Circularly polarized array antenna device

Abstract

The antenna device (120) is formed by arranging a plurality of radiating elements, each radiating circularly polarized waves, in a grid pattern of 3 rows and 10 columns. The plurality of radiating elements include four types of radiating elements (121a to 121d) that are rotationally symmetrical with each other. The plurality of radiating elements include: a first element group (U1) arranged in a grid pattern of 3 rows and 3 columns on one end side; and a second element group (U2) arranged in a grid pattern of 3 rows and 3 columns on the other end side. The first central element arranged in the center of the first element group (U1) is an element of a type obtained by rotating the second central element arranged in the center of the second element group (U2) by 180 degrees.

Description

Technical Field

[0001] The present disclosure relates to a circularly polarized array antenna device. Background Art

[0002] Circularly polarized array antennas are achieved by closely arranging multiple radiating elements, each radiating circularly polarized waves. While the magnitude of the rotating electric field of an ideal circularly polarized wave is constant, in reality, the magnitude of the rotating electric field is not constant and may deform into an elliptical shape. The ratio of the minor axis to the major axis of the ellipse of a circularly polarized wave is called the "axial ratio." To achieve ideal circularly polarized waves, it is necessary to improve the axial ratio characteristics.

[0003] A technique for improving the axial ratio characteristics of circularly polarized array antennas is called a sequential array. In a sequential array, multiple circularly polarized radiating elements are arranged at arbitrary angles. This arrangement is known to improve the axial ratio characteristics of the circularly polarized array antenna as a whole, even when the axial ratio characteristics of individual radiating elements are poor.

[0004] Japanese Patent Application Laid-Open No. 6-140835 discloses a circularly polarized array antenna device comprising a plurality of circularly polarized radiating elements arranged in a grid pattern. In this circularly polarized array antenna, 16 circularly polarized radiating elements are sequentially arranged in a grid pattern of four rows and four columns (even-numbered rows and even-numbered columns), with adjacent radiating elements positioned so that they are rotated by a predetermined angle and parallel to each other.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 6-140835 Summary of the Invention

[0008] Problems to be solved by the invention

[0009] When arranging a plurality of circularly polarized radiating elements in a grid pattern, the axial ratio characteristics can be more effectively improved if they are arranged in a grid pattern with an even number of rows and an even number of columns, as in the circularly polarized array antenna disclosed in Japanese Patent Application Laid-Open No. 6-140835.

[0010] However, in some cases where circularly polarized array antennas are installed, the size of the circularly polarized array antenna is limited, and the number of rows arranged may have to be an odd number rather than an even number (i.e., the number of radiating elements in a column has to be an odd number). In this case, it becomes difficult to envision improving the axial ratio characteristics.

[0011] The present disclosure is made to solve such problems, and its purpose is to easily improve the axial ratio characteristics in a circularly polarized array antenna device in which multiple radiating elements each capable of radiating circularly polarized waves are arranged in a grid pattern, even when the number of arranged rows is an odd number.

[0012] Solutions for solving problems

[0013] The circularly polarized array antenna device disclosed in the present invention is a circularly polarized array antenna device formed by arranging a plurality of elements that can radiate circularly polarized waves in a grid shape. When an odd number greater than 3 is set to N and an odd number greater than 1 is set to M, the plurality of elements include: a first element group, which is arranged in a grid shape of N rows and M columns on one end side of the area where the plurality of elements are arranged; and a second element group, which is arranged in a grid shape of N rows and M columns on the other end side of the area where the plurality of elements are arranged. The plurality of elements include a plurality of elements that are in a rotationally symmetric positional relationship with each other. The first central element arranged in the center of the first element group is an element of the type obtained by rotating the second central element arranged in the center of the second element group by 180 degrees.

[0014] In the above-described element unit, the first central element, located at the center of the first element group (arranged in a grid pattern with N rows and M columns (odd rows and odd columns) at one end), and the second central element, located at the center of the second element group (arranged in a grid pattern with N rows and M columns (odd rows and odd columns) at the other end), are radiating elements rotated 180 degrees relative to each other. This allows the directional distortions in the first and second central elements to cancel each other out. As a result, the first and second element groups, as a pair, can be arranged nearly sequentially. This facilitates improved axial ratio characteristics even when the number of rows is odd.

[0015] Effects of the Invention

[0016] According to the present disclosure, in a circularly polarized array antenna apparatus in which a plurality of radiating elements each capable of radiating circularly polarized waves are arranged in a lattice pattern, the axial ratio characteristic can be easily improved even when the number of rows of the arrangement is an odd number. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is an example of a block diagram of a communication device to which an antenna device is applied.

[0018] Figure 2 This is a perspective view of the inside of the communication device.

[0019] Figure 3 This is a diagram showing the arrangement of multiple radiating elements of an antenna device.

[0020] Figure 4This is a partially enlarged view showing the arrangement of the radiation elements of the third element group arranged in the central portion of the antenna device.

[0021] Figure 5 This is a partially enlarged view showing the arrangement of the radiation elements of the first element group and the second element group, which are respectively arranged at the left end portion and the right end portion of the antenna device.

[0022] Figure 6 This is a partially enlarged view showing the arrangement of the radiation elements of the first element group at the left end portion and the second element group at the right end portion of the antenna device according to the first modification. DETAILED DESCRIPTION

[0023] Hereinafter, the embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and their description will not be repeated.

[0024] (Basic Structure of Communication Device)

[0025] Figure 1 This is an example of a block diagram of a communication device 10 employing the antenna device 120 of this embodiment. The communication device 10 is configured to transmit circularly polarized waves from the antenna device 120. For example, the communication device 10 may be a terminal that transmits data to a wearable terminal (such as a head-mounted display) whose relative position to the communication device 10 can be changed. Furthermore, the communication device 10 may be a communication terminal compliant with "WiGig," a wireless communication standard primarily using the 60 GHz frequency band.

[0026] Communication device 10 includes an antenna module 100 including an antenna device 120 and a BBIC 200 constituting a baseband signal processing circuit. In addition to antenna device 120, antenna module 100 also includes an RFIC 110, which serves as an example of a power supply component. Communication device 10 up-converts signals transmitted from BBIC 200 to antenna module 100 into high-frequency signals, which are then radiated from antenna device 120. It also down-converts high-frequency signals received by antenna device 120 and processes the signals using BBIC 200.

[0027] The antenna device 120 includes a plurality of radiating elements 121 each configured to radiate a circularly polarized wave. Figure 1 For ease of explanation, only the structures corresponding to four of the multiple radiating elements 121 included in antenna device 120 are shown, and the structures corresponding to other radiating elements 121 having the same structure are omitted. In this embodiment, radiating element 121 is a patch antenna having a substantially square flat plate shape.

[0028] RFIC 110 includes switches 111A to 111D, 113A to 113D, and 117 , power amplifiers 112AT to 112DT, low-noise amplifiers 112AR to 112DR, attenuators 114A to 114D, phase shifters 115A to 115D, a signal combiner / demultiplexer 116 , a mixer 118 , and an amplifier circuit 119 .

[0029] When transmitting a high-frequency signal, switches 111A to 111D and 113A to 113D are switched toward power amplifiers 112AT to 112DT, and switch 117 is connected to the transmitting-side amplifier of amplifier circuit 119. When receiving a high-frequency signal, switches 111A to 111D and 113A to 113D are switched toward low-noise amplifiers 112AR to 112DR, and switch 117 is connected to the receiving-side amplifier of amplifier circuit 119.

[0030] The signal transmitted from BBIC 200 is amplified by amplifier circuit 119 and up-converted by mixer 118. The high-frequency signal obtained by up-conversion, i.e., the transmission signal, is demultiplexed into four signals by signal combiner / demultiplexer 116. These signals are then supplied to different radiating elements 121 via four signal paths. By adjusting the phase shifting degrees of phase shifters 115A to 115D arranged in each signal path, circularly polarized waves with the same phase are radiated from antenna device 120.

[0031] The high-frequency signals received by each radiating element 121 are respectively combined by the signal combiner / demultiplexer 116 via four different signal paths. The combined received signals are down-converted by the mixer 118, amplified by the amplifier circuit 119, and transmitted to the BBIC 200.

[0032] RFIC 110 is formed, for example, as a single-chip integrated circuit component including the aforementioned circuit structure. Alternatively, the devices corresponding to each radiating element 121 in RFIC 110 (switch, power amplifier, low-noise amplifier, attenuator, phase shifter) may be formed as a single-chip integrated circuit component for each corresponding radiating element 121.

[0033] (Configuration of antenna device and radiating element)

[0034] Figure 2 This is a perspective view showing the interior of the communication device 10. The communication device 10 is covered by a housing 11. The housing 11 houses an antenna device 120, an RFIC 110, a mounting substrate 20, and the like.

[0035] The antenna device 120 includes a plate-shaped dielectric substrate 131 having a multilayer structure and a plurality of radiating elements 121 arranged inside the dielectric substrate 131. The dielectric substrate 131 is arranged on the side surface 22 of the mounting substrate 20 via the RFIC 110. Figure 2 As shown, the normal direction of the side surface 22 of the mounting substrate 20 is also called the "Z-axis direction", the normal direction of the main surface 21 of the mounting substrate 20 is also called the "X-axis direction", and the direction perpendicular to the Z-axis direction and the X-axis direction is also called the "Y-axis direction".

[0036] An antenna layer is provided on dielectric substrate 131. This antenna layer has an arrangement region where multiple radiating elements 121 are arranged. Within this arrangement region, multiple radiating elements 121 are arranged in a grid pattern along the X-axis and Y-axis directions. Specifically, 30 radiating elements 121 are arranged in a grid pattern of 3 rows and 10 columns, with the X-axis direction forming "rows" and the Y-axis direction forming "columns."

[0037] Generally, when arranging a plurality of circularly polarized radiating elements in a grid pattern, arranging them in a grid pattern with an even number of rows and an even number of columns, as in the circularly polarized array antenna disclosed in Japanese Patent Application Laid-Open No. 6-140835, can more effectively improve the axial ratio characteristics.

[0038] However, in the antenna device 120 of this embodiment, the length of the dielectric substrate 131 in the X-axis direction is restricted by the thickness (X-axis length) T of the housing 11. Due to this constraint, the number of rows in which the multiple radiating elements 121 are arranged in the antenna device 120 of this embodiment is three (odd rows). Therefore, without any countermeasures, it may be difficult to improve the axial ratio characteristics compared to a case where the multiple radiating elements 121 are arranged in a grid pattern with an even number of rows and columns.

[0039] Therefore, in the antenna device 120 of the present embodiment, by arranging the plurality of radiating elements 121 as follows, the axial ratio characteristics can be easily improved even when the number of rows in which the plurality of radiating elements 121 are arranged is three (odd-numbered rows).

[0040] Figure 3 This diagram illustrates the arrangement of multiple radiating elements 121 in antenna device 120 according to this embodiment. In this embodiment, as described above, 30 radiating elements 121 are arranged in a grid pattern of 3 rows and 10 columns. Each radiating element 121 has two feed points. For example, two high-frequency signals with a relative phase difference of 90° are supplied to the two feed points of each radiating element 121 from a hybrid circuit (not shown). Consequently, circularly polarized waves are radiated from each radiating element 121.

[0041] The 30 radiating elements 121 include a plurality of four types of radiating elements, namely, first type radiating element 121a, second type radiating element 121b, third type radiating element 121c, and fourth type radiating element 121d, which are positioned in a rotationally symmetrical relationship with each other.

[0042] The first-type radiating element 121a has a feed point located on the negative side of the Y axis relative to the plane center, and a feed point located on the positive side of the X axis relative to the plane center. The second-type radiating element 121b is a radiating element obtained by rotating the first-type radiating element 121a 90 degrees clockwise and translating it. The third-type radiating element 121c is a radiating element obtained by rotating the first-type radiating element 121a 270 degrees clockwise and translating it. The fourth-type radiating element 121d is a radiating element obtained by rotating the first-type radiating element 121a 180 degrees clockwise with the plane center as the rotation axis and translating it.

[0043] Furthermore, if the rotational position (rotation angle) of the first-type radiating element 121a is represented as the "reference (0 degrees)", the clockwise rotational position of each radiating element 121 is represented as "90 degrees", the rotational position of the second-type radiating element 121b is represented as "270 degrees", and the rotational position of the fourth-type radiating element 121d is represented as "180 degrees". In view of this, if the phase of the signal supplied to the first-type radiating element 121a is represented as the "reference phase", the phase shift degrees of the phase shifters 115A to 115D are adjusted so that the phase of the signal supplied to the second-type radiating element 121b is "reference phase - 90 degrees", the phase of the signal supplied to the third-type radiating element 121c is "reference phase - 270 degrees", and the phase of the signal supplied to the fourth-type radiating element 121d is "reference phase - 180 degrees". As a result, circularly polarized waves of the same phase are radiated from the respective radiating elements 121 of the antenna device 120 .

[0044] Hereinafter, the nine radiating elements 121 arranged from the first to the third columns on the left end of the 30 radiating elements 121 will also be referred to as "first element group U1," the nine radiating elements 121 arranged from the eighth to the tenth columns on the right end will also be referred to as "second element group U2," and the twelve radiating elements 121 arranged from the fourth to the seventh columns in the center will also be referred to as "third element group U3." Hereinafter, any integer between 1 and 3 will be referred to as n, any integer between 1 and 4 will be referred to as m, and the grid position in the nth row and mth column will be referred to as (n×m).

[0045] Figure 4This is a partially enlarged view showing the arrangement of the radiating elements 121 of the third element group U3 disposed in the central portion of the antenna device 120. The 12 radiating elements 121 included in the third element group U3 include three each of four types of radiating elements 121a to 121d.

[0046] The first-type radiating elements 121a are arranged in the (1×1), (2×3), and (3×1) arrays of the third element group U3. The second-type radiating elements 121b are arranged in the (1×2), (2×4), and (3×2) arrays of the third element group U3. The third-type radiating elements 121c are arranged in the (1×3), (2×1), and (3×3) arrays of the third element group U3. The fourth-type radiating elements 121d are arranged in the (1×4), (2×2), and (3×4) arrays of the third element group U3. Furthermore, the first to fourth columns of the third element group U3 are the fourth to seventh columns of the antenna device 120 as a whole, respectively.

[0047] This arrangement allows any radiating element 121 in the third element group U3 to be arranged in a different type from any radiating element 121 arranged vertically, horizontally, or diagonally around it. Consequently, in the third element group U3, the four types of radiating elements 121a through 121d are arranged evenly in the same number (three each) to achieve overall balance. As a result, the axial ratio characteristics can be easily improved.

[0048] However, both the first element group U1 on the left and the second element group U2 on the right are arranged in a grid pattern of three rows and three columns (odd rows and odd columns), and include nine (an odd number) radiating elements 121. Therefore, unlike the third element group U3, the first and second element groups U1 and U2 cannot evenly arrange the four types of radiating elements 121a to 121d in equal numbers, resulting in sections where radiating elements of the same type are adjacent to each other. Consequently, the first and second element groups U1 and U2 cannot each achieve the same sequential arrangement as the third element group U3.

[0049] Therefore, in this embodiment, the first element group U1 at the left end and the second element group U2 at the right end are considered a pair of element groups, and the central radiating elements 121 of the first and second element groups U1 and U2 are rotated 180 degrees relative to each other. In other words, the radiating element 121 arranged at the center of the first element group U1 (hereinafter referred to as the "first central element") is a type of radiating element 121 obtained by rotating the central radiating element 121 of the second element group U2 (hereinafter referred to as the "second central element") by 180 degrees. This allows the same number (two) of four different radiating elements 121a to 121d to be arranged at positions other than the center in each of the first and second element groups U1 and U2, and allows the directional distortion of the first and second central elements to be mutually offset. As a result, the entire pair of element groups, the first and second element groups U1 and U2, can be arranged in a nearly sequential arrangement, thereby improving the axial ratio characteristics.

[0050] Figure 5 It is a partially enlarged view showing the arrangement of the radiation elements 121 of the first element group U1 and the second element group U2 respectively arranged at the left end portion and the right end portion of the antenna device 120 .

[0051] The first-type radiating element 121a is arranged in the (1×1) and (3×3) pairs of the first element group U1. The second-type radiating element 121b is arranged in the (1×2) and (3×2) pairs of the first element group U1. The third-type radiating element 121c is arranged in the (2×1) and (2×3) pairs of the first element group U1. The fourth-type radiating element 121d is arranged in the (1×3) and (3×1) pairs of the first element group U1.

[0052] Similarly, the first-type radiating element 121a is arranged in the (1×1) and (3×3) pairs of the second element group U2. The second-type radiating element 121b is arranged in the (1×2) and (3×2) pairs of the second element group U2. The third-type radiating element 121c is arranged in the (2×1) and (2×3) pairs of the second element group U2. The fourth-type radiating element 121d is arranged in the (1×3) and (3×1) pairs of the second element group U2. Furthermore, the first to third rows of the second element group U2 are the eighth to tenth rows of the antenna device 120 as a whole, respectively.

[0053] With this arrangement, in each of the first element group U1 and the second element group U2 , the same number (two) of four types of radiating elements 121 a to 121 d are arranged at positions other than the center (2×2), and adjacent radiating elements are of different types.

[0054] Furthermore, a second-type radiating element 121b is arranged as the first central element in the center (2×2) of the first element group U1. A third-type radiating element 121c is arranged as the second central element in the center (2×2) of the second element group U2. This third-type radiating element 121c is a radiating element obtained by rotating the second-type radiating element 121b, which served as the first central element, 180 degrees. This arrangement makes the first central element the same type as the second-type radiating element 121b located vertically adjacent to it within the first element group U1, and the second central element the same type as the third-type radiating element 121c located horizontally adjacent to it within the second element group U2. However, since the first and second central elements are radiating elements 121 that are rotated 180 degrees relative to each other, the directional distortion in the first and second central elements can be offset. As a result, the first and second element groups U1 and U2 can be arranged in a nearly sequential manner, improving the axial ratio characteristics.

[0055] As described above, the antenna device 120 of this embodiment is formed by arranging a plurality of radiating elements 121 each radiating circularly polarized waves in a lattice pattern of 3 rows and 10 columns. The plurality of radiating elements 121 include four types of radiating elements 121a to 121d that are rotationally symmetrical with each other.

[0056] The plurality of radiation elements 121 include: a first element group U1, which is arranged in a grid pattern of 3 rows and 3 columns on one end side; a second element group U2, which is arranged in a grid pattern of 3 rows and 3 columns on the other end side; and a third element group U3, which is arranged in a grid pattern of 3 rows and 4 columns in the central portion between the first element group U1 and the second element group U2.

[0057] In the third element group U3 in the center, the four types of radiating elements 121a to 121d are arranged in equal numbers (three each) in order. This ensures overall balance in the third element group U3 and facilitates improvement in axial ratio characteristics.

[0058] On the other hand, in the first and second element groups U1 and U2, since they are not arranged sequentially in isolation, the first and second element groups U1 and U2 are considered a pair of element groups, with the first and second central elements being radiating elements 121 rotated 180 degrees relative to each other. This allows the same number (two) of four radiating elements 121a to 121d to be arranged at positions other than the center in each of the first and second element groups U1 and U2, and allows the directional distortion of the first and second central elements to be mutually offset. As a result, the first and second element groups U1 and U2 can be arranged nearly sequentially as a pair, improving the axial ratio characteristics.

[0059] As a result, in the antenna device 120 in which the plurality of radiating elements 121 each capable of radiating circularly polarized waves are arranged in a lattice pattern, the axial ratio characteristic can be easily improved even if the number of rows of the arrangement is three (an odd number).

[0060] The "antenna device 120" and "plurality of radiating elements 121" of this embodiment can correspond to the "circularly polarized array antenna device" and "plurality of elements," respectively, of the present disclosure. Furthermore, the "first element group U1," "second element group U2," and "third element group U3" of this embodiment can correspond to the "first element group," "second element group," and "third element group," respectively, of the present disclosure. Furthermore, the "second type radiating element 121b" arranged in the center (2x2) of the first element group U1 and the "third type radiating element 121c" arranged in the center (2x2) of the second element group U2 of this embodiment can correspond to the "first central element" and "second central element," respectively, of the present disclosure. In addition, the "first type radiating element 121a", "second type radiating element 121b", "third type radiating element 121c" and "fourth type radiating element 121d" of this embodiment can respectively correspond to the "first type element", "second type element", "third type element" and "fourth type element" of the present disclosure.

[0061] <Variation 1>

[0062] In the above embodiment, an example was described in which the first element group U1 and the second element group U2 were each arranged in a grid pattern of three rows and three columns. However, when N is an odd number greater than or equal to 3 and M is an odd number greater than or equal to 1, the first element group U1 and the second element group U2 may be arranged in a grid pattern of N rows and M columns, and are not necessarily limited to three rows and three columns.

[0063] Figure 6 This is a partially enlarged view showing the arrangement of the radiation elements 121 of the first element group U1A at the left end portion and the second element group U2A at the right end portion of the antenna device 120A according to the first modification.

[0064] The first element group U1A and the second element group U2A are arranged in a grid pattern of three rows and one column. The third type radiating element 121c is arranged in the (1×1) grid of the first element group U1A. The fourth type radiating element 121d is arranged in the (3×1) grid of the first element group U1A. The first type radiating element 121a is arranged in the (1×1) grid of the second element group U2A. The second type radiating element 121b is arranged in the (3×1) grid of the second element group U2A. With this arrangement, the four types of radiating elements 121a to 121d are arranged in equal numbers (one each) at each of the four corners of the first and second element groups U1 and U2.

[0065] Furthermore, a second-type radiating element 121b is arranged as the first central element in the center (2×1) of the first element group U1A. A third-type radiating element 121c is arranged as the second central element in the center (2×1) of the second element group U2A. This third-type radiating element 121c is a radiating element obtained by rotating the second-type radiating element 121b, which served as the first central element, 180 degrees. This arrangement allows the first and second central elements to cancel out directional distortion. As a result, the first and second element groups U1 and U2 can be arranged in a nearly sequential arrangement, improving axial ratio characteristics.

[0066] The “first element group U1A” and the “second element group U2A” of the present modification example 1 can correspond to the “first element group” and the “second element group” of the present disclosure, respectively.

[0067] <Variation 2>

[0068] In the above-mentioned embodiment, an example is described in which the third element group U3 is arranged in a grid pattern of 3 rows and 4 columns between the first element group U1 and the second element group U2. However, the third element group U3 may be arranged in a grid pattern of odd rows and even columns, and the number of rows and columns of the third element group U3 is not necessarily limited to the above-mentioned "3 rows" and "4 columns".

[0069] Alternatively, the third element group U3 may not be included, and only the first element group U1 and the second element group U2 may be included.

[0070] <Variation 3>

[0071] In the above embodiment, the two-point feeding type radiating element 121 is described as a circularly polarized radiating element. However, a degenerate single-point feeding type radiating element may be used by making the shape of the radiating element asymmetrical.

[0072] <Variation 4>

[0073] In the above embodiment, the radiating element 121 is described as an example of a patch antenna. However, the radiating element 121 is not limited to a patch antenna and can be any antenna capable of radiating circularly polarized waves. For example, the radiating element 121 may be a slot antenna.

[0074] The embodiments disclosed herein are to be considered in all respects as illustrative and non-restrictive. The scope of the present disclosure is indicated by the claims rather than the description of the embodiments above, and is intended to encompass all modifications within the meaning and scope equivalent to the claims.

[0075] Description of Reference Numerals

[0076] 10. Communication device; 11. Housing; 20. Mounting substrate; 21. Main surface; 22. Side surface; 100. Antenna module; 111A to 111D, 113A to 113D, 117. Switch; 112AR to 112DR, Low-noise amplifier; 112AT to 112DT, Power amplifier; 114A to 114D, Attenuator; 115A to 115D, Phase shifter; 116, Signal combiner / demultiplexer; 118, Mixer; 119, Amplifier circuit; 120, 120A, Antenna device; 121. Radiating element; 121a, First type radiating element; 121b, Second type radiating element; 121c, Third type radiating element; 121d, Fourth type radiating element; 131, Dielectric substrate; U1, U1A, First element group; U2A, U2, Second element group; U3, Third element group.

Claims

1. A circularly polarized array antenna device, wherein: The circularly polarized array antenna device is formed by arranging a plurality of elements capable of radiating circularly polarized waves in a grid pattern. When N is an odd number greater than or equal to 3 and M is an odd number greater than or equal to 1, The plurality of elements include: a first element group arranged in a grid pattern of N rows and M columns on one end side of the region where the plurality of elements are arranged; and The second element group is arranged in a grid pattern of N rows and M columns on the other end side of the region where the plurality of elements are arranged, The plurality of elements include a plurality of elements that are in a rotationally symmetrical positional relationship with each other. The first central element arranged at the center of the first element group is an element obtained by rotating the second central element arranged at the center of the second element group by 180 degrees. The first central element and the second central element can cancel each other's directional distortion.

2. The circularly polarized array antenna device according to claim 1, wherein: The plurality of elements include 4 types of elements, The four elements include a first element, a second element obtained by rotating the first element 90 degrees in a predetermined direction, a third element obtained by rotating the first element 270 degrees in the predetermined direction, and a fourth element obtained by rotating the first element 180 degrees in the predetermined direction.

3. The circularly polarized array antenna device according to claim 2, wherein: The first element group and the second element group are arranged in a grid shape of 3 rows and 3 columns respectively. At positions other than the center of the first element group, two of each of the four elements are arranged. At positions other than the center of the second element group, two of each of the four elements are arranged. The first central element disposed at the center of the first element group is any one of the four types of elements. The second central element disposed at the center of the second element group is an element of a type obtained by rotating the first central element by 180 degrees.

4. The circularly polarized array antenna device according to claim 2, wherein: The first element group and the second element group are arranged in a grid pattern of 3 rows and 1 column, respectively. Different types of elements are arranged at positions other than the center of the first element group and at positions other than the center of the second element group, respectively. The first central element disposed at the center of the first element group is any one of the four types of elements. The second central element disposed at the center of the second element group is an element of a type obtained by rotating the first central element by 180 degrees.

5. The circularly polarized array antenna device according to any one of claims 1 to 4, wherein: The circularly polarized array antenna device further includes a third element group, which is disposed between the first element group and the second element group and arranged in a lattice shape.

6. The circularly polarized array antenna device according to any one of claims 2 to 4, wherein: The circularly polarized array antenna device further includes a third element group, which is arranged between the first element group and the second element group and is arranged in a grid pattern of 3 rows and 4 columns. When n is an integer from 1 to 3, m is an integer from 1 to 4, and the grid position at the nth row and the mth column is expressed as (n×m), The first type of elements are arranged at (1×1), (2×3), and (3×1) of the third element group, the second type of elements are arranged at (1×2), (2×4), and (3×2) of the third element group, the third type of elements are arranged at (1×3), (2×1), and (3×3) of the third element group, and the fourth type of elements are arranged at (1×4), (2×2), and (3×4) of the third element group.

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