Antenna device and control method

Abstract

The spatial resolution of the virtual array antenna and the accuracy of the virtual array antenna's target direction estimation are adjusted according to the purpose. [Solution] The antenna device according to the embodiment comprises a reference signal generation unit, a first module, a second module, and a phase value generation unit. The phase value generation unit generates a first phase value based on the phase difference of the received signals in at least two virtual antennas, which are formed based on the received signals received by at least a portion of the first receiving antenna and the second receiving antenna when the first transmitting antenna transmits a transmission signal based on the first reference signal. The first transmission processing circuit shifts the phase of the second reference signal, which is transmitted by the second transmitting antenna after the first transmitting antenna, by the first phase value.

Description

[Technical Field]

[0001] Embodiments of the present invention relate to an antenna device and a control method. [Background technology]

[0002] Antenna devices used for target direction estimation and other similar tasks require improved spatial resolution. In recent years, instead of actually increasing the number of antennas to improve spatial resolution, MIMO (Multi Input Multi Output) array antennas have been developed that virtually form many antennas through signal processing.

[0003] However, further extending the spatial resolution of virtual array antennas presents challenges such as increased complexity in antenna placement and wiring on the substrate, leading to increased power loss and development costs. Furthermore, there is a need for a technology that can adjust two conflicting functions—improving the spatial resolution of virtual array antennas and improving the accuracy of target direction estimation—according to the purpose of the antenna device. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2024-103732 [Overview of the project] [Problems that the invention aims to solve]

[0005] Therefore, the problem that the present invention aims to solve is to provide an antenna device and control method that can adjust, according to the purpose, the improvement of the spatial resolution of the virtual array antenna and the improvement of the accuracy of the target direction estimation of the virtual array antenna. [Means for solving the problem]

[0006] The antenna device according to the embodiment comprises a reference signal generation unit, a first module, a second module, and a phase value generation unit. The first module is supplied with a first reference signal from the reference signal generation unit. The first module includes a first number of first transmitting antennas arranged in a first direction at first intervals, and a second number of first receiving antennas arranged in the first direction at second intervals. The second module is supplied with a second reference signal from the reference signal generation unit. The second module includes a third number of second transmitting antennas arranged in the first direction at first intervals, a fourth number of second receiving antennas arranged in the first direction at second intervals, and a first transmission processing circuit. The distance between the receiving antenna closest to the second module among the first receiving antennas and the receiving antenna closest to the first module among the second receiving antennas is the second interval. The phase value generation unit generates a first phase value based on the phase difference of the received signals in at least two virtual antennas, which are formed based on the received signals received by at least a portion of the first receiving antenna and the second receiving antenna when the first transmitting antenna transmits a transmission signal based on the first reference signal. The first transmission processing circuit shifts the phase of the second reference signal, which is transmitted by the second transmitting antenna after the first transmitting antenna, by the amount of the first phase value. [Brief explanation of the drawing]

[0007] [Figure 1] A diagram showing an example configuration of the first module used in the antenna device according to the first comparative example. [Figure 2] This figure shows an example of the configuration of the antenna device according to the first embodiment. [Figure 3] This figure shows the transmission timing of each transmitting antenna and the reception timing of each receiving antenna in the second comparative example. [Figure 4] A figure showing an example of a virtual array antenna formed by the antenna device according to the second comparative example. [Figure 5] A diagram showing the transmission timing of each transmitting antenna and the reception timing of each receiving antenna in the first embodiment. [Figure 6] A diagram showing an example of a virtual array antenna formed by the antenna device according to the first embodiment. [Figure 7] A block diagram showing an electrical configuration example of the antenna device according to the second comparative example. [Figure 8] A block diagram showing an electrical configuration example of the antenna device according to the first embodiment. [Figure 9] A diagram showing a graph of the simulation results of target direction estimation by the antenna device and the like according to the first embodiment. [Figure 10] A diagram showing a first configuration example of the first module and the second module in the first embodiment. [Figure 11] A diagram showing a second configuration example of the first module and the second module in the first embodiment. [Figure 12] A diagram showing a third configuration example of the first module and the second module in the first embodiment. [Figure 13] A diagram showing a fourth configuration example of the first module and the second module in the first embodiment. [Figure 14] A diagram showing an example of a virtual array antenna in the first modification. [Figure 15] A diagram showing a configuration example of the antenna device according to the second embodiment. [Figure 16] A diagram showing an example of a virtual antenna formed by the antenna device according to the third comparative example. [Figure 17] A diagram showing an example of a virtual array antenna formed by the antenna device according to the second embodiment. [Figure 18] A block diagram showing an electrical configuration example of the antenna device according to the second embodiment. [Figure 19] A block diagram showing the electrical configuration of the antenna device according to the second modification. [Figure 20] A block diagram showing an electrical configuration example of the antenna device according to the third embodiment. [Figure 21] A block diagram showing an electrical configuration example of the antenna device according to the third modification. [Figure 22]A block diagram showing an example of the electrical configuration of the antenna device according to the fourth modified example. [Figure 23] This figure shows an example of an application of the antenna device according to this embodiment. [Modes for carrying out the invention]

[0008] The embodiments will be described below with reference to the drawings. The following description exemplifies devices and control methods for realizing the technical concept of the embodiments, and the technical concept of the embodiments is not limited to the structure, shape, arrangement, material, etc. of the components described below. Modifications that a person skilled in the art can easily conceive of are naturally included within the scope of disclosure. In order to make the explanation clearer, the size, thickness, planar dimensions, or shape of each element may be schematically represented in the drawings with modifications from the actual embodiments. Multiple drawings may include elements with different dimensional relationships or ratios. In multiple drawings, the same reference numeral may be used for corresponding elements to omit redundant explanations. Some elements may be given multiple names, but these examples of names are merely illustrative and do not preclude the use of other names for these elements. Similarly, elements that do not have multiple names may also be given other names. In the following description, "connection" means not only direct connection but also connection via other elements.

[0009] (First Embodiment) First, the first embodiment will be described. The antenna device according to the first embodiment is used, for example, to transmit radio waves to a target, receive the radio waves reflected by the target, and estimate the direction of the target. An example of radio waves used as radar signals in this embodiment is radio waves with wavelengths from 1 millimeter to 30 millimeters. Radio waves with wavelengths from 1 millimeter to 10 millimeters are also called millimeter waves, and radio waves with wavelengths from 10 millimeters to 100 millimeters are also called microwaves. Another example of radio waves is radio waves with wavelengths from 100 micrometers to 1 millimeter, which are called terahertz waves.

[0010] Figure 1 shows an example configuration of the first module 10 used in the antenna device according to the first comparative example.

[0011] The first module 10 in the first comparative example includes at least one IC, N1 (first number) transmitting antennas Tx1, Tx2, Tx3, Tx4, and M1 (second number) receiving antennas Rx1, Rx2, Rx3, Rx4. In the example in Figure 1, both N1 and M1 are positive integers, in this case 4. The transmitting antennas Tx1, Tx2, Tx3, Tx4 and the receiving antennas Rx1, Rx2, Rx3, Rx4 are connected to an IC on a single board, for example.

[0012] The transmitting antennas Tx1, Tx2, Tx3, and Tx4 are arranged in a first direction with a first interval dt, forming a linear array antenna. Hereinafter, the transmitting antennas Tx1, Tx2, Tx3, and Tx4 may be collectively referred to as the transmitting array antenna. The first interval dt is, for example, approximately half a wavelength d (=λ / 2) of the wavelength with the highest intensity included in the electromagnetic waves transmitted from the transmitting antenna and the electromagnetic waves received from the receiving antenna. The first direction is, for example, the direction along the X axis. Approximately half a wavelength refers to wavelengths included within ±30%, preferably within ±20%, and more preferably within ±10% of the half wavelength.

[0013] The receiving antennas Rx1, Rx2, Rx3, and Rx4 are arranged in the first direction with a second interval dr, forming a linear array antenna. Hereafter, the receiving antennas Rx1, Rx2, Rx3, and Rx4 may be collectively referred to as the receiving array antenna. The second interval dr is, for example, the number of receiving antennas with approximately half a wavelength d (i.e., dr = N1 × dt). In the example in Figure 1, the distance from the receiving antenna Rx1 closest to the left end 1 of the first module 10 to the left end 1 is half the distance of the second interval dr (= dr / 2). Similarly, the distance from the receiving antenna Rx4 closest to the right end 2 of the first module 10 to the right end 2 is half the distance of the second interval dr. In other words, the length dl in the X-axis direction of the first module 10 is the second interval dr × M1 (number of receiving antennas).

[0014] In the example shown in Figure 1, the transmitting antennas Tx1, Tx2, Tx3, and Tx4 are positioned between the receiving antennas Rx2 and R3. Furthermore, the transmitting antennas Tx1, Tx2, Tx3, and Tx4 and the receiving antennas Rx1, Rx2, Rx3, and Rx4 are aligned on the same straight line, and the center positions of the transmitting array antennas and the center positions of the receiving array antennas are approximately the same.

[0015] Since the transmitting antenna and receiving antenna are interchangeable, in the following explanation, the transmitting antenna may be referred to as the receiving antenna, and the receiving antenna as the transmitting antenna.

[0016] Here, according to the method for forming a MIMO array antenna, 16 virtual antennas (MIMO antennas) r1 to r16 are formed from the transmitting antennas Tx1, Tx2, Tx3, Tx4 and the receiving antennas Rx1, Rx2, Rx3, Rx4, as shown in the lower part of Figure 1. In other words, by using a transmitting array antenna containing N1 transmitting antennas and a receiving array antenna containing M1 receiving antennas, a virtual array antenna (MIMO array antenna) containing N1 × M1 virtual antennas can be formed.

[0017] Specifically, transmitting antennas Tx1, Tx2, Tx3, and Tx4 transmit radio waves corresponding to the transmission signals of each transmitting antenna Tx1, Tx2, Tx3, and Tx4 within a fixed field of view. Transmitting antennas Tx1, Tx2, Tx3, and Tx4 are time-division driven and controlled to transmit radio waves corresponding to the transmission signals of each transmitting antenna Tx1, Tx2, Tx3, and Tx4 at different timings. Radio waves transmitted from transmitting antenna Tx1 are received by receiving antennas Rx1, Rx2, Rx3, and Rx4. Radio waves transmitted from transmitting antenna Tx2 are received by receiving antennas Rx1, Rx2, Rx3, and Rx4. Radio waves transmitted from transmitting antenna Tx3 are received by receiving antennas Rx1, Rx2, Rx3, and Rx4. Radio waves transmitted from transmitting antenna Tx4 are received by receiving antennas Rx1, Rx2, Rx3, and Rx4.

[0018] Here, we consider the received signal received by the receiving antenna Rx1 in a situation where the k-th target Pk lies on the extension of the line at an angle θ from the antenna device. The propagation path of the received signal received by the receiving antenna Rx1 after the radio waves transmitted from the transmitting antenna Tx1 are reflected by target Pk, and the propagation path of the received signal received by the receiving antenna Rx1 after the radio waves transmitted from the transmitting antenna Tx2 are reflected by target Pk, have a difference (path difference) corresponding to the distance between the transmitting antenna Tx1 and the transmitting antenna Tx2 (first interval dt). This difference causes a phase difference between the two received signals. Hereafter, we will denote the phase difference caused by the difference in the above propagation paths as φ.

[0019] Furthermore, there is a difference between the propagation path of the received signal transmitted from transmitting antenna Tx1, reflected by target Pk and received by receiving antenna Rx1, and the propagation path of the received signal transmitted from transmitting antenna Tx3, reflected by the target and received by receiving antenna Rx1, depending on the distance between transmitting antenna Tx1 and transmitting antenna Tx3 (first interval dt × 2). This difference results in a phase difference of 2φ between the two received signals. Similarly, there is a difference between the propagation path of the received signal transmitted from transmitting antenna Tx1, reflected by target Pk and received by receiving antenna Rx1, and the propagation path of the received signal transmitted from transmitting antenna Tx4, reflected by target Pk and received by receiving antenna Rx1, depending on the distance between transmitting antenna Tx1 and transmitting antenna Tx4 (first interval dt × 3). In other words, a phase difference of 3φ results in the two received signals.

[0020] Thus, the receiving antenna Rx1 can obtain four received signals as radio waves are transmitted by the respective transmitting antennas Tx1, Tx2, Tx3, and Tx4. The phase differences of each received signal are 0, φ, 2φ, and 3φ, respectively, with reference to the phase of the received signal received after the radio waves are reflected by the target Pk. This means that the received signals are the same as when radio waves transmitted from one transmitting antenna and reflected by the target Pk are received by each of the four receiving antennas arranged at a first interval dt.

[0021] In other words, by transmitting radio waves in a time-division manner through transmitting antennas Tx1, Tx2, Tx3, and Tx4, four virtual antennas r1, r2, r3, and r4 can be formed based on the received signal received by receiving antenna Rx1, with a first interval dt in the X-axis direction. Furthermore, the phase difference φ can be defined as the phase difference of the received signals in two adjacent virtual antennas among the four virtual antennas r1, r2, r3, and r4.

[0022] Next, in a similar situation, consider the phase difference between the received signal received by receiving antenna Rx1 and the received signal received by receiving antenna Rx2. The propagation path of the received signal received by receiving antenna Rx2 after the radio waves transmitted from transmitting antenna Tx1 are reflected at target Pk, and the propagation path of the received signal received by receiving antenna Rx1 after the same radio waves are reflected at target Pk, differs according to the distance between receiving antenna Rx1 and receiving antenna Rx2 (first interval dt × 4). In other words, a phase difference of 4φ occurs between the two received signals.

[0023] Similarly, there is a difference between the propagation path of the received signal received by the receiving antenna Rx2 after the radio waves transmitted from the transmitting antenna Tx2 are reflected by the target Pk and received by the receiving antenna Rx2, and the propagation path of the received signal received by the receiving antenna Rx1 after the same radio waves are reflected by the target Pk, corresponding to the distance between the receiving antenna Rx1 and the receiving antenna Rx2 (first interval dt × 4). Similarly, there is a difference between the received signal received by the receiving antenna Rx2 after the radio waves transmitted from the other transmitting antennas Tx3 and Tx4 are reflected by the target and received by the receiving antenna Rx2, and the received signal received by the receiving antenna Rx1 after the same radio waves are reflected by the target, corresponding to the distance between the receiving antenna Rx1 and the receiving antenna Rx2 (first interval dt × 4).

[0024] Thus, the receiving antenna Rx2 can obtain four received signals as the radio waves transmitted in time division by each transmitting antenna Tx1, Tx2, Tx3, and Tx4 are reflected at the target Pk. The phase difference between each received signal received by the receiving antenna Rx2 and each received signal received by the receiving antenna Rx1 is 4φ. That is, if we use the phase of the received signal received by the receiving antenna Rx1 as the reference, the phase differences of each received signal received by the receiving antenna Rx2 are 4φ, 5φ, 6φ, and 7φ, which are obtained by adding 4φ to the phase differences of each received signal received by the receiving antenna Rx1 (0, φ, 2φ, 3φ). This means that the received signals are the same as when radio waves transmitted from one transmitting antenna and reflected at the target Pk are received by each of the four receiving antennas arranged at a first interval dt.

[0025] In other words, by transmitting radio waves in a time-division manner through transmitting antennas Tx1, Tx2, Tx3, and Tx4, four virtual antennas r5, r6, r7, and r8 can be formed based on the received signal received by receiving antenna Rx2, with a first interval dt in the X-axis direction.

[0026] Similarly, for receiving antennas Rx3 and Rx4, based on the received signal received by receiving antenna Rx3, four virtual antennas r9, r10, r11, and r12 are formed, arranged in the X-axis direction with a first interval dt. Based on the received signal received by receiving antenna Rx4, four virtual antennas r13, r14, r15, and r16 are formed, arranged in the X-axis direction with a first interval dt. In other words, with the transmitting antennas Tx1, Tx2, Tx3, and Tx4 and receiving antennas Rx1, Rx2, Rx3, and Rx4 shown in Figure 1, 16 non-overlapping virtual antennas r1 to r16 can be formed.

[0027] Here, we will explain using equations how 16 non-overlapping virtual antennas are formed using the transmitting antennas Tx1, Tx2, Tx3, Tx4 and receiving antennas Rx1, Rx2, Rx3, Rx4 shown in Figure 1. For the sake of simplicity, we will assume that the centers of transmitting antennas Tx2 and Tx3 are the origin, and that the center positions of transmitting antennas Tx2 and Tx3 are the same as the center positions of receiving antennas Rx2 and Rx3. Furthermore, we will assume that the k-th target Pk lies on the extension of the antenna device at an angle θ, as shown in Figure 1.

[0028] In this case, the received data x(t) at a certain time t can be modeled as shown in Equation 1.

[0029]

number

[0030] a t (θ k ) and a r (θ k The midpoint between transmitting antenna Tx2 and transmitting antenna Tx3 in Figure 1 can be defined as shown in Equations 2 and 3.

[0031]

number

[0032] at (θ k ) and a r (θ k ) of the Kronecker product, and for any k, the mode vector a v (θ k ) of the virtual array antenna, can be expressed as in Equation 4 below.

[0033]

Equation

[0034] According to Equation 4, since it includes 16 phase states, it can be seen that based on 4 transmitting antennas and 4 receiving antennas, a virtual array antenna is formed in which 16 antennas are arranged in the x-axis direction at the first interval dt. Also, as can be seen from Equation 4, there are no overlapping components in the mode vector a v (θ k ). That is, by arranging the transmitting antennas Tx1, Tx2, Tx3, Tx4 and the receiving antennas Rx1, Rx2, Rx3, Rx4 as shown in the upper figure of FIG. 1, it can be seen from Equation 4 that 16 virtual antennas r1 to r16 (first virtual array antenna 10a) without overlap can be formed.

[0035] To further improve the spatial resolution of the virtual array antenna 10a, the number of antennas can be increased. However, there is a limit to the number of antennas that can be connected to the same IC. For example, a method of increasing the number of antennas can be considered by connecting a plurality of ICs in series on the same substrate. By supplying a common reference signal (local signal) to the plurality of serially connected ICs, coherence can be maintained and spatial resolution corresponding to the number of antennas can be realized. However, generally, it is necessary to wire the transmitting antenna and the receiving antenna from the IC with equal lengths respectively. Therefore, when increasing the number of antennas so that the virtual antennas do not overlap, the wiring from a plurality of ICs on the same substrate to the corresponding plurality of transmitting antennas and plurality of receiving antennas becomes complicated. Also, extension and detour of the power supply line are required, and there is a possibility that the radiation loss increases.

[0036] Therefore, in this embodiment, we consider increasing the aperture length of the antenna device by linking together two modules, each already equipped with a receiving antenna and a transmitting antenna, as shown in the first module 10 of the antenna device according to the first comparative example. In the following description, "linking together" means arranging multiple modules on the same straight line and controlling them in conjunction.

[0037] Figure 2 shows an example of the configuration of the antenna device according to this embodiment. The antenna device according to this embodiment has a second module 20 in addition to the first module 10 described in Figure 1.

[0038] The second module 20 includes at least one IC, N2 (third number) transmitting antennas Tx5, Tx6, Tx7, Tx8, and M2 (fourth number) receiving antennas Rx5, Rx6, Rx7, Rx8. Each transmitting antenna Tx5, Tx6, Tx7, Tx8 is connected to the IC. Each receiving antenna Rx5, Rx6, Rx7, Rx8 is also connected to the IC. In the example in Figure 2, N2 and M2 are both positive integers, in this case 4. The arrangement of the transmitting antennas Tx5, Tx6, Tx7, Tx8 and the receiving antennas Rx5, Rx6, Rx7, Rx8 is the same as in the first module 10. Note that the first module 10 and the second module 20 may be constructed on different circuit boards or may be placed on the same circuit board.

[0039] The first module 10 and the second module 20 are arranged on a straight line in the X-axis direction. In this arrangement, the distance between the receiving antenna Rx4, which is closest to the second module 20 among the receiving antennas Rx1, Rx2, Rx3, and Rx4 of the first module 10, and the receiving antenna Rx5, which is closest to the first module 10 among the receiving antennas Rx5, Rx6, Rx7, and Rx8 of the second module 20, is the second interval dr. In the example shown in Figure 2, the distance from the receiving antenna Rx1, which is closest to the right end 2 of the first module 10, to the right end 2 is half the distance of the second interval dr (=dr / 2). Similarly, the distance from the receiving antenna Rx5, which is closest to the left end 3 of the second module 20, to the left end 3 is half the distance of the second interval dr. Therefore, by placing the first module 10 and the second module 20 adjacent to each other without any gaps, the distance between the receiving antenna Rx4 and the receiving antenna Rx5 can be set to the second interval dr.

[0040] Furthermore, the distance between transmitting antenna Tx1 and transmitting antenna Tx5 is, for example, an integer multiple of the first interval dt. Here, we will explain assuming that it is 16dt (4dr).

[0041] Figure 3 shows the transmission timing of each transmitting antenna Tx1 to Tx8 and the reception timing of each receiving antenna Rx1 to Rx8 in the second comparative example of the first embodiment. The arrows in Figure 3 indicate the time direction.

[0042] As shown in Figure 3, when the transmitting antenna Tx1 of the first module 10 transmits radio waves, all the receiving antennas Rx1 to Rx8 of the first module 10 and the second module 20 receive the radio waves (received signals) reflected from the target. Then, when the transmitting antenna Tx2 of the first module 10 transmits radio waves, all the receiving antennas Rx1 to Rx8 of the first module 10 and the second module 20 receive the radio waves reflected from the target.

[0043] Similarly thereafter, when the transmitting antennas Tx3 and Tx4 of the first module 10 transmit radio waves, all the receiving antennas Rx1 to Rx8 of the first module 10 and the second module 20 receive the radio waves reflected by the target.

[0044] Next, when the transmitting antenna Tx5 of the second module 20 transmits a radio wave, all the receiving antennas Rx1 to Rx8 of the first module 10 and the second module 20 receive the radio wave (received signal) reflected from the target. Similarly thereafter, each time the transmitting antennas Tx6, Tx7, and Tx8 of the second module 20 transmit a radio wave, all the receiving antennas Rx1 to Rx8 of the first module 10 and the second module 20 each receive the radio wave reflected from the target.

[0045] Figure 4 shows an example of a virtual array antenna formed by the antenna device according to the second comparative example of the first embodiment.

[0046] The virtual array antenna consists of a first virtual array antenna 10a and a second virtual array antenna 20a. For the sake of explanation, in Figure 4, the first virtual array antenna 10a and the second virtual array antenna 20a are shown offset vertically, but in reality, the first virtual array antenna 10a and the second virtual array antenna 20a are formed to be aligned in the same straight line.

[0047] The first virtual array antenna 10a includes virtual antennas r1 to r32 arranged on a straight line in the X-axis direction with a second interval dr. The first virtual array antenna 10a is formed based on the received signals received by the receiving antennas Rx1 to Rx8 of the first module 10 and the transmitting antennas Tx1 to Tx4 of the first module 10, respectively.

[0048] The second virtual array antenna 20a includes virtual antennas r33 to r64 arranged on a straight line in the X-axis direction with a second spacing dr. The second virtual array antenna 20a is formed based on the received signals received by the receiving antennas Rx1 to Rx8 of the first module 10 and the second module 20, where each radio wave transmitted from the transmitting antennas Tx5 to Tx8 of the second module 20 is received.

[0049] Here, for example, if eight transmitting antennas and eight receiving antennas are ideally arranged, 64 ((N1+N2)×(M1+M2)) virtual array antennas can be formed, maximizing the aperture length. However, if two identical modules are simply connected to increase the number of each antenna, the number of virtual antennas remains at 48, as shown in Figure 4. This is because, in region A with a phase difference of 16φ to 31φ, overlap occurs in the received signals received by each receiving antenna (so-called overlap).

[0050] Specifically, for example, virtual antenna r1 is formed based on the received signal received by the receiving antenna Rx1 of the first module 10 when the transmitting antenna Tx1 of the first module 10 transmits radio waves. Virtual antenna r17 is formed based on the received signal received by the receiving antenna Rx5 of the second module 20 when the transmitting antenna Tx1 of the first module 10 transmits radio waves. In other words, the phase difference between virtual antenna r1 and virtual antenna r17 is determined according to the distance between the receiving antenna Rx1 and the receiving antenna Rx5. In the example in Figure 2, the distance between the receiving antenna Rx1 and the receiving antenna Rx5 is 4dr (=16dt). Therefore, the phase difference between virtual antenna r1 and virtual antenna r17 is 16φ.

[0051] Furthermore, the virtual antenna r33 is formed based on the received signal received by the receiving antenna Rx1 of the first module 10 when the transmitting antenna Tx5 of the second module 20 transmits radio waves. On the other hand, as described above, the virtual antenna r1 is formed based on the received signal received by the receiving antenna Rx1 of the first module 10 when the transmitting antenna Tx1 of the first module 10 transmits radio waves. In other words, the phase difference between virtual antenna r1 and virtual antenna r33 is determined according to the distance between transmitting antenna Tx1 and transmitting antenna Tx5. In the example in Figure 2, the distance between transmitting antenna Tx1 and transmitting antenna Tx5 is 4dr (=16dt). Therefore, the phase difference between virtual antenna r1 and virtual antenna r33 is 16φ. Hereafter, the phase difference between a certain virtual antenna and virtual antenna r1 will be simply referred to as the phase difference.

[0052] Thus, the phase difference of virtual antenna r17 and the phase difference of virtual antenna r33 are both 16φ. In other words, virtual antenna r17 and virtual antenna r33 are formed at the same position.

[0053] Similarly, the phase differences of virtual antennas r18 to r32 are the same as the phase differences of virtual antennas r34 to r48. In other words, the actual number of virtual antennas formed is 48, which is the total number of received signals (64) minus the 16 signals that overlap. Although there is a number of antennas that could potentially form 64 virtual antennas, only 48 virtual antennas are formed.

[0054] Therefore, in this embodiment, the aperture length of the virtual array antenna is further expanded by shifting the phase of the radio waves transmitted by the second transmitting antenna of module 20, following the transmitting antennas Tx1 to Tx4 of module 10, so as to reduce overlap. Hereinafter, the radio waves before phase shifting will be referred to as the "reference signal". Note that "shifting the phase" includes rotating the phase of a radio wave, applying a phase rotation to a radio wave, multiplying a radio wave by a predetermined value, etc.

[0055] The operation of the antenna device according to this embodiment will be described below with reference to Figures 5 and 6.

[0056] Figure 5 shows the transmission timing of radio waves from each transmitting antenna Tx1 to Tx8 and the reception timing of each receiving antenna Rx1 to Rx8 in the first embodiment. The arrows in Figure 5 indicate the time direction.

[0057] Similar to Figure 3, the transmitting antennas Tx1, Tx2, Tx3, and Tx4 of the first module 10 transmit a transmission signal based on a reference signal in a time-division manner, so that all the receiving antennas Rx1 to Rx8 of the first module 10 and the second module 20 each receive the received signal reflected from the target.

[0058] In this embodiment, the antenna device calculates (estimates) the phase difference φ of the received signals between two adjacent virtual antennas r1 to r32 of the first virtual array antenna 10a at timing T when the transmitting antenna Tx4 of the first module 10 has finished transmitting radio waves. The phase difference φ can be determined, for example, by comparing the received signal received by the receiving antenna Rx1 when the transmitting antenna Tx1 transmits a transmission signal based on a reference signal, with the received signal received by the receiving antenna Rx1 when the transmitting antenna Tx2 transmits a transmission signal based on a reference signal.

[0059] The antenna device calculates (generates) a value indicating the amount of phase rotation of the radio waves (hereinafter referred to as the phase value) based on array processing information indicating the number of virtual antennas that overlap and the phase difference φ. The array processing information will be described later. In the example in Figure 5, since there are 16 virtual antennas that overlap, the phase value will be between 1φ and 16φ, for example, 16φ.

[0060] The antenna system shifts the phase of the reference signal by a phase value of 16φ and transmits it from the transmitting antennas Tx5, Tx6, Tx7, and Tx8 of the second module.

[0061] Figure 6 shows an example of a virtual array antenna formed by the antenna device according to the first embodiment. Similar to Figure 4, the virtual array antenna consists of a first virtual array antenna 10a and a second virtual array antenna 20a.

[0062] Here, because the phase of the reference signal transmitted from the second module 20 is shifted by 16φ, the phase of the received signals received by the receiving antennas Rx1 to Rx8 of the first module 10 and the second module 20 is also shifted by 16φ. In other words, each of the virtual antennas r33 to r64 included in the second virtual array antenna 20a is formed with a positive shift of 16φ. Note that the "positive direction" is the direction that reduces the number of antennas that overlap, and the "negative direction" is the direction that increases the number of antennas that overlap.

[0063] Specifically, in the example shown in Figure 6, the phase difference of virtual antenna r33 becomes 16φ + 16φ = 32φ when receiving a received signal shifted by 16φ. Similarly, the phase difference of virtual antenna r34 becomes 17φ + 16φ = 33φ when receiving a received signal shifted by 16φ. In the same way, each of the virtual antennas r35 to r64 included in the second virtual array antenna 20a is shifted by 16φ in the positive direction. As a result, a total of 64 virtual antennas r1 to r64 with non-overlapping phase differences can be formed, as shown in Figure 6.

[0064] Figure 7 is a block diagram showing an example of the electrical configuration of an antenna device according to the second comparative example. The antenna device according to the second comparative example includes a reference signal generation unit 30, a first module 10, a second module 20, and a signal processing unit 40.

[0065] The reference signal generation unit 30 generates a linear frequency-modulated continuous wave (L-FMCW) whose frequency increases linearly over time, for example, using a synthesizer. The L-FMCW signal is also called a chirp signal.

[0066] The reference signal generation unit 30 supplies the generated L-FMCW signal as a reference signal to the first module 10 and the second module 20, respectively. Hereinafter, the reference signal supplied to the first module 10 will be referred to as the first reference signal, and the reference signal supplied to the second module 20 will be referred to as the second reference signal. The reference signal generation unit 30 generates the first and second reference signals at different timings and supplies them to the first and second transmission circuits 12 and 22. This controls the transmission of the first and second reference signals from each transmitting antenna Tx1 to Tx8 at different timings.

[0067] The first module 10 includes a D / A converter 11, a first transmitting circuit 12, transmitting antennas Tx1 to Tx4, receiving antennas Rx1 to Rx4, a first receiving circuit 13, a mixer 14, and an A / D converter 15. The D / A converter 11 and the first transmitting circuit 12 may be provided for each of the transmitting antennas Tx1 to Tx4, and the first receiving circuit 13, mixer 14, and A / D converter 15 may be provided for each of the receiving antennas Rx1 to Rx4.

[0068] The first reference signal supplied from the reference signal generation unit 30 is input to the first transmission circuit 12 via the D / A converter 11. The first transmission circuit 12 performs transmission processing such as amplification and frequency conversion on the first reference signal, and supplies the processed first reference signal as radio waves (transmission signals) to the transmitting antennas Tx1 to Tx4, respectively.

[0069] Transmitting antennas Tx1 to Tx4 radiate the above radio waves within a fixed field of view.

[0070] The receiving antennas Rx1 to Rx4 receive radio waves reflected from the target. The receiving antennas Rx1 to Rx4 supply the received signals to the first receiving circuit 13. The first receiving circuit 13 performs reception processing such as amplification and frequency conversion on each received signal and inputs them to the first input terminals of the mixer 14. The first reference signal is input to the second input terminal of the mixer 14.

[0071] The mixer 14 multiplies each received signal by the first reference signal to generate an IF (intermediate frequency) signal. The generated IF signal is supplied to the signal processing unit 40 via the A / D converter 15.

[0072] The second module 20, like the first module 10, includes a D / A converter 21, a second transmitting circuit 22, transmitting antennas Tx5 to Tx8, receiving antennas Rx5 to Rx8, a second receiving circuit 23, a mixer 24, and an A / D converter 25. The D / A converter 21 and the second transmitting circuit 22 may be provided for each of the transmitting antennas Tx5 to Tx8, and the second receiving circuit 23, mixer 24, and A / D converter 25 may be provided for each of the receiving antennas Rx5 to Rx8.

[0073] The second reference signal supplied from the reference signal generation unit 30 is input to the second transmission circuit 22 via the D / A converter 21. The second transmission circuit 22 performs transmission processing such as amplification and frequency conversion on the second reference signal, and supplies the processed second reference signal as radio waves (transmission signals) to the transmitting antennas Tx5 to Tx8, respectively.

[0074] Transmitting antennas Tx5 to Tx8 radiate the above radio waves within a constant field of view.

[0075] The receiving antennas Rx5 to Rx8 receive radio waves reflected from the target. The receiving antennas Rx5 to Rx8 supply the received signals to the second receiving circuit 23. The second receiving circuit 23 performs reception processing such as amplification and frequency conversion on each received signal and inputs them to the first input terminal of the mixer 24. The second reference signal is input to the second input terminal of the mixer 24. The mixer 14 multiplies each received signal and the second reference signal to generate an IF signal. The generated IF signal is supplied to the signal processing unit 40 via the A / D converter 15.

[0076] The processing of the D / A converter 21, second transmitting circuit 22, transmitting antennas Tx5~Tx8, receiving antennas Rx5~Rx8, second receiving circuit 23, mixer 24, and A / D converter 25 is the same as in the first module 10.

[0077] The signal processing unit 40 processes the IF signals output from the first module 10 and the second module 20 to form a virtual array antenna (virtual antennas r1 to r64) with an antenna spacing of approximately half a wavelength d (first spacing dt). In other words, the signal processing unit 40 determines the reflection intensity for each distance from the antenna device to the target by determining the amplitude of the frequency domain signal of the IF signal output from the first module 10 and the second module 20, assuming that 48 receiving antennas are installed on the same straight line at the first spacing dt.

[0078] In this case, overlap occurs in region A of the received signal with a phase difference of 16φ to 30φ in the virtual array antenna, resulting in low spatial resolution. Therefore, the antenna device according to this embodiment has a configuration for shifting the phase of signals transmitted from the transmitting antennas Tx5 to Tx8 of the second module 20.

[0079] Figure 8 is a block diagram showing an example of the electrical configuration of the antenna device according to this embodiment. Note that parts similar to those in the second comparative example are denoted by the same reference numerals, and their detailed descriptions are omitted. The antenna device according to this embodiment includes a phase value generation unit 50 in addition to the antenna device according to the second comparative example. Furthermore, the second module 20 includes a first transmission processing circuit 51.

[0080] The phase value generation unit 50 generates the amount of phase rotation (phase value) of the radio waves transmitted by the transmitting antennas Tx5 to Tx8 of the second module 20.

[0081] More specifically, the phase value generation unit 50 calculates the phase difference φ of the received signals in two adjacent virtual antennas among a plurality of virtual antennas formed based on the received signals received by the receiving antennas Rx1 to Rx8 when the transmitting antennas Tx1 to Tx4 of the first module 10 transmit radio waves. The phase difference φ is calculated based on the received signals of at least two of the above plurality of virtual antennas. Specifically, for example, it can be determined by comparing the received signal received by the receiving antenna Rx1 when the transmitting antenna Tx1 transmits radio waves (i.e., the received signal of virtual antenna r1) with the received signal received by the receiving antenna Rx1 when the transmitting antenna Tx2 transmits radio waves (i.e., the received signal of virtual antenna r2). Alternatively, the phase difference φ can be calculated by dividing by 2 the phase difference obtained by comparing the received signal received by receiving antenna Rx1 when transmitting antenna Tx1 transmits radio waves (i.e., the received signal of virtual antenna r1) with the received signal received by receiving antenna Rx1 when transmitting antenna Tx3 transmits radio waves (i.e., the received signal of virtual antenna r3). ​​Alternatively, the phase difference φ can be calculated based on the received signals of three or more virtual antennas. The method for calculating the phase difference φ is not limited to the method introduced here and can be calculated using two or more pieces of information from various virtual antennas.

[0082] Furthermore, the phase value generation unit 50 acquires array processing information from the signal processing unit 40. The array processing information indicates the number of virtual antennas that overlap when no phase rotation amount (phase value) is applied to the radio waves transmitted by the transmitting antennas Tx5 to Tx8 of the second module 20. The array processing information is determined by the number of modules to be connected, the number and arrangement of receiving and transmitting antennas included in the modules, etc. For example, the array processing information for the l-th module is N × M × (L-1) × (l-1), where L is the number of connected modules, N is the number of transmitting antennas included in one module, and M is the number of receiving antennas included in one module. Note that l, L, N, and M are integers of 2 or greater.

[0083] The phase value generation unit 50 generates a phase value by multiplying the calculated phase difference φ by the acquired array processing information. The phase value is a positive integer multiple of the phase difference φ. The phase value for the reference signal supplied to the l-th module is between 1φ and N×M×(L-1)×(l-1)×φ. For example, the phase value for the l-th module is N×M×(L-1)×(l-1)×φ. When the first module 10 and the second module 60 are configured as shown in Figure 2, the phase value for the second module 60 is 16φ. The phase value generation unit 50 outputs the generated phase value to the second module 20.

[0084] The first transmission processing circuit 51 of the second module 20 shifts the phase of the second reference signal supplied from the reference signal generation unit 30 by the phase value output from the phase value generation unit 50, and outputs it to the second transmission circuit 22 via the D / A converter 21. The first transmission processing circuit 51 may also shift the phase of the second reference signal using a phase shifter (not shown) installed between the D / A converter 21 and the second transmission circuit 21. The phase shifter may be one typically used for calibration or beamforming. In this case, the first transmission processing circuit 51 provides the phase value output from the phase value generation unit 50 to the phase shifter. As a result, the phase of the first reference signal after conversion by the D / A converter 21 is shifted by the phase value by the phase shifter and output to the second transmission circuit 22. The transmitting antennas Tx5 to Tx8 transmit radio waves with the phase of the second reference signal shifted by the phase value as the transmission signal.

[0085] As a result, the phase of the received signal received by the receiving antennas Rx1 to Rx8 (i.e., the phase of the virtual antennas r33 to r64) is shifted by the phase value generated by the phase value generation unit 50 compared to the second comparative example. Here, the phase of the virtual antennas formed as shown in Figure 4 is shifted by a phase value of 16φ. As a result, 64 non-overlapping virtual antennas can be formed as shown in Figure 6.

[0086] Figure 9 shows graphs of simulation results for estimating the direction of a target by the antenna device according to the first embodiment, the antenna device according to the second comparative example of the first embodiment, and the case where eight transmitting antennas and eight receiving antennas are ideally arranged, when the target is located at a position of +15 degrees from the antenna device. The vertical axis of Figure 9 represents the reflection intensity. The horizontal axis of Figure 9 represents the angle.

[0087] The thin solid line graph shows the results when using the antenna device according to the second comparative example shown in Figures 3 and 7. The thick solid line graph shows the results when using the antenna device of another comparative example, which has one module with eight transmitting antennas and eight receiving antennas ideally arranged. The dashed line graph shows the results when using the antenna device according to this embodiment.

[0088] As shown in Figure 9, the antenna device according to this embodiment has the same spatial resolution (angular resolution) as an antenna device with eight transmitting antennas and eight receiving antennas ideally arranged. Furthermore, the antenna device according to this embodiment has a higher spatial resolution (angular resolution) than the antenna device according to the second comparative example. Although not shown in the figures, the antenna device according to this embodiment can also obtain the same spatial resolution (angular resolution) as an antenna device with four transmitting antennas and four receiving antennas ideally arranged, even when there are multiple targets.

[0089] As described above, in this embodiment, the antenna device calculates the phase difference φ of the received signals between two adjacent virtual antennas among a plurality of virtual antennas r1 to r32 formed based on the received signals received by the receiving antennas Rx1 to Rx8 (first receiving antenna and second receiving antenna) when the transmitting antennas Tx1 to Tx4 (first transmitting antenna) of the first module 10 transmit a transmission signal based on a first reference signal. The phase difference φ is calculated based on the received signals of at least two of the plurality of virtual antennas. The antenna device then generates a phase value based on the phase difference φ and shifts the phase of the second reference signal transmitted by the transmitting antennas Tx5 to Tx8 (second transmitting antenna) of the second module 20 by the phase value.

[0090] This makes it possible to form an optimal number of virtual antennas with no overlap (i.e., no overlap) relative to the number of transmitting and receiving antennas. Furthermore, by connecting multiple modules having the same configuration as in this embodiment, the spatial resolution of the antenna device can be easily increased without complicating the wiring.

[0091] Note that the configurations of the first module 10 and the second module 20 are not limited to those shown in Figure 2, and may be changed depending on the shape and size of the substrate on which the transmitting antenna and receiving antenna are placed. Other examples of the configurations of the first module 10 and the second module 20 will be described below.

[0092] Figure 10 shows a first configuration example of the first module 10 and the second module 20 in the first embodiment. In the first configuration example, the distance d1 from the receiving antenna Rx4 of the first module 10 to the right end 2 is shorter than dr / 2 shown in Figure 1. Also, the distance d3 from the receiving antenna Rx1 of the second module 20 to the left end 3 is shorter than dr / 2.

[0093] In this case, the receiving antennas R4, which is closest to the second module 20 among the receiving antennas Rx1 to Rx4 of the first module 10, and the receiving antenna Rx4, which is closest to the first module 10 among the receiving antennas Rx4 to Rx8 of the second module 20, are arranged so that the distance between them equals the second interval dr. That is, the distances d1 and d3 in Figure 10, plus the space d2 between the first module 10 and the second module 20, are added together to equal the second interval dr. Furthermore, the distance between the transmitting antenna Tx1, which is closest to the left end 1 of the first module 10, and the transmitting antenna Tx5, which is closest to the left end 3 of the second module 20, is arranged so that, for example, the distance between them is an integer multiple of the first interval dt. In the example in Figure 10, this is 16dt (4dr).

[0094] Figure 11 shows a second configuration example of the first module 10 and the second module 20. In Figure 2, the transmitting antennas Tx1, Tx2, Tx3, and Tx4 were positioned between the receiving antennas Rx2 and Rx3. In the second configuration example, the transmitting antennas Tx1, Tx2, Tx3, and Tx4 are positioned between the receiving antennas Rx1 and Rx2 of the first module 10. In this case, the transmitting antennas Tx5, Tx6, Tx7, and Tx8 of the second module 20 are positioned between the receiving antennas Rx5 and Rx6 of the second module 20. Furthermore, the distance between the transmitting antenna Tx1 closest to the left end 1 of the first module 10 and the transmitting antenna Tx5 closest to the left end 3 of the second module 20 is, for example, an integer multiple of the first interval dt. In the example in Figure 11, this is 16dt (4dr).

[0095] Furthermore, the transmitting antennas Tx1, Tx2, Tx3, and Tx4 may be positioned between the receiving antenna Rx3 and the receiving antenna Rx4, and the transmitting antennas Tx5, Tx6, Tx7, and Tx8 may be positioned between the receiving antenna Rx7 and the receiving antenna Rx8.

[0096] Figure 12 shows a third configuration example of the first module 10 and the second module 20. In Figure 2, the transmitting antennas Tx1, Tx2, Tx3, Tx4 and the receiving antennas Rx1, Rx2, Rx3, Rx4 were arranged to be aligned on the same line. On the other hand, in the third configuration example, the transmitting antennas Tx1, Tx2, Tx3, Tx4 of the first module 10 are positioned offset upwards from the receiving antennas Rx1, Rx2, Rx3, Rx4. Similarly, the transmitting antennas Tx5, Tx6, Tx7, Tx8 of the second module 20 are positioned offset upwards from the receiving antennas Rx5, Rx6, Rx7, Rx8. In the third configuration example, the transmitting antennas Tx1, Tx2, Tx3, and Tx4 of the first module 10 may be positioned lower than the receiving antennas Rx1, Rx2, Rx3, and Rx4. Similarly, the transmitting antennas Tx5, Tx6, Tx7, and Tx8 of the second module 20 may be positioned lower than the receiving antennas Rx5, Rx6, Rx7, and Rx8. The transmitting antennas Tx1 to Tx8 are positioned such that the vertical distance between them and the receiving antennas Rx1 to Rx8 is sufficiently small relative to the distance between the antenna device and the target. Furthermore, the distance between the transmitting antenna Tx1 closest to the left end 1 of the first module 10 and the transmitting antenna Tx5 closest to the left end 3 of the second module 20 is, for example, an integer multiple of the first interval dt. In the example in Figure 12, this is 16dt (4dr). Thus, even if the transmitting antennas Tx1~Tx8 and receiving antennas Rx1~Rx8 are not aligned in the same straight line, their effect can be ignored if the distance to the target is sufficiently large.

[0097] Figure 13 shows a fourth configuration example of the first module 10 and the second module 20. In the example in Figure 12, the transmitting antennas of both the first module 10 and the second module 20 were positioned offset upwards compared to the receiving antennas. On the other hand, in the fourth configuration example, the transmitting antennas Tx1, Tx2, Tx3, and Tx4 of the first module 10 are offset upwards, and the transmitting antennas Tx5, Tx6, Tx7, and Tx8 of the second module 20 are offset downwards. Alternatively, the transmitting antennas Tx1, Tx2, Tx3, and Tx4 of the first module 10 may be offset downwards, and the transmitting antennas Tx5, Tx6, Tx7, and Tx8 of the second module 20 may be offset upwards. The transmitting antennas Tx1 to Tx8 are positioned such that the vertical distance between them and the receiving antennas Rx1 to Rx8 is sufficiently small relative to the distance between the antenna device and the target. Furthermore, the distance between the receiving antenna Rx1 closest to the left end 1 of the first module 10 and the receiving antenna Rx5 closest to the left end 3 of the second module 20 is, for example, an integer multiple of the first interval dt. In the example in Figure 13, this is 16dt (4dr). Thus, even in the fourth configuration example, if the transmitting antennas Tx1~Tx8 and the receiving antennas Rx1~Rx8 are not aligned on the same line, their effect can be ignored if the distance to the target is sufficiently far.

[0098] Note that the configurations of the first module 10 and the second module 20 are not limited to those shown in Figures 2 and 10-12, but are acceptable as long as they are arranged in a way that allows for the formation of a virtual array antenna at equal intervals.

[0099] (First variation) The first modification differs from the first embodiment described above in that it forms virtual antennas in such a way that overlap is intentionally created.

[0100] The phase value generation unit 50 according to the first modified example generates a phase value based on the acquired phase difference φ and array processing information based on the number of virtual antennas that cause overlap. The phase value for the l-th module is set to, for example, 1 or more and less than N × M × (L-1) × (l-1) × φ, where N is the number of transmitting antennas, M is the number of receiving antennas, and L is the number of modules to be linked.

[0101] Figure 14 shows an example of a virtual array antenna in the first modified example. Here, we will explain an example where the phase value is set to 14φ.

[0102] In this case, the transmitting antennas Tx5 to Tx8 of the second module 20 transmit a transmission signal based on a second reference signal with a phase shift of 14φ. As a result, the phase of the received signal received by the receiving antennas Rx1 to Tx8 (i.e., the phase of the virtual antennas r33 to r64) is shifted by 14φ compared to the second comparative example. This allows for overlap between the two virtual antennas (virtual antennas r31 and r33, and virtual antennas r32 and r34), as shown in Figure 14.

[0103] Although this explanation describes setting the phase value to a positive value, it is also possible to set the phase value to a negative value. In this case, the phase of the received signal received by receiving antennas Rx1 to Tx8 will shift in the negative direction, which allows for an increase in the number of overlapping antennas compared to the second comparative example.

[0104] For example, in situations where the antenna device is close to the target, variations in the direction (angle θ) of the reflected waves from the target may occur, making it impossible to form a virtual array antenna at equal intervals. As a result, variations may also occur in the angle estimation results for the target.

[0105] On the other hand, as in the first modified example, by intentionally creating overlap and performing phase interpolation on the overlapping parts, the accuracy of target direction estimation can be improved.

[0106] Another application example is when the target is moving; in such situations, the phase of the received signals from the virtual antennas, which would normally overlap, changes due to the target's movement. Therefore, by performing phase interpolation for the virtual antennas that would normally overlap, the phase fluctuations caused by the target's movement can be compensated for, thereby improving the accuracy of target direction estimation.

[0107] (Second Embodiment) Next, a second embodiment will be described. In the second embodiment, the connection of three modules will be described.

[0108] Figure 15 shows an example of the configuration of an antenna device according to the second embodiment. As shown in Figure 15, the antenna device according to the second embodiment has a third module 60 in addition to the first module 10 and the second module 20.

[0109] The third module 60 includes at least one IC, N3 (fifth number) transmitting antennas Tx9, Tx10, Tx11, Tx12, and M3 (sixth number) receiving antennas Rx9, Rx10, Rx11, Rx12. Each transmitting antenna Tx9, Tx10, Tx11, Tx12 is connected to the IC. Each receiving antenna Rx9, Rx10, Rx11, Rx12 is connected to the IC. In the example in Figure 15, N3 and M3 are both positive integers, in this case 4. The arrangement of the transmitting antennas Tx9, Tx10, Tx11, Tx12 and the receiving antennas Rx9, Rx10, Rx11, Rx12 is the same as that of the first module 10 and the second module 20. The first module 10, the second module 20, and the third module 60 may be configured on different substrates, or they may be arranged on the same substrate.

[0110] The first module 10, the second module 20, and the third module 60 are arranged on the same straight line in the X-axis direction. In this arrangement, the second module 20 and the third module 60 are positioned such that the distance between the receiving antenna Rx8, which is closest to the third module 60 among the receiving antennas Rx5, Rx6, Rx7, and Rx8 of the second module 20, and the receiving antenna Rx9, which is closest to the second module 20 among the receiving antennas Rx9, Rx10, Rx11, and Rx12 of the third module 60, is the second interval dr. The distance between the transmitting antenna Tx5 and the transmitting antenna Tx9 is, for example, an integer multiple of the first interval dt, which in this case is 16dt (=4dr).

[0111] Note that the configurations of the antennas in the first module 10, the second module 20, and the third module 60 are not limited to those shown in Figure 15. For example, any or all of the first module 10, the second module 20, and the third module 60 may have the configurations shown in any of Figures 11 to 13. Alternatively, as shown in Figure 10, a space may be provided between the first module 10, the second module 20, and the third module 60 such that the distance between each receiving antenna Rx1 to Rx12 is the second interval dr.

[0112] Here, we will describe the antenna device according to the third comparative example. In the antenna device according to the third comparative example, when the transmitting antenna Tx1 of the first module 10 transmits radio waves, all the receiving antennas Rx1 to Rx12 of the first module 10, the second module 20, and the third module 60 receive the radio waves (received signals) reflected from the target. Subsequently, when the transmitting antenna Tx2 of the first module 10 transmits radio waves, all the receiving antennas Rx1 to Rx12 of the first module 10, the second module 20, and the third module 60 receive the radio waves reflected from the target.

[0113] Similarly thereafter, when the transmitting antennas Tx3 and Tx4 of the first module 10 transmit radio waves, all the receiving antennas Rx1 to Rx12 of the first module 10, the second module 20, and the third module 60 receive the radio waves reflected from the target.

[0114] Next, when the transmitting antenna Tx5 of the second module 20 transmits a radio wave, all the receiving antennas Rx1 to Rx12 of the first module 10, the second module 20, and the third module 60 receive the radio wave (received signal) reflected from the target. Similarly thereafter, each time the transmitting antennas Tx6, Tx7, and Tx8 of the second module 20 transmit a radio wave, all the receiving antennas Rx1 to Rx12 of the first module 10, the second module 20, and the third module 60 each receive the radio wave reflected from the target.

[0115] Next, when the transmitting antenna Tx9 of the third module 60 transmits a radio wave, all the receiving antennas Rx1 to Rx12 of the first module 10, the second module 20, and the third module 60 receive the radio wave (received signal) reflected from the target. Similarly thereafter, each time the transmitting antennas Tx10, Tx11, and Tx12 of the third module 60 transmit a radio wave, all the receiving antennas Rx1 to Rx12 of the first module 10, the second module 20, and the third module 60 each receive the radio wave reflected from the target.

[0116] Figure 16 shows an example of a virtual antenna formed by the antenna device according to the third comparative example. The antenna device according to the third comparative example forms a first virtual array antenna 10a, 10b, 10c, a second virtual array antenna 20a, 20b, 20c, and a third virtual array antenna 60a, 60b, 60c.

[0117] The first virtual array antenna 10a includes 16 virtual antennas formed based on the received signals received by the receiving antennas Rx1 to Rx4 of the first module 10 when the transmitting antennas Tx1 to Tx4 of the first module 10 transmit radio waves. The first virtual array antenna 10b includes 16 virtual antennas formed based on the received signals received by the receiving antennas Rx5 to Rx8 of the second module 20 when the transmitting antennas Tx1 to Tx4 of the first module 10 transmit radio waves. The first virtual array antenna 10c includes 16 virtual antennas formed based on the received signals received by the receiving antennas Rx9 to Rx12 of the third module 60 when the transmitting antennas Tx1 to Tx4 of the first module 10 transmit radio waves.

[0118] Similarly, the second virtual array antenna 20a includes 16 virtual antennas formed based on the received signals received by the receiving antennas Rx1 to Rx4 of the first module 10 as the transmitting antennas Tx5 to Tx8 of the second module 20 transmit radio waves. The second virtual array antenna 20b includes 16 virtual antennas formed based on the received signals received by the receiving antennas Rx5 to Rx8 of the second module 20 as the transmitting antennas Tx5 to Tx8 of the second module 20 transmit radio waves. The second virtual array antenna 20c includes 16 virtual antennas formed based on the received signals received by the receiving antennas Rx9 to Rx12 of the third module 60 as the transmitting antennas Tx5 to Tx8 of the second module 20 transmit radio waves.

[0119] Furthermore, the third virtual array antenna 60a includes 16 virtual antennas formed based on the received signals received by the receiving antennas Rx1 to Rx4 of the first module 10 when the transmitting antennas Tx9 to Tx12 of the third module 60 transmit radio waves. The third virtual array antenna 60b includes 16 virtual antennas formed based on the received signals received by the receiving antennas Rx5 to Rx8 of the second module 20 when the transmitting antennas Tx9 to Tx12 of the third module 60 transmit radio waves. The third virtual array antenna 60c includes 16 virtual antennas formed based on the received signals received by the receiving antennas Rx9 to Rx12 of the third module 60 when the transmitting antennas Tx9 to Tx12 of the third module 60 transmit radio waves.

[0120] Here, for example, if we ideally arrange N transmitting antennas and M receiving antennas in L times the number of each, we can form N × L × M × L virtual array antennas and maximize the aperture length. However, if we simply connect L modules of the same configuration to increase the number of each antenna, the number of virtual antennas will remain N × M × (2L-1). This is because, for example, if we connect three modules, as shown in Figure 16, there will be overlap in the received signals received by each receiving antenna in the region C with a phase difference of 16φ to 64φ.

[0121] Therefore, in the second embodiment, the aperture length of the virtual array antenna is further expanded by shifting the phases of the radio waves transmitted by the transmitting antennas Tx5 to Tx8 of the second module 20, following the transmitting antennas Tx1 to Tx4 of the first module 10, and the phases of the radio waves transmitted by the transmitting antennas Tx9 to Tx12 of the third module 60, respectively, so as to reduce the overlap.

[0122] Figure 17 shows an example of a virtual array antenna formed by the antenna device according to the second embodiment. Here, the phase of the radio waves transmitted by the transmitting antennas Tx5 to Tx8 of the second module 20 is shifted by 32φ. In addition, the phase of the radio waves transmitted by the transmitting antennas Tx9 to Tx12 of the third module 60 is shifted by 64φ.

[0123] Each of the virtual antennas included in the second virtual array antenna 20a is shifted by 32φ in phase from the reference signal transmitted from the second module 20, and as a result, the received signals received by each receiving antenna Rx1 to Rx12 are also shifted by 32φ. Consequently, each of the virtual antennas included in the second virtual array antennas 20a, 20b, and 20c is shifted by 32φ in the positive direction. This allows each of the virtual antennas included in the second virtual array antennas 20a, 20b, and 20c to be formed so as not to overlap with each of the virtual antennas included in the first virtual array antennas 10a, 10b, and 10c.

[0124] Furthermore, each of the virtual antennas included in the third virtual array antenna 60a is shifted by 64φ in phase from the reference signal transmitted from the third module 60, causing the received signals received by each receiving antenna Rx1 to Rx12 to also be shifted by 64φ. As a result, each of the virtual antennas included in the third virtual array antennas 60a, 60b, and 60c is shifted by 64φ in the positive direction. This allows the third virtual array antennas 60a, 60b, and 60c to be formed so as not to overlap with the first virtual array antennas 10a, 10b, and 10c, and the second virtual array antennas 20b and 20c.

[0125] Therefore, according to the second embodiment, a total of 144 virtual array antennas can be formed.

[0126] Figure 18 is a block diagram showing an example of the electrical configuration of an antenna device according to the second embodiment. Note that parts similar to those in the first embodiment are denoted by the same reference numerals, and their detailed descriptions are omitted.

[0127] The antenna device according to the second embodiment includes a reference signal generation unit 30, a first module 10, a second module 20, a third module 60, a signal processing unit 40, and a phase value generation unit 50. The reference signal generation unit 30 supplies the generated reference signal (L-FMCW signal) to the first module 10 and the second module 20, as well as to the third module 60. Hereinafter, the reference signal supplied to the third module 60 will be referred to as the third reference signal.

[0128] The third module 60 includes a D / A converter 61, a third transmitting circuit 62, transmitting antennas Tx9~Tx12, receiving antennas Rx9~Rx12, a third receiving circuit 63, a mixer 64, an A / D converter 65, and a second transmitting processing circuit 52. The processing of the D / A converter 61, the third transmitting circuit 62, transmitting antennas Tx9~Tx12, receiving antennas Rx9~Rx12, the third receiving circuit 63, the mixer 64, and the A / D converter 65 is the same as that of the first module 10 and the second module 20.

[0129] Here, the phase value generation unit 50 generates the amount of phase rotation of the radio waves transmitted by the transmitting antennas Tx5 to Tx8 of the second module 20 (hereinafter referred to as the first phase value) and the amount of phase rotation of the radio waves transmitted by the transmitting antennas Tx9 to Tx12 of the third module 60 (hereinafter referred to as the second phase value).

[0130] More specifically, the phase value generation unit 50 calculates the phase difference φ of the received signals in two adjacent virtual antennas among a plurality of virtual antennas (first virtual array antenna 10a) formed based on the received signals received by the receiving antennas Rx1 to Rx4 of the first module 10 when the transmitting antennas Tx1 to Tx4 of the first module 10 transmit radio waves. The method for determining the phase difference φ is the same as in the first embodiment.

[0131] Furthermore, the phase value generation unit 50 obtains first array processing information corresponding to the second module 20 and second array processing information corresponding to the third module 60 from the signal processing unit 40. The first and second array processing information indicates the number of virtual antennas that overlap. The array processing information is determined by the number of modules to be connected, the number of receiving antennas and transmitting antennas included in the modules, and the arrangement of the receiving antennas and transmitting antennas. For example, the first array processing information corresponding to the l-th module is N × M × (L-1) × (l-1), where L is the number of connected modules, N is the number of transmitting antennas included in one module, and M is the number of receiving antennas included in one module.

[0132] The phase value generation unit 50 generates a first phase value by multiplying the calculated phase difference φ by the acquired first array processing information. The phase value generation unit 50 outputs the generated first phase value to the second module 20. It also generates a second phase value by multiplying the calculated phase difference φ by the acquired second array processing information. The phase value generation unit 50 outputs the generated second phase value to the third module 60. The l-th phase value of the reference signal supplied to the l-th module out of L modules is, for example, N × M × (L-1) × (l-1) × φ.

[0133] The first transmission processing circuit 51 of the second module 20 shifts the phase of the second reference signal supplied from the reference signal generation unit 30 by a first phase value output from the phase value generation unit 50, and outputs it to the second transmission circuit 22 via the D / A converter 21. The transmitting antennas Tx5 to Tx8 transmit radio waves with the phase of the second reference signal shifted by the first phase value. The first transmission processing circuit 51 may also shift the phase of the second reference signal using a phase shifter (not shown) provided between the D / A converter 21 and the second transmission circuit 21, similar to the first embodiment.

[0134] Similarly, the second transmission processing circuit 52 of the third module 60 shifts the phase of the third reference signal supplied from the reference signal generation unit 30 by the second phase value output from the phase value generation unit 50, and outputs it to the third transmission circuit 62 via the D / A converter 61. The transmitting antennas Tx9 to Tx12 transmit radio waves with the phase of the third reference signal shifted by the second phase value. The second transmission processing circuit 52 may also shift the phase of the third reference signal using a phase shifter (not shown) provided between the D / A converter 61 and the third transmission circuit 62, similar to the first embodiment.

[0135] In the second embodiment, three modules were described as being linked together, but four or more modules may be linked together in a similar manner. In this case, when a radio wave is transmitted by the transmitting antenna of the first module, a phase value corresponding to each of the second and subsequent modules is generated based on the phase difference of the received signal received by the receiving antenna of the first module. For example, when L modules are linked together, the phase value corresponding to the l-th module is set to be between 1 and N × M × (L-1) × (l-1) × φ, as the amount of phase shift of the reference signal supplied to the l-th module. Then, based on this phase difference, the phase of the radio wave (reference signal) transmitted by the second and subsequent modules is shifted by the phase value corresponding to that module. This allows for further linking of modules, efficiently expanding the aperture length of the virtual antenna.

[0136] (Second variation) In the second embodiment, both the first and second phase values ​​were generated based on the received signals received by the receiving antennas Rx1 to Rx4 of the first module 10. In the second modified example, the second phase value differs from the second embodiment in that it is generated based on the received signals received by the receiving antennas Rx5 to Rx8 of the second module 20.

[0137] Figure 19 is a block diagram showing an example of the electrical configuration of an antenna device according to a second modified example. Note that parts similar to those in the second embodiment described above are denoted by the same reference numerals, and their detailed descriptions are omitted.

[0138] The antenna device according to the second modified example includes a first phase value generation unit 53 and a second phase value generation unit 54 instead of the phase value generation unit 50 of the second embodiment.

[0139] The first phase value generation unit 53 calculates the first phase difference φ1 between two adjacent virtual antennas among a plurality of virtual antennas (virtual antennas included in the first virtual array antenna 10a) formed based on the received signals received by the receiving antennas Rx1 to Rx4 of the first module 10 when the transmitting antennas Tx1 to Tx4 of the first module 10 transmit radio waves. The first phase value generation unit 53 generates a first phase value based on the calculated first phase difference φ1 and the first array processing information obtained from the signal processing unit 40. The first phase value generation unit 53 outputs the generated first phase value to the second module 20.

[0140] The first transmission processing circuit 51 of the second module 20 shifts the phase of the second reference signal supplied from the reference signal generation unit 30 by the first phase value output from the phase value generation unit 50, and outputs it to the second transmission circuit 22 via the D / A converter 21. The transmitting antennas Tx5 to Tx8 transmit radio waves in which the phase of the second reference signal has been shifted by the first phase value.

[0141] The second phase value generation unit 54 calculates the second phase difference φ2 between two adjacent virtual antennas among a plurality of virtual antennas (a plurality of virtual antennas included in the first virtual array antenna 10b) that are formed based on the received signals received by the receiving antennas Rx5 to Rx8 of the second module 20 when the transmitting antennas Tx1 to Tx4 of the first module 10 transmit radio waves. The second phase value generation unit 54 generates a second phase value based on the calculated second phase difference φ2 and the second array processing information obtained from the signal processing unit 40. The second phase value generation unit 54 outputs the generated second phase value to the third module 60.

[0142] The second transmission processing circuit 52 of the third module 60 shifts the phase of the third reference signal supplied from the reference signal generation unit 30 by the second phase value output from the second phase value generation unit 54, and outputs it to the third transmission circuit 62 via the D / A converter 61. The transmitting antennas Tx9 to Tx12 transmit radio waves in which the phase of the third reference signal has been shifted by the second phase value.

[0143] As described above, in the second modified example, the second phase value output to the third module 60 is generated based on the received signal received by the receiving antennas Rx5 to Rx8 of the second module 20. This allows the received signal received by the receiving antennas Rx5 to Rx8 of the second module 20, which are closer to the third module 60, to be used, thereby improving the accuracy of angle estimation compared to using the received signal received by the receiving antennas Rx1 to Rx4 of the first module 10. The second modified example is effective, for example, when the target is fluctuating (moving).

[0144] (Third embodiment) In the first embodiment, the aperture length of the virtual array antenna was increased by shifting the phase of the transmitted signal (reference signal) when transmitting radio waves. The third embodiment differs from the first embodiment in that, when receiving radio waves, the aperture length of the virtual array antenna is increased by shifting the phase of the received signal.

[0145] Figure 20 is a block diagram showing an example of the electrical configuration of an antenna device according to the third embodiment. Parts similar to those in the first embodiment are denoted by the same reference numerals, and their detailed descriptions are omitted. Furthermore, this description focuses on the case where the first module 10 and the second module 20 are connected and arranged as shown in Figure 2. Additionally, the transmitting antennas Tx1~Tx4 of the first module and the transmitting antennas Tx5~Tx8 of the second module are time-division driven, operating so that the transmitting antennas Tx1~Tx4 of the first module transmit radio waves sequentially, followed by the transmitting antennas Tx5~Tx8 of the second module. As each transmitting antenna Tx1~Tx8 transmits radio waves, all receiving antennas Rx1~Rx8 receive the radio waves reflected from the target.

[0146] The antenna device according to the third embodiment includes a reference signal generation unit 30, a first module 10, a second module 20, a signal processing unit 40, and a phase value generation unit 50.

[0147] The phase value generation unit 50 calculates the phase difference φ of the received signals between two adjacent virtual antennas among a plurality of virtual antennas formed based on the received signals received by the receiving antennas Rx1 to Rx8 when the transmitting antennas Tx1 to Tx4 of the first module 10 transmit radio waves. The phase value generation unit 50 also obtains array processing information from the signal processing unit 40 and generates a phase value by multiplying the phase difference φ by the array processing information. The generation of the phase value is the same as in the first embodiment described above.

[0148] Here, the phase value generation unit 50 outputs the generated phase value to the signal processing unit 40. In other words, in the third embodiment, the second module 20 transmits a transmission signal based on the second reference signal from the transmitting antennas Tx5 to Tx8 without shifting the phase of the second reference signal.

[0149] The receiving antennas Rx1 to Rx8 receive radio waves reflected from the target. The received signals received by the receiving antennas Rx1 to Rx8 are supplied to the signal processing unit 40 via the mixers 14 and 24 and the A / D converters 15 and 25, respectively.

[0150] The signal processing unit 40 includes a receiving processing circuit 55. The receiving processing circuit 55 generates a first filter 56 based on the phase value output from the phase value generation unit 50. The receiving processing circuit 55 inputs the received signals output from the first module 10 and the second module 20 to the first processing circuit 56.

[0151] The first filter 56 shifts the phase of each input received signal by the phase value generated by the phase value generation unit 50. This makes it possible to form 64 non-overlapping virtual antennas, similar to the first embodiment where the phase was shifted during transmission.

[0152] According to the third embodiment, it is not necessary to provide the first transmission processing circuit 51 in the second module 20. Therefore, the configuration of each module can be simplified compared to the first embodiment.

[0153] (Third variation) The third modification describes a configuration in which, when three modules are connected, the phase of the received signal is shifted during radio wave reception.

[0154] Figure 21 shows an example of the electrical configuration of the antenna device according to the third modified example. Components similar to those in the second and third embodiments are denoted by the same reference numerals, and their detailed descriptions are omitted. Furthermore, this explanation focuses on the case where the first module 10, the second module 20, and the third module 60 are connected and arranged as shown in Figure 15.

[0155] The transmitting antennas Tx1-Tx4 of the first module, Tx5-Tx8 of the second module, and Tx9-Tx12 of the third module operate in a time-division multiplex configuration. The first module's transmitting antennas Tx1-Tx4 transmit radio waves sequentially, followed by the second module's transmitting antennas Tx5-Tx8. Then, after the second module's transmitting antennas Tx5-Tx8 transmit radio waves sequentially, the third module's transmitting antennas Tx9-Tx12 transmit radio waves sequentially. Furthermore, when transmitting antenna Tx1 transmits radio waves, all receiving antennas Rx1-Rx12 receive the radio waves reflected from the target. Similarly, when each of the transmitting antennas Tx2-Tx12 transmits radio waves, all receiving antennas Rx1-Rx12 receive the radio waves reflected from the target.

[0156] The antenna device according to the third modified example includes a reference signal generation unit 30, a first module 10, a second module 20, a third module 60, a signal processing unit 40, and a phase value generation unit 50.

[0157] Similar to the second embodiment, the phase value generation unit 50 calculates the phase difference φ of the received signals between two adjacent virtual antennas among a plurality of virtual antennas (first virtual array antennas 10a) formed based on the received signals received by the receiving antennas Rx1 to Rx4 of the first module 10 when the transmitting antennas Tx1 to Tx4 of the first module 10 transmit radio waves. Based on the phase difference φ and the first array processing information corresponding to the second module 20 obtained from the signal processing unit 40, the phase value generation unit 50 generates a first phase value.

[0158] Furthermore, the phase value generation unit 50 generates a second phase value based on the phase difference φ and the second array processing information corresponding to the third module 60 obtained from the signal processing unit 40.

[0159] The phase value generation unit 50 outputs the generated first phase value and second phase value to the signal processing unit 40.

[0160] The receiving processing circuit 55 of the signal processing unit 40 generates a first filter 56 based on a first phase value output from the phase value generation unit 50. The receiving processing circuit 55 inputs the received signals received by the receiving antennas Rx1 to Rx12 of the first module 10, the second module 20, and the third module 60, as radio waves are transmitted by the transmitting antennas Tx5 to Tx8 of the second module 20, to the first filter 56. The first filter 56 shifts the phase of each of the input received signals by the first phase value generated by the phase value generation unit 50.

[0161] As a result, second virtual array antennas 20a, 20b, and 20c are formed that do not overlap in phase with the first virtual array antennas 10a, 10b, and 10c, similar to the case where the phase is shifted during transmission as shown in Figure 17 (second embodiment).

[0162] Furthermore, the receiving processing circuit 55 of the signal processing unit 40 generates a second filter 57 based on the second phase value output from the phase value generation unit 50. The receiving processing circuit 55 inputs the received signals received by the first module 10, the second module 20, and the receiving antennas Rx1 to Rx12 of the third module 60, as radio waves are transmitted by the transmitting antennas Tx9 to Tx12 of the third module 60, into the second filter 57. The second filter 57 shifts the phase of each of the input received signals by the second phase value generated by the phase value generation unit 50.

[0163] As a result, similar to the case where the phase is shifted during transmission as shown in Figure 17 (second embodiment), a third virtual array antenna 60a, 60b, 60c is formed that does not overlap with the first virtual array antennas 10a, 10b, 10c and the second virtual array antennas 20a, 20b, 20c.

[0164] (Fourth variation) In the third modified example, both the first and second phase values ​​were generated based on the received signals received by the receiving antennas Rx1 to Rx4 of the first module 10. In the fourth modified example, the second phase value differs from the third modified example in that it is generated based on the received signals received by the receiving antennas Rx5 to Rx8 of the second module 20.

[0165] Figure 22 is a block diagram showing an example of the electrical configuration of the antenna device according to the fourth modified example. Note that parts similar to those in the second and third modified examples described above are denoted by the same reference numerals, and their detailed explanations are omitted.

[0166] The antenna device according to the fourth modification includes a first phase value generation unit 53 and a second phase value generation unit 54 instead of the phase value generation unit 50 of the third modification.

[0167] The first phase value generation unit 53 calculates the first phase difference φ1 between two adjacent virtual antennas among a plurality of virtual antennas (virtual antennas included in the first virtual array antenna 10a) formed based on the received signals received by the receiving antennas Rx1 to Rx4 of the first module 10 when the transmitting antennas Tx1 to Tx4 of the first module 10 transmit radio waves. The first phase value generation unit 53 generates a first phase value based on the calculated first phase difference φ1 and the first array processing information obtained from the signal processing unit 40. The first phase value generation unit 53 outputs the generated first phase value to the signal processing unit 40.

[0168] Furthermore, the second phase value generation unit 54 calculates the second phase difference φ2 between two adjacent virtual antennas among the multiple virtual antennas (multiple virtual antennas included in the first virtual array antenna 10b) formed based on the received signals received by the receiving antennas Rx5 to Rx8 of the second module 20 when the transmitting antennas Tx1 to Tx4 of the first module 10 transmit radio waves. The second phase value generation unit 54 generates a second phase value based on the calculated second phase difference φ2 and the second array processing information obtained from the signal processing unit 40. The second phase value generation unit 54 generates a second phase value based on the second phase difference φ2 and the second array processing information corresponding to the third module 60 obtained from the signal processing unit 40. The second phase value generation unit 54 outputs the generated second phase value to the signal processing unit 40.

[0169] The processing of the signal processing unit 40 is the same as in the third modified example. That is, the receiving processing circuit 55 of the signal processing unit 40 generates a first filter 56 based on a first phase value. The first filter 56 shifts the phase of each of the received signals received by the receiving antennas Rx1 to Rx12 as radio waves are transmitted by the transmitting antennas Tx5 to Tx8 of the second module 20 by the first phase value.

[0170] Similarly, the receiving processing circuit 55 generates a second filter 57 based on the second phase value. The second filter 57 shifts the phase of each of the received signals received by the receiving antennas Rx1 to Rx12 by the second phase value as radio waves are transmitted by the transmitting antennas Tx9 to Tx12 of the third module 60.

[0171] This allows for the formation of a virtual array antenna where each virtual antenna does not overlap (no overlap occurs), similar to the third modified example.

[0172] Furthermore, in the second embodiment, second modified example, third embodiment, third modified example, and fourth modified example described above, a configuration that intentionally causes overlap may be adopted, as in the first modified example, by setting the phase value corresponding to each module to 1 or more and less than N×M×(L-1)×(l-1)×φ.

[0173] (Examples of application) The antenna device according to the above-described embodiment can be applied to the following electronic device. Figure 23 shows an example of an application of the antenna device according to the above-described embodiment. This electronic device consists of an array antenna 110 positioned opposite a target (e.g., a person) 133, a detection device 100 connected to the array antenna 110, and a display device 120 connected to the detection device 100. The array antenna 110 includes multiple modules (transmitting antennas and receiving antennas) from the above-described embodiment. The size of the array antenna 110 (e.g., the number of modules to be connected) depends on the size of the target 133. Radio waves are radiated from the array antenna 110 in the Z direction perpendicular to the antenna substrate.

[0174] The detection device 100 can obtain an image of the target 133 in a plane 131 that is parallel to the array antenna 110 and is located in the direction of transmission of radio waves transmitted from the array antenna 110. The position of the plane 131 from which the image is obtained depends on the time from transmission to reception of the radio waves. By setting the time from transmission to reception of the radio waves according to the positions of many planes 131 in the three-dimensional space 130 and obtaining images of many different positions on the planes 131, a three-dimensional image of the target 133 can be obtained. One example of the use of this detection device 100 is body checks of users at airports, train stations, etc.

[0175] The detection device 100 includes a transmitter 101 and a receiver 102 connected to each antenna in the array antenna 110. Alternatively, the number of transmitters 101 or receivers 102 may be equal to the number of antennas, and each transmitter 101 or receiver 102 may be connected to a specific antenna. Alternatively, fewer transmitters 101 or receivers 102 may be provided than the number of antennas, and each transmitter 101 or receiver 102 may be connected to multiple antennas via a selector.

[0176] The transmitter 101 and receiver 102 are controlled by the controller 104. The transmitter 101 and receiver 102 are connected to the controller 104 by wire or wireless connection. The controller 104 controls the transmission frequency, bandwidth, and transmission timing for each antenna of the transmitter 101, and controls the reception timing (time from transmission to reception) of the receiver 102 for each antenna. The received signal from one antenna corresponds to the image signal of one pixel of the target 133. The controller 104 sequentially changes the antennas (also called scanning) and changes the reception timing. The reflected waves from the target 133 of the radio waves transmitted from each transmitting antenna are received by the receiving antennas.

[0177] The received signal from the receiver 102 is supplied to the image generation circuit 103, which generates an image signal representing a three-dimensional image of the target 133. The receiver 102 and the image generation circuit 103 are connected by wire or wireless. The image generation circuit 103 is also controlled by the controller 104. The image reconstruction algorithm of the image generation circuit 103 can use time-domain methods, frequency-domain methods, or any other arbitrary algorithm.

[0178] The image signal generated by the image generation circuit 103 is supplied to the display device 120 and displayed. By observing this image, it is possible to detect whether the target 133 is possessing a dangerous object (e.g., a gun) 132. The image generation circuit 103 and the display device 120 are also connected by wire or wireless.

[0179] According to at least one embodiment described above, it is possible to provide an antenna device and control method that can adjust, according to the purpose, the improvement of the spatial resolution of the virtual array antenna and the improvement of the accuracy of the target direction estimation of the virtual array antenna.

[0180] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims and their equivalents. [Explanation of Symbols]

[0181] 10...First module, 20...Second module, 30...Reference signal generation unit, 40...Signal processing unit, 50...Phase value generation unit, 53...First phase value generation unit, 54...Second phase value generation unit, 51...First transmission processing circuit, 52...Second transmission processing circuit, 55...Receiving processing circuit, 56...First filter, 57...Second filter, 60...Third module, Tx1~Tx12...Transmitting antennas, Rx1~Rx12...Receiving antennas, r1~r64...Virtual antennas, dt...First interval, dr...Second interval.

Claims

1. Reference signal generation unit, A first module that is supplied with a first reference signal from the reference signal generation unit, A second module is supplied with a second reference signal from the reference signal generation unit, Phase value generation unit, It is equipped with, The first module includes a first number of first transmitting antennas arranged in a first direction at first intervals, and a second number of first receiving antennas arranged in the first direction at second intervals. The second module includes a third number of second transmitting antennas arranged in the first direction at the first interval, a fourth number of second receiving antennas arranged in the first direction at the second interval, and a first transmission processing circuit. The distance between the receiving antenna closest to the second module among the first receiving antennas and the receiving antenna closest to the first module among the second receiving antennas is the second distance. The phase value generation unit generates a first phase value based on the phase difference of the received signals in at least two virtual antennas, which are formed based on the received signals received by at least a portion of the first receiving antenna and the second receiving antenna when the first transmitting antenna transmits a transmission signal based on the first reference signal. The first transmission processing circuit shifts the phase of the second reference signal transmitted by the second transmitting antenna after the first transmitting antenna by the first transmitting antenna by the first phase value. Antenna device.

2. The first phase value is a positive value. The antenna device according to claim 1.

3. The first phase value is a positive integer multiple of the phase difference. The antenna device according to claim 1.

4. The system has L modules (where L is 2 or more), including the first module and the second module. Each of the L modules includes N transmitting antennas arranged in the first direction at first intervals and M receiving antennas arranged in the first direction at second intervals. When the phase difference is φ, The first phase value is the amount of phase shift of the reference signal supplied to the l-th module among the L modules, and is between 1 and N × M × (L-1) × (l-1) × φ. The antenna device according to claim 3.

5. The system further comprises a third module that is supplied with a third reference signal from the reference signal generation unit, The third module includes a fifth number of third transmitting antennas arranged in the first direction at first intervals, a sixth number of third receiving antennas arranged in the first direction at second intervals, and a second transmitting processing circuit. The distance between the second receiving antenna closest to the third module and the third receiving antenna closest to the second module is the second distance. The phase value generation unit further generates a second phase value different from the first phase value based on the phase difference. The second transmission processing circuit shifts the phase of the third reference signal transmitted by the third transmitting antenna after the second transmitting antenna by the second phase value. The antenna device according to claim 1.

6. The system has L modules (where L is 3 or more), including the first module, the second module, and the third module. Each of the L modules includes N transmitting antennas arranged in the first direction at first intervals and M receiving antennas arranged in the first direction at second intervals. When the phase difference is φ, The first phase value and the second phase value are, respectively, the amount of phase shift of the reference signal supplied to the l-th module among the L modules, and are between 1 and N × M × (L-1) × (l-1) × φ. The antenna device according to claim 5.

7. Reference signal generation unit, A first module that is supplied with a first reference signal from the reference signal generation unit, A second module is supplied with a second reference signal from the reference signal generation unit, Receiving processing circuit and Phase value generation unit, It is equipped with, The first module comprises a first number of first transmitting antennas arranged in a first direction at first intervals, and a second number of first receiving antennas arranged in the first direction at second intervals. The second module comprises a third number of second transmitting antennas arranged in the first direction at the first interval, and a fourth number of second receiving antennas arranged in the first direction at the second interval, The distance between the receiving antenna closest to the second module among the first receiving antennas and the receiving antenna closest to the first module among the second receiving antennas is the second distance. The phase value generation unit generates a first phase value based on the phase difference of the received signals in at least two virtual antennas, which are formed based on the received signals received by at least a portion of the first receiving antenna and the second receiving antenna when the first transmitting antenna transmits a transmission signal based on the first reference signal. The receiving processing circuit shifts the phase of the received signals received by the first receiving antenna and the second receiving antenna by the first phase value, by having the second transmitting antenna transmit a transmission signal based on the second reference signal following the first transmitting antenna. Antenna device.

8. The system further comprises a third module that is supplied with a third reference signal from the reference signal generation unit, The third module comprises a fifth number of third transmitting antennas arranged in the first direction at a first interval, and a sixth number of third receiving antennas arranged in the first direction at a second interval. The distance between the second receiving antenna closest to the third module and the third receiving antenna closest to the second module is the second distance. The phase value generation unit further generates a second phase value different from the first phase value based on the phase difference. The receiving processing circuit, when the third transmitting antenna transmits a transmission signal based on the third reference signal following the second transmitting antenna, shifts the phases of the received signals of the first receiving antenna, the second receiving antenna, and the third receiving antenna by the second phase value. The antenna device according to claim 7.

9. The first phase value is generated based on the phase difference of the received signals in at least two virtual antennas, which are formed based on the received signal received by at least a portion of the first receiving antenna among the plurality of virtual antennas. The second phase value is generated based on the phase difference of the received signals in at least two virtual antennas, which are formed based on the received signal received by at least a portion of the second receiving antenna among the plurality of virtual antennas. The antenna device according to claim 5 or claim 8.

10. A control method for controlling an antenna device comprising a reference signal generation unit, a first module supplied with a first reference signal from the reference signal generation unit, a second module supplied with a second reference signal from the reference signal generation unit, and a phase value generation unit, The first module includes a first number of first transmitting antennas arranged in a first direction at first intervals, and a second number of first receiving antennas arranged in the first direction at second intervals. The second module includes a third number of second transmitting antennas arranged in the first direction at the first interval, a fourth number of second receiving antennas arranged in the first direction at the second interval, and a first transmission processing circuit. The distance between the receiving antenna closest to the second module among the first receiving antennas and the receiving antenna closest to the first module among the second receiving antennas is the second distance. The phase value generation unit generates a first phase value based on the phase difference of the received signals in at least two virtual antennas, which are formed based on the received signals received by at least a portion of the first receiving antenna and the second receiving antenna when the first transmitting antenna transmits a transmission signal based on the first reference signal. The first transmission processing circuit shifts the phase of the second reference signal transmitted by the second transmitting antenna after the first transmitting antenna by the first phase value. Control method.

11. A control method for controlling an antenna device comprising a reference signal generation unit, a first module supplied with a first reference signal from the reference signal generation unit, a second module supplied with a second reference signal from the reference signal generation unit, a receiving processing circuit, and a phase value generation unit, The first module comprises a first number of first transmitting antennas arranged in a first direction at first intervals, and a second number of first receiving antennas arranged in the first direction at second intervals. The second module comprises a third number of second transmitting antennas arranged in the first direction at the first interval, and a fourth number of second receiving antennas arranged in the first direction at the second interval, The distance between the receiving antenna closest to the second module among the first receiving antennas and the receiving antenna closest to the first module among the second receiving antennas is the second distance. The phase value generation unit generates a first phase value based on the phase difference of the received signals in at least two virtual antennas, which are formed based on the received signals received by at least a portion of the first receiving antenna and the second receiving antenna when the first transmitting antenna transmits a transmission signal based on the first reference signal. The receiving processing circuit causes the second transmitting antenna to transmit a transmission signal based on the second reference signal following the first transmitting antenna, thereby shifting the phase of the received signals received by the first receiving antenna and the second receiving antenna by the first phase value. Control method.

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