Reflectarray and manufacturing method thereof

Abstract

To provide a reflect array that constructs an antenna on the reflect array in which the incident angle of the reflect array and the direction of the maximum directivity point are matched, and makes it easier to adjust the direction of the reflect array.SOLUTION: A reflect array has a metamaterial reflector and an auxiliary antenna. The positional relationship between the metamaterial reflector and the auxiliary antenna is fixed. The maximum directivity direction of the metamaterial reflector and the design incident direction and design reflection direction of the auxiliary antenna are substantially the same.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a reflectarray, and more particularly to a reflectarray that configures an antenna in which the angle of incidence of a reflector coincides with the direction of the maximum point of directivity, thereby facilitating adjustment of the direction of the reflector of the reflector, and a manufacturing method thereof. [Background technology]

[0002] Reflectarrays are used in a variety of applications in communications. For example, base stations use base station antennas to send and receive radio waves to and from communication terminals such as mobile phones. As frequencies increase in 5G standards, the directionality of radio waves increases, and communication can become difficult if there are obstructions. Even in such cases, by using a reflectarray that uses metamaterials or the like to change the direction of radio waves, it becomes easier to send and receive communication radio waves to and from communication terminals that are located in places that are not directly visible from the base station. FIG. 1 shows an example in which a Massive MIMO base station antenna 2 and a reflectarray 100 that is a metamaterial reflector 110 are used, and FIG. 2 shows the reflectarray 100 that is a metamaterial reflector 110. Communication radio waves incident from the base station antenna 2 at a predetermined incident angle IN are reflected at a predetermined reflection angle OUT. Note that, hereinafter, the incident angle IN and reflection angle OUT may be referred to as the incident angle IN and reflection angle OUT, respectively. The incident angle IN and reflection angle OUT may also be used to mean the incident direction and reflection direction, respectively. The reflectarray 100 can be designed with any angle of incidence and reflection. Here, the angles of incidence and reflection are the angles of incidence and reflection that cause maximum reflection of incident radio waves. Generally, maximum reflection also occurs when the incident direction and reflection direction are opposite. In other words, even for radio waves incident from the designed reflection direction, maximum reflection occurs in the designed incident direction. Patent Document 1 describes a reflector that uses a metamaterial. Antennas that use metamaterials are also known (Patent Document 2). Paragraph 0181 of Patent Document 3 states, "The material of the reflector is (omitted) a metamaterial structure, etc.", and paragraph 0014 of Patent Document 4 states, "In passive reflectors, metamaterial reflectors in particular allow the propagation direction and beam width to be designed as desired." [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-57723 [Patent Document 2] Patent Publication No. 2021-27468 [Patent Document 3] Japanese Patent Application Publication No. 2019-36783 [Patent Document 4] Patent Publication No. 2021-125779 Summary of the Invention [Problem to be solved by the invention]

[0004] A reflectarray that uses the metamaterial described above as a reflector can arbitrarily design the angle of incidence and reflection. In other words, the angle of incidence of the reflectarray can be freely set in the vertical or horizontal direction, but when installing the reflectarray, the angle of incidence of the reflector must be precisely directed toward the base station antenna, and the direction of the designed angle of incidence must be precisely aligned with the direction of the base station (direction of the incident wave). Previously, adjusting the angle of incidence toward the base station antenna was done visually, making it difficult and time-consuming to align the angle accurately. Therefore, an object of the present invention is to provide a reflectarray and a manufacturing method thereof in which an antenna is configured on the reflectarray such that the angle of incidence of the reflectarray matches the direction of the maximum directivity point, thereby facilitating the direction adjustment of the reflectarray 100. Note that, hereinafter, the direction of the maximum directivity point may be referred to as the maximum directivity direction. [Means for solving the problem]

[0005] The reflectarray according to claim 1 of the present invention comprises: It has a metamaterial reflector and an auxiliary antenna, The relative positions of the metamaterial reflector and auxiliary antenna are fixed. This reflectarray is characterized in that the designed incident direction of the metamaterial reflector and the maximum direction of the directivity of the auxiliary antenna are approximately the same. A reflectarray according to claim 2 of the present invention comprises: The reflectarray according to claim 1, further comprising an adjustment unit that adjusts the positions or directions of the metamaterial reflector and the auxiliary antenna while keeping the positional relationship between the metamaterial reflector and the auxiliary antenna fixed. A reflectarray according to claim 3 of the present invention comprises: 3. The reflectarray according to claim 1, wherein the metamaterial reflector and the auxiliary antenna are formed on the same plane. A reflectarray according to claim 4 of the present invention comprises: The reflectarray according to claim 3, wherein a plurality of auxiliary antennas are arranged radially from the center. A reflectarray according to claim 5 of the present invention comprises: The reflectarray according to claim 3, wherein the two auxiliary antennas are arranged diagonally. A reflectarray according to claim 6 of the present invention comprises: The reflectarray according to claim 3, wherein four auxiliary antennas are arranged at four corners. A reflectarray according to claim 7 of the present invention comprises: 7. The reflectarray according to claim 5, wherein the auxiliary antenna is arranged outside the Fresnel radius of the metamaterial reflector. A reflectarray according to claim 8 of the present invention comprises: 8. The reflectarray according to claim 1, further comprising an auxiliary communication unit connected to the auxiliary antenna. A reflectarray according to claim 9 of the present invention comprises: Equipped with multiple metamaterial reflectors, 9. The reflectarray according to claim 1, wherein the positional relationship between the designed incident directions of the multiple metamaterial reflectors and the auxiliary antenna is fixed. A reflectarray according to claim 10 of the present invention comprises: The reflectarray according to any one of claims 1 to 8, wherein the metamaterial reflector and the auxiliary antenna are formed on a printed circuit board. With the above-described configuration, the present invention can facilitate adjustment of the direction of the reflectarray. A method for manufacturing a reflectarray according to claim 11 of the present invention includes the steps of: A manufacturing method of a reflector array according to claim 10, characterized in that the metamaterial reflector and the auxiliary antenna are manufactured by etching as a print pattern on a printed circuit board. With the above-described configuration, the present invention makes it possible to manufacture a reflectarray that achieves the above-described effects in the same process, thereby reducing costs and enabling precise fine adjustment of the metamaterial reflector and auxiliary antenna during manufacturing. [Brief explanation of the drawings]

[0006] [Figure 1] 1 shows an example of the configuration of a conventional reflectarray. [Figure 2] 1 shows an example of the configuration of a conventional reflectarray. [Figure 3] 1 shows an example of the configuration of a reflectarray in an embodiment of the present invention. [Figure 4] 1 shows an example of the configuration of a reflectarray in an embodiment of the present invention. [Figure 5] 1 shows an example of the configuration of a reflectarray in an embodiment of the present invention. [Figure 6] 1 shows an example of the configuration of a reflectarray in an embodiment of the present invention. [Figure 7] 1 shows an example of the configuration of a reflectarray in an embodiment of the present invention. [Figure 8] 1 shows an example of the configuration of a reflectarray in an embodiment of the present invention. [Figure 9] 1 shows an example of the configuration of a reflectarray in an embodiment of the present invention. [Figure 10] 1 shows an example of the configuration of a reflectarray in an embodiment of the present invention. [Figure 11] 1 shows an example of the configuration of a reflectarray in an embodiment of the present invention. [Figure 12] 1 shows an example of the configuration of a reflectarray in an embodiment of the present invention. [Figure 13] 1 shows a manufacturing method of a reflectarray in one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0007] FIG. 3 shows an example of the configuration of a reflectarray 100 according to an embodiment of the present invention. The reflectarray 100 includes a metamaterial reflector 110 and an auxiliary antenna 120 . The positional relationship between metamaterial reflector 110 and auxiliary antenna 120 is fixed. Here, the positional relationship includes not only the positions but also the angle between metamaterial reflector 110 and auxiliary antenna 120, that is, the orientation.

[0008] The designed incident direction 110IM of the metamaterial reflector and the maximum direction of the directivity of the auxiliary antenna 120 are substantially the same. In order to ensure that the maximum point of the reflector's incident angle IN coincides with the maximum point of the antenna's directivity, a measuring device such as a spectrum analyzer or scanner is connected to the antenna output, and the direction is adjusted to maximize the reception level, so that the reflectarray reflector automatically points accurately in the direction of the base station. Since the direction adjustment, which previously relied on visual inspection, can now be performed using a measuring instrument, the incident angle IN of the reflectarray 100 can be accurately aimed at the base station antenna 2, and the adjustment time can also be reduced.

[0009] FIG. 4 shows an example of the configuration of a reflectarray 100 according to an embodiment of the present invention. In this embodiment, the metamaterial reflector 110 and the auxiliary antenna 120 are formed on the same plane. Here, "on the same plane" means that they are essentially on the same plane. For example, there may be irregularities of a few percent relative to the area where the antenna is formed, and they do not have to be completely on the same plane. An auxiliary antenna 120 is configured as an array antenna on the same plane as the reflectarray reflector, with the incident angle IN of the reflector coinciding with the maximum point of the directivity direction. With this configuration, auxiliary antenna 120 is constructed on the same plane as the reflectarray reflector, with the incident angle IN of the reflector coinciding with the direction of the maximum directivity point, resulting in a reflector structure that makes it easy to adjust the direction of the reflectarray reflector.

[0010] In one embodiment, the metamaterial reflector 110 and the auxiliary antenna 120 may be formed on a printed circuit board. With this configuration, the auxiliary antenna 120 can be manufactured by etching a print pattern onto a printed circuit board. Because the reflectarray reflector is also manufactured using the same method, the reflector and antenna can be manufactured using the same process.

[0011] FIG. 5 shows an example of the configuration of a reflectarray 100 according to an embodiment of the present invention. In this embodiment, multiple auxiliary antennas 120 are arranged radially from the center. In this embodiment, three auxiliary antennas 120 are arranged at three ends of a substantially equilateral triangular metamaterial reflector 110, but a configuration in which four auxiliary antennas 120 are provided at the four corners of a square or rectangular metamaterial reflector 110, or a configuration in which multiple auxiliary antennas 120 are provided at the ends of a circular metamaterial reflector 110 at positions approximately equiangular from the center of the circle, may also be used.

[0012] FIG. 6 shows an example of the configuration of a reflectarray 100 according to an embodiment of the present invention. In this embodiment, two auxiliary antennas 120 are arranged diagonally. Here, "diagonally" refers to a diagonal line centered on metamaterial reflector 110. In other words, the midpoint of the diagonal line approximately coincides with the midpoint of metamaterial reflector 110. By arranging auxiliary antenna 120 on the diagonal line, the direction of the reflected wave from auxiliary antenna 120 can be made closer to the incident direction of metamaterial reflector 110.

[0013] 7 and 8 show an example of the configuration of a reflectarray 100 according to an embodiment of the present invention. In this embodiment, four auxiliary antennas 120 are arranged at the four corners. Furthermore, each auxiliary antenna 120 is connected to the end of the metamaterial reflector 110 by a feeder 115. As shown in Figure 8, in this embodiment as well, the design incident direction 110IM of the metamaterial reflector, indicated by the incident angle IN in the figure, and the maximum direction 120RM of the directivity of the auxiliary antenna, indicated by the reflection angle OUT in the figure, are approximately the same. By arranging auxiliary antenna 120 at the four corners, the reflected wave of auxiliary antenna 120 can be brought closer to the incident direction of metamaterial reflector 110. This effect is particularly noticeable when metamaterial reflector 110 is approximately rectangular or even approximately square, but it goes without saying that this is also effective in other cases.

[0014] FIG. 9 shows an example of the configuration of a reflectarray 100 according to an embodiment of the present invention. In this embodiment, the auxiliary antenna 120 is disposed outside the Fresnel radius 110F of the metamaterial reflector 110. This configuration ensures the performance of metamaterial reflector 110, while making effective use of the area outside Fresnel radius 110F, which has little effect on metamaterial reflector 110. In particular, manufacturing costs can often be reduced by making metamaterial reflector 110 approximately rectangular or square, and in this case, the four corners outside Fresnel radius 110F can also be effectively utilized. In particular, when auxiliary antennas 120 are provided at the four corners of a rectangle or square centered on metamaterial reflector 110, there is also the effect of being able to move the direction of the reflected wave from auxiliary antenna 120 closer to the designed incident direction 110IM of metamaterial reflector 110.

[0015] FIG. 10 shows an example of the configuration of a reflectarray 100 according to an embodiment of the present invention. In this embodiment, the reflectarray 100 includes an adjustment unit 130 . Adjustment unit 130 adjusts the positions or directions of metamaterial reflector 110 and auxiliary antenna 120 while keeping the positional relationship between metamaterial reflector 110 and auxiliary antenna 120 fixed. The adjustment can be performed manually. In this embodiment as well, the design incident direction 110IM of the metamaterial reflector, indicated by the incident angle IN in the figure, and the maximum direction 120RM of the directivity of the auxiliary antenna, indicated by the reflection angle OUT in the figure, are approximately the same. The adjustment may be performed remotely via communication by providing an adjustment communication unit within the adjustment unit 130. This configuration makes it easy to perform fine adjustments after installation. By connecting communication equipment to this reflectarray 100, it can be used not only for direction adjustment but also as a communication antenna.

[0016] FIG. 11 shows an example of the configuration of a reflectarray 100 according to an embodiment of the present invention. In this embodiment, the reflectarray 100 has an auxiliary communication unit 140 connected to the auxiliary antenna 120.

[0017] To the antenna output, wireless devices for data communication, such as surveillance cameras and sensors, and wireless terminals are connected as auxiliary communication units 140. With this configuration, the antenna can ensure communication with the base station, while the reflector can separate weak electric field areas where radio waves from the base station antenna 2 do not directly reach.

[0018] FIG. 12 shows an example of the configuration of a reflectarray 100 according to an embodiment of the present invention. This embodiment includes a plurality of metamaterial reflectors 110. In particular, this embodiment includes four metamaterial reflectors 110, each designed to accommodate incidence from a different base station.

[0019] The multiple metamaterial reflectors 110 have a fixed positional relationship between their designed incident directions and the auxiliary antennas 120 . It goes without saying that the number of metamaterial reflectors 110 is not limited to four and may be any other number such as two or three. Furthermore, metamaterial reflector 110 may be configured to have a curved surface so that the design angle of incidence IN changes continuously. This configuration allows one reflectarray 100 to serve base stations at multiple locations, and also makes adjustments during installation easier.

[0020] The reflectarray 100 described above can be manufactured by etching the auxiliary antenna 120 as a print pattern on a printed circuit board. The reflectarray reflector is also manufactured using the same method, so the reflector and antenna can be manufactured using the same process. FIG. 13 shows a method for manufacturing the reflectarray 100 according to one embodiment of the present invention. This manufacturing method is a method for manufacturing a reflectarray in which the metamaterial reflector 110 and auxiliary antenna 120 of the above-mentioned reflectarray 100 are formed on a printed circuit board, and the metamaterial reflector 110 and auxiliary antenna 120 are manufactured by etching as a printed pattern on the printed circuit board.

[0021] Specifically, when manufacturing begins (S0), first, a resist is formed in a resist forming step (S1), then etching is performed in an etching step (S2), and the resist is removed in a resist removing step (S3). After that, cleaning is performed in a cleaning step (S4), and then inspection is performed in an inspection step (S5). Then, manufacturing is completed (S6). In this example, metamaterial reflector 110, such as a reflectarray reflector, and an array antenna, which is auxiliary antenna 120, are manufactured by etching on a printed circuit board in the same process. Specifically, metamaterial reflector 110 and auxiliary antenna 120 are manufactured simultaneously through a resist formation step (S1), an etching step (S2), and a resist removal step (S3). According to this manufacturing method, it is possible to manufacture the metamaterial reflector 110 such as a reflectarray reflector and the auxiliary antenna 120 in the same process. With the above-described configuration, the present invention makes it possible to manufacture the reflectarray 100 that achieves the above-described effects in the same process, thereby reducing costs and enabling precise fine adjustment of the metamaterial reflector 110 and the auxiliary antenna 120 during manufacturing. Furthermore, the present invention is not limited to the above configuration as long as metamaterial reflector 110 and auxiliary antenna 120 are manufactured by the same method. Looking at the details, this configuration also includes a configuration in which metamaterial reflector 110 and auxiliary antenna 120 are manufactured in sequence. For example, even if metamaterial reflector 110 and auxiliary antenna 120 can be manufactured in a continuous process, the actual manufacturing process can be shortened, and the positional relationship between metamaterial reflector 110 and auxiliary antenna 120 can be adjusted with high precision.

[0022] The present invention is not limited to the above-described embodiments, and it goes without saying that various embodiments are included within the scope of the present invention. The metamaterial reflector and auxiliary antenna can also be made of a reflector other than a metamaterial. [Explanation of symbols]

[0023] 100 Reflect Array 110, 111, 112, 113 Metamaterial reflectors 115 Feeder 110IM Metamaterial reflector design incident direction 110F Fresnel radius 120 Auxiliary Antenna 120RM Maximum direction of auxiliary antenna directivity 130 Adjustment section 140 Auxiliary Communications Unit 2 Base Station Antenna IN angle of incidence OUT reflection angle

Claims

1. It has a metamaterial reflector and an auxiliary antenna, a positional relationship between the metamaterial reflector and the auxiliary antenna is fixed; A reflectarray, wherein a designed incident direction of the metamaterial reflector and a maximum direction of directivity of the auxiliary antenna are substantially the same.

2. 2. The reflectarray according to claim 1, further comprising an adjustment unit that adjusts positions or directions of the metamaterial reflector and the auxiliary antenna while maintaining a fixed positional relationship between the metamaterial reflector and the auxiliary antenna.

3. 3. The reflectarray according to claim 1, wherein the metamaterial reflector and the auxiliary antenna are formed on the same plane.

4. The reflectarray according to claim 3 , wherein a plurality of the auxiliary antennas are arranged radially from the center of the metamaterial reflector.

5. The reflectarray according to claim 3 , wherein the two auxiliary antennas are arranged on a diagonal line of the metamaterial plate that passes through the center of the metamaterial reflector.

6. The reflectarray according to claim 3 , wherein the four auxiliary antennas are arranged at four corners of the metamaterial reflector, which is square or rectangular.

7. 7. The reflectarray according to claim 5, wherein the auxiliary antenna is disposed outside a Fresnel radius of the metamaterial reflector.

8. 8. The reflectarray according to claim 1, further comprising an auxiliary communication unit connected to the auxiliary antenna.

9. A plurality of the metamaterial reflectors are provided, 9. The reflectarray according to claim 1, wherein a positional relationship between the design incident directions of the plurality of metamaterial reflectors and the auxiliary antenna is fixed.

10. 10. The reflectarray according to claim 1, wherein the metamaterial reflector and the auxiliary antenna are formed on a printed circuit board.

11. 11. The method for manufacturing a reflector array according to claim 10, wherein the metamaterial reflector and the auxiliary antenna are manufactured by etching as a print pattern on the printed circuit board.

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