JP5815448B2 - Phased array transmitter - Google Patents

Description

  The present invention relates to a phased array transmission apparatus that transmits a radio signal using a phased array antenna.

  The phased array antenna technology is a technology widely used in the fields of wireless communication and radar, and by applying this technology to a transmitter, it becomes possible to form a beam directivity and electronically scan the beam. . For example, in the wireless communication field, it is possible to form a beam to improve the antenna gain and extend the range of the communication area, or to dynamically control the cover area according to the number of accommodated users in the base station. . In radar applications, a beam with a sharp directivity formed by a phased array antenna is radiated from a transmitter to a detection target, thereby suppressing reflection (clutter reflection) from a non-detection target and detecting accuracy. There is an effect of improving.

  A transmitter using the phased array antenna technology appropriately arranges a plurality of antenna elements in an array and appropriately sets each phase and amplitude of a plurality of parallel transmission systems (hereinafter referred to as “transmission branches”) that feed each antenna element. By controlling, a desired directivity gain is obtained as an antenna. The phase and amplitude of each transmission branch are controlled with high accuracy. However, if an error occurs in these, for example, the shape of the beam collapses, so that a strong beam other than the main beam is generated and the characteristics deteriorate.

  For this reason, in wireless transmission using a phased array antenna, a technique for correcting the error is required when an error occurs in the control of the amplitude and phase between transmission branches. There are various causes of errors such as performance variations of components used in circuit mounting, process variations on integrated circuits, changes due to usage environment (for example, temperature), and performance variations of power supply used in each transmission branch. Factors are considered.

  As a technique for correcting a phase error and an amplitude error in wireless transmission using a phased array antenna, there is a conventional example disclosed in Patent Document 1, for example. The array antenna transmission device and the reception device of Patent Literature 1 are configured to include an RF transmission unit that feeds power to a plurality of antennas to form a beam, and a calibration RF for detecting an amplitude phase error of each transmission branch. A receiving unit, a fast Fourier transform unit, and a calibration value measuring unit are provided separately. In order to realize error correction, a calibration value for error detection and correction is calculated by sequentially receiving the transmission signal of each transmission branch extracted by the changeover switch. Based on the calculated calibration value, the phase error and the amplitude error are corrected by feeding back to each transmission branch.

  Further, for example, in the phased array antenna apparatus disclosed in Patent Document 2, information on the correction phase storage device that stores the correction phase information and the delay time of each real-time delay phase shifter is acquired, and each real-time delay phase shift is acquired. And a correction phase indicating circuit for indicating a correction phase corresponding to the delay time of the detector, and a phase error between the transmission branches is corrected by the phase shifter and the delay device.

JP 2005-348236 A JP 2002-76743 A

  However, in the conventional example described in Patent Document 1, in order to detect the phase error and the amplitude error of each transmission branch, the phase error is obtained by down-converting the loopback signal of the transmission system and performing the FFT operation. This is a configuration in which a calibration receiving system for detecting the signal is added. For this reason, a circuit amount and power consumption will become large.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to suppress an increase in circuit or power consumption in wireless transmission using a phased array antenna, and to reduce transmission signals between transmission branches with a simple configuration. It is to enable correction of phase error and amplitude error.

  The present invention provides a transmission unit that transmits a radio frequency transmission signal, a phase adjustment unit that adjusts the phase of the transmission signal, an amplitude adjustment unit that adjusts the amplitude of the transmission signal, and an output signal of the transmission unit in space. A first transmission branch and a second transmission branch, the first transmission branch and the second transmission having an antenna unit that radiates to the antenna unit and a coupler unit that extracts a part of the output of the transmission unit First and second branch detectors for detecting the output level from each coupler unit of the branch, signal combiner for combining the outputs from the coupler units of the first and second transmission branches, and the signal combiner A combined detection unit for detecting the output level from the unit, an amplitude control unit for controlling the amplitude adjustment unit by detection output by the first and second branch detection units, and a detection output by the combined detection unit Thus providing phased array transmitting apparatus and a phase controller for controlling said phase adjusting unit.

  According to this configuration, the increase in circuit or power consumption is suppressed, and the phase error and amplitude error of the transmission signal between the transmission branches can be corrected with a simple configuration, and a highly accurate transmission beam is formed in the phased array antenna. It becomes possible.

  According to the present invention, in wireless transmission using a phased array antenna, an increase in circuit or power consumption is suppressed, and a phase error and an amplitude error of a transmission signal between transmission branches can be corrected with a simple configuration.

The block diagram which shows the structure of the phased array transmission apparatus which concerns on 1st Embodiment The block diagram which shows the structure of the phased array transmitter which concerns on 2nd Embodiment The block diagram which shows the structure of the phased array transmitter which concerns on 3rd Embodiment The block diagram which shows the structure of the phased array transmission apparatus which concerns on 4th Embodiment It is operation | movement explanatory drawing of the synthetic | combination distribution part in 4th Embodiment, (A) is a figure which shows an input / output terminal, (B) is a figure which shows an example of the correspondence of the amplitude and phase of each input / output terminal.

  Embodiments of a phased array transmission apparatus according to the present invention will be described below. In the following embodiments, the same components are denoted by the same reference numerals, and the description thereof will be omitted because it is redundant. Here, a wireless transmission device using a phased array antenna technique (a wireless transmission device using a phased array antenna) is referred to as a “phased array transmission device”.

(First embodiment)
FIG. 1 is a block diagram showing a configuration of a phased array transmission apparatus according to the first embodiment of the present invention. In the first embodiment, a configuration example having two transmission branches as a plurality of parallel transmission systems is shown. Note that the present invention can also be applied to a configuration having three or more transmission branches.

  The phased array transmission apparatus according to the first embodiment includes transmission branches 101 and 102, a signal synthesis unit 110, branch detection units 121 and 122, a synthesis detection unit 130, a phase control unit 140, and an amplitude control unit 150.

  The transmission branches 101 and 102 have functions of feeding a transmission signal to each of a plurality of antennas in the phased array transmission apparatus, modulating the transmission signal, and up-converting to a radio frequency signal. Each transmission branch 101, 102 has the same configuration.

  That is, the transmission branch 101 includes an antenna unit 11, a coupler unit 161, a transmission unit 171, a phase adjustment unit 181, and an amplitude adjustment unit 191, and the transmission branch 102 includes an antenna unit 12, a coupler unit 162, a transmission unit 172, and a phase. An adjustment unit 182 and an amplitude adjustment unit 192 are included.

  The antenna units 11 and 12 radiate transmission signals to space, and constitute an array antenna by an array of a plurality of antennas. In a phased array antenna, the shape of a transmission beam is theoretically determined by the directivity of a single antenna, the arrangement interval of a plurality of antennas, and the level and phase of a transmission signal fed to each antenna.

  The couplers 161 and 162 are provided in the vicinity of the antenna end in front of the antennas 11 and 12, respectively, and have a function of extracting a part of the transmission signal to be fed. In consideration of quality degradation of the transmission signal, the extraction level is set to be about 1/10 or less of the transmission signal. For the high-frequency transmission signal, the couplers 161 and 162 are, for example, distributed coupling lines that are coupled to the transmission path of the transmission signal by electric field coupling or magnetic field coupling, or capacitors, inductors, transformers having relatively small capacitance values. This can be realized by passive circuits.

  The transmission units 171 and 172 include high-frequency circuits (RF circuits) such as power amplifiers and mixer circuits 1711 and 1712, and have functions of modulating a transmission signal and up-converting to a radio frequency band.

  The phase adjustment units 181 and 182 have a function of adjusting the phase of the transmission signal in each of the transmission branches 101 and 102, and are realized by a phase shifter, for example. In the phased array transmission apparatus, the phase required for each transmission branch is theoretically determined from the required specifications such as the shape and direction of the transmission beam and the sidelobe suppression amount, but the phase adjustment units 181 and 182 require the necessary phase shift. Adjustments are made to make the quantity.

  Note that the phase adjustment of the transmission signal may be performed on either the baseband signal or the radio frequency signal. Further, the phase may be adjusted with respect to the local oscillation signal used when up-converting the baseband signal.

  That is, the phase adjustment units 181 and 182 may be provided in a baseband circuit as shown in the illustrated example, or may be provided in a radio frequency band circuit. That is, it may be provided inside the transmission units 171 and 172, or may be provided between the coupler units 161 and 162 and the transmission units 171 and 172, or a local oscillation signal source (not shown) and the transmission unit 171, It may be provided between the up-conversion mixer circuits 1711 and 1712 at 172.

  The amplitude adjusters 191 and 192 have a function of adjusting the amplitude of the transmission signal in each of the transmission branches 101 and 102, and are realized by circuits such as a variable gain amplifier and a variable attenuator. In the phased array transmission apparatus, the amplitude required for each transmission branch is theoretically determined from the required specifications such as the shape and direction of the transmission beam and the sidelobe suppression amount, but the signal level required by the amplitude adjustment units 191 and 192 is determined. (Amplitude) is adjusted.

  The amplitude adjustment of the transmission signal may be performed on either the baseband signal or the radio frequency signal. Further, the amplitude of the local oscillation signal used when up-converting the baseband signal may be adjusted.

  That is, the amplitude adjusters 191 and 192 may be provided in a baseband circuit as in the illustrated example, or may be provided in a radio frequency band circuit, like the phase adjusters 181 and 182. That is, it may be provided inside the transmission units 171 and 172, or may be provided between the coupler units 161 and 162 and the transmission units 171 and 172, or a local oscillation signal source (not shown) and the transmission unit 171, It may be provided between the up-conversion mixer circuits 1711 and 1712 at 172.

  Further, the arrangement order of the transmission units 171 and 172, the phase adjustment units 181 and 182 and the amplitude adjustment units 191 and 192 is not limited to the illustrated order, and may be arranged in any order.

  The signal synthesis unit 110 is connected to the extraction output ends of the coupler units 161 and 162 and has a function of adding the output of the extraction signals of the coupler unit 161 and the coupler unit 162. The signal synthesizer 110 is realized by a passive circuit such as a Wilkinson power synthesizer that synthesizes two signals.

  The output of the signal synthesizing unit 110 has the maximum amplitude when the input signals from the coupler unit 161, the coupler unit 162, and the same amplitude and phase. On the other hand, when the two input signals from the couplers 161 and 162 have the same amplitude and opposite phase, that is, a phase difference of 180 degrees, the output of the signal synthesizer 110 becomes zero.

  The branch detection units 121 and 122 are connected to the extraction output ends of the coupler units 161 and 162, and have a function of measuring the transmission output levels of the transmission branches 101 and 102 by detecting the outputs of the coupler units 161 and 162, respectively. Have. The branch detectors 121 and 122 are realized by a simple and low-power circuit such as a square detector using a diode or FET. Further, the branch detectors 121 and 122 can improve the detection performance by combining an amplifier and a detector as necessary.

  The synthesis detection unit 130 is connected to the output terminal of the signal synthesis unit 110 and has a function of detecting and measuring the output level of the signal synthesis unit 110. Similar to the branch detection units 121 and 122, the synthesis detection unit 130 is realized by a simple and low-power circuit such as a square detector using a diode or an FET, for example. Further, the combining detector 130 can improve the detection performance by combining an amplifier and a detector as necessary.

The phase control unit 140 is connected to the output terminal of the synthesis detection unit 130 and the amplitude control unit 150, and controls the phase adjustment units 181 and 182 provided in the transmission branches 101 and 102 according to the output of the synthesis detection unit 130. It has a function. The phase control unit 140 adjusts the amount of phase shift in the phase adjustment units 181 and 182 according to the information on the amount of phase shift calculated based mainly on the desired transmission beam specification, thereby transmitting the transmission signals of the transmission branches 101 and 102. Adjust the phase.
In addition, the phase control unit 140 causes the phase adjustment units 181 and 182 to correct the phase error between the transmission branches based on the output information from the synthesis detection unit 130 and the amplitude control information from the amplitude control unit 150. Make fine adjustments. The phase control unit 140 has a phase correction table that holds information on the amount of phase shift in the phase adjustment units 181 and 182. The phase correction table may be provided in the phase adjustment units 181 and 182.

  The amplitude control unit 150 is connected to the output terminals of the branch detection units 121 and 122, and controls the amplitude adjustment units 191 and 192 provided in the transmission branches 101 and 102 according to the outputs of the two branch detection units 121 and 122, respectively. It has the function to do. The amplitude control unit 150 adjusts the level in the amplitude adjustment units 191 and 192 mainly according to the information on the amplitude amount calculated based on the desired transmission beam specifications, so that the levels (amplitudes) of the transmission signals of the transmission branches 101 and 102 are adjusted. ).

  In addition, the amplitude control unit 150 operates to finely adjust the amplitude adjustment units 191 and 192 so as to correct the amplitude error between the transmission branches based on the output information from the branch detection units 121 and 122. In addition, the amplitude control unit 150 exchanges amplitude control information and phase control information with the phase control unit 140. The amplitude control unit 150 has an amplitude correction table that holds information on amplitude adjustment amounts in the amplitude adjustment units 191 and 192. The amplitude correction table may be provided in the amplitude adjustment units 191 and 192.

  The phase control unit 140 and the amplitude control unit 150 can be realized by digital signal processing by an information processing circuit including a processor and a memory. Each function is realized by executing a predetermined process by operating a software program in the processor. it can.

  The functions of the level detection of the detector output from the synthesis detection unit 130 in the phase control unit 140 and the level detection of the detector output from the branch detection units 121 and 122 in the amplitude control unit 150 are, for example, an ADC (AD converter) The phase control unit 140 and the amplitude control unit 150 compare the detection level information realized by the circuit and digitally converted with, for example, a threshold stored in advance, or store the output value for a certain period of time. Then, level detection is performed by outputting the maximum value within that period.

  An error correction procedure regarding the phase error and amplitude error between the transmission branches in the present embodiment will be described.

As a first procedure, the amplitude controller 150 adjusts the amplitude adjusters 191 and 192 so that the transmission output levels of the transmission branch 101 and the transmission branch 102 are the same. The amplitude control unit 150 compares the detection outputs of the branch detection unit 121 and the branch detection unit 122 and checks whether they are the same.
If the two detection outputs are not the same, there is an error in the amplitude characteristic between the transmission branches. Therefore, the amplitude control unit 150 and the amplitude adjustment unit 191 and the amplitude adjustment so that the two detection output levels are the same. One or both of the units 192 are finely adjusted to correct the amplitude of the transmission signal. For example, the amplitude adjustment units 191 and 192 finely adjust the other in a state in which one is fixed as a reference.

  As a second procedure, in a state where the transmission output levels of the transmission branch 101 and the transmission branch 102 are the same, the phase control unit 140 sets the phase adjustment units 181 and 182 to make the phases of the two transmission branches in phase. adjust.

  The phase control unit 140 stores the detection output of the synthesis detection unit 130 from an ADC (not shown), finely adjusts one or both of the phase adjustment unit 181 and the phase adjustment unit 182, and outputs the detection output of the synthesis detection unit 130 Select the adjustment amount that maximizes.

  Note that the adjustment amount that maximizes the detection output of the synthesis detection unit 130 corresponds to an in-phase condition in which the phase characteristics between the transmission branches are the same, and also corresponds to a phase error in each transmission branch.

  In addition, the phase adjustment units 181 and 182 can be easily adjusted by finely adjusting the other in a state where one is fixed as a reference.

  As a third procedure, the phase control unit 140 adjusts the phase adjustment units 181 and 182 so that the phases of the two transmission branches are opposite in phase with the transmission output levels of the transmission branch 101 and the transmission branch 102 being the same. To do.

  The phase control unit 140 stores the detection output of the synthesis detection unit 130 from an ADC (not shown), finely adjusts one or both of the phase adjustment unit 181 and the phase adjustment unit 182, and outputs the detection output of the synthesis detection unit 130 Select the adjustment amount that minimizes.

  Note that the adjustment amount that minimizes the detection output of the synthesis detection unit 130 corresponds to an anti-phase condition for the phase characteristic between the transmission branches to be 180 degrees different, and also corresponds to a phase error in each transmission branch.

  In addition, the phase adjustment units 181 and 182 can be easily adjusted by finely adjusting the other in a state where one is fixed as a reference.

  As a fourth procedure, the phase control unit 140 creates or updates a phase correction table for adjusting the phase error in each transmission branch. The phase control unit 140 calculates the phase error inherent in each transmission branch from the adjustment amount for obtaining the in-phase condition and the anti-phase condition obtained in the second and third procedures, and obtains correction data in the phase correction table. Generate or update. In other words, the adjustment amount is recorded in the correction table as an inter-branch phase error, and an accurate phase adjustment can be performed by taking into account when setting an arbitrary amount of phase shift.

  The adjustment amount obtained in the second procedure is basically the same as the adjustment amount obtained in the third procedure. Therefore, the validity of the adjustment amount obtained by the second procedure can be evaluated by the third procedure. For example, this is effective when the phase errors of the branches differ due to the nonlinearity factors of the phase adjustment units 181 and 182. In this case, correction data is derived for each of the in-phase condition and the anti-phase condition, and for phase setting between 0 degrees and 180 degrees, the correction data can be calculated by interpolation based on the two correction data.

  The amplitude controller 150 also creates or updates an amplitude correction table for adjusting the amplitude error in each transmission branch. The amplitude control unit 150 generates or updates correction data in the amplitude correction table based on the amplitude error inherent in each transmission branch obtained by the fine adjustment result of the amplitude in the first procedure.

  For example, in the first procedure, first, the amplitude control unit 150 sets the amplitude adjustment units 191 and 192 so that the transmission output levels of the transmission branches 101 and 102 are the same, but the outputs of the branch detection units 121 and 122 are the same. If they are not the same, it is determined that an amplitude error has occurred between the branches. Next, the amplitude control unit 150 determines an adjustment amount for adjusting one or both of the amplitude adjustment units 191 and 192 so that the outputs of the branch detection units 121 and 122 are the same. This adjustment amount becomes correction data for the amplitude error.

  The error correction related to the phase error and the amplitude error between the transmission branches is performed by the above procedure. Thereafter, for each of the transmission branches 101 and 102, by controlling the phase adjustment units 181 and 182 and the amplitude adjustment units 191 and 192 based on the phase correction table and the amplitude correction table, a desired beam directivity can be obtained. In the adjustment of the phase and the amplitude of the transmission beam, it is possible to form a transmission beam in which errors between transmission branches are suppressed.

  In actual operation, for example, it is conceivable that the error value between the transmission branches changes due to a change in the environment, and it is effective to perform the error correction procedure periodically.

  In the transmission branches 101 and 102, when the phase error varies depending on the amplitude of the transmission signal, for example, the phase error may be obtained and corrected for each amplitude required in actual use. Further, when the phase shift characteristics of the phase shifters of the phase adjusters 181 and 182 are nonlinear, for example, a phase error may be obtained and corrected for each phase shift amount required in actual use.

  Even when one of the second procedure and the third procedure is performed, the amplitude error and the phase error can be obtained and corrected. However, in order to improve the information accuracy of the correction table, it is desirable to perform both the second procedure and the third procedure.

  As described above, in the first embodiment, the signal synthesis unit 110 and a plurality of detection units including the branch detection units 121 and 122 and the synthesis detection unit 130 are provided, and phase errors and amplitude errors between a plurality of transmission branches are provided. Perform detection and adjustment.

  Therefore, according to this embodiment, it is possible to detect an error in amplitude and phase characteristics between two transmission branches by a configuration using a signal synthesis unit and a detection unit that can be implemented in a small size and low power, and by a simple procedure, Phase error and amplitude error can be corrected. Thereby, as a whole, it is possible to realize a phased array transmission apparatus that detects and corrects amplitude and phase characteristic errors in each transmission branch with a simple configuration.

  In addition, since a part of the transmission signal is extracted from each transmission branch by the couplers 161 and 162, the impedance change at the time of switching the switch is changed for a high-frequency transmission signal, unlike the configuration in which the transmission branch measured by the switch is switched. Can suppress the influence on the characteristics of the transmitted wave.

  Furthermore, since a calibration receiving system is unnecessary, it is possible to suppress an increase in circuit, an increase in power consumption, and an increase in cost due to a highly accurate receiving circuit.

  In addition, it is not necessary to acquire correction information for phase error in the transmission system in advance by any method and store it in the correction phase storage device, so that the dynamic change in which the error changes due to a change in the environment (for example, temperature) Can respond.

  Further, since the amplitude adjustment units 191 and 192 are provided as correction means for the amplitude error, side lobe deterioration can be suppressed similarly to the phase error.

  As a result, in the phased array transmission apparatus of the present embodiment, desired beam directivity can be obtained by calibrating the amplitude phase adjustment between transmission branches, and deterioration of the sidelobe suppression amount can be suppressed. Compared with the configuration of the conventional system including a reception system that down-converts a transmission signal by a mixer, the configuration of the present embodiment can mount additional circuits necessary for calibration at a small size, low cost, and low power. Even in the case of a chip, the structure is highly mountable.

(Second Embodiment)
FIG. 2 is a block diagram showing a configuration of a phased array transmission apparatus according to the second embodiment of the present invention. In the second embodiment, a configuration example in which the branch detection unit is excluded from the configuration of the first embodiment shown in FIG. Note that the present invention can also be applied to a configuration having three or more transmission branches.

  The phased array transmission apparatus according to the second embodiment has a configuration that does not include the branch detection units 121 and 122, and an output terminal of the synthesis detection unit 230 is connected to the phase control unit 240 and the amplitude control unit 250. Is input to each control unit. Other configurations are the same as those in the first embodiment, and a description thereof will be omitted.

  The synthesis detection unit 230 has the functions of the branch detection units 121 and 122 in addition to the function of the synthesis detection unit 130 in the first embodiment. The combined detector 230 can be configured using a detector circuit such as a diode or an FET, for example, on the mounting surface, as in the first embodiment.

  The basic operation of the second embodiment is the same as that of the first embodiment, and here, the description will focus on the parts that are different from the first embodiment.

  In the error correction procedure for the phase error and amplitude error between the transmission branches, as a first procedure, the amplitude control unit 250 selects one transmission branch when checking the transmission output level of each transmission branch 101, 102. The transmission operation is performed and the signal level of the transmission branch in operation is detected with reference to the output from the synthesis detector 230.

  Then, the amplitude controller 250 sequentially operates all the transmission branches, detects the signal level, detects the levels of all the transmission branches, and compares the levels of all the transmission branches, thereby comparing the amplitude error between the branches. Can be detected. Thereafter, the amplitude controller 250 adjusts the amplitude adjusters 191 and 192 so that the transmission output levels of the transmission branch 101 and the transmission branch 102 are the same.

  The subsequent second to fourth procedures are the same as those in the first embodiment. As the second procedure, the phase control unit 240 is configured so that the transmission output levels of the transmission branch 101 and the transmission branch 102 are the same. The phase adjusters 181 and 182 are adjusted so that the phases of the two transmission branches are in phase. As a third procedure, the phase control unit 240 adjusts the phases of the two transmission branches to the opposite phases while the transmission output levels of the transmission branch 101 and the transmission branch 102 are the same. Adjust. As a fourth procedure, the phase control unit 240 creates or updates a phase correction table for phase adjustment, and the amplitude control unit 250 creates or updates an amplitude correction table for amplitude adjustment.

  In the second embodiment, compared to the configuration of the first embodiment in which the transmission output level of each transmission branch can be detected simultaneously, the error correction processing takes time because the level detection is performed sequentially. An error detection system can be configured with a small number of detectors. Therefore, it is possible to detect and correct the phase error and the amplitude error with a simpler configuration.

  As described above, according to the second embodiment, it is possible to detect an error in amplitude and phase characteristics between two transmission branches with a simpler configuration than in the first embodiment, and it is simple. With this procedure, it is possible to correct the phase error and the amplitude error. Thereby, as a whole, it is possible to realize a phased array transmission apparatus that detects and corrects amplitude and phase characteristic errors in each transmission branch with a simple configuration.

(Third embodiment)
FIG. 3 is a block diagram showing a configuration of a phased array transmission apparatus according to the third embodiment of the present invention. In the third embodiment, a configuration example including three or more transmission branches in the configuration of the first embodiment shown in FIG.

  FIG. 3 shows a configuration example including four transmission branches. That is, each transmission branch 101 to 104 has antenna units 11 to 14, coupler units 161 to 164, transmission units 171 to 174, phase adjustment units 181 to 184, and amplitude adjustment units 191 to 194, respectively. The configurations of the transmission branches 101 to 104 are the same as those in the first embodiment, and a description thereof will be omitted.

  Further, inter-branch error detection units 331, 332, and 333 are provided between the two transmission branches, and a phase amplitude control unit 350 that controls the phase adjustment units 181 to 184 and the amplitude adjustment units 191 to 194 of each transmission branch. It has. The phase amplitude control unit 350 has functions of a phase control unit and an amplitude control unit.

  The basic operation is the same as in the first embodiment. Hereinafter, operations of the inter-branch error detection units 331 to 333 and the phase amplitude control unit 350 in the third embodiment will be described.

  The inter-branch error detection units 331, 332, and 333 are each configured to include the signal synthesis unit 110, the branch detection units 121 and 122, and the synthesis detection unit 130 in the first embodiment. The inter-branch error detection units 331 to 333 synthesize and detect extracted signals from two adjacent transmission branches, and output a combined detection output to the phase amplitude control unit 350.

  For example, when there are N transmission branches, (N−1) combined detection outputs are output to the phase amplitude control unit 350. Further, the inter-branch error detection units 331 to 333 detect the extracted signals of the individual transmission branches and output them to the phase amplitude control unit 350. For example, when there are N transmission branches, N detection outputs are output to the phase amplitude control unit 350.

  Similarly to the second embodiment, the inter-branch error detection units 331 to 333 sequentially output the transmission signals of one transmission branch without providing the branch detection unit, and perform the transmission of each transmission branch by the synthesis detection unit. The extracted signal may be detected and output.

  The phase / amplitude control unit 350 is based on the output signal level information of each transmission branch output from the inter-branch error detection units 331 to 333 and the signal level information obtained by synthesizing signals between adjacent transmission branches. According to the error correction procedure described in the embodiment, the phase error and the amplitude error are detected and corrected.

  Regarding phase error correction, the phase error between all transmission branches can be grasped by sequentially detecting the phase error between adjacent transmission branches. Therefore, according to the present embodiment, for the phased array transmission system having N transmission branches, the signal synthesis unit and the synthesis detection unit are used as error detection units for all combinations (N × (N−1) / 2). The phase error of the entire phased array transmission system can be corrected by the (N-1) signal synthesis unit and synthesis detection unit. For amplitude error correction, N branch detection units are required as error detection units for a phased array transmission system having N transmission branches.

  According to the third embodiment, in the phased array transmission apparatus using three or more antennas, the amplitude and phase characteristic errors between all the transmission branches can be detected as in the first embodiment, and simple. According to the procedure, the phase error and the amplitude error can be corrected. As a result, by controlling many antennas, it is possible to realize a phased array transmission apparatus capable of forming a beam with high accuracy in a transmission apparatus that performs beam formation with higher directivity.

(Fourth embodiment)
FIG. 4 is a block diagram showing a configuration of a phased array transmission apparatus according to the fourth embodiment of the present invention. The fourth embodiment shows an example in which the configuration of the error detection unit between transmission branches in the configuration of the first embodiment shown in FIG. 1 is changed. Note that the present invention can also be applied to a configuration having three or more transmission branches.

  The phased array transmission apparatus according to the fourth embodiment replaces the signal synthesis unit 110 in the configuration of FIG. 1 with a synthesis / distribution unit 410, changes the function of the signal synthesis unit, and has two outputs. Are provided with two synthesis detectors 431 and 432 for detecting the two outputs respectively. The output terminals of the synthesis detection units 431 and 432 are connected to the phase control unit 440, and detection signals indicating the two output levels of the synthesis distribution unit 410 are input to the phase control unit 440. Other configurations are the same as those in the first embodiment, and a description thereof will be omitted.

  As in the second embodiment, the configuration is such that the transmission signal of one transmission branch is sequentially output and the extraction signal of each transmission branch is detected and output by the synthesis detection unit without providing the branch detection unit. Also good.

  The basic operation is the same as in the first embodiment. Hereinafter, operations of the combining / distributing unit 410, the combining / detecting units 431 and 432, and the phase control unit 440 in the fourth embodiment will be described.

  The combining / distributing unit 410 is configured using, for example, a 90-degree hybrid circuit, and has two inputs A and B and two outputs C and D. The basic function of the 90-degree hybrid circuit is described, for example, in Reference 1 (“Practical microwave circuit design guide” written by Yoshihiro Konishi, General Electronic Publishing Company, June 1996, page 13 of the first edition).

  5A and 5B are diagrams for explaining the operation of the combining / distributing unit 410 using a 90-degree hybrid circuit. FIG. 5A shows an input / output terminal, and FIG. 5B shows an example of the correspondence between the amplitude and phase of each input / output terminal. FIG. The relationship with the output signal when two signals are input to the 90-degree hybrid circuit is shown.

  When the amplitudes of the input A and the input B are the same, the output C and the output D change due to the phase relationship. When the input A and the input B are in phase, the output C and the output D have the same amplitude. Further, when the phases of the input A and the input B are shifted, the amplitudes of the output C and the output D are different. Therefore, whether or not the two signals of the input A and the input B are in phase can be determined by whether or not the amplitudes of the output C and the output D are the same. When the phases of the input A and the input B are shifted by 90 degrees, one of the two outputs becomes zero.

  The synthesis detection units 431 and 432 have a function of detecting and measuring the output levels of the two outputs C and D of the synthesis distribution unit 410.

  The error correction procedure in the fourth embodiment differs from the procedure shown in the first embodiment in the following points.

  In the fourth embodiment, in the second procedure, the phase control unit 440 transmits the transmission by selecting an adjustment amount at which the outputs of the two synthesis detection units 431 and 432 connected to the synthesis distribution unit 410 are the same. Find in-phase conditions for the same phase between branches. Next, in the third procedure, the phase control unit 440 adjusts the phase adjustment units 181 and 182 so that the phase difference between the two transmission branches is 90 degrees, and one output of the synthesis distribution unit 410 is By selecting the minimum adjustment amount, a condition is found where the phase characteristics between the transmission branches are different by 90 degrees.

  The phase error between the transmission branches can be detected and corrected by the adjustment amounts of the phase adjustment units 181 and 182 performed in these procedures. The phase control unit 440 calculates the phase error inherent in each transmission branch from the phase shift amount information for obtaining the 90-degree difference condition and the in-phase condition obtained in the second and third procedures, and Generate or update correction data.

  In the configuration of the fourth embodiment, as described in the third procedure of the first embodiment, when the phase between the two transmission branches is set to have a difference of 180 degrees, in FIG. Since the two outputs C and D of the combining / distributing unit 410 are equal, it cannot be distinguished from the case where there is no phase difference between transmission branches. However, since the two outputs of the combining / distributing unit 410 are in an anti-phase relationship, if a configuration for combining and detecting the two output signals of the combining / distributing unit 410 is added, the transmission branch is further rotated between the transmission branches. It is also possible to make a determination in the case of a phase difference.

  According to the fourth embodiment, it is possible to detect an error in the amplitude and phase characteristics between the transmission branches when the phase difference between the transmission branches is 90 degrees compared to the first embodiment. Therefore, phase correction information at the time of the 90-degree difference condition can be added to the phase correction table at the time of the in-phase and 180-degree difference conditions obtained in the first embodiment. In this case, it is possible to realize a phased array transmission apparatus that enables correction with higher accuracy.

  In the above embodiment, the method for detecting and correcting the phase error between the transmission branches from the two phase conditions by performing both the second procedure and the third procedure in the error correction procedure has been described. However, even if either one is performed, the phase error between the transmission branches can be detected and corrected.

  Note that, for example, the signal combining unit or the combining / distributing unit shown in the above embodiment is difficult to design as an ideally operating circuit, and an error may occur. However, since the design error of the circuit can be estimated in advance, the amplitude adjustment unit and the phase adjustment unit may be controlled and corrected in consideration of the design error.

  In this embodiment, in a phased array antenna transmission apparatus that forms a beam by a phased array antenna using a plurality of antennas and radiates it in space, when correcting the amplitude and phase error of the high-frequency signal characteristics between the transmission branches, Phase errors and amplitude errors between branches can be detected and corrected.

  For this reason, it is possible to detect and correct both the phase error and the amplitude error of the transmission signal between the transmission branches with a simple configuration, that is, with a small circuit scale and power consumption, while suppressing an increase in circuit or power consumption.

  By correcting the phase error and the amplitude error between the transmission branches, it is possible to form a highly accurate transmission beam, improve the directivity gain in the main beam direction, and suppress the radiation level in the unnecessary direction. This is effective for controlling the communication area in wireless communication, improving the link budget, or improving detection accuracy by suppressing clutter reflection or multipath from unnecessary directions in the radar.

  In addition, the phased array transmission apparatus according to the present embodiment can be mounted with a signal synthesis unit and a detection unit that detect errors using a simple passive circuit. For this reason, low power consumption of the circuit can be realized, characteristics can be easily ensured even for a high-frequency transmission signal such as a millimeter wave band, and application to a system using a high frequency is possible. Furthermore, in application to high frequency bands, circuit parts that process high-frequency signals, such as the signal synthesizer, detector, and coupler, can be mounted using circuits that are highly compatible with integration, and the entire system can be mounted in a small size. Is possible.

  The present invention is intended to be variously modified and applied by those skilled in the art based on the description in the specification and well-known techniques without departing from the spirit and scope of the present invention. Included in the scope for protection. In addition, the constituent elements in the above-described embodiment may be arbitrarily combined without departing from the spirit of the invention.

  The present invention has an effect that a phase and amplitude error between transmission branches can be corrected with a simple configuration. The phased array transmission apparatus according to the present invention is capable of realizing highly accurate beam forming with suppressed side lobes with a smaller size, lower cost, and lower power consumption than the conventional one, and a transmission apparatus in a wireless communication system that requires beam forming ( For example, it is useful as a base station), a radar apparatus whose detection accuracy is improved by beam forming, or a wireless chip for realizing them.

11, 12, 13, 14 Antenna unit 101, 102, 103, 104 Transmission branch 110, 210 Signal synthesis unit 121, 122 Branch detection unit 130, 230, 431, 432 Synthesis detection unit 140, 240, 440 Phase control unit 150, 250 Amplitude control unit 161, 162, 163, 164 Coupler unit 171, 172, 173, 174 Transmitter unit 181, 182, 183, 184 Phase adjustment unit 191, 192, 193, 194 Amplitude adjustment unit 331, 332, 333 Inter-branch error Detector 350 Phase amplitude controller 410 Composite distributor

Claims (6)

A transmitter for transmitting a radio frequency transmission signal;
A phase adjustment unit for adjusting the phase of the transmission signal;
An amplitude adjuster for adjusting the amplitude of the transmission signal;
An antenna unit that radiates the output signal of the transmission unit into space;
A coupler unit for extracting a part of the output of the transmission unit;
Comprising a first transmission branch and a second transmission branch,
First and second branch detectors for detecting output levels from the respective coupler units of the first transmission branch and the second transmission branch;
A signal synthesis unit for synthesizing outputs from the coupler units of the first and second transmission branches;
A synthesis detection unit for detecting an output level from the signal synthesis unit;
An amplitude control unit that controls the amplitude adjustment unit by detection output from the first and second branch detection units;
A phase control unit that controls the phase adjustment unit according to a detection output by the synthesis detection unit;
A phased array transmitter comprising: A transmitter for transmitting a radio frequency transmission signal;
A phase adjustment unit for adjusting the phase of the transmission signal;
An amplitude adjuster for adjusting the amplitude of the transmission signal;
An antenna unit that radiates the output signal of the transmission unit into space;
A coupler unit for extracting a part of the output of the transmission unit;
Comprising a first transmission branch and a second transmission branch,
A signal synthesis unit for synthesizing outputs from the coupler units of the first and second transmission branches;
A detection unit that detects an output level from the signal combining unit, and detects an output level from each coupler unit of the first transmission branch and the second transmission branch; and
An amplitude control unit that controls the amplitude adjustment unit according to a detection output of an output level from each coupler unit of the first transmission branch and the second transmission branch by the synthesis detection unit;
A phase control unit that controls the phase adjustment unit by a detection output of the output level from the signal synthesis unit by the synthesis detection unit;
A phased array transmitter comprising: The phased array transmission device according to claim 1 or 2,
When correcting phase and amplitude errors between the first and second transmission branches,
The amplitude control unit includes at least one amplitude adjustment unit of the first transmission branch and the second transmission branch in order to make the transmission output level of the first transmission branch and the second transmission branch the same. Adjust
In a state in which the transmission output levels of the first and second transmission branches are the same, the phase control unit includes an in-phase condition that maximizes the combined output level of the signal combining unit, and a combined output level of the signal combining unit. A phased array transmission device that detects at least one of the anti-phase conditions that minimizes and adjusts the phase adjustment unit of at least one of the first transmission branch and the second transmission branch. The phased array transmission device according to claim 1 or 2,
Comprising three or more transmission branches including the first and second transmission branches;
The signal synthesizer for detecting a phase error and an amplitude error between the first and second transmission branches using two of the three or more transmission branches as the first and second transmission branches. And a phased array transmission apparatus comprising an inter-branch error detection unit including the synthesis detection unit. The phased array transmission device according to claim 1 or 2,
The signal combining unit has two inputs for inputting outputs from the coupler units of the first and second transmission branches and two outputs for combining and distributing input signals to the two inputs. When the input signals from the first transmission branch and the second transmission branch have the same amplitude, if the two input signals have the same phase, a signal having the same amplitude is output from the two outputs. A function of a synthesizing / distributing unit that outputs and outputs a signal having a different amplitude from the two outputs when the two input signals have different phases;
When correcting phase and amplitude errors between the first and second transmission branches,
The amplitude control unit is an amplitude adjustment unit of at least one of the first transmission branch and the second transmission branch so that the transmission output levels of the first transmission branch and the second transmission branch have the same amplitude. Adjust
In a state in which the transmission output levels of the first and second transmission branches are the same, the phase control unit has an in-phase condition in which two output levels of the combining / distributing unit are the same, and two of the combining / distributing units A phased array transmission apparatus that detects a 90-degree difference condition in which one of output levels of an amplitude is zero and adjusts a phase adjustment unit of at least one of the first transmission branch and the second transmission branch. The phased array transmitter according to any one of claims 1 to 5,
A phase correction table having correction data for adjusting a phase error in each transmission branch of the first and second transmission branches;
An amplitude correction table having correction data for adjusting an amplitude error in each transmission branch of the first and second transmission branches,
The phase control unit creates or updates the phase correction table, adjusts the phase adjustment unit according to correction data of the phase correction table,
The phased array transmission apparatus, wherein the amplitude control unit creates or updates the amplitude correction table and adjusts the amplitude adjustment unit based on correction data of the amplitude correction table.

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