Phased array antenna device

Abstract

This phased array antenna device comprises: a storage unit (7) that stores the antenna coupling coefficients of antenna elements; a calculation unit (8) that calculates, from information stored in the storage unit, the adjustment amount of the active reflection coefficient of each of the antenna elements such that the phase of the active reflection coefficient of the antenna element on the antenna element side as viewed from an amplifier is uniformly dispersed between 0 π and 2 π and the amplitude of the active reflection coefficient of the antenna element becomes a previously prescribed value or less; adjustment circuits (5-n) that each are connected between the antenna element and the amplifier and adjust the active reflection coefficient of a transmission signal after amplification by the amplifier; an adjustment circuit control unit (9) that controls the adjustment circuit in accordance with the reflection coefficient adjustment amount output from the calculation unit, and an excitation phase control unit (10) that controls the phase of a signal to be input to a phase shifter by the phase of the reflection coefficient adjustment amount output from the calculation unit and an excitation phase corresponding to a beam directivity direction.

Description

Phased Array Antenna Device

[0001] The present disclosure relates to a phased array antenna device.

[0002] A phased array antenna device (hereinafter, may be simply abbreviated by terms such as "phased array" or "array antenna device") is a high-functional antenna device capable of electronically and rapidly scanning a beam direction, and is composed of various high-frequency components such as antenna elements, amplifiers, phase shifters, power distribution / combination circuits, etc.

[0003] Generally, in a phased array, in order to prevent a reflected wave called an active reflected wave generated by the influence of mutual coupling between antenna elements from returning from the antenna port to the component side such as an amplifier, a non-reversible circuit element such as an isolator or a circulator is arranged between the amplifier and the antenna element. However, from the viewpoints of size, loss, cost, etc., a phased array without arranging an isolator or a circulator (hereinafter, may be denoted as "isolator / circulator-less") is desired.

[0004] The configuration of such an isolator / circulator-less phased array antenna device is disclosed in, for example, Patent Document 1. Generally, in a phased array, when scanning a beam from the boresight direction where the antenna has the maximum gain, there is a problem that the antenna gain of the beam decreases. Also, with respect to the amplifier output, there is a problem that the output tends to decrease because the impedance of the antenna port varies with the beam scanning angle. In Patent Document 1, in order to solve these problems, a configuration is presented in which the output characteristics of the amplifier are adjusted by the amplifier or an impedance matching circuit between the amplifier and the antenna element so that the output characteristics of the amplifier are maximized at a beam scanning angle different from the boresight direction where the antenna gain is maximum. With such a configuration, it is possible to obtain a characteristic in which the equivalent isotropic radiated power EIRP (Equivalent Isotropic Radiation Power), which is the product of the antenna gain and the transmission output power during beam scanning, is maximized.

[0005] Japanese Patent No. 7482037

[0006] In an isolator / circulator-less antenna device configuration such as the one disclosed in Patent Document 1, the reflection phase from the antenna port changes with respect to the pass-through phase of the connection section (waveguide) connecting the amplifier and the antenna element, and the output power of the phased array fluctuates with respect to the pass-through phase of the connection section.

[0007] This disclosure was made to solve these problems and aims to provide a robust phased array antenna device in which the output power fluctuation is smaller with respect to the change in the pass-through phase of the connection between the amplifier and the antenna element.

[0008] One aspect of a phased array antenna device according to an embodiment of the present disclosure comprises: a plurality of phase shifters that adjust the phase of a supplied transmission signal according to the beam directivity direction; a plurality of amplifiers that amplify the transmission signal after phase adjustment by the plurality of phase shifters; and a plurality of antenna elements that radiate the transmission signal after amplification by the plurality of amplifiers into space, wherein the antenna coupling coefficient storage unit stores the antenna coupling coefficients of the plurality of antenna elements, and from the information stored in the antenna coupling coefficient storage unit, the phase of the active reflection coefficients of the plurality of antenna elements on the antenna element side as seen from the plurality of amplifiers is evenly distributed between 0 and 2π, and the active reflection coefficients of the plurality of antenna elements The system further comprises: a reflection coefficient adjustment amount calculation unit that calculates the amount of adjustment for the active reflection coefficient of the plurality of antenna elements so that the amplitude of the number is less than or equal to a predetermined value; a plurality of reflection coefficient adjustment circuits connected between the plurality of antenna elements and the plurality of amplifiers, which adjust the active reflection coefficient of the transmitted signal after amplification by the plurality of amplifiers; a reflection coefficient adjustment circuit control unit that controls the plurality of reflection coefficient adjustment circuits according to the reflection coefficient adjustment amount output from the reflection coefficient adjustment amount calculation unit; and an excitation phase control unit that controls the phase of the signal input to the plurality of phase shifters according to the phase of the reflection coefficient adjustment amount output from the reflection coefficient adjustment amount calculation unit and the excitation phase corresponding to the beam directing direction.

[0009] According to the phased array antenna device of the embodiment of this disclosure, fluctuations in output power can be made smaller in response to fluctuations in the pass-through phase of the connection between the amplifier and the antenna element.

[0010] This figure shows the configuration of a phased array antenna device according to Embodiment 1. This figure shows the relationship between the load-pull characteristics of the amplifier and the active reflection coefficient of the phased array antenna. This figure shows an example of the relationship between the pass phase and the output power of the phased array antenna device. This figure shows an example of the hardware configuration. This figure shows an example of the hardware configuration. This figure shows an example of the arrangement of the active reflection coefficient. This figure shows the mathematical model of the array antenna. This figure shows the configuration of a phased array antenna device according to Embodiment 2. This figure shows the relationship between the load-pull characteristics of the amplifier after reflection phase adjustment and the active reflection coefficient of the phased array antenna. This figure shows the relationship between the pass phase and the output power of the phased array antenna. This figure shows the configuration of a phased array antenna device according to Embodiment 3. This figure shows the configuration of a phased array antenna device according to Embodiment 4. This figure shows the configuration of a phased array antenna device according to Embodiment 5.

[0011] Various embodiments of this disclosure will be described in detail below with reference to the drawings. In the drawings, identical or similar parts are denoted by the same or similar reference numerals, and redundant descriptions of such parts will be omitted. In this disclosure, the term "or" is used in the sense of an inclusive OR unless otherwise stated.

[0012] Embodiment 1. <Configuration> A phased array antenna device according to Embodiment 1 of the present disclosure will be described with reference to Figure 1. Figure 1 is a configuration diagram showing a phased array antenna device according to Embodiment 1 of the present disclosure.

[0013] In Figure 1, the phased array antenna device consists of a signal generator 1, a transmitter 20, a distribution circuit 2, a phase shifter 3-n (n=1, 2, ..., N), an amplifier 4-n (n=1, 2, ..., N), a reflection coefficient adjustment circuit 5-n (n=1, 2, ..., N), an antenna element 6-n (n=1, 2, ..., N), an antenna coupling coefficient storage unit 7, a reflection coefficient adjustment amount calculation unit 8, a reflection coefficient adjustment circuit control unit 9, and an excitation phase control unit 10. Note that N represents the number of array antenna systems.

[0014] The array antenna device shown in Figure 1 is designed to solve the problem of conventional technology, in which the output power of the phased array fluctuates with respect to the pass phase at the connection between the amplifier and the antenna elements. Here, the problems of the conventional technology will be explained in more detail with reference to Figures 2 and 3. Figure 2 shows the relationship between the load-pull characteristics of the amplifier (i.e., the output power characteristics with respect to the reflection coefficient) and the active reflection coefficient of the array antenna. The active reflection coefficient is the reflection coefficient of the antenna in the operating state and is expressed by the antenna coupling coefficient and the excitation amplitude phase of the antenna elements. Figure 3 shows an example of the relationship between the pass phase and the output power of the array antenna device.

[0015] As shown in Figure 2, the active reflection coefficient of an array antenna rotates due to the pass-through phase between the amplifier and the antenna elements. As a result, the output power of the array antenna (the combined power of each antenna element) fluctuates depending on the pass-through phase.

[0016] Figure 3 shows an example of the relationship between the passphase and the output power of an array antenna device. It can be seen that the output power is small when the passphase is around 90 degrees and large when it is around 270 degrees, indicating a large fluctuation.

[0017] Generally, precisely controlling the pass-through phase at the connection between the amplifier and the antenna element is difficult in manufacturing, and the optimal phase relationship changes with beam scanning. Therefore, output power fluctuations are unavoidable in principle in isolator / circulator-less antenna configurations. Patent Document 1 does not disclose the configuration of an antenna device that suppresses output power fluctuations.

[0018] The phased array antenna device of this disclosure solves the problem that the output power of the phased array fluctuates with respect to the pass phase at the connection between the amplifier and the antenna elements.

[0019] Referring again to Figure 1, the components of the phased array antenna device of this disclosure will be described. First, the signal generator 1 generates a baseband signal as the transmission signal (hereinafter sometimes simply referred to as "signal"). The signal generator 1 supplies the generated baseband signal to the transmitter 20. The transmitter 20 converts the supplied baseband signal from a digital value to an analog value and also converts its frequency to an RF (Radio Frequency) band signal. It also adjusts the power so that the transmission power is at an appropriate value.

[0020] The transmission signal from the signal generator 1 passes through the transmitter 20 and is divided into N parts by the distribution circuit 2. The distributed transmission signals are then sent to the transmission systems of each array antenna. Each distributed transmission signal is then sent to the antenna element 6-n via the phase shifter 3-n, amplifier 4-n, and reflection coefficient adjustment circuit 5-n, and radiated into space. The phase shifter 3-n adjusts the phase of the transmission signal after distribution by the distribution circuit 2 according to the beam directivity direction. The amplifier 4-n amplifies the transmission signal after phase adjustment by the phase shifter 3-n. The reflection coefficient adjustment circuit 5-n is connected between the antenna element 6-n and the amplifier 4-n and adjusts the reflection coefficient under the control of the reflection coefficient adjustment circuit control unit 9. The reflection coefficient adjustment circuit 5-n may include a variable attenuator or variable amplifier for adjusting the amplitude. The reflection coefficient adjustment circuit 5-n may also include a variable phase shifter for adjusting the phase, or instead of a variable phase shifter, it may include a switching circuit for switching the line length.

[0021] The antenna coupling coefficient storage unit 7 stores the antenna coupling coefficient of the antenna element 6-n and retains the antenna coupling coefficient obtained in advance through analysis or measurement.

[0022] The reflection coefficient adjustment amount calculation unit 8 calculates a reflection coefficient adjustment amount that minimizes fluctuations in the output power of the array antenna, based on the antenna coupling coefficient information stored in the antenna coupling coefficient storage unit 7. An example of the calculation of the reflection coefficient adjustment amount will be described later.

[0023] The reflection coefficient adjustment circuit control unit 9 controls the reflection coefficient adjustment circuit 5-n based on the reflection coefficient adjustment amount calculated by the reflection coefficient adjustment amount calculation unit 8.

[0024] The excitation phase control unit 10 determines the phase to be set in the phase shifter 3-n based on the reflection coefficient adjustment amount calculated by the reflection coefficient adjustment amount calculation unit 8 and the beam scanning phase in the desired direction, and controls the phase shifter 3-n.

[0025] Here, the signal generator 1, antenna coupling coefficient storage unit 7, reflection coefficient adjustment amount calculation unit 8, reflection coefficient adjustment circuit control unit 9, or excitation phase control unit 10 are composed of, for example, semiconductor integrated circuits or one-chip microcontrollers that implement a processor (also called a Central Processing Unit, arithmetic unit, microprocessor, microcomputer, or DSP (Digital Signal Processor)).

[0026] In the example shown in Figure 1, it is assumed that the signal generator 1, antenna coupling coefficient storage unit 7, reflection coefficient adjustment amount calculation unit 8, reflection coefficient adjustment circuit control unit 9, or excitation phase control unit 10 are each composed of dedicated hardware (processing circuit 101) as shown in Figure 4, but these may also be composed of a computer.

[0027] In the case of a computer-based system, as shown in Figure 5, a program describing the processing details of the signal generator 1, antenna coupling coefficient storage unit 7, reflection coefficient adjustment amount calculation unit 8, reflection coefficient adjustment circuit control unit 9, or excitation phase control unit 10 is stored in the computer's memory 102, and the computer's processor 103 reads and executes the program stored in memory 102.

[0028] <Operation> Below, an example of the operation of the phased array antenna device according to Embodiment 1 shown in Figure 1 will be described.

[0029] First, signal generator 1 generates the transmission signal. The transmission signal is an arbitrary modulated signal, and signal generator 1 generates the desired signal according to the use case.

[0030] Next, the reflection coefficient adjustment amount calculation unit 8 calculates the reflection coefficient adjustment amount from the antenna coupling coefficients stored in the antenna coupling coefficient storage unit 7. As shown in Figure 2, the active reflection coefficient calculated from the excitation amplitude phase and antenna coupling coefficient of the multiple antenna elements of the array antenna rotates due to the pass phase between the amplifier and the antenna elements, affecting the fluctuation of the array antenna output power. Therefore, in order to be robust against rotation due to the pass phase, the active reflection coefficients of the multiple antenna elements of the array antenna are adjusted to be circumferential, for example, as shown in Figure 6. In such a case, even if the active impedance of the array antenna rotates due to the pass phase, the output power of the array antenna does not change significantly and remains at a nearly constant output power level, thus providing robustness.

[0031] The adjustment method can be explained, for example, by the mathematical model of the array antenna shown in Figure 7. From the relationship of the parameters, the following equation (1) is derived, and by setting the active reflection coefficient Γn to an ideal circumferential arrangement and solving for the amplitude αn and phase βn of the reflection coefficient adjustment amount using various optimization methods based on the antenna coupling coefficient Cnm stored in the antenna coupling coefficient memory unit 7, an appropriate reflection coefficient adjustment amount is determined.

[0032] In this way, the reflection coefficient adjustment amount calculation unit 8 calculates the adjustment amount for the active reflection coefficients of the multiple antenna elements (6-1 to 6-N) from the information stored in the antenna coupling coefficient storage unit 7, such that the phases of the active reflection coefficients of the multiple antenna elements (6-1 to 6-N) on the antenna element side as seen from the multiple amplifiers (4-1 to 4-N) are evenly distributed between 0 and 2π, and the amplitudes of the active reflection coefficients of the multiple antenna elements (6-1 to 6-N) are less than or equal to a predetermined value.

[0033] To ensure that the phases are evenly distributed between 0 and 2π, the phase intervals may be set to equal intervals, such as 2π / N. Furthermore, the amplitudes of the active reflection coefficients of multiple antenna elements may be equal.

[0034] Here, the active reflection coefficient Γn is described as being in an ideal circular arrangement, but it does not necessarily have to be in a circular arrangement. A similar effect can be obtained if the active reflection coefficient is scattered so that it does not concentrate at a single point.

[0035] The reflection coefficient adjustment amount calculated in this manner is set to the reflection coefficient adjustment circuit 5-n via the reflection coefficient adjustment circuit control unit 9. That is, the reflection coefficient adjustment circuit control unit 9 controls the reflection coefficient adjustment circuit 5-n according to the reflection coefficient adjustment amount calculated by the reflection coefficient adjustment amount calculation unit 8.

[0036] Furthermore, when the reflection coefficient is adjusted as described above, the phase in each transmitting system of the array antenna will vary by the amount of adjustment, making it impossible to simply direct the beam in the desired direction. Therefore, in the excitation phase control unit 10, in addition to the beam scanning phase in the desired direction, a correction phase for the phase variation due to the reflection coefficient adjustment amount is added and set in the phase shifter 3-n, thereby enabling proper beam scanning.

[0037] Although an example for a specific beam scanning direction is shown here, the appropriate reflection coefficient adjustment amount will differ depending on the beam scanning direction. Therefore, the reflection coefficient adjustment amount calculation unit 8 may adaptively calculate the reflection coefficient adjustment amount according to the beam scanning angle and set the calculated reflection coefficient adjustment amount in the reflection coefficient adjustment circuit 5-n.

[0038] By performing this series of operations, it is possible to suppress fluctuations in the output power of the array antenna due to the pass-through phase at the connection between the amplifier and the antenna elements, which was a challenge in isolator / circulator-less antenna configurations, and beam scanning can also be performed appropriately.

[0039] As is clear from the above, according to this embodiment 1, it is possible to provide a robust array antenna device that can suppress fluctuations in output power regardless of the pass-through phase of the connection between the amplifier and the antenna element.

[0040] In the above embodiment 1, a method was described in which the reflection coefficient adjustment amount calculation unit 8 calculates the adjustment amount from the information stored in the antenna coupling coefficient storage unit 7. However, the phased array antenna device may be modified so that the calculation result of the reflection coefficient adjustment amount calculation unit 8 is stored in a storage unit not shown. In this modification, the reflection coefficient adjustment circuit control unit 9 controls a plurality of reflection coefficient adjustment circuits (5-1 to 5-N) based on the reflection coefficient adjustment amount stored in such a storage unit not shown. Furthermore, the excitation phase control unit 10 controls the phase of the transmission signal input to a plurality of phase shifters (3-1 to 3-N) based on the phase of the reflection coefficient adjustment amount and the excitation phase corresponding to the beam directing direction, based on the reflection coefficient adjustment amount stored in such a storage unit not shown.

[0041] Embodiment 2. In Embodiment 1 described above, the array antenna output power was made robust by appropriately setting the reflection coefficient using the reflection coefficient adjustment circuit 5-n. Next, Embodiment 2 describes a form in which only the phase of the reflection coefficient is adjusted.

[0042] Figure 8 is a configuration diagram showing an array antenna device according to Embodiment 2 of the present disclosure. In Figure 8, the same reference numerals as in Figure 1 indicate the same or corresponding parts, so their explanation is omitted. In Embodiment 2, the signal flow or operation is the same as in Embodiment 1.

[0043] The difference between Embodiment 2 and Embodiment 1 is that in Embodiment 1, the reflection coefficient adjustment amount is calculated from the antenna coupling coefficient stored in the antenna coupling coefficient storage unit 7 and set for the reflection coefficient adjustment circuit 5-n connected between the amplifier 4-n and the antenna element 6-n. In contrast, in Embodiment 2, the reflection phase adjustment amount calculation unit 11 calculates only the adjustment amount of the reflection phase (that is, the phase of the reflection coefficient), and adjusts the reflection phase adjustment circuit 13-n via the reflection phase adjustment circuit control unit 12. That is, the phased array antenna device according to Embodiment 2 includes a reflection phase adjustment amount calculation unit 11 instead of the reflection coefficient adjustment amount calculation unit 8, a reflection phase adjustment circuit control unit 12 instead of the reflection coefficient adjustment circuit control unit 9, and a reflection phase adjustment circuit 13-n instead of the reflection coefficient adjustment circuit 5-n. The reflection phase adjustment circuit 13-n only needs to have a function of adjusting the phase, and may be a phase adjustment circuit that switches the line length or a phase shifter.

[0044] As an adjustment method, for example, it can be explained from the mathematical model of the array antenna shown in FIG. 7. In FIG. 7, αn of the parameter αn·exp(jβn) of the reflection coefficient adjustment circuit is fixed, and only βn is adjusted.

[0045] From the relationship of the parameters, the following formula (2) is derived. By setting the active reflection coefficient Γn to an ideal circular arrangement and solving for the phase βn of the reflection phase adjustment amount based on the antenna coupling coefficient Cnm stored in the antenna coupling coefficient storage unit 7, an appropriate reflection phase adjustment amount is determined.

[0046] As an example, FIG. 9 shows the relationship between the load pull characteristics of the amplifier after reflection phase adjustment and the active reflection coefficient of the array antenna. Although the amplitude of the reflection coefficient cannot be changed, by varying the phase between 0 and 360 degrees, the same effect as in Embodiment 1 can be obtained. FIG. 10 shows the relationship between the passing phase and the output power of the array antenna. By applying the present disclosure, even if the passing phase between the power amplifier and the antenna element changes, the output power of the array antenna will take a substantially constant value, and the array antenna will have robustness.

[0047] By performing this series of operations, it is possible to suppress the variation in the transmission output of the array antenna due to the passing phase of the connection part between the amplifier and the antenna element, which was an issue in the antenna configuration without an isolator / circulator, and it is also possible to appropriately perform beam scanning.

[0048] As is clear from the above, according to the second embodiment, it is possible to provide a robust array antenna device that can suppress output power variation by appropriately adjusting the reflection phase between the amplifier and the antenna element regardless of the passing phase of the connection part between the amplifier and the antenna element.

[0049] In the above second embodiment, the mode in which the reflection phase adjustment amount calculation unit 11 calculates the adjustment amount from the information stored in the antenna coupling coefficient storage unit 7 has been described. However, the phased array antenna device may be modified so that the calculation result of the reflection phase adjustment amount calculation unit 11 is stored in a storage unit (not shown). When modified in this way, the reflection phase adjustment circuit control unit 12 controls the plurality of reflection phase adjustment circuits (13-1 to 13-N) based on the reflection phase adjustment amount stored in such a storage unit (not shown). Further, the excitation phase control unit 10 controls the phase of the transmission signal input to the plurality of phase shifters (3-1 to 3-N) based on the reflection phase adjustment amount stored in such a storage unit (not shown) and the excitation phase corresponding to the beam pointing direction.

[0050] Embodiment 3. In the above first embodiment, the output power of the array antenna was made robust by appropriately setting the reflection coefficient in the reflection coefficient adjustment circuit 5-n via the reflection coefficient adjustment circuit control unit 9. Similarly, in the second embodiment, the output power of the array antenna was made robust by appropriately setting the reflection phase in the reflection phase adjustment circuit 13-n via the reflection phase adjustment circuit control unit 12. The set value of this reflection coefficient adjustment circuit or reflection phase adjustment circuit may be a fixed value.

[0051] FIG. 11 is a configuration diagram showing a phased array antenna device according to the third embodiment of the present disclosure. In FIG. 11, the same reference numerals as in FIG. 1 indicate the same or corresponding parts, and thus the description thereof is omitted. In this embodiment, the signal flow or operation is the same as in the first or second embodiment.

[0052] The difference is that in Embodiment 1 or 2, the reflection coefficient (or phase) adjustment amount was calculated and the reflection coefficient (or phase) adjustment circuit was controlled according to the result, whereas in Embodiment 3, the reflection coefficient (or phase) adjustment amount is calculated in advance, the calculated adjustment amount is stored in the reflection coefficient adjustment amount storage unit 14, and a fixed reflection coefficient adjustment amount is set in advance in the reflection coefficient adjustment circuit.

[0053] Embodiment 3 does not include the reflection coefficient adjustment calculation unit and reflection coefficient adjustment circuit control unit that were provided in Embodiment 1 or 2, thus reducing the complexity of the hardware configuration, calculation processing, or control processing.

[0054] As is clear from the above, according to this embodiment 3, it is possible to provide a robust array antenna device that can suppress array antenna output power fluctuations with a configuration that reduces hardware configuration, computation processing, or control processing.

[0055] Embodiment 4. In Embodiments 1 to 3 described above, the array antenna output power was made robust by appropriately setting the reflection coefficient in the reflection coefficient adjustment circuit or the reflection phase adjustment circuit. However, depending on the relationship between the amount of reflection coefficient adjustment and the power amplifier output characteristics, an amplitude distribution is formed in each antenna element, and furthermore, the antenna radiation pattern fluctuates due to the rotation caused by the passing phase between the amplifier and the antenna element, which causes the amplitude distribution to fluctuate. Therefore, Embodiment 4 shows an example of suppressing fluctuations in the antenna radiation pattern.

[0056] Figure 12 is a configuration diagram showing a phased array antenna device according to Embodiment 4 of the present disclosure. In Figure 12, the same reference numerals as in Figure 1 indicate the same or corresponding parts, so their explanation is omitted. In this embodiment, the signal flow or operation is the same as in Embodiments 1 to 3.

[0057] The difference between Embodiment 4 and Embodiments 1 to 3 is that the phased array antenna device according to Embodiment 4 has an amplifier output characteristic storage unit 16, and the reflection coefficient adjustment amount calculation unit 8, in conjunction with the information from the antenna coupling coefficient storage unit 7, determines the reflection coefficient adjustment amount for each antenna element so that the output power of the amplifier is not biased among antenna elements that are close to each other. "Close to each other" can be interpreted as "adjacent." As a simple method, a method may be used in which the reflection coefficient adjustment amount is determined so that the output power of the amplifier is random in the array antenna aperture.

[0058] In Embodiment 4, by varying the amplitude distribution (amplifier output power) in the array antenna aperture, it becomes possible to suppress radiation pattern fluctuations with respect to phase rotation due to the pass phase between the amplifier and the antenna elements.

[0059] As is clear from the above, according to this embodiment 4, it is possible to provide a robust array antenna device that can suppress array antenna output power fluctuations and radiation pattern fluctuations.

[0060] Embodiment 5. In Embodiments 1 to 4 described above, the array antenna configuration was one in which the phase of the antenna elements was changed using an analog method. However, a DBF (Digital Beam Forming) antenna configuration in which excitation weights are applied using a digital stage may also be used.

[0061] Figure 13 is a configuration diagram showing an array antenna device according to Embodiment 5 of the present disclosure. In Figure 13, the same reference numerals as in Figure 1 indicate the same or corresponding parts, so their explanation is omitted.

[0062] In embodiments 1 to 4, the output signals from the signal generator 1 and the transmitter 20 are distributed by the distribution circuit 2, and the phase of each antenna element system is adjusted by the phase shifter 3-n.

[0063] In contrast, in Embodiment 5, as shown in Figure 13, a transmitter 20-n is connected to each antenna element system, and an excitation weight multiplication unit 15-n is provided between the transmitter 20-n and the signal generator 1. With this configuration, the excitation weight multiplication unit 15-n multiplies the digital signal generated by the signal generator 1 by the excitation weight, thereby applying beam scanning phase and amplitude weights.

[0064] The signals from each antenna element system, multiplied by the excitation weight, are converted from digital to analog values ​​by transmitter 20-n, and then frequency conversion to the RF (Radio Frequency) band and power adjustment are performed. The signal flow or operation is the same as in Embodiments 1 to 4.

[0065] Thus, Embodiment 5 is a configuration in which the analog beamforming antenna configuration of Embodiments 1 to 4 is replaced with a DBF (Digital Beam Forming) antenna configuration. Even with such a DBF configuration, the same effects as in the analog configuration can be obtained.

[0066] As is clear from the above, according to this embodiment 5, it is possible to provide a robust array antenna device that can suppress array antenna output power fluctuations even in a DBF configuration.

[0067] <Note> Some aspects of the various embodiments described above are summarized below. (Note 1) The phased array antenna device according to Note 1 comprises: a plurality of phase shifters (3-n) that adjust the phase of the supplied transmission signal according to the beam directivity direction; a plurality of amplifiers (4-n) that amplify the transmission signal after phase adjustment by the plurality of phase shifters; a plurality of antenna elements (6-n) that radiate the transmission signal after amplification by the plurality of amplifiers into space; an antenna coupling coefficient storage unit (7) that stores the antenna coupling coefficients of the plurality of antenna elements; a reflection coefficient adjustment amount calculation unit (8) that calculates the amount of adjustment for the active reflection coefficients of the plurality of antenna elements from the information stored in the antenna coupling coefficient storage unit so that the phase of the active reflection coefficients of the plurality of antenna elements on the antenna element side as seen from the plurality of amplifiers is evenly distributed between 0 and 2π, and the amplitude of the active reflection coefficients of the plurality of antenna elements is less than or equal to a predetermined value; and a plurality of reflection coefficient adjustment circuits (5-n) connected between the plurality of antenna elements and the plurality of amplifiers that adjust the active reflection coefficients of the transmission signal after amplification by the plurality of amplifiers. The system further includes: a reflection coefficient adjustment circuit control unit (9) that controls the plurality of reflection coefficient adjustment circuits according to the reflection coefficient adjustment amount output from the reflection coefficient adjustment amount calculation unit; and an excitation phase control unit (10) that controls the phase of the signals input to the plurality of phase shifters according to the phase of the reflection coefficient adjustment amount output from the reflection coefficient adjustment amount calculation unit and the excitation phase corresponding to the beam directing direction.(Note 2) The phased array antenna device according to Note 2 comprises: a plurality of phase shifters (3-n) that adjust the phase of the supplied transmission signal according to the beam directing direction; a plurality of amplifiers (4-n) that amplify the transmission signal after phase adjustment by the plurality of phase shifters; a plurality of antenna elements (6-n) that radiate the transmission signal after amplification by the plurality of amplifiers into space; a plurality of reflection coefficient adjustment circuits (5-n) connected between the plurality of antenna elements and the plurality of amplifiers; a reflection coefficient adjustment circuit control unit (9) that controls the plurality of reflection coefficient adjustment circuits based on the stored reflection coefficient adjustment amounts from a storage unit that stores the reflection coefficient adjustment amounts of the plurality of antenna elements calculated in advance; and an excitation phase control unit (10) that controls the phase of the signal input to the plurality of phase shifters based on the phase of the reflection coefficient adjustment amount and the excitation phase corresponding to the beam directing direction, based on the stored reflection coefficient adjustment amount. (Note 3) The phased array antenna device according to Note 3 is the phased array antenna device described in Note 1, wherein the reflection coefficient adjustment amount calculation unit calculates the reflection coefficient adjustment amount according to the beam scanning angle, and the reflection coefficient adjustment circuit control unit controls the reflection coefficient adjustment circuit according to the calculated reflection coefficient adjustment amount.(Note 4) The phased array antenna device according to Note 4 comprises: a plurality of phase shifters (3-n) that adjust the phase of the supplied transmission signal according to the beam directivity direction; a plurality of amplifiers (4-n) that amplify the transmission signal after phase adjustment by the plurality of phase shifters; a plurality of antenna elements (6-n) that radiate the transmission signal after amplification by the plurality of amplifiers into space; an antenna coupling coefficient storage unit (7) that stores the antenna coupling coefficients of the plurality of antenna elements; a reflection phase adjustment amount calculation unit (11) that calculates the amount of adjustment for the active reflection coefficient of the plurality of antenna elements from the information stored in the antenna coupling coefficient storage unit so that the phase of the active reflection coefficient of the plurality of antenna elements on the antenna element side as seen from the plurality of amplifiers is evenly distributed between 0 and 2π; a plurality of reflection phase adjustment circuits (13-n) connected between the plurality of antenna elements and the plurality of amplifiers that adjust the phase of the active reflection coefficient of the transmission signal after amplification by the plurality of amplifiers; and a reflection phase adjustment circuit control unit (12) that controls the plurality of reflection phase adjustment circuits according to the reflection coefficient adjustment amount output from the reflection phase adjustment amount calculation unit. A phased array antenna device comprising: an excitation phase control unit (10) that controls the phase of signals input to the plurality of phase shifters based on the reflection phase adjustment amount of the reflection coefficient adjustment amount output from the reflection phase adjustment amount calculation unit and the excitation phase corresponding to the beam directing direction; (Note 5) The phased array antenna device according to Note 5 comprises: a plurality of phase shifters (3-n) that adjust the phase of the supplied transmission signal according to the beam direction; a plurality of amplifiers (4-n) that amplify the transmission signal after phase adjustment by the plurality of phase shifters; a plurality of antenna elements (6-n) that radiate the transmission signal after amplification by the plurality of amplifiers into space; a plurality of reflection phase adjustment circuits (13-n) connected between the plurality of antenna elements and the plurality of amplifiers; a reflection phase adjustment circuit control unit (12) that controls the plurality of reflection phase adjustment circuits based on the stored reflection phase adjustment amounts from a storage unit that stores the reflection phase adjustment amounts of the plurality of antenna elements calculated in advance; and an excitation phase control unit (10) that controls the phase of the signal input to the plurality of phase shifters according to the stored reflection phase adjustment amounts and the excitation phase corresponding to the beam direction.(Note 6) The phased array antenna device according to Note 6 is the phased array antenna device described in Note 4, wherein the reflection phase adjustment amount calculation unit calculates the reflection phase adjustment amount according to the beam scanning angle, and the reflection phase adjustment circuit control unit controls the reflection phase adjustment circuit according to the calculated reflection phase adjustment amount. (Note 7) The phased array antenna device according to Note 7 is the phased array antenna device described in either Note 1 or 3, wherein the reflection coefficient adjustment amount calculation unit calculates the adjustment amount for the active reflection coefficient of the plurality of antenna elements from the information of the antenna coupling coefficient storage unit such that the phase of the active reflection coefficient on the antenna element side as seen from the plurality of amplifiers is equally spaced between 0 and 2π at intervals of 2π / number of elements, and the amplitude of the active reflection coefficient of the plurality of antenna elements is equal in amplitude. (Note 8) The phased array antenna device according to Note 8 is a phased array antenna device described in either Note 4 or Note 6, wherein the reflection phase adjustment amount calculation unit calculates the amount of reflection phase adjustment for the plurality of antenna elements from the information of the antenna coupling coefficient storage unit so that the phase of the active reflection coefficient on the antenna element side as seen from the plurality of amplifiers is equally spaced between 0 and 2π at intervals of 2π / number of elements. (Note 9) The phased array antenna device according to Note 9 is a phased array antenna device described in either Note 1 or Note 3, wherein the reflection coefficient adjustment amount calculation unit calculates the reflection coefficient adjustment amount so that there is no bias in the distribution of output power for antenna elements that are close to each other. (Note 10) The phased array antenna device according to Note 10 is a phased array antenna device described in either Note 4 or Note 6, wherein the reflection phase adjustment amount calculation unit calculates the reflection phase adjustment amount so that there is no bias in the distribution of output power for antenna elements that are close to each other. (Note 11) The phased array antenna device according to Note 11 is a phased array antenna device described in any one of Notes 1 to 3, 7, or 9, wherein the phase adjustment in the reflection coefficient adjustment circuit is performed by switching the line length.(Note 12) The phased array antenna device according to Note 12 is a phased array antenna device described in any one of Notes 4 to 6, 8, or 10, wherein the phase adjustment in the reflection phase adjustment circuit is performed by switching the line length. (Note 13) The phased array antenna device according to Note 13 is a phased array antenna device described in any one of Notes 1 to 3, 7, or 9, wherein the reflection coefficient adjustment circuit includes a phase shifter. (Note 14) The phased array antenna device according to Note 14 is a phased array antenna device described in any one of Notes 4 to 6, 8, or 10, wherein the reflection phase adjustment circuit includes a phase shifter. (Note 15) The phased array antenna device according to Note 15 is a phased array antenna device described in any one of Notes 1 to 14, wherein the supplied transmission signal is a digital signal, and instead of the plurality of phase shifters, it further comprises a plurality of excitation weight multipliers (15-n) that multiply the digital signal by an excitation weight, and the excitation phase control unit controls the excitation weight by the phase of the reflection coefficient adjustment amount and the excitation phase corresponding to the beam directing direction.

[0068] Furthermore, it is possible to combine embodiments, or to modify or omit each embodiment as appropriate.

[0069] The technology for suppressing output power fluctuations disclosed herein can be applied to and used in phased array antenna devices.

[0070] 1 Signal generator, 2 Distribution circuit, 3-n Phase shifter, 4-n Amplifier, 5-n Reflection coefficient adjustment circuit, 6-n Antenna element, 7 Antenna coupling coefficient memory unit, 8 Reflection coefficient adjustment amount calculation unit, 9 Reflection coefficient adjustment circuit control unit, 10 Excitation phase control unit, 11 Reflection phase adjustment amount calculation unit, 12 Reflection phase adjustment circuit control unit, 13-n Reflection phase adjustment circuit, 14 Reflection coefficient adjustment amount memory unit, 16 Amplifier output characteristic memory unit, 20 (20-n) Transmitter, 101 Processing circuit, 102 Memory, 103 Processor.

Claims

1. A plurality of phase shifters that adjust the phase of the supplied transmission signal according to the beam direction; a plurality of amplifiers that amplify the transmission signal after phase adjustment by the plurality of phase shifters; a plurality of antenna elements that radiate the transmission signal after amplification by the plurality of amplifiers into space; an antenna coupling coefficient storage unit that stores the antenna coupling coefficients of the plurality of antenna elements; a reflection coefficient adjustment amount calculation unit that calculates an adjustment amount for the active reflection coefficient of the plurality of antenna elements from the information stored in the antenna coupling coefficient storage unit such that the phase of the active reflection coefficient of the plurality of antenna elements on the antenna element side as seen from the plurality of amplifiers is evenly distributed between 0 and 2π, and the amplitude of the active reflection coefficient of the plurality of antenna elements is less than or equal to a predetermined value; a plurality of reflection coefficient adjustment circuits connected between the plurality of antenna elements and the plurality of amplifiers that adjust the active reflection coefficient of the transmission signal after amplification by the plurality of amplifiers; and a reflection coefficient adjustment circuit control unit that controls the plurality of reflection coefficient adjustment circuits according to the reflection coefficient adjustment amount output from the reflection coefficient adjustment amount calculation unit. A phased array antenna device further comprising: an excitation phase control unit that controls the phase of signals input to the plurality of phase shifters based on the phase of the reflection coefficient adjustment amount output from the reflection coefficient adjustment amount calculation unit and the excitation phase corresponding to the beam directing direction; 2. A phased array antenna device comprising: a plurality of phase shifters that adjust the phase of a supplied transmission signal according to the beam direction; a plurality of amplifiers that amplify the transmission signal after phase adjustment by the plurality of phase shifters; a plurality of antenna elements that radiate the transmission signal after amplification by the plurality of amplifiers into space; a plurality of reflection coefficient adjustment circuits connected between the plurality of antenna elements and the plurality of amplifiers; a reflection coefficient adjustment circuit control unit that controls the plurality of reflection coefficient adjustment circuits based on the stored reflection coefficient adjustment amounts from a storage unit that stores the reflection coefficient adjustment amounts of the plurality of antenna elements calculated in advance; and an excitation phase control unit that controls the phase of the signal input to the plurality of phase shifters based on the phase of the reflection coefficient adjustment amount and the excitation phase corresponding to the beam direction, based on the stored reflection coefficient adjustment amount.

3. The phased array antenna apparatus according to claim 1, wherein the reflection coefficient adjustment amount calculation unit calculates the reflection coefficient adjustment amount according to the beam scanning angle, and the reflection coefficient adjustment circuit control unit controls the reflection coefficient adjustment circuit according to the calculated reflection coefficient adjustment amount.

4. A plurality of phase shifters that adjust the phase of the supplied transmission signal according to the beam direction; a plurality of amplifiers that amplify the transmission signal after phase adjustment by the plurality of phase shifters; a plurality of antenna elements that radiate the transmission signal after amplification by the plurality of amplifiers into space; an antenna coupling coefficient storage unit that stores the antenna coupling coefficients of the plurality of antenna elements; a reflection phase adjustment amount calculation unit that calculates the amount of adjustment for the active reflection coefficient of the plurality of antenna elements from the information stored in the antenna coupling coefficient storage unit so that the phase of the active reflection coefficient of the plurality of antenna elements on the antenna element side as seen from the plurality of amplifiers is evenly distributed between 0 and 2π; a plurality of reflection phase adjustment circuits connected between the plurality of antenna elements and the plurality of amplifiers to adjust the phase of the active reflection coefficient of the transmission signal after amplification by the plurality of amplifiers; a reflection phase adjustment circuit control unit that controls the plurality of reflection phase adjustment circuits according to the reflection coefficient adjustment amount output from the reflection phase adjustment amount calculation unit; and an excitation phase control unit that controls the phase of the signal input to the plurality of phase shifters according to the reflection phase adjustment amount of the reflection coefficient adjustment amount output from the reflection phase adjustment amount calculation unit and the excitation phase according to the beam direction. A phased array antenna system equipped with the following features.

5. A phased array antenna device comprising: a plurality of phase shifters that adjust the phase of a supplied transmission signal according to the beam direction; a plurality of amplifiers that amplify the transmission signal after phase adjustment by the plurality of phase shifters; a plurality of antenna elements that radiate the transmission signal after amplification by the plurality of amplifiers into space; a plurality of reflection phase adjustment circuits connected between the plurality of antenna elements and the plurality of amplifiers; a reflection phase adjustment circuit control unit that controls the plurality of reflection phase adjustment circuits based on the stored reflection phase adjustment amounts from a storage unit that stores pre-calculated reflection phase adjustment amounts for the plurality of antenna elements; and an excitation phase control unit that controls the phase of the signal input to the plurality of phase shifters based on the stored reflection phase adjustment amounts and excitation phase corresponding to the beam direction.

6. The phased array antenna apparatus according to claim 4, wherein the reflection phase adjustment amount calculation unit calculates the reflection phase adjustment amount according to the beam scanning angle, and the reflection phase adjustment circuit control unit controls the reflection phase adjustment circuit according to the calculated reflection phase adjustment amount.

7. The phased array antenna apparatus according to claim 1 or 3, wherein the reflection coefficient adjustment amount calculation unit calculates the amount of adjustment for the active reflection coefficient of the plurality of antenna elements from the information of the antenna coupling coefficient storage unit such that the phase of the active reflection coefficient on the antenna element side as seen from the plurality of amplifiers is between 0 and 2π at equal intervals of 2π / number of elements, and the amplitude of the active reflection coefficient of the plurality of antenna elements is equal in amplitude.

8. The phased array antenna apparatus according to claim 4 or 6, wherein the reflection phase adjustment amount calculation unit calculates the amount of reflection phase adjustment for the plurality of antenna elements from the information of the antenna coupling coefficient storage unit such that the phase of the active reflection coefficient on the antenna element side as seen from the plurality of amplifiers is equally spaced between 0 and 2π at intervals of 2π / number of elements.

9. The phased array antenna apparatus according to claim 1 or 3, wherein the reflection coefficient adjustment amount calculation unit calculates the reflection coefficient adjustment amount so that there is no bias in the distribution of output power for antenna elements that are in close proximity to each other.

10. The phased array antenna apparatus according to claim 4 or 6, wherein the reflection phase adjustment amount calculation unit calculates the reflection phase adjustment amount so that there is no bias in the distribution of output power for antenna elements that are close to each other.

11. A phased array antenna device according to any one of claims 1 to 3, 7, or 9, wherein the phase adjustment in the reflection coefficient adjustment circuit is performed by switching the line length.

12. A phased array antenna apparatus according to any one of claims 4 to 6, 8, or 10, wherein the phase adjustment in the reflection phase adjustment circuit is performed by switching the line length.

13. The phased array antenna apparatus according to any one of claims 1 to 3, 7, or 9, wherein the reflection coefficient adjustment circuit comprises a phase shifter.

14. The phased array antenna apparatus according to any one of claims 4 to 6, 8, or 10, wherein the reflection phase adjustment circuit comprises a phase shifter.

15. The phased array antenna apparatus according to any one of claims 1 to 14, wherein the supplied transmission signal is a digital signal, and the apparatus further comprises a plurality of excitation weight multipliers that multiply the digital signal by an excitation weight instead of the plurality of phase shifters, and the excitation phase control unit controls the excitation weight by the phase of the reflection coefficient adjustment amount and the excitation phase corresponding to the beam directing direction.

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