excitation vector V _d (ideal vector).

In the example of FIG. 4, when the number of times of switching M is 2 (M = 2), the combined vector 34 is selected by the vector comparing unit 9 from the plurality of combined vectors v _k calculated by the combined vector calculating unit 8. Is done.
Further, when the number of times of switching M is 3 (M = 3), the combined vector 35 is selected by the vector comparing unit 9 from the plurality of combined vectors v _k calculated by the combined vector calculating unit 8.
At this time, as is clear from FIG. 4, when the number of times of switching M is three (M = 3) rather than the composite vector 34 selected when the number of times of switching M is two (M = 2). The synthesized vector 35 selected in (1) has a smaller Euclidean distance and is closer to the excitation vector V _d (ideal vector).
Therefore, as the number of times of switching M is larger, the quantization error reduction accuracy is improved.

As is apparent from the above, according to the first embodiment, among the excitation phases that can be set for the phase shifters 2-1 to 2 -N, a plurality of combinations of excitation phases β _{m, k corresponding to} the number of times of switching are provided. selected for each combination of the excitation phase beta _{m, k,} and the synthetic vector calculation unit 8 for calculating a resultant vector v _k phasor indicated excitation phase beta _{m, k} of the switching circuits minutes, the composite vector calculator 8 A vector comparison unit 9 for selecting a synthesis vector v _k most correlated with the excitation vector V _d indicating the excitation amplitude phase set by the excitation distribution setting unit 6 from the synthesis vectors v _k calculated for each combination; And the phase shifter control signal output unit 10 sets the excitation phase β indicated by the combined vector v _k selected by the vector comparison unit 9 in the phase shifters 2-1 to 2-N, so that the phase shift is performed. To control the amount of phase shift in units 2-1 to 2-N Therefore, without adding hardware such as a variable attenuator to the phased array antenna 4, it is possible to reduce the quantization error of the phase shifters 2-1 to 2-N and realize low side lobe. There is an effect that can.

In the first embodiment, the combined vector calculation unit 8 selects excitation phases β _{m, k corresponding to} the number of switching times (M) from among the excitation phases that can be set for the phase shifters 2-1 to 2-N. seek combinations, each combination of the excitation phase beta _{m, k,} although an example of calculating the combined vector v _k of the phase vector representing the excitation phase beta _{m, k} of the M component in accordance with the combination, the phase shift Among the excitation phases that can be set for the devices 2-1 to 2 -N, only the excitation phase of the phase vector whose Euclidean distance from the ideal excitation vector V _d is smaller than a preset threshold value is left (excitation vector V Exclude the excitation phase of the phase vector whose Euclidean distance from _d is greater than the threshold), and find the combination of excitation phases β _{m, k for} the number of switching times (M) from the remaining excitation phases, and the excitation for each combination of phase β _{m, k,} May be calculated synthetic vector v _k phasor indicated excitation phase beta _{m, k} of the M component in accordance with the combination.

Embodiment 2. FIG.
In the second embodiment, description will be made assuming that the antenna apparatus includes N element antennas and operates as a transmission / reception antenna.
FIG. 5 is a block diagram showing an antenna apparatus according to Embodiment 2 of the present invention. In the figure, the same reference numerals as those in FIG.
The transmitter 41 generates a transmission signal and outputs the transmission signal to the power combiner / distributor 42.
When the power combiner / distributor 42 receives a transmission signal from the transmitter 41, the power combiner / distributor 42 distributes the power of the transmission signal to N and outputs a plurality of signals to the phase shifters 2-1 to 2-N, while the phase shifter 2 When -1 to 2-N adjust the phase of the signal received by the element antennas 1-1 to 1-N, a plurality of signals after phase adjustment are combined and the combined signal is output to the receiver 11. The power combiner / distributor 42 constitutes a combiner and a distributor.

In the example of FIG. 5, the phased array antenna 4, the phase shifter control device 5, the receiver 11, the transmitter 41, the excitation time setting unit 12, the time average processing unit 13, and the signal processing unit 14 that are components of the antenna device. Although each of them is configured with dedicated hardware, for example, components other than the phased array antenna 4, the receiver 11, and the transmitter 41 may be configured with a computer.
When components other than the phased array antenna 4, the receiver 11, and the transmitter 41 are configured by a computer, the processing contents of the phase shifter control device 5, the excitation time setting unit 12, the time average processing unit 13, and the signal processing unit 14 are described. The described program may be stored in the memory of the computer, and the CPU of the computer may execute the program stored in the memory.
FIG. 6 is a flowchart showing the processing contents (antenna excitation method) of the antenna device according to the second embodiment of the present invention.

Next, the operation will be described.
First, the excitation distribution setting unit 6 of the phase shifter control device 5 is the ideal excitation distribution of the element antennas 1-1 to 1-N in order to realize a desired radiation pattern, as in the first embodiment. The excitation amplitude phase _An (n = 1, 2,..., N) is set (step ST11 in FIG. 6).
Next, similarly to the first embodiment, the phase switching number setting unit 7 sets the switching number M for switching the excitation phases of the phase shifters 2-1 to 2-N in a time division manner (step ST12).
Moreover, the excitation time setting part 12 sets the excitation time of the excitation phase switched by a time division similarly to the said Embodiment 1 (step ST13).

When the phase switching number setting unit 7 sets the switching number M, the combined vector calculation unit 8 can select among the excitation phases that can be set for the phase shifters 2-1 to 2-N, as in the first embodiment. A combination of excitation phases β _{m, k corresponding to} the number of switching times (M) is _obtained .
When the combined vector calculation unit 8 obtains a combination of K excitation phases β _{m, k} , for each combination of the excitation phases β _{m, k} , M combinations related to the combination are _obtained as in the first embodiment. The combined vector v _k of the phase vectors (M phase vectors) indicated by the excitation phase β _{m, k} is calculated (step ST14).

When the composite vector calculation unit 8 calculates K composite vectors v _k , the vector comparison unit 9 is set by the excitation distribution setting unit 6 from among the K composite vectors v _k as in the first embodiment. The synthesized vector v _k most correlated with the excitation vector V _d indicating the excitation amplitude phase thus selected is selected (step ST15).
The phase shifter control signal output unit 10 is set by the excitation time setting unit 12 as in the first embodiment when the vector comparison unit 9 selects the combined vector v _k most correlated with the excitation vector V _d. During the excitation time, the excitation phase β indicated by the combined vector v _k selected by the vector comparison unit 9 is set in the phase shifters 2-1 to 2-N (step ST16).

The transmitter 41 generates a transmission signal and outputs the transmission signal to the power combiner / distributor 42.
When the power combiner / distributor 42 receives the transmission signal from the transmitter 41, the power combiner / distributor 42 distributes the power of the transmission signal to N and outputs a plurality of signals to the phase shifters 2-1 to 2-N.
When the phase shifters 2-1 to 2 -N receive the signal distributed by the power combiner / distributor 42, the phase shifters 2-1 to 2 -N receive the signal by the amount of phase shift indicated by the excitation phase β set by the phase shifter control signal output unit 10. And the phase-adjusted signal is output to the element antennas 1-1 to 1-N (step ST17).
Thereby, the signal after phase adjustment is radiated | emitted to space from the element antenna 1-1 to 1-N (step ST18).

A part of the signal radiated from the element antennas 1-1 to 1-N is reflected (or scattered) by the target to be observed and returns to the phased array antenna 4.
The element antennas 1-1 to 1-N receive the signal that has been reflected back by the target (step ST19).

When the element antennas 1-1 to 1 -N receive signals, the phase shifters 2-1 to 2 -N receive the element by the amount of phase shift indicated by the excitation phase β set by the phase shifter control signal output unit 10. The phase of the signal received by antennas 1-1 to 1-N is adjusted (step ST20).
The power combiner / distributor 42 combines the signals whose phases are adjusted by the phase shifters 2-1 to 2 -N and outputs the combined signal to the receiver 11.
The receiver 11 detects the combined signal output from the power combiner / distributor 42, performs A / D conversion on the combined signal, and outputs digital data that is a digital combined signal to the time average processing unit 13.
When receiving the digital data from the time average processing unit 13, the time average processing unit 13 accumulates the digital data (step ST21).

The excitation phase β set in the phase shifters 2-1 to 2 -N is switched by the phase shifter control signal output unit 10 every time the excitation time set by the excitation time setting unit 12 elapses. Until the number of switching times β reaches M times, the processes of steps ST17 to ST21 are repeatedly executed. When the number of switching of the excitation phase β reaches M times, M digital data are accumulated in the time average processing unit 13, and the process proceeds to step ST23 (step ST22).
When the time average processing unit 13 accumulates the M digital data, the time average processing unit 13 calculates an average value (time integration value) of the M digital data (step ST23).
When the signal processing unit 14 receives the average value of the M pieces of digital data from the time average processing unit 13, the signal processing unit 14 performs, for example, processing for detecting a desired signal from the average value of the digital data.

As apparent from the above, according to the second embodiment, a plurality of combinations of excitation phases β _{m, k corresponding to} the number of switching times are selected from the excitation phases that can be set for the phase shifters 2-1 to 2 -N. selected for each combination of the excitation phase beta _{m, k,} and the synthetic vector calculation unit 8 for calculating a resultant vector v _k phasor indicated excitation phase beta _{m, k} of the switching circuits minutes, the composite vector calculator 8 A vector comparison unit 9 for selecting a synthesis vector v _k most correlated with the excitation vector V _d indicating the excitation amplitude phase set by the excitation distribution setting unit 6 from the synthesis vectors v _k calculated for each combination; And the phase shifter control signal output unit 10 sets the excitation phase β indicated by the combined vector v _k selected by the vector comparison unit 9 in the phase shifters 2-1 to 2-N, so that the phase shift is performed. To control the amount of phase shift in units 2-1 to 2-N Therefore, without adding hardware such as a variable attenuator to the phased array antenna 4, it is possible to reduce the quantization error of the phase shifters 2-1 to 2-N and realize low side lobe. There is an effect that can.
Further, according to the second embodiment, since the transmission and reception of the signal are linked, the effect of averaging the digital data by the time average processing unit 13 is great, and the quantization error (passing amplitude error, An effect of minimizing the (passing phase error) can be achieved.

Embodiment 3 FIG.
7 is a block diagram showing an antenna apparatus according to Embodiment 3 of the present invention. In the figure, the same reference numerals as those in FIG.
The calibration matrix setting unit 51 sets a calibration matrix G ⁻¹ which is an inverse matrix of a mutual coupling matrix G (a complex number having amplitude and phase information) indicating the influence of mutual coupling between the element antennas 1-1 to 1-N. It is a setting part.
As with the excitation distribution setting unit 6 in FIG. 1, the excitation distribution setting unit 52 has an excitation amplitude phase V ₁ that is an ideal excitation distribution of the element antennas 1-1 to 1-N in order to realize a desired radiation pattern. Then, using the calibration matrix G ⁻¹ set by the calibration matrix setting unit 51, the excitation amplitude phase V ₀ calibrating the mutual coupling between the element antennas 1-1 to 1-N is calculated. It is a setting part.
The phase switching frequency setting unit 7, the calibration matrix setting unit 51, and the excitation distribution setting unit 52 constitute setting means.

  In the third embodiment, an example in which the calibration matrix setting unit 51 and the excitation distribution setting unit 52 are applied to the antenna apparatus of FIG. 1 is shown. However, the calibration matrix setting unit 51 and the excitation distribution setting unit 52 are replaced with the antenna of FIG. You may make it apply to an apparatus.

Next, the operation will be described.
However, since the components other than the calibration matrix setting unit 51 and the excitation distribution setting unit 52 are the same as those in the first and second embodiments, only the processing contents of the calibration matrix setting unit 51 and the excitation distribution setting unit 52 will be described here. .
The calibration matrix setting unit 51 sets a calibration matrix G ⁻¹ that is an inverse matrix of the mutual coupling matrix G indicating the influence of mutual coupling between the element antennas 1-1 to 1-N.

As with the excitation distribution setting unit 6 in FIG. 1, the excitation distribution setting unit 52 has an excitation amplitude phase V that is an ideal excitation distribution of the element antennas 1-1 to 1-N in order to realize a desired radiation pattern. Set ₁
However, since the excitation amplitude phase V ₁ does not consider the influence of the mutual coupling between the element antennas 1-1 to ₁ -N, the influence of the mutual coupling between the element antennas 1-1 to 1-N is large. In this case, there is a possibility that the reduction accuracy of the quantization error of the phase shifters 2-1 to 2-N is deteriorated.
The excitation amplitude phase V ₁ set by the excitation distribution setting unit 52, the mutual coupling matrix G indicating the influence of mutual coupling between the element antennas 1-1 to 1-N, and the element antennas 1-1 to 1-N There is a relationship expressed by the following equation (3) with the excitation amplitude phase V ₀ calibrating the mutual coupling between the two.
V ₁ = GV ₀ (3)
FIG. 8 is a conceptual diagram showing the relationship of equation (3).

If the equation (3) is transformed into the following equation (4), the excitation amplitude phase V ₁ set by the excitation distribution setting unit 52 and the calibration matrix G ⁻¹ set by the calibration matrix setting unit 51 (mutually) And the excitation amplitude phase V ₀ calibrating the mutual coupling between the element antennas 1-1 to 1-N can be calculated using the inverse matrix of the coupling matrix G).
V ₀ = G ⁻¹ V ₁ (4)
Therefore, the excitation distribution setting unit 52 calculates the excitation amplitude phase V ₀ calibrating the mutual coupling between the element antennas 1-1 to 1-N according to the equation (4), and calculates the excitation amplitude phase V ₀ . The result is output to the vector comparison unit 9.

As apparent from the above, according to the third embodiment, after the excitation distribution setting unit 52 sets the excitation amplitude phase V ₁ that is an ideal excitation distribution of the element antennas 1-1 to 1-N, Since the calibration matrix G ⁻¹ set by the calibration matrix setting unit 51 is used, the excitation amplitude phase V ₀ calibrating the mutual coupling between the element antennas 1-1 to 1-N is calculated. Even when the influence of mutual coupling between the element antennas 1-1 to 1-N is large, there is an effect that it is possible to increase the accuracy of reducing the quantization error of the phase shifters 2-1 to 2-N.

Embodiment 4 FIG.
In the first to third embodiments, as a method for selecting the combined vector v _k most correlated with the excitation vector V _d indicating the excitation amplitude phase set by the excitation distribution setting unit 6, the vector comparison unit 9 performs synthesis. The Euclidean distance L between the combined vector v _k calculated for each combination by the vector calculating unit 8 and the excitation vector V _d is calculated, and the combined vector v _k calculated for each combination by the combined vector calculating unit 8 Although Euclidean distance L between the excitation vector V _d showed that selecting a minimum resultant vector, the correlation coefficient between the resultant vector v _k that has been calculated for each combination with the excitation vector V _d by combining vector calculator 8 cos [theta] And a coefficient of correlation co with the excitation vector V _d out of the combined vectors v _k calculated for each combination by the combined vector calculation unit 8. A combined vector having sθ closest to 1 may be selected.

式（５）において、Ａは励振ベクトルＶ_d、Ｂ_kは合成ベクトルｖ_kである。 Specifically, the combined vector most correlated with the excitation vector V _d is selected as follows.
When the composite vector calculation unit 8 calculates K composite vectors v _k , the vector comparison unit 9 calculates the phase relationship between the K composite vectors v _k and the excitation vector V _d as shown in the following equation (5). The number cos θ is calculated.

In Expression (5), A is an excitation vector V _d , and B _k is a composite vector v _k .

Vector comparison unit 9 calculates the correlation coefficient cos [theta] and the K resultant vector v _k and the excitation vector V _d, in those correlation coefficients cos [theta], identifies a correlation coefficient cos [theta] closest to 1, as the resultant vector v _k which is the most correlated with the excitation vector V _d, selects the combined vector is close to the correlation coefficient cosθ most 1 between its excitation vector V _d.
According to this selection method, the combined vector v _k most correlated with the excitation vector V _d can be selected with a simple algorithm.

  In the present invention, within the scope of the invention, any combination of the embodiments, or any modification of any component in each embodiment, or omission of any component in each embodiment is possible. .

1-1 to 1-N element antenna, 2-1 to 2-N phase shifter, 3 power combiner (combining means), 4 phased array antenna, 5 phase shifter controller, 6 excitation distribution setting unit (setting means) ), 7 Phase switching number setting unit (setting unit), 8 combined vector calculating unit (combined vector calculating unit), 9 vector comparing unit (combined vector selecting unit), 10 phase shifter control signal output unit (phase shift amount control unit) ), 11 receiver, 12 excitation time setting unit, 13 time average processing unit (time average processing means), 14 signal processing unit, 20 excitation vector V _d , 21-23 phase vector, 24, 26 composite vector, 25, 27 Composite vector averaged by the number of switchings, 31, 32, 33 phase vector, 34, 35 Composite vector averaged by the number of switchings, 41 Transmitter, 42 Power combiner / distributor (combining means, distributing means), 51 calibration matrix setting unit (setting unit), 52 excitation distribution setting unit (setting unit).

Claims (8)

A plurality of element antennas constituting a phased array antenna;
A plurality of phase shifters for adjusting the phase of the signal received by the element antenna;
Setting means for setting the number of times of switching the time distribution of the excitation distribution of the element antenna and the excitation phase of the phase shifter;
A plurality of combinations of excitation phases corresponding to the number of switching times are selected from excitation phases that can be set for the phase shifter, and a combined vector of phase vectors indicated by the excitation phases corresponding to the number of switching times for each combination of the excitation phases. Combined vector calculation means for calculating
A synthesized vector selecting means for selecting a synthesized vector correlated with an excitation vector indicating an excitation distribution set by the setting means from the synthesized vectors calculated for each combination by the synthesized vector calculating means;
A phase shift amount control means for controlling the phase shift amount of the phase shifter according to the excitation phase indicated by the composite vector selected by the composite vector selection means;
Combining means for combining signals whose phases are adjusted by the plurality of phase shifters;
An antenna device comprising: a time average processing means for calculating a time average of the signals synthesized by the synthesis means. Distribution means for distributing the transmission signal into a plurality of signals;
A plurality of phase shifters for adjusting the phase of the signal distributed by the distribution means;
A plurality of element antennas for transmitting signals whose phases are adjusted by the plurality of phase shifters;
Setting means for setting the number of times of switching the time distribution of the excitation distribution of the element antenna and the excitation phase of the phase shifter;
A plurality of combinations of excitation phases corresponding to the number of switching times are selected from excitation phases that can be set for the phase shifter, and a combined vector of phase vectors indicated by the excitation phases corresponding to the number of switching times for each combination of the excitation phases. Combined vector calculation means for calculating
A synthesized vector selecting means for selecting a synthesized vector correlated with an excitation vector indicating an excitation distribution set by the setting means from the synthesized vectors calculated for each combination by the synthesized vector calculating means;
An antenna apparatus comprising: a phase shift amount control unit that controls a phase shift amount of the phase shifter in accordance with an excitation phase indicated by the combined vector selected by the combined vector selection unit. When the plurality of element antennas are used as receiving antennas for receiving signals in addition to being used as transmitting antennas for transmitting signals whose phases are adjusted by the plurality of phase shifters,
The plurality of phase shifters have a function of adjusting a phase of a signal received by the element antenna while adjusting a phase of a signal distributed by the distributing unit;
Combining means for combining signals whose phases are adjusted by the plurality of phase shifters;
3. The antenna apparatus according to claim 2, further comprising time average processing means for calculating a time average of the signals synthesized by the synthesis means.   The said setting means sets the excitation distribution of the said element antenna using the calibration matrix which calibrates the mutual coupling between these element antennas, The any one of Claims 1-3 characterized by the above-mentioned. The antenna device according to item.   The synthesized vector selecting means calculates a Euclidean distance between the synthesized vector calculated for each combination by the synthesized vector calculating means and the excitation vector indicating the excitation distribution set by the setting means, and the combined vector calculating means 5. The antenna device according to claim 1, wherein a composite vector is selected from composite vectors calculated every time based on a Euclidean distance from the excitation vector. 6.   The synthesized vector selecting means calculates a correlation coefficient between the synthesized vector calculated for each combination by the synthesized vector calculating means and the excitation vector indicating the excitation distribution set by the setting means, and the synthesized vector calculating means The antenna according to any one of claims 1 to 4, wherein a composite vector is selected from composite vectors calculated for each combination based on a correlation coefficient with the excitation vector. apparatus. A phase adjustment processing step in which a plurality of phase shifters adjust phases of signals received by a plurality of element antennas constituting the phased array antenna;
A setting processing step for setting a switching frequency for switching the time distribution of the excitation distribution of the element antenna and the excitation phase of the phase shifter;
A combined vector calculating means selects a plurality of combinations of excitation phases for the number of switching times from among excitation phases that can be set for the phase shifter, and for each combination of excitation phases, the excitation phase for the number of switching times is selected. A combined vector calculation processing step for calculating a combined vector of the phase vectors shown;
A synthesis vector selecting unit selects a synthesis vector correlated with an excitation vector indicating the excitation distribution set in the setting processing step from the synthesis vectors calculated for each combination in the synthesis vector calculation processing step. A vector selection processing step;
A phase shift amount control processing step for controlling a phase shift amount of the phase shifter according to an excitation phase indicated by the composite vector selected in the composite vector selection processing step;
A synthesizing unit that synthesizes a plurality of signals whose phases have been adjusted in the phase adjustment processing step;
An antenna excitation method comprising: a time average processing step, wherein a time average processing means calculates a time average of the signals combined in the combining processing step. A distribution processing step in which the distribution means distributes the transmission signal into a plurality of signals;
A plurality of phase shifters adjust the phase of the signal distributed in the distribution processing step, and output a phase-adjusted signal to a plurality of element antennas; and
A setting processing step for setting a switching frequency for switching the time distribution of the excitation distribution of the element antenna and the excitation phase of the phase shifter;
A combined vector calculating means selects a plurality of combinations of excitation phases for the number of switching times from among excitation phases that can be set for the phase shifter, and for each combination of excitation phases, the excitation phase for the number of switching times is selected. A combined vector calculation processing step for calculating a combined vector of the phase vectors shown;
A synthesis vector selecting unit selects a synthesis vector correlated with an excitation vector indicating the excitation distribution set in the setting processing step from the synthesis vectors calculated for each combination in the synthesis vector calculation processing step. A vector selection processing step;
An antenna excitation method comprising: a phase shift amount control unit that controls a phase shift amount of the phase shifter in accordance with an excitation phase indicated by the combined vector selected in the combined vector selection processing step.

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