Reflectarray and wireless communication device

Abstract

The present invention is a reflect array 1 for which it is possible to set a reflection angle for electric waves that is an angle other than specular reflection, the reflect array 1 comprising a plurality of arranged cells 10. Each of the plurality of cells 10 has at least two main resonant elements 21, 22 and one parasitic resonance element 30 joined with the at least two main resonant elements 21, 22. The parasitic resonance element 30 is capable of adjusting resonance frequency, and by joining with the at least two adjacent main resonant elements 21, 22 and adjusting the resonance frequency of the main resonant elements 21, 22, adjusts the reflection phase of the reflect array surface.

Description

[Technical Field]

[0001] The present invention relates to a reflectarray and a wireless communication device including the reflectarray. [Background technology]

[0002] There have been known technologies relating to directional arrays such as reflectarrays that adjust and reflect radio waves from base stations. For example, Patent Document 1 proposes a wave shaping device that adjusts the reflection direction by utilizing coupling between a resonator and a parasitic resonator. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent No. 6755179 Summary of the Invention [Problem to be solved by the invention]

[0004] The wave shaping device described in Patent Document 1 adjusts the reflection direction using an array in which multiple cells (see Figure 1) are arranged, each cell having one parasitic resonator and one diode for adjusting the resonant frequency of the parasitic resonator for one main resonator. Here, this configuration adjusts the reflection direction for vertically polarized waves, but each cell of the array has the same number of parasitic resonators and diodes as the main resonators, so the number of parts per polarization direction is large.

[0005] The present disclosure provides a reflectarray and a wireless communication device that can reduce the number of parasitic resonating elements relative to a main resonating element in the array. [Means for solving the problem]

[0006] The present disclosure provides a reflectarray capable of setting the reflection angle of radio waves to an angle other than specular reflection, A plurality of cells arranged in an array, Each of the plurality of cells has at least two main resonant elements and one parasitic resonant element coupled to the at least two main resonant elements, The parasitic resonator element has an adjustable resonant frequency, and adjusts the reflection phase of the reflectarray surface by coupling to the at least two adjacent main resonator elements and adjusting the resonant frequency of the main resonator element. A reflectarray and a wireless communication device having the reflectarray are provided. [Effects of the Invention]

[0007] According to the present disclosure, in a reflect array, the number of parasitic resonant elements relative to the main resonant element in the array can be reduced. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 10 is a diagram showing an example of a conventional cell in which one parasitic resonator and one diode are provided for one main resonator. [Figure 2] FIG. 2 is a diagram illustrating the operation of a wireless communication device according to an embodiment of the present invention. [Figure 3] 1 is a schematic block diagram of an apparatus for wireless communication according to an embodiment of the present invention; [Figure 4] 1 is a schematic side view of a wireless communication device according to an embodiment of the present invention; [Figure 5] FIG. 2 is a diagram showing an arrangement of a plurality of cells in the reflect array according to the first embodiment of the present invention. [Figure 6] FIG. 10 is an explanatory diagram of a mechanism for adjusting the reflection angle in the reflect array of the present invention. [Figure 7] FIG. 1 is a conceptual diagram of the reflection angle of the reflect array of the present invention. [Figure 8] FIG. 3 is an explanatory diagram of a voltage application pattern of cells arranged in the reflect array of the first embodiment. [Figure 9] FIG. 10 is a schematic diagram of a main resonant element and a parasitic resonant element of each cell of a reflectarray in a comparative example. [Figure 10] 5A and 5B are schematic diagrams showing a first state and a second state of a cell of a comparative example. [Figure 11] FIG. 10 is a diagram illustrating frequencies in a first state and a second state of a cell of a comparative example. [Figure 12] 3 is a schematic diagram of a main resonant element and a parasitic resonant element of each cell of the reflect array according to the first embodiment of the present invention. FIG. [Figure 13] 2A and 2B are schematic diagrams illustrating a first state and a second state of a cell according to a first embodiment of the present invention. [Figure 14] FIG. 4 is an explanatory diagram of frequencies in a first state and a second state of a cell according to the first embodiment. [Figure 15] 1 is a cross-sectional view of a cell in a first configuration example of an embodiment of the present invention. [Figure 16] FIG. 4 is a cross-sectional view of a cell in a second configuration example of an embodiment of the present invention. [Figure 17] 10A and 10B are schematic diagrams of the main resonator element and the parasitic resonator element of each cell, including modified examples of the element parts of the parasitic resonator element. [Figure 18] FIG. 10 is an explanatory diagram of the reflection angle on the surface of the reflect array according to the second embodiment, which is achieved by changing the voltage application pattern. [Figure 19] FIG. 10 is a schematic diagram of a main resonant element and a parasitic resonant element in each cell of a reflect array according to a second embodiment of the present invention. [Figure 20] 5A and 5B are schematic diagrams illustrating a first state and a second state of a cell according to a second embodiment. [Figure 21] FIG. 10 is a schematic diagram of a measurement model of a main resonant element and a parasitic resonant element in each cell of a reflectarray according to a comparative example. [Figure 22] 22 is a diagram showing the reflection phase and phase difference when the PIN diode is ON and OFF in the measurement model of the comparative example of FIG. 21. [Figure 23] 22 is a graph showing the reflection intensity of the measurement model of the comparative example of FIG. 21 when the PIN diode is ON and OFF. [Figure 24] 1 is a schematic diagram of a measurement model of a main resonant element and a parasitic resonant element in each cell of a reflectarray according to the present invention. [Figure 25] 25 is a diagram showing the reflection phase and phase difference when the PIN diode is ON and OFF in the measurement model of the present invention in FIG. 24. [Figure 26]25 is a graph showing the reflection intensity of the measurement model of the present invention in FIG. 24 when the PIN diode is ON and OFF. [Figure 27] 25 is a radar chart showing reflections of the measurement model of the present invention in FIG. 24 when the target reflection angle is 30°. [Figure 28] FIG. 10 is a diagram showing an arrangement of a plurality of cells and subarrays in a reflectarray according to a second embodiment of the present invention. [Figure 29] FIG. 10 is an explanatory diagram of a voltage application pattern of cells arranged in a reflect array according to a second embodiment. [Figure 30] FIG. 10 is a diagram showing an arrangement of a plurality of cells and subarrays in a reflectarray according to a third embodiment of the present invention. [Figure 31] FIG. 10 is an explanatory diagram of a voltage application pattern of cells arranged in a reflect array according to a third embodiment. [Figure 32] FIG. 10 is a diagram showing cells in the case of horizontal polarization in a reflect array according to a fourth embodiment of the present invention. [Figure 33] FIG. 10 is a diagram showing cells in the case of vertical polarization in a reflect array according to a fourth embodiment of the present invention. [Figure 34] FIG. 10 is an explanatory diagram of a voltage application pattern of a subarray in the reflect array of the fourth embodiment. [Figure 35] 13 is a radar chart showing reflections of vertically polarized waves of the measurement model of the fourth embodiment when the target reflection angle is 0° and when the target reflection angle is 30°. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that for ease of understanding, the scale of each component in the drawings may differ from the actual scale. Directions such as parallel, right-angled, orthogonal, horizontal, vertical, up-down, left-right, and the like are permissible to the extent that they do not impair the functions and effects of the embodiments. The shape of the corners is not limited to right angles, and may be rounded in an arched shape. Parallel, right-angled, orthogonal, horizontal, and vertical may include approximately parallel, approximately right-angled, approximately orthogonal, approximately horizontal, and approximately vertical.

[0010] In this specification, a three-dimensional Cartesian coordinate system with three axes (X-axis, Y-axis, and Z-axis) is used, with the width direction of the wall being the X-axis, the height direction of the wall being the Y-axis, and the thickness direction of the wall being the Z-axis. The direction from the bottom to the top of the wall is the +Y-axis, and the opposite direction is the -Y-axis. The direction from indoors to outdoors is the +Z-axis, and the opposite direction is the -Z-axis. In the following explanations of Figures 4 and 5, the +Y-axis direction may be referred to as up, and the -Y-axis direction may be referred to as down. The +Z-axis direction may be referred to as the outdoor side, and the -Z-axis direction may be referred to as the indoor side.

[0011] The X-axis, Y-axis, and Z-axis directions represent directions parallel to the X-axis, Y-axis, and Z-axis, respectively. The X-axis, Y-axis, and Z-axis directions are perpendicular to each other. The XY plane, YZ plane, and ZX plane represent imaginary planes parallel to the X-axis and Y-axis directions, imaginary planes parallel to the Y-axis and Z-axis directions, and imaginary planes parallel to the Z-axis and X-axis directions, respectively.

[0012] <Wireless communication device> FIG. 2 is a diagram illustrating the operation of the wireless communication device according to one embodiment of the present invention.

[0013] The wireless communication device 100 of the present invention is placed, for example, on a wall or window of an outdoor building BD. The wireless communication device 100 has a reflectarray 1 (see FIG. 3), and the reflectarray 1 of the present invention is a directivity control array called a RIS (Reconfigurable Intelligent Surface) that can adjust the directivity of a beam.

[0014] The type of building BD in which the wireless communication device 100 is installed is arbitrary, but may be, for example, a building in an area where high-rise buildings stand side by side. In areas where high-rise buildings stand side by side, dead zones (areas or spaces with poor communication environments, also called "dead zones") where radio waves cannot reach properly are likely to occur. The wireless communication device 100 of the present invention delivers radio waves to dead zones by controlling the direction of the beam of reflected radio waves.

[0015] 2, the radiation patterns of radio waves retransmitted from the radio relay station RB and radio waves reflected from the radio communication device 100 are schematically shown by hatched areas. As shown in FIG. 2, in areas with many high-rise buildings, a radio relay station RB may be installed outdoors to widen the range over which radio waves can be transmitted. The radio relay station RB receives radio waves and retransmits them, thereby outputting the radio waves so as to widen the range. The radio relay station RB may be installed near the radio communication device 100 by a distance of several tens of centimeters to several meters, or may be installed away from the radio communication device 100 by a distance of several tens of meters to several kilometers.

[0016] The wireless communication device 100 of the present invention can deliver radio waves to blind areas that are blocked by buildings by changing the direction of the beam of the incident radio waves and directing the beam in a specific direction or by generating multiple beams.

[0017] 2, an outdoor user terminal U1 and an outdoor user terminal U2 can communicate with each other via the wireless communication device 100. Specifically, for example, radio waves transmitted from the outdoor user terminal U1 are reflected by the wireless communication device 100 and received by the outdoor user terminal U2, thereby establishing communication between the outdoor user terminals U1 and U2.

[0018] 2, for example, radio waves transmitted from an outdoor user terminal U1 are reflected by the wireless communication device 100 and incident on the wireless relay station RB, so that they can be received by the user terminal or a wireless base station via the wireless communication device 100 and the wireless relay station RB. Furthermore, for example, radio waves transmitted from a user terminal or a wireless base station are re-transmitted by the wireless relay station RB and reflected by the wireless communication device 100, so that they can be received by a user terminal U3 that was originally located in a blind zone via the wireless relay station RB and the wireless communication device 100.

[0019] Although Figure 2 shows an example in which a wireless relay station RB is provided in addition to the wireless communication device 100, it is also possible to not provide a wireless relay station RB and instead directly reflect radio waves coming from a wireless base station or the like by the reflect array 1 of the wireless communication device 100.

[0020] Here, the radio waves received by the wireless communication device 100 may be used in any communication system, such as LTE (Long Term Evolution), LTE-A (LTE-Advanced), a fifth-generation mobile communication system, UMB (Ultra Mobile Broadband), IEEE802.11 (Wi-Fi (registered trademark)), IEEE802.16 (WiMAX (registered trademark), IEEE802.20, UWB (Ultra-Wideband), Bluetooth (registered trademark), LPWA (Low Power Wide Area), or other extended communication systems. Note that as the frequency increases, propagation loss due to reflection and diffraction increases, making such blind spots more likely to occur. Therefore, the wireless communication device 100 is suitable for communications using relatively high frequencies.

[0021] Fig. 3 is a schematic block diagram of a wireless communication device 100 according to an embodiment of the present invention. Fig. 4 is a schematic side view of the wireless communication device 100 according to an embodiment of the present invention.

[0022] The wireless communication device 100 of the present invention has a reflectarray 1 and a control unit 5. As shown in Fig. 3, the control unit 5 of the present invention is realized by, for example, a microcomputer (MICOM).

[0023] The control unit 5 receives input of the incident wave source position (including the direction of arrival of the plane wave by setting it at infinity) and reflection direction instructions (directivity instructions) from the outside, and controls the reflection angles of each of the multiple cells of the reflectarray 1. The input to the control unit 5 from the outside is input, for example, from a management computer (not shown) that manages the building BD or a user terminal U1. The control unit 5 operates based on a power supply voltage generated by a power supply generation unit (not shown).

[0024] 4, the reflectarray 1 and the control unit 5 of the wireless communication device 100 of the present invention are provided on a wall 6. Here, when the wireless communication device 100 is provided on the wall 6 of the building BD, the height from the ground is preferably 1 to 14 m, and particularly preferably 2 to 10 m, from the viewpoint of radio wave efficiency.

[0025] 4 shows an example in which the wireless communication device 100 is disposed on an outdoor wall 6, but the reflectarray 1 in the wireless communication device 100 may be disposed on a windowpane. When the reflectarray 1 is disposed on a windowpane, the substrate 11 and the conductors 12 (see FIGS. 15 and 16) are preferably made of a transparent dielectric material (an example of a base material having a visible light transmittance of 50% or more). When the reflectarray 1 is disposed on a windowpane, the control unit 5 may be disposed away from the reflectarray 1 at another location, such as a wall adjacent to the windowpane or the frame of the windowpane.

[0026] Furthermore, the wireless communication device 100 of the present invention may be installed on an indoor wall or window glass, which contributes to reducing blind spots indoors.

[0027] <Reflect Array> FIG. 5 is an explanatory diagram showing an arrangement of a plurality of cells in the reflect array 1 according to the first embodiment of the present invention.

[0028] As shown in Fig. 5, the reflectarray 1 of the present invention has a plurality of cells 10 regularly arranged. The cells 10 are unit cells that serve as repeating units, and in the example shown in Fig. 5, for example, 10 sets of cells are arranged in the vertical direction and 20 sets of cells are arranged in the horizontal direction.

[0029] In addition, in the first embodiment, two main resonant elements 21 and 22, which are reflective elements, are arranged side by side, one above the other, within each cell 10, so that adjacent cells 10 have a vertically elongated shape in which the vertical inter-cell distance D, which is the distance between the center positions of the cells, is longer than the horizontal inter-cell distance d.

[0030] By controlling the ON / OFF of the plurality of cells 10 arranged in this manner, the reflect array 1 can set the angle at which the incident radio waves are reflected in a desired direction.

[0031] The arrangement of the cells 10 in the reflect array 1 shown in FIG. 5 is an example, and the number of cells provided in the array may be approximately several tens to several thousands.

[0032] Fig. 6 is an explanatory diagram of the mechanism for adjusting the reflection angle in the reflectarray of the present invention, and Fig. 7 is a conceptual diagram of the reflection angle of the reflectarray of the present invention.

[0033] The reflectarray of the present invention is an array that is called a RIS (Reconfigurable Intelligent Surface) and is capable of adjusting beam directivity.

[0034] In the reflectarray 1, the phase of the radio waves is changed when they are reflected at each location, i.e., for each cell 10 called a unit cell, and by arranging these cells in an array, the direction of the beam, which is the reflected radio waves, is adjusted.

[0035] In detail, because radio waves are incident obliquely on the outer surface of the cell, the reflection phase can be changed in one cell by setting the phase difference of the radio waves reflected by the reflecting element (main resonator element) for each location, taking into account the inter-cell distance d. By making this different for each location, it is possible to change the overall reflection direction.

[0036] For example, when a plane wave incident along the x-axis is reflected along the x-axis, the reflection direction can be changed by adding a phase at each location x. Here, if ψ is the angle of incidence and Φ is the angle of reflection, the phase of the incident wave is expressed as -kxsinψ, and the phase of the reflected wave is expressed as -kxsinΦ.

[0037] As a result, the reflection phase for each position x becomes "-kx(sinΦ-sinψ)" when reflected, and if this meets certain conditions, the reflection direction can be changed. Therefore, in order to change the reflection direction in each cell, it is important to ensure that the phase difference of the reflected radio waves is approximately 180°.

[0038] In this way, the wireless communication device 100 of the present invention can change the direction of the beam of radio waves emitted from a 5G base station, etc., and direct the beam in various directions or in any desired direction, or can create multiple beams.

[0039] Note that Figure 6 describes the case where a wave incident along the x-axis is reflected along the x-axis, but the reflectarray of the present invention also functions as a reflector that can set the reflection angle to an angle other than specular reflection when the wave is incident along the y-axis, when the wave is incident and reflected at an angle oblique to the x-axis and y-axis, or when a wave other than a plane wave is incident.

[0040] In Figure 7, (a) is a diagram showing the case where the incident angle of the radio waves is inclined with respect to the surface of the reflectarray (radio wave incident angle in≠0°), and (b) is a diagram showing the case where the incident angle of the radio waves is perpendicular to the surface of the reflectarray (radio wave incident angle in=0°).

[0041] Fig. 8 is an explanatory diagram of the voltage application pattern of the cells arranged in the reflectarray of the first embodiment of the present invention. Fig. 8 shows the voltage application pattern when radio waves are incident from the direction of the Z axis perpendicular to the surface of the reflectarray as shown in Fig. 7(b), where (a) shows the voltage application pattern when the target angle is 0°, (b) shows the voltage application pattern when the target angle is 30°, (c) shows the voltage application pattern when the target angle is 45°, and (d) shows the voltage application pattern when the target angle is 60°, as shown in Fig. 7(b).

[0042] In the present invention, a voltage application pattern (ON / OFF pattern) is calculated within a microcomputer for each incident wave source position and target angle as a directivity instruction for the reflectarray. The target angle of the reflection angle for vertically polarized waves corresponds to the tilt angle θ of the vertical direction with respect to the Z axis, which is the incident direction, as shown in Figure 7(b).

[0043] In FIG. 8, among the cells 10 that are unit elements, the cells to which a DC voltage is applied, that is, the cells 10 in which the PIN diode 41 (see FIG. 12) is turned ON, are shown by hatching.

[0044] When the reflection angle is 0°, radio waves incident from the Z axis return in the direction of the Z axis. In this case, as shown in Figure 8(a), no voltage is applied to all cells 10 of the reflect array 1, and all diodes are in the OFF state. Furthermore, comparing Figures 8(b) to (d), the larger the reflection angle, the narrower the intervals between the ON / OFFs in the horizontal direction.

[0045] In this embodiment, when the reflection angle is other than 0°, the reflection angle changes in the horizontal direction with respect to vertically polarized waves.

[0046] In this way, the directivity can be adjusted by changing the voltage application pattern of the cells in the reflectarray 1. Furthermore, the directivity can be dynamically changed by changing the voltage application pattern over time.

[0047] The ON / OFF pattern of the cells shown in FIG. 8 is an example, and the ON / OFF pattern of the cells may be changed in the vertical direction as well depending on the target angle.

[0048] Note that Figure 8 shows an example in which the ON / OFF of the cells is controlled in a consistent manner in the vertical direction, and the horizontal angle is changed relative to the vertically polarized wave. However, by changing the ON / OFF pattern of the cells in the vertical direction, it is also possible to change the reflection direction in both the vertical and horizontal directions relative to the vertically polarized wave.

[0049] <Intra-cell structure of comparative example> FIG. 9 is a schematic diagram of a main resonant element and a parasitic resonant element in each cell of a reflectarray in a comparative example.

[0050] The cell 9 of the comparative example has one main resonant element 70 and one parasitic resonant element 80 adjacent to the main resonant element 70. The parasitic resonant element 80 is provided with a PIN diode 91 that electrically controls the resonance value.

[0051] In this comparative example, the parasitic resonator element 80 has a first element part 81 that is parallel to one side of the main resonator element 70 and close to the main resonator element 70, and a second element part 82 that is parallel to the first element part 81. In the example of Fig. 9, the first element part 81 is made up of one linear element, and the second element part 82 is made up of one linear element.

[0052] In this comparative example, the distance between the first element part 81, which is the nearest element, and one side 71 of the main resonant element is such that the parasitic resonant element 80 interacts with the main resonant element .

[0053] Furthermore, the two element parts 81 and 82 of the parasitic resonator element 80 are coupled together by a PIN diode 91. In addition, in the parasitic resonator element 80, RF chokes 92 and 93 are provided at the ends of the two element parts 81 and 82 on both sides of the PIN diode 91. A control voltage VB is applied to the open end of one of the RF chokes 92, and the other RF choke 93 is grounded (GND).

[0054] Here, the states of the cell according to the comparative example will be described with reference to Fig. 10 and Fig. 11. Fig. 10 is a schematic diagram of the first and second states of the cell according to the comparative example. Fig. 11 is an explanatory diagram of the frequencies of the first and second states of the cell according to the comparative example.

[0055] In the parasitic resonant element 80 of the comparative example, the diode 91 is in an ON state, and the first element part 81 and the second element part 82 are connected as shown in FIG. 10(a).

[0056] With the diode 91 in the OFF state, the parasitic resonator element 80 is in a state in which the first element part 81 and the second element part 82 are disconnected from each other. Therefore, in the parasitic resonator element 80, only the adjacent first element part 81 interacts with the main resonator element 70, resulting in an electrical state as shown in FIG. 10(b).

[0057] 10(a) and 10(b), the element length constituting the parasitic resonant element 80 is longer in the state of FIG. 10(a). Therefore, when the diode is in the OFF state, the resonance frequency of the fundamental mode of the element alone increases by the amount that the parasitic resonant element 80 becomes shorter, and as shown in FIGS. 11(a) and 11(d), the resonance frequency of the parasitic resonant element alone becomes fcpara1. <fcpara2となる。

[0058] Here, the parasitic resonating element 80 is assembled in close proximity to the main resonating element 70 with dimensions that allow them to interact with each other.

[0059] 11(a), when the parasitic resonance frequency fcpara1 of the element alone in the OFF state is far from the main resonance frequency fmain of the main resonance element 70 alone, the frequency reconstructed by the interaction in the assembled state changes little from the resonance frequency of the element alone, resulting in two reconstructed resonance frequencies fr1a and fr1b that are almost the same as the resonance frequency of the element alone. This state shown in FIG. 11(b) is called the first state of the cell.

[0060] On the other hand, when the parasitic resonant frequency fcpara2 of the element alone in the ON state is close to the main resonant frequency fmain of the main resonant element of the element alone, as shown in Figure 11(d), in the assembled state, the frequency reconstructed by the interaction shifts significantly, with little change from the resonant frequency of the element alone, splitting it up and down, resulting in two reconstructed resonant frequencies fr2a and fr2b that are widely separated in high and low. This state, shown in Figure 11(c), is called the second state of the cell.

[0061] Furthermore, in the state shown in Figures 11(b) and 11(c) where the frequency has been reconstructed in this manner, the absolute value of the difference (reflection phase difference) between the reflection phase in the first state and the reflection phase in the second state at the frequency of the input radio wave is approximately 180°.

[0062] In this way, since the difference in reflection phase between the first state and the second state is approximately 180°, the reflection phase of the cell 9 in the comparative example can be adjusted, thereby allowing the reflect array in which the cells 9 are arranged to function as a reflector with adjustable directivity.

[0063] In this manner, in the known configuration relating to the comparative example, for a specific polarized wave in one direction (in this example, vertical polarized wave), one parasitic resonant element and one PIN diode for electrically controlling the parasitic resonant element were provided for one main resonant element in the corresponding cell.

[0064] Here, PIN diodes consume high power and are expensive components. Furthermore, if there are many reflective elements (main resonator elements) per reflectarray, there may be as many as 1,000 to 3,000 of them, and even in that case, the same number of PIN diodes are arranged, and because PIN diodes are electronic components, they fail more frequently than reflective elements.

[0065] Therefore, it is desirable to reduce the number of PIN diodes used per reflector to reduce power consumption by the PIN diodes, reduce the cost of the array, and reduce the chance of component failure.

[0066] <Cell structure of the first embodiment of the present invention> The structure of each cell according to the first embodiment of the present invention will now be described with reference to Fig. 12 to Fig. 16. Fig. 12 is a schematic diagram of a main resonant element and a parasitic resonant element of each cell of the reflect array according to the first embodiment of the present invention.

[0067] In this embodiment, each cell 10 of the plurality of cells has two main resonance elements 21, 22 and one parasitic resonance element 30 that is provided between the two main resonance elements 21, 22 and is not in contact with the main resonance elements 21, 22.

[0068] In each cell 10, the main resonant elements 21 and 22 and the parasitic resonant element 30 are conductors (also referred to as conductive portions, conductive patterns, or conductor patterns) 12 provided on the substrate 11. The cross-sectional structure will be described later with reference to FIGS. 15 and 16.

[0069] 12, the main resonator elements 21 and 22 are rectangular (patch-shaped) having a predetermined area. The main resonator elements 21 and 22 function as reflectors. g 1 / 2λ for g It has a side of ±10%.

[0070] The desired frequency band of the radio waves reflected by the reflectarray 1 of the present invention is, for example, 0.3 to 100 GHz. More specifically, examples of the frequency band include the UHF (Ultra High Frequency) band of 0.3 to 3 GHz, the SHF (Super High Frequency) band of 3 to 30 GHz, and the EHF (Extremely High Frequency) band of 30 to 300 GHz.

[0071] In the present invention, the frequency at which it functions as a reflector with adjustable directivity changes depending on the size of one side of the main resonant elements 21 and 22, which are reflective elements, the inter-cell spacing d, and the element length of the parasitic resonant element 30, so it is preferable to set the size appropriately depending on the frequency band to be used.

[0072] In addition, Figure 12 shows an example in which the main resonance elements 21 and 22 have a rectangular shape, but the shape of the main resonance element may be a shape with a portion cut out from a rectangle (see Figure 24), a semicircular shape, a polygonal shape, etc., as long as it has a predetermined area and has sides parallel to the first elements 311 and 321 that are closest to the parasitic resonance element 30.

[0073] 12, the parasitic resonator element 30 is configured to include two H-shaped element parts. Specifically, one element part 31 has a first element 311, a second element 312, and a third element 313.

[0074] The first element 311 is closest to the main resonance element 21 and extends parallel to one side 211 of the main resonance element 21. One end of the second element 312 contacts the approximate center of the first element 311 and extends in a direction away from the main resonance element 21. The third element 313 contacts the other end of the second element 312 and extends approximately parallel to the first element 311.

[0075] The other H-shaped element part 32 of the parasitic resonator element 30 includes similar elements 321, 322, and 323 that are symmetrical to the element part 31 in the vertical direction.

[0076] The distance between the first element 311, which is the nearest element, and one side 211 of the main resonance element 21 is set so that the parasitic resonance element 30 interacts with the main resonance element 21, and the wavelength of the frequency of the incident radio wave on the substrate is set to λ g Then, 1 / 10λ g It is preferable that the wavelength is 1 / 30λ or less. g Similarly, the distance between the first element 321, which is the nearest element, and one side 221 of the main resonant element 22 is preferably about 1 / 10λ so that the parasitic resonant element 30 interacts with the main resonant element 22. g It is preferable that the wavelength is 1 / 30λ or less. g It is more preferable that the amount is about 1000 .mu.m.

[0077] Furthermore, the third elements 313 and 323 of the two element parts 31 and 32 of the parasitic resonator element 30 are coupled together by a PIN diode 41 .

[0078] In the parasitic resonator element 30, RF chokes 42, 43 are provided on both sides of the PIN diode 41 at the open ends of the third elements 313, 323 of the two element parts 31, 32. A control voltage (VB) is applied to the open end of one of the RF chokes 42, and the other RF choke 43 is grounded (GND).

[0079] In this way, in the configuration of the present invention, for a specific polarized wave in one direction (vertical polarized wave in this example), one parasitic resonant element and one PIN diode for electrically controlling the parasitic resonant element are provided for two main resonant elements in the corresponding cell, which means that one diode is sufficient for two reflecting elements.

[0080] Therefore, in the present invention, the number of parasitic resonator elements and PIN diodes is half the number of the main resonator elements, which are reflecting elements. As a result, even when the same number of reflecting elements (main resonator elements) as in the comparative example is provided, the number of parts per reflectarray, i.e., the number of parasitic resonators relative to the main resonator, can be reduced.

[0081] In addition, since the number of PIN diodes relative to the main resonator element can be reduced, the power consumption per reflectarray can be reduced and the cost of components can be suppressed. Furthermore, even if the number of reflectors (main resonator elements) per reflectarray is around 1,000 to 3,000, the chance of failure due to PIN diodes can be reduced.

[0082] The resonant frequency of the parasitic resonant element 30 of the present invention can be adjusted to a first parasitic resonant frequency fpara1 or a second parasitic resonant frequency fpara2 by electrical control. In this example, the electrical switch that electrically controls the parasitic resonant element 30 is a PIN diode 41, but the electrical switch may also be a field effect transistor (FET), a transistor, a variable capacitor, or the like.

[0083] 12 shows an example in which the two element parts included in the parasitic resonant element are H-shaped, but the element parts may have other shapes. Other shapes of the element parts will be described later with reference to FIG.

[0084] Next, the behavior of the cell of the present invention will be described with reference to Fig. 13 and Fig. 14. Fig. 13 is a schematic diagram of the first state and the second state of the cell of the first embodiment of the present invention. Fig. 14 is an explanatory diagram of the frequencies of the first state and the second state of the cell of the first embodiment.

[0085] When the PIN diode 41 is ON, the parasitic resonant element 30 of the present invention is in a state in which the third elements 313 and 323 are connected to each other and the two element parts 31 and 32 are electrically connected, as shown in Fig. 13(a). At this time, due to the element lengths of the two H-shaped element parts 31 and 32 connected to the parasitic resonant element 30, the resonant frequency of the element itself becomes the first parasitic resonant frequency fpara1 (Fig. 14(a)), and in the assembled state, it is in the first state (Fig. 14(b)).

[0086] On the other hand, when the PIN diode 41 is OFF, as shown in FIG. 13(b), the third elements 313 and 323 of the parasitic resonant element 30 are not connected, and the two element parts 31 and 32 are electrically disconnected. In this case, due to the element length of each of the independent H-shaped element parts 31 and 32, the resonant frequency of the parasitic resonant element 30 alone becomes the second parasitic resonant frequency fpara2 (FIG. 14(d)), and in the assembled state, it becomes the second state (FIG. 14(c)). Note that the electrical shape of the parasitic resonant frequency when the PIN diode 41 is OFF as shown in FIG. 13(b) is the same as that when the diode is ON in the comparative example cell shown in FIG. 10(a).

[0087] In each cell 10 of the present invention, the parasitic resonant element 30 is assembled close to the main resonant elements 21, 22 with a size that allows it to interact with (electrically couple to) the main resonant elements 21, 22.

[0088] When the parasitic resonance element 30 is compared between the state shown in Fig. 13(a) and the state shown in Fig. 13(b), the element length of the former is longer. Therefore, in the state where the diode 41 is OFF, the resonance frequency of the basic mode of the element alone increases as the element length becomes shorter. As shown in Figs. 14(a) and 14(d), the resonance frequency of the parasitic resonance element alone is fpara1 < fpara2.

[0089] Furthermore, the parasitic resonance element 30 according to the present invention has a plurality of resonance modes. Generally, for a resonance element having a plurality of resonance modes, the resonance frequency becomes higher as the order increases. Thus, fpara1 (basic mode) < fpara1 (second mode), fpara2 (basic mode) < fpara2 (second mode). Also, from the above, due to the relationship fpara1 (basic mode) < fpara2 (basic mode), fpara1 (second mode) < fpara2 (second mode).

[0090] Here, as shown in Figs. 14(a) and 14(d), the first parasitic resonance frequency fpara1 (basic mode) and the second parasitic resonance frequency fpara2 (basic mode) of the parasitic resonance element 30 in the basic mode are smaller than the main resonance frequency fmain of the element alone.

[0091] Also, when there are a plurality of resonance modes in the first state and the second state of the parasitic resonance element, regardless of the order of the modes, the one closest to the main resonance frequency will be the object of interaction.

[0092] As shown in Fig. 14(a), one of the higher-order modes of the first parasitic resonance frequency of the element alone is closer to the main resonance frequency of the element alone than the basic mode of the first parasitic resonance frequency of the element alone, and |fpara1 (higher-order mode) - fmain| < |fpara1 (basic mode) - fmain|. Therefore, in this example, among the modes of the first parasitic resonance frequency, the one with the closest frequency fpara1 (higher-order mode) becomes the object of interaction with the main resonance frequency fmain of the element alone.

[0093] Furthermore, one of the higher modes of the first parasitic resonant frequencies of the element alone, fpara1 (higher mode), which is the closest in frequency, is within ±3% of the main resonant frequency fmain of the element alone. That is, one of the first parasitic resonant frequencies of the element alone and the main resonant frequency of the element alone have a relationship of |first parasitic resonant frequency of the element alone−main resonant frequency of the element alone| / main resonant frequency of the element alone≦3%.

[0094] Therefore, since the parasitic resonance frequency fpara1 (secondary mode) of the element unit is close to the main resonance frequency fmain of the main resonance element of the element unit, in the assembled state, as shown in FIG. 14(b), the frequency reconstructed by the interaction is significantly shifted above and below the resonance frequency of the element unit, resulting in two reconstructed resonance frequencies fr11 and fr12 that are widely separated in height, as shown in FIG. 14(b). This state is called the first state of the cell. The two reconstructed resonance frequencies fr11 and fr12 that are separated by the interaction are, for example, within a range of ±5% to ±20% of the main resonance frequency fmain of the element unit.

[0095] 14(d), one of the higher modes of the second parasitic resonance frequency of the element alone is farther from the main resonance frequency of the element alone than the fundamental mode of the second parasitic resonance frequency of the element alone, so that |fpara2 (higher mode) - fmain| > |fpara2 (fundamental mode) - fmain|. Therefore, in this example, of the modes of the second parasitic resonance frequency, fpara2 (fundamental mode), which has the closest frequency, is the one that interacts with the main resonance frequency fmain of the element alone.

[0096] Here, the fundamental mode fpara2 (fundamental mode) having the closest frequency among the modes of the first parasitic resonance frequency of the element alone is outside the range of ±3% of the main resonance frequency fmain of the element alone.

[0097] Therefore, since the parasitic resonant frequency fpara2 (fundamental mode) of the element alone is far from the main resonant frequency fmain of the main resonant elements 21 and 22 of the element alone, in the assembled state, as shown in Figure 14 (c), the frequency reconstructed by interaction has little variation from the resonant frequency of the element alone. Therefore, the two reconstructed resonant frequencies fr21 and fr22 have almost the same values ​​as the resonant frequencies fmain and fpara2 (fundamental mode) of the element alone. This state is called the second state of the cell.

[0098] 14(b) and 14(c) in which the frequency has been reconstructed, the absolute value of the difference (reflection phase difference) between the reflection phase in the first state and the reflection phase in the second state at the frequency of the input radio wave is approximately 180°, which is 180°±45°.

[0099] In this way, since the difference in reflection phase between the first state and the second state is approximately 180°, the cell 10 of the present invention becomes capable of adjusting the reflection phase, thereby allowing the reflect array 1 in which the cells 10 are arranged to function as a reflector with adjustable directivity.

[0100] Furthermore, in this configuration, since the fundamental mode when ON resonates at a frequency lower than the main resonant frequency, each cell 10 is designed so that "the mode of the resonant frequency that couples when ON is a higher-order mode, and the higher-order mode of the parasitic resonant element is within ±3% of the main resonant frequency of the main resonator's single main resonant element."

[0101] By doing this, the element length of the parasitic resonator element 30 can be designed to be longer than in the configuration of the comparative example, so that the two main resonator elements 21 and 22 can be controlled by one parasitic resonator element 30 without narrowing the space between the adjacent main resonator elements 21 and 22.

[0102] Here, the main resonant frequency of the main resonant element is designed to match the frequency of the incident radio waves. However, it is possible that the frequency of the incident radio waves may deviate for some reason. In the present invention, when the deviation of the frequency of the incident radio waves from the main resonant frequency of the element alone is within ±20%, the absolute value of the difference in the reflection phase between the first state and the second state is 180°±45°, and the reflector can be used as a directivity-adjustable reflector, allowing the angle at which the radio waves are reflected to be changed.

[0103] (Application example) In addition, in this embodiment, a configuration in which two main resonator elements and one parasitic resonator element are provided in each cell has been described. However, each cell may have at least two main resonator elements (including three or more) and at least one parasitic resonator element (including two or more). In this case, when supporting one polarization, the number of main resonator elements is greater than the number of parasitic resonator elements. Even in this case, the parasitic resonator element can adjust the parasitic resonant frequency to two or more, and is coupled to two or more adjacent main resonator elements to form a reconfigured resonant frequency, thereby adjusting the reflection phase of the reflectarray surface.

[0104] When one parasitic resonator element is provided for three or more main resonator elements in each cell, the parasitic resonator element has a first element that is closest to each main resonator element and is parallel to a side of the main resonator element.

[0105] For example, when three main resonance elements are controlled by one parasitic resonance element, the main resonance elements are arranged in a triangular shape with one side facing inward, and the parasitic resonance element has a first element that extends in a direction approximately parallel to one inner side of the main resonance element and is arranged as part of three sides of the triangle.

[0106] Similarly, when four, five, ... n main resonance elements are controlled by one parasitic resonance element, the main resonance elements are arranged in an n-gon shape with one side facing inward, and the parasitic resonance element has a first element that extends in a direction approximately parallel to one inner side of the main resonance element and is arranged as part of the n sides of the n-gon.

[0107] In this case, when the resonant frequency of one parasitic resonator element in a cell is set to a first parasitic resonant frequency, it couples with two or more adjacent main resonator elements to create a first state. When the resonant frequency of one parasitic resonator element in a cell is set to a second parasitic resonant frequency, it couples with two or more adjacent main resonator elements to create a second state in that cell. By designing the absolute value of the difference between the reflection phase in the first state and the reflection phase in the second state at a specific radio wave frequency to be 180°±45°, the reflector can be used as a directivity-adjustable reflector, allowing the angle at which radio waves are reflected to be changed.

[0108] 14 described above, an example in which "the coupled resonant frequency mode when the parasitic resonant element is ON is a higher-order mode than when the parasitic resonant element is OFF" has been described. However, by changing the design of the parasitic resonant element in the present invention, for example, as in the comparative example, "the coupled resonant frequency mode when the parasitic resonant element is OFF and ON may be the same resonant mode (for example, the fundamental mode)." Alternatively, by further designing, "the coupled parasitic resonant frequency mode when the parasitic resonant element is OFF may be a higher-order mode than the coupled parasitic resonant frequency when the parasitic resonant element is ON." In either case, the parasitic resonant element is designed so that one mode of the resonant frequency when the parasitic resonant element is ON or OFF is within ±3% of the main resonant frequency of the main resonant element of the element alone.

[0109] (Cross-section) 15 is a cross-sectional view of the cell 10 in the first configuration example of one embodiment of the present invention, specifically, a cross-sectional view taken along the line AA' in FIG.

[0110] The main resonator elements 21 and 22 and the conductor 12 of the parasitic resonator element 30 are provided on a first surface of a substrate 11. The substrate 11 is made of, for example, resin. In this configuration, the substrate 11 is formed by laminating two substrates 111 and 112, and the first substrate 111 has a first surface on which the conductor 12 is mounted, and the first surface is patterned by etching.

[0111] A ground plane 14 is provided so as to face the first surface of the substrate 11.

[0112] Also, through holes 113 and 114 are formed penetrating through the substrate 111, the ground plane 14, and the substrate 112 in the thickness direction. The through holes 113 and 114 are wiring regions W1 and W2 that provide electrical continuity between the substrates by plating or the like, and are connected to the third elements 313 and 323 of the parasitic resonator element 30 on the first surface via RF chokes 42 and 43, respectively.

[0113] The wiring area W1 is connected to the ground plane 14 and has the same potential as the ground plane 14.

[0114] Furthermore, on the rear surface side of the substrate 112, wiring W3 connected to the wiring area W2 is exposed on the rear surface side, and is connected to a control voltage VB from the microcomputer (control unit 5) through a pattern formed on the rear surface side. Note that the wiring area W1 and the wiring area W3 are not connected.

[0115] FIG. 16 is a cross-sectional view of a cell 10α in a second configuration example of one embodiment of the present invention.

[0116] In this configuration, a hole 115 that is connected to the through-hole 114 and is parallel to the first surface is formed in the second substrate 112α.

[0117] In this configuration, the wiring connected to the wiring area W2 of the through hole 114 and connected to the control voltage VB is not exposed on the back side, but is realized by the inner layer wiring W4 in the hole portion 115 of the laminated substrate. Note that the wiring area W1 and the inner layer wiring W4 are not connected.

[0118] (Modification of Parasitic Resonant Element) Although FIG. 12 shows an example in which the two element parts included in the parasitic resonant element in the first embodiment of the present invention are H-shaped, the element parts may have other shapes.

[0119] 17A and 17B are diagrams showing modified examples of the parasitic resonant element, in which Fig. 17A shows a configuration in which the element parts are h-shaped, and Fig. 17B shows a configuration in which the element parts are U-shaped.

[0120] 17(a) includes a parasitic resonator element 30A having an h-shaped element part 31A, which has a first element 311, a second element 312, and a third element 313A. The first element 311 and the second element 312 have the same configuration as in FIG.

[0121] One end of the third element 313A of this modified example is connected to the other end of the second element 312, and extends substantially parallel to the first element 311. The element part 32A has the same shape as the element part 31A and is symmetrical in the up-down direction.

[0122] 17(b), a U-shaped element part 31B included in a parasitic resonant element 30B has a first element 311, a second element 312B, and a third element 313. The first element 311 and the third element 313 have the same configuration as in FIG.

[0123] The second element 312B of this modified example has one end in contact with the end of the first element 311, extends in a direction away from the main resonance element 21, and has the other end in contact with the end of the third element 313. The element part 32B has the same shape as the element part 31B and is symmetrical in the up-down direction.

[0124] In these modified examples, when the PIN diode 41 is ON, the parasitic resonant element 30A (30B) connects the third elements 313A, 323A (313, 323) of the paired element parts 31A, 32A (31B, 32B) to each other, and the two element parts 31A, 32A (31B, 32B) are electrically connected. In this case, due to the element lengths of the two connected element parts of the parasitic resonant element, the resonant frequency of the element itself becomes the first parasitic resonant frequency, and the first state is entered.

[0125] On the other hand, when the PIN diode 41 is OFF, the two third elements 313A, 323A (313, 323) are not connected to each other, and the two element parts 31A, 32A (31B, 32B) are electrically disconnected. At this time, the resonant frequency of the parasitic resonant element becomes the second parasitic resonant frequency due to the element length of one element part, and the parasitic resonant element enters the second state.

[0126] In the above first embodiment and modified example, an example has been described in which the two paired element parts that make up the parasitic resonant element have three elements, first to third, but the element parts may also have four or more elements.

[0127] For example, in the configuration of Fig. 12, a fourth element that intersects with the second element and is parallel to the first and third elements may be provided between the first element, which is the nearest element, and the third element connected to the PIN diode, to form the element parts in a skewer-like configuration.Furthermore, the first element and the third element may be bent to form a step (see Fig. 24).

[0128] Second Embodiment FIG. 18 is an explanatory diagram of the reflection angle on the surface of the reflect array 2 according to the second embodiment, which is realized by changing the voltage application pattern.

[0129] In the first embodiment, each cell 10 was provided with a parasitic resonant element that interacted in the vertical direction, so only vertically polarized waves could be reflected in the reflect array with an adjustable reflection angle.However, in the reflect array 2 of the second embodiment (see Figure 28), in addition to vertically polarized waves, the reflection angle of horizontally polarized waves can also be changed vertically and horizontally.

[0130] FIG. 19 is a schematic diagram of a main resonant element and a parasitic resonant element in each cell 20 of a reflect array 2 according to the second embodiment of the present invention.

[0131] Each cell 20 of the plurality of cells in this embodiment includes four main resonance elements 21, 22, 23, and 24 arranged two by two in the vertical and horizontal directions, and four parasitic resonance elements 30-1, 30-2, 33-1, and 33-2 sandwiched between adjacent main resonance elements.

[0132] The parasitic resonator elements 30-1, 30-2, 33-1, and 33-2 of this embodiment are provided adjacent to each of the four main resonator elements 21, 22, 23, and 24 in two directions perpendicular to each other.

[0133] The parasitic resonator elements 30-1 and 30-2 located on the left and right sides of FIG. 19 have the same configuration as the parasitic resonator element 30 in FIG. 12, and are configured to include two H-shaped element parts.

[0134] One element part 31 of the parasitic resonator element 30-1 has a first element 311, a second element 312, and a third element 313, and the first element 311 is the nearest element and extends parallel to the first side (one side) 211 of the adjacent main resonator element 21.

[0135] The other element part 32 of the parasitic resonator element 30-1 includes similar elements 321, 322, and 323 that are vertically symmetrical to the element part 31, and the first element 321 is closest to the first side (one side) 221 of the main resonator element 22.

[0136] Furthermore, the third elements 313 and 323 of the two element parts 31 and 32 of the parasitic resonator element 30-1 are coupled together by a PIN diode 41-1.

[0137] In the parasitic resonant element 30-1, RF chokes 42, 43 are provided on both sides of the PIN diode 41 at the open ends of the third elements 313, 323 of the two element parts 31, 32. A control voltage VB is applied to the open end of one of the RF chokes 42, and the other RF choke 43 is grounded (GND).

[0138] The parasitic resonator elements 30-1 and 30-2 have the same configuration of the elements of the element parts 31 and 32 and the PIN diodes 41-1 and 41-2, but since the RF chokes 42 and 43 are located outside the substrate, the positions of the RF chokes 42 and 43 are symmetrical.

[0139] Moreover, the parasitic resonator elements 33-1 and 33-2 located at the top and bottom of FIG. 19 are configured by turning the parasitic resonator element 30 of FIG. 12 sideways, and are configured to include two H-shaped element parts.

[0140] More specifically, one element part 34 of the parasitic resonator element 33-1 has a first element 341, a second element 342, and a third element 343. The first element 341 is closest to the main resonator element 21 and extends parallel to a second side (another side) 212 that is perpendicular to one side 211 of the main resonator element 21 and extends at a right angle to the side 211. One end of the second element 342 contacts an approximate center portion of the first element 341 and extends in a direction away from the main resonator element 21. The third element 343 contacts the other end of the second element 342 and extends approximately parallel to the first element 341.

[0141] The other element part 35 of the parasitic resonator element 33-1 includes similar elements 351, 352, and 353 that are symmetrical to the element part 34, and the first element 351 is closest to the second side (one side) 232 of the main resonator element 23.

[0142] Furthermore, the third elements 343 and 353 of the two element parts 34 and 35 of the parasitic resonator element 33-1 are coupled together by a PIN diode 44-1.

[0143] In the parasitic resonator element 33-1, RF chokes 45 and 46 are provided on both sides of the PIN diode 44-1 at the open ends of the third elements 343 and 353 of the two element parts. A control voltage VB is applied to the open end of one of the RF chokes 45, and the other RF choke 46 is grounded (GND).

[0144] The parasitic resonator elements 33-1 and 33-2 have the same configuration of the elements of the element parts 34 and 35 and the PIN diodes 44-1 and 44-2, but since the RF chokes 45 and 46 are located outside the substrate, the positions of the RF chokes 45 and 46 are symmetrical.

[0145] In this embodiment, the parasitic resonator element 30-1 is arranged so as to be able to interact with the main resonator elements 21 and 22, and the parasitic resonator element 30-2 is arranged so as to be able to interact with the main resonator elements 23 and 24. Therefore, the distance between the first element 311 and one side 211 (231) of the main resonator element 21 (23) and the distance between the first element 321 and one side 221 (241) of the main resonator element 22 (24) are 1 / 10λ g It is preferable that the wavelength is 1 / 30λ or less. g It is more preferable that the amount is about 1000 .mu.m.

[0146] Furthermore, the parasitic resonator element 33-1 is arranged so as to be able to interact with the main resonator elements 21 and 23, and the parasitic resonator element 33-2 is arranged so as to be able to interact with the main resonator elements 22 and 24. Therefore, the distance between the first element 341 and the other side 212 (222) of the main resonator element 21 (22), and the distance between the first element 351 and the other side 232 (242) of the main resonator element 23 (24) are 1 / 10λ g It is preferable that the wavelength is 1 / 30λ or less. g It is more preferable that the amount is about 1000 .mu.m.

[0147] In the configuration of this embodiment, when vertically polarized waves are incident and the angle is adjusted in the vertical direction, parasitic resonant elements 30-1 and 30-2 are adjusted, and when horizontally polarized waves are incident and the angle is adjusted in the horizontal direction, parasitic resonant elements 33-1 and 33-2 are adjusted.

[0148] In this configuration, for vertical polarization, one parasitic resonator element 30-1, 30-2 is arranged to be able to interact with each other for two sets of two main resonators (21, 22) and (23, 24), and PIN diodes 41-1, 41-2 are provided to electrically control the parasitic resonators 30-1, 30-2.

[0149] In addition, for horizontally polarized waves, one parasitic resonator element 33-1, 33-2 is arranged to interact with each of two sets of two main resonators (21, 23) and (22, 24), and PIN diodes 44-1, 44-2 are provided to electrically control the parasitic resonators 33-1, 33-2.

[0150] FIG. 20 is a schematic diagram showing the first and second states of the cell 20 of the second embodiment.

[0151] In this embodiment, when the PIN diodes 41-1 and 41-2 are ON, the third elements of the parasitic resonant elements 30-1 and 30-2 that interact in the vertical direction are connected to each other, and the two element parts 31 and 32 are electrically connected, as shown in Fig. 20(a). In this case, due to the element lengths of the two H-shaped element parts 31 and 32 connected by the parasitic resonant elements, the resonant frequency of the element itself becomes the first parasitic resonant frequency fpara1, and the first state is reached.

[0152] On the other hand, when the PIN diodes 41-1 and 41-2 are OFF, as shown in Figure 20(b), there is no connection between the third elements of the parasitic resonant elements 30-1 and 30-2, and the two element parts 31 and 32 are electrically disconnected. At this time, due to the element length of the independent H-shaped element part 31 (32), the resonant frequency of the element itself of the parasitic resonant elements 30-1 and 30-2 becomes the second parasitic resonant frequency fpara2, and the second state is reached.

[0153] Here, in order to perform regular adjustment within the cell 20, the first parasitic resonant frequency fpara1 and the second parasitic resonant frequency fpara2 of the parasitic resonant element 30-1, which interact with each other in the vertical direction, and the first parasitic resonant frequency fpara1 and the second parasitic resonant frequency fpara2 of the parasitic resonant element 30-2 are set to be approximately equal.

[0154] 20(a), when the PIN diodes 44-1 and 44-2 are ON, the third elements of the parasitic resonant elements 33-1 and 33-2 that interact in the lateral direction are connected to each other, and the two element parts 34 and 35 are electrically connected. In this case, due to the element length of the two H-shaped element parts 34 and 35 connected to the parasitic resonant element, the resonant frequency of the element itself becomes the first parasitic resonant frequency fpara1, and the first state is reached.

[0155] On the other hand, when the PIN diodes 44-1 and 44-2 are OFF, as shown in Figure 20(b), there is no connection between the third elements of the parasitic resonant elements 33-1 and 33-2, and the two element parts 34 and 35 are electrically disconnected. At this time, due to the element length of the single independent H-shaped element part 34 (35), the resonant frequency of the single element of the parasitic resonant elements 33-1 and 33-2 becomes the second parasitic resonant frequency fpara2, and the second state is entered.

[0156] In addition, in order to regularly adjust within the cell 20, the first parasitic resonant frequency fpara1 and the second parasitic resonant frequency fpara2 of the parasitic resonant element 33-1, which interact with each other laterally, and the first parasitic resonant frequency fpara1 and the second parasitic resonant frequency fpara2 of the parasitic resonant element 33-2 are set to be approximately equal.

[0157] In addition, in this embodiment, the first and second parasitic resonant frequencies of the parasitic resonant elements 30-1 and 30-2 that interact in the vertical direction may be equal to or different from the first and second parasitic resonant frequencies of the parasitic resonant elements 33-1 and 33-2 that interact in the horizontal direction.

[0158] The reconfigured frequencies when the cell 20 is in the first state and the second state are the same as those shown in Fig. 14(b) and Fig. 14(c) above. Note that the first parasitic resonance frequency and the second parasitic resonance frequency shown in this embodiment may be the same as or different from those in the first embodiment.

[0159] Also in this embodiment, in the first and second states in which the frequency is reconstructed, the absolute value of the difference (reflection phase difference) between the reflection phase in the first state and the reflection phase in the second state at the frequency of the input radio wave is approximately 180°±45°.

[0160] Thus, in this embodiment, the difference in reflection phase between the first state and the second state is approximately 180°, making it possible for the cells 20 to adjust the reflection phase, thereby allowing the reflect array 2 in which the cells 20 are arranged to function as a reflector with adjustable directivity.

[0161] Furthermore, by assembling such cells 20, the reflect array according to this embodiment can function as an RIS that can adjust the reflection angle for two polarized waves, that is, vertically polarized waves and horizontally polarized waves.

[0162] Therefore, in this embodiment, when considering polarization in one direction, the number of parasitic resonant elements and PIN diodes arranged is half the number of the main resonant elements, which are reflecting elements, so the number of parts per reflect array can be reduced.

[0163] ((Example)) The inventors created a comparative example and a measurement model of the present invention to verify whether the model reflectarray functions as a reflector with adjustable directivity.

[0164] (Example 1 (Comparative Example)) 21 is a schematic diagram of a measurement model of the main resonant element and the parasitic resonant element in each cell 9C of the reflectarray according to the comparative example, in which the RF choke is omitted.

[0165] 21, in order to accommodate both vertically polarized waves and horizontally polarized waves, a parasitic resonator element is provided for each of the polarization directions for one main resonator element. That is, two parasitic resonator elements 80C and 83 are provided adjacent to one main resonator element 70C in two orthogonal directions.

[0166] A parasitic resonator element 80C in FIG. 21 that corresponds to vertically polarized waves differs from the configuration of the comparative example in FIG. 8 in that it includes an element part 81C that is made up of three elements and an element part 82 that is made up of one linear element.

[0167] The element part 81C has a first element 811, a second element 812, and a third element 813.

[0168] The first element 811 is closest to the main resonance element 70C and extends parallel to one side of the main resonance element 70C. One end of the second element 812 contacts the approximate center of the first element 811 and extends in a direction away from the main resonance element 70C. The third element 813 contacts the other end of the second element 812 and extends approximately parallel to the first element 811.

[0169] Parasitic resonator element 83, which is compatible with horizontally polarized waves, has a configuration in which the orientation of parasitic resonator element 80C is changed, and includes element part 84 made up of three elements and element part 85 made up of one linear element.

[0170] The element part 84 has a first element 841 , a second element 842 , and a third element 843 .

[0171] The first element 841 is closest to the main resonance element 70C and extends parallel to one side of the main resonance element 70C. One end of the second element 842 contacts approximately the center of the first element 841 and extends in a direction away from the main resonance element 70C. The third element 843 contacts the other end of the second element 842 and extends approximately parallel to the first element 841.

[0172] The main resonator element 70C according to this configuration has a rectangular shape with a portion missing. Specifically, the first side 701 of the rectangular shape, which corresponds to vertical polarization and faces the first element 811 closest to the parasitic resonator element 80C, and the second side 702, which corresponds to horizontal polarization and faces the first element 841 closest to the parasitic resonator element 83, have rectangular recesses in the center.

[0173] The first elements 811 and 841 of the parasitic resonator elements 80C and 83, which are closest to the recessed sides 701 and 702 of the main resonator element 70C, are bent along the recessed sides 71C and 72C.

[0174] Furthermore, in this configuration, two element parts 81C and 82 of the parasitic resonator element 80C are coupled by a PIN diode 91, and two element parts 84 and 85 of the parasitic resonator element 83 are coupled by a PIN diode 94.

[0175] Figure 22 is a graph showing the reflection phase and phase difference when the PIN diode is ON and OFF for the comparative example model of Figure 21. In Figure 22(a), the solid line shows the reflection phase when the PIN diode is ON, and the dotted line shows the reflection phase when it is OFF. In Figure 22(a), the vertical axis represents the reflection phase, and the horizontal axis represents the frequency.

[0176] Figure 22(b) shows the phase difference between the reflection phase when the PIN diode in Figure 22(a) is ON and the reflection phase when it is OFF. In Figure 22(b), the vertical axis represents the reflection phase difference, and the horizontal axis represents frequency.

[0177] The graph in Figure 22(a) shows the phase of the reflected radio wave returning to the Z axis when the radio wave is incident from the Z axis as in Figure 7(b). As shown in Figure 22(a), the reflection phase of the reflected wave when ON and the reflection phase of the reflected wave when OFF shift at approximately the same slope in the 25 to 30 GHz band.

[0178] Therefore, in the band of 25.4 to 30 GHz in the phase difference graph of FIG. 22(b), the phase difference is +180° or −180°, and the absolute value of the phase difference is within the range of 180°±45° indicated by hatching.

[0179] When the absolute value of this phase difference is within 180°±45°, it functions as a reflector with adjustable directivity, so the frequency range in which it operates particularly well is above 135° or below -135° in Figure 22(b).

[0180] FIG. 23 is a diagram showing the reflection intensity of the comparative example model of FIG. 21 when the PIN diode is ON and OFF.

[0181] In Figure 23, the solid line indicates the reflection intensity when the PIN diode is ON, and the dotted line indicates the reflection intensity when it is OFF. The dips in the waveform indicate the resonance positions.

[0182] 23, the drop (1) when the PIN diode is ON is the loss due to resonance of the main resonant element, and the drop (2) is the loss due to resonance of the parasitic resonant element, which is made up of one element part, in the ON state.

[0183] The drops (3) and (4) when the PIN diode is turned off are losses due to resonance caused by reconfiguration (coupling) due to interactions in the fundamental mode.

[0184] Here, it is preferable that the reflection intensity is large (for example, about 0 to -3 dB) within the band (phase 180°±30°). When the measurement model of this comparative example is used with radio waves at a frequency of 28 GHz, this reflection intensity is satisfied.

[0185] Here, when applying this measurement result to the example of frequency behavior in Fig. 11, as shown in Fig. 23, the main resonant frequency fmain of the main resonant element of the element alone is 29 GHz (1), and the first parasitic resonant frequency fcpara1 of the parasitic resonant element of the element alone is 18 GHz (2). Also, the second parasitic resonant frequency fcpara2 of the parasitic resonant element of the element alone is 29 GHz, the same as the main resonant frequency. Then, in the second state, the resonant frequency fr2a reconstructed by the interaction is 32.0 GHz (4), and fr2b is 25.4 GHz (3).

[0186] Therefore, the frequency band between the two reconstructed resonant frequencies fr2a and fr2b shown in Figure 11(b) is the frequency band where a frequency difference of 180°±45° is realized, as shown in Figure 22(b), and 25.4 to 32.0 GHz is the frequency range in which this comparative example model operates suitably.

[0187] (Example 2 (Second embodiment of the present invention)) 24 is a schematic diagram of a measurement model of the main resonant element and the parasitic resonant element in each cell of the reflectarray according to the present invention. Note that the RF choke is omitted in FIG.

[0188] Like the second embodiment, this measurement model corresponds to two directions of polarization, and each cell 20C of the multiple cells has four main resonance elements 21C, 22C, 23C, and 24C arranged two by two vertically and horizontally, and four parasitic resonance elements 30-1C, 30-2C, 33-1C, and 33-2C sandwiched between adjacent main resonance elements.

[0189] In this measurement model, the parasitic resonant elements 30-1C, 30-2C, 33-1C, and 33-2C are provided adjacent to each of the four main resonant elements 21C, 22C, 23C, and 24C in two directions perpendicular to each other.

[0190] The main resonator element according to this configuration has a rectangular shape with a portion missing. Specifically, two sides of each rectangle are recessed: first sides 211C, 221C, 231C, and 241C, which correspond to vertically polarized waves and face the nearest first elements of parasitic resonators 30-1C and 30-2C; and first sides 212C, 222C, 232C, and 242C, which correspond to horizontally polarized waves and face the nearest first elements of parasitic resonators 33-1C and 33-2C.

[0191] The first elements 311C, 321C, 341C, and 351C that are closest to the recessed side of the main resonance element are bent along the recessed side.

[0192] Furthermore, element part 31C of parasitic resonator element 30-1C, which corresponds to vertical polarization, has a fourth element 314 that is orthogonal to second element 312 and is provided between first element 311C and third element 313. Similarly, element parts 32C of parasitic resonator elements 30-1C and 30-2C and element parts 34C and 35C of parasitic resonator elements 33-1C and 33-2C also have fourth elements 324, 344, and 354.

[0193] Figure 25 is a graph showing the reflection phase and phase difference when the PIN diode is ON and OFF for the measurement model of the present invention shown in Figure 24. In Figure 25(a), the solid line shows the reflection phase when the PIN diode is ON, and the dotted line shows the reflection phase when it is OFF. In Figure 25(a), the vertical axis represents the reflection phase, and the horizontal axis represents the frequency.

[0194] Figure 25(b) shows the phase difference between the reflection phase when the PIN diode in Figure 25(a) is ON and the reflection phase when it is OFF. In Figure 25(b), the vertical axis represents the reflection phase difference, and the horizontal axis represents frequency.

[0195] The graph in Figure 25(a) shows the phase of the reflected radio wave returning to the Z axis when the radio wave is incident from the Z axis as in Figure 7(b). As shown in Figure 26(a), the reflection phase of the reflected wave when ON and the reflection phase of the reflected wave when OFF shift at approximately the same slope in the 25 to 30 GHz band.

[0196] Therefore, in the band of 25.7 to 29.9 GHz in the graph of FIG. 26(b), the phase difference is +180° or −180°, and the absolute value of the phase difference in this range is within the hatched range of 180°±45°.

[0197] When the absolute value of this phase difference is within 180°±45°, it functions as a reflector with adjustable directivity, so the frequency range in which it operates particularly well is above 135° or below -135° in Figure 25(b).

[0198] FIG. 26 is a diagram showing the reflection intensity of the measurement model of the present invention shown in FIG. 24 when the PIN diode is ON and OFF.

[0199] In Figure 26, the solid line indicates the reflection intensity when the PIN diode is OFF, and the dotted line indicates the reflection intensity when it is ON. The dips in the waveform indicate the resonance positions.

[0200] 26, the drop (1) when the PIN diode is OFF is the loss due to resonance of the main resonant element, and the drop (2) is the loss due to resonance of the parasitic resonant element, which is composed of one element part in the OFF state.

[0201] The dips (3) and (4) when the PIN diode is ON are losses due to resonances that are reconstructed (coupling) due to interactions in higher-order modes, while dip (5) is a loss due to the fundamental resonance mode of the parasitic resonant element that does not interact.

[0202] Here, it is preferable that the reflection intensity is large (for example, about 0 to -3 dB) within the band (phase 180°±30°). When this measurement model of the present invention is used with radio waves at a frequency of 28 GHz, this reflection intensity is satisfied.

[0203] For example, when applying this measurement result to the frequency example shown in FIG. 14, as shown in FIG. 26, the main resonant frequency fmain of the main resonant element and the parasitic resonant frequency fpara1 of the second mode of the parasitic resonant element in the first state are 28 GHz (1). The parasitic resonant frequency of the fundamental mode of the parasitic resonant element in the first state is 10 GHz (5). The second parasitic resonant frequency fpara2 of the parasitic resonant element of the element alone is 18 GHz (2). In the first state, the resonant frequency fr11 reconstructed by the interaction is 29.9 GHz (3), and fr12 is 25.7 GHz (4).

[0204] Therefore, the frequency band between the two reconstructed resonant frequencies fr11 and fr12 shown in Figure 14(b) is the frequency band where a frequency difference of 180°±45° is realized, as shown in Figure 25(b), and 25.7 to 29.9 GHz is the frequency range in which this model operates suitably.

[0205] FIG. 27 is a radar chart showing reflections of the measurement model of the present invention shown in FIG. 24 when the target reflection angle is 30°.

[0206] In this measurement, the target reflection angle of 30° was achieved by turning the cell diode on and off, as shown in FIG. 29(b) described later.

[0207] As shown in Figure 27, when radio waves are incident from the surface in a direction perpendicular to the reflectarray surface, they are largely reflected in the 30° and -30° directions. This means that by controlling the target angle at 30°, it is possible to reflect radio waves in the desired directions of 30° and -30°.

[0208] In this way, in the reflectarray of the present invention, even if the number of parasitic reflecting elements (parasitic resonating elements) and diodes for control is reduced, the directivity of the radio waves of the reflectarray can be directed in a desired direction.

[0209] (Control of the second embodiment) FIG. 28 is a diagram showing an arrangement of a plurality of cells 20 and subarrays in the reflectarray 2 according to the second embodiment of the present invention.

[0210] As shown in FIG. 28, the reflect array 2 can also be formed by arranging a plurality of cells 20 according to the second embodiment in the vertical and horizontal directions on the substrate 11D.

[0211] In this embodiment, each of the plurality of cells 20 has two horizontal subarrays XSA and XSB in the vertical direction, and also has two vertical subarrays YSA and YSB in the horizontal direction.

[0212] The horizontal subarray XS is an area where the same phase shift is given when adjusting the angle with respect to horizontal polarization, and is a horizontally long area where main resonant elements, parasitic resonant elements, and main resonant elements are arranged in the X direction (horizontal direction) as (21, 33-1, 23) / (22, 33-2, 24). In the horizontal subarray XS, the parasitic resonant elements 33-1 and 33-2, whose resonance value is electrically controlled by PIN diodes 44-1 and 44-2, are coupled to the two horizontally arranged main resonant elements (21, 23) and (22, 24), respectively, to adjust the reconstructed resonant frequency.

[0213] The vertical subarray YS is an area where the same phase shift is given when adjusting the angle with respect to vertical polarization, and is a vertically long area where main resonant elements, parasitic resonant elements, and main resonant elements are arranged in the Y direction (vertical direction) as (21, 30-1, 22) / (23, 30-2, 24). In the vertical subarray YS, the parasitic resonant elements 30-1 and 30-2, whose resonance value is electrically controlled by PIN diodes 40-1 and 40-2, are coupled to the two vertically arranged main resonant elements (21, 22) and (23, 24), respectively, to adjust the reconstructed resonant frequency.

[0214] FIG. 29 is an explanatory diagram of a voltage application pattern of cells arranged in the reflect array 2 of the second embodiment.

[0215] In the reflectarray 2 of FIG. 28, when changing the horizontal angle with respect to horizontally polarized waves, the horizontal subarrays XS indicated by bold frames are controlled to be turned ON / OFF in the vertical direction as shown in FIG. 29(a).

[0216] On the other hand, in the reflectarray 2 of FIG. 28, when changing the vertical angle with respect to vertically polarized waves, the vertical subarray YS indicated by a bold frame is controlled to be turned on and off in the horizontal direction as shown in FIG. 29(b).

[0217] Here, in the reflectarray 2 of the present embodiment having the configuration shown in Figure 28, if the distance (inter-element distance) between the main resonant elements 21, 23 in the horizontal subarray YS is ddi, the distance between horizontally adjacent horizontal subarrays XS, more specifically, the distance Dds between the PIN diodes 44-1, which are electrical switches, of horizontally adjacent subarrays XS is 2ddi.

[0218] Here, the spacing Ddi between the main resonance elements 21 and 23 is preferably set to approximately 1 / 2λ0, where λ0 is the free space wavelength of the radio wave frequency. For example, it is 1 / 2λ0±20%. Therefore, in this embodiment, the distance Dds between the horizontal subarrays in the X direction is two times the spacing ddi between the main resonance elements 21 and 23, and therefore the spacing between adjacent horizontal subarrays XS is λ0.

[0219] The same is true for the vertical subarrays YS, and the distance between the vertical subarrays YS in the Y direction is two times the distance between the main resonance elements 21 and 22, so the distance between adjacent vertical subarrays YS is λ0.

[0220] Third Embodiment FIG. 30 is a diagram showing an arrangement of a plurality of cells and subarrays in the reflect array 3 according to the third embodiment of the present invention.

[0221] In this embodiment, unlike the first embodiment in which the cells are regularly arranged in the vertical and horizontal directions as shown in FIG. 6, the plurality of cells 50 in the reflect array 3 are arranged in a staggered pattern.

[0222] More specifically, in this embodiment, each of the multiple cells 50 has two main resonance elements 201 and 202, and a parasitic resonance element 301 coupled to the two main resonance elements 201 and 202, arranged in the X direction (horizontal direction, first direction) in the order of the main resonance element 201, the parasitic resonance element 301, and the main resonance element 202. In each cell 50, the parasitic resonance element 301, the resonance value of which is electrically controlled by a PIN diode 401, is coupled to the two main resonance elements 201 and 202 arranged horizontally, thereby adjusting the reconfigured resonance frequency.

[0223] Furthermore, the plurality of cells 50 are provided in the X direction and the Y direction perpendicular to the X direction, and in the reflect array 3, the main resonant elements 200, which are reflective elements, are arranged at equal intervals at least in the horizontal direction.

[0224] In this embodiment, each of the multiple cells 50 has a main resonant element 201, a parasitic resonant element 301, and a main resonant element 202 arranged in the X direction, so that each cell 50 becomes a horizontal sub-array, which is an area where the same phase shift is given when adjusting the angle with respect to horizontal polarization.

[0225] In this embodiment, a cell group of one cell (a cell group indicated by a dotted line in FIG. 30 ) and a cell group of a second cell adjacent to the first cell in the Y direction (a cell group indicated by a two-dot chain line in FIG. 30 ) are shifted in the horizontal direction (X direction) for each row, so that the multiple cells are arranged in a staggered manner. Note that the horizontal shift width between the cell group of the first cell and the cell group of the second cell is the sum of one main resonance element and one parasitic resonance element. As a result, in the staggered arrangement, the main resonance element 202-1 at the other end side (+X side) of the X direction of one horizontal subarray (XS1) and the main resonance element 201-2 at one end side (−X side) of the X direction of the second horizontal subarray (XS2) adjacent to the first horizontal subarray (XS1) in the Y direction are positioned to coincide (overlap) with each other in the X direction.

[0226] Fig. 31 is an explanatory diagram of voltage application patterns of horizontal subarrays XS arranged in the reflectarray 3 of the third embodiment. Fig. 31 shows the voltage application patterns when radio waves are incident from the direction of the Z axis perpendicular to the surface of the reflectarray 3, with (a) the voltage application pattern when the target angle is 0°, (b) the voltage application pattern when the target angle is 30°, (c) the voltage application pattern when the target angle is 45°, and (d) the voltage application pattern when the target angle is 60°. Specifically, the target angles in Figs. 31(b) to (d) correspond to the voltage application patterns when the target angle in the X-axis direction (φ=0 degree direction) is 30 degrees (φ=0 degree, θ=30 degrees), 45 degrees (φ=0 degree, θ=45 degrees), and 60 degrees (φ=0 degree, θ=60 degrees).

[0227] In the present invention, as described above, a voltage application pattern (ON / OFF pattern) is calculated within a microcomputer for each incident wave source position and target angle as a directivity instruction for the reflectarray. The target angle of the reflection angle for horizontally polarized waves in Figure 30 corresponds to the lateral (horizontal) tilt angle with respect to the Z axis, which is the incident direction.

[0228] In the reflect array 3 of this embodiment, when the angle is changed in the horizontal direction relative to the horizontal polarization, the horizontal subarray YS is ON / OFF controlled so that it extends in the vertical direction while increasing / decreasing or meandering, including the main resonant elements whose X direction coincides, as shown in Figures 31(b) to 31(d).

[0229] It is known that the greater the spacing between subarrays in an antenna or reflector, the more likely it is that a phenomenon called a grating lobe will occur, in which a beam is radiated in an undesired direction different from the intended direction. When a grating lobe occurs, the scanning angle of the arrayed reflecting elements in the direction of the beam narrows. This reduction in the beam scanning angle due to grating lobes hardly occurs when the element spacing d is 1 / 2λ0, but as the element spacing d becomes larger than 1 / 2λ0, the reduction in the scanning angle becomes greater.

[0230] In this embodiment, the distance di between the main resonant elements 201 and 202 in the horizontal subarray XS is set to 1 / 2λ0±20%, where λ0 is the free space wavelength of the radio wave frequency. In this case, the distance between adjacent horizontal subarrays XS (cells 50), i.e., the distance D3 between the PIN diodes 401-1 and 401-2 that form the connection points of the parasitic resonant elements 301-1 and 301-2, is equal to the distance di between the main resonant elements in the X direction, and is 1 / 2λ0±20%, just like di.

[0231] Therefore, in this embodiment, when the reflection direction is set in the horizontal direction (X direction) as shown in Figures 31(b) to 31(d), the spacing between horizontal subarrays in the X direction is approximately 1 / 2λ0, which is thought to reduce the angular region in which a reduction in the beam scanning angle due to grating lobes occurs.

[0232] 30 and 31 show a reflectarray 3 whose horizontal angle is adjustable with respect to horizontally polarized waves, and an example is shown in which the first direction is the horizontal direction (X direction) in Fig. 30, but the reflectarray of this embodiment can also be configured so that its vertical angle is adjustable with respect to vertically polarized waves. In that case, the first direction is the Y direction (vertical direction), and each of the multiple cells is similarly arranged in a staggered manner with the main resonance element, parasitic resonance element, and main resonance element lined up in the Y direction (vertical direction).

[0233] With this configuration, the reflect array 3 of this embodiment can change the reflection angle for polarized waves in a specific direction without causing a reduction in the beam scanning angle due to grating lobes.

[0234] Also in this embodiment, for a specific polarized wave in one direction (horizontal polarized wave in the example of FIG. 30), one parasitic resonant element and one PIN diode for electrically controlling the parasitic resonant element are provided for two main resonant elements in the corresponding cell. That is, one diode is sufficient for two reflecting elements.

[0235] Therefore, in this embodiment, the number of parasitic resonant elements and PIN diodes is half the number of the main resonant elements, which are reflective elements, so the number of parts per reflect array, i.e., the number of parasitic resonant elements and PIN diodes relative to the main resonant elements in the reflect array, can be reduced.

[0236] <Fourth embodiment> Fig. 32 is a diagram showing cells in the case of horizontally polarized waves in the reflect array 4 according to the fourth embodiment of the present invention. Fig. 33 is a diagram showing cells in the case of vertically polarized waves in the reflect array 4 according to the fourth embodiment of the present invention.

[0237] In this embodiment, the cell boundary changes depending on the direction of polarization. In the case of horizontal polarization (polarization with an electric field in the X-axis direction), the main resonance element, parasitic resonance element, and main resonance element lined up in the X-axis direction form a horizontally long unit cell, as shown by the dotted line in Fig. 32. On the other hand, in the case of vertical polarization (polarization with an electric field in the Y-axis direction), the main resonance element, parasitic resonance element, and main resonance element lined up in the Y-axis direction form a vertically long unit cell, as shown by the dashed-dotted line in Fig. 33.

[0238] In the reflectarray 4 of this embodiment, in addition to the horizontal subarrays XS, the vertical subarrays YS are also arranged in a staggered manner.

[0239] 32 , similarly to the third embodiment, the reflectarray 4 of this embodiment has a plurality of horizontal subarrays XS, each of which has two main resonant elements 201, 202 and one parasitic resonant element 301 provided between and coupled to the two main resonant elements 201, 202, with the main resonant element 201, parasitic resonant element 301, and the main resonant element 202 aligned in the horizontal direction. In the case of horizontal polarization, the horizontal subarray XS serves as a unit cell. In each horizontal subarray XS, the parasitic resonant element 301, the resonance value of which is electrically controlled by a PIN diode 401, is coupled to the two horizontally aligned main resonant elements 201, 202, thereby adjusting the reconstructed resonant frequency.

[0240] 33, there are multiple vertical subarrays YS, each of which has two main resonance elements and one parasitic resonance element 302 provided between and coupled to the two main resonance elements 202, 201, with the main resonance element 202, parasitic resonance element 302, and main resonance element 201 aligned in the vertical direction. In the case of vertical polarization, the vertical subarray YS serves as a unit cell. In each vertical subarray XS, the parasitic resonance element 302, the resonance value of which is electrically controlled by a PIN diode 402, is coupled to the two vertically aligned main resonance elements 202, 201, thereby adjusting the reconstructed resonance frequency.

[0241] In this embodiment, the main resonant elements 200, which are reflective elements, are arranged at equal intervals in the vertical and horizontal directions, that is, in a square arrangement.

[0242] In the horizontal direction, as in the third embodiment, the multiple horizontal subarrays XS are arranged in a staggered pattern so that the horizontal positions of the main resonance element 202-1 on the other horizontal end side (+X side) of one horizontal subarray XS1 and the main resonance element 201-2 on one horizontal end side (-X side) of the second horizontal subarray XS2 adjacent to the one horizontal subarray XS1 in the vertical direction are aligned.

[0243] Furthermore, the parasitic resonator element 301-1 of the vertical subarray YS1 is arranged adjacent to the main resonator element 202-1 at the other horizontal end of one horizontal subarray XS1 and the main resonator element 201-2 at one horizontal end of the second horizontal subarray XS2, so that the multiple vertical subarrays YS are arranged in a staggered pattern.

[0244] By connecting in this manner, the multiple vertical subarrays YS are also staggered so that the horizontal positions of the main resonance element 201-2 on the other vertical end side (+Y side) of one vertical subarray YS1 and the main resonance element 202-2 on one vertical end side (-Y side) of a second vertical subarray YS2 adjacent to the first vertical subarray YS1 in the horizontal direction are aligned.

[0245] In other words, the main resonant elements 200 are arranged at equal intervals vertically and horizontally on the substrate 11F of the reflect array 4, and in odd-numbered rows such as the first row, the parasitic resonant elements 301 (control elements) are present, absent, present, absent, ... in the horizontal direction, and in even-numbered rows such as the second row, the parasitic resonant elements 301 are present, absent, present, absent, ... in the horizontal direction. Similarly, in odd-numbered columns such as the first column, the parasitic resonant elements (control elements) 302 are present, absent, present, absent, ... in the vertical direction, and in odd-numbered columns such as the second column, the parasitic resonant elements 302 are present, absent, present, absent, ... in the vertical direction,

[0246] With this configuration, the reflect array 4 of this embodiment can change the reflection angle for vertically polarized waves and horizontally polarized waves.

[0247] Fig. 34 is an explanatory diagram of a voltage application pattern of a subarray in the reflectarray 4 of the fourth embodiment. Fig. 34(a) shows an example where the target angle is 30 degrees (φ=0 degrees, θ=30 degrees) in the X-axis direction (φ=0 degree direction) for horizontally polarized waves. Fig. 34(b) shows an example where the target angle is 30 degrees (φ=30 degrees, θ=0 degrees) in the Y-axis direction (θ=0 degree direction) for vertically polarized waves.

[0248] In the reflectarray 4 of this embodiment, when the angle of the vertical direction with respect to the horizontal polarization is changed, as shown in Fig. 34(a), the horizontal subarray XS shown in a thick frame is ON / OFF controlled so that it extends in the vertical direction while increasing or decreasing, including the main resonance element whose X direction coincides with the horizontal subarray XS. Note that when the target angle is 30°, the ON cells extend in the vertical direction while increasing or decreasing as shown in Fig. 34(a), but when the target angle is other angles, the ON cells may extend in the vertical direction while meandering as shown in Fig. 31(c) and (d) above.

[0249] In this embodiment, when the reflection direction is set in the horizontal direction (X direction) as shown in FIG. 34(a), the spacing between horizontal subarrays in the X direction is approximately 1 / 2λ0, as in the third embodiment, and therefore it is thought that the angular region in which reduction in the beam scanning angle due to grating lobes occurs can be reduced.

[0250] On the other hand, in the reflectarray 4 of this embodiment, when the angle of the horizontal direction with respect to the vertical polarization is changed, the vertical subarray YS is ON / OFF controlled so that it extends in the horizontal direction while increasing or decreasing, including the main resonance elements whose Y direction coincides, as shown in Fig. 34(b). Note that when the target angle is 30°, the ON cells extend in the horizontal direction while increasing or decreasing, as shown in Fig. 34(b), but when the target angle is other angles, the ON cells may extend in the horizontal direction while meandering.

[0251] In this embodiment, the main resonant elements 200 are arranged at equal intervals in the vertical and horizontal directions, and therefore the interval diy between the main resonant elements 202, 201 in the horizontal subarray YS is also set to 1 / 2λ0±20%, where λ0 is the free space wavelength of the radio wave frequency. In this case, the interval between adjacent vertical subarrays YS shown in Fig. 33, i.e., the interval D3y between the PIN diodes 402-1, 402-2 which are the connection points of the parasitic resonant elements 302-1, 302-2, is equal to diy in the Y direction and is therefore 1 / 2λ0±20%, like diy.

[0252] Therefore, in this embodiment, when the reflection direction is set in the vertical direction (Y direction) as shown in FIG. 34(b), the spacing between horizontal subarrays in the Y direction is approximately 1 / 2λ0, which is thought to reduce the angular region in which a reduction in the beam scanning angle due to grating lobes occurs.

[0253] Example 3 Here, Fig. 35 shows a radar chart of vertically polarized waves of the measurement model of the fourth embodiment. Fig. 35(a) shows the reflection when the target reflection angle is 0°, and Fig. 35(b) shows the reflection when the target reflection angle is 30°.

[0254] In this measurement, the target reflection angles of 0° and 30° were achieved by turning the cell diode on and off for vertically polarized waves, as shown in FIG. 34(b).

[0255] In the case of a target angle of 0° shown in Figure 35(a), when radio waves are incident from a direction perpendicular to the surface of the reflectarray, it can be seen that the radio waves are largely reflected in the 0° direction. This means that by controlling the target angle at 0°, it is possible to reflect the radio waves in the desired direction of 0°.

[0256] In the case of a target angle of 0° shown in Figure 35(b), when radio waves are incident from a direction perpendicular to the surface of the reflectarray, it can be seen that the radio waves are largely reflected in the 30° direction. This means that by controlling the target angle at 30°, it is possible to reflect the radio waves in the desired direction of 30°.

[0257] From these measurement results, it can be said that the reflectarray of this embodiment can direct the directivity of the radio waves of the reflectarray in the desired direction. Furthermore, since the waves were reflected at the target angle in both cases of target angles of 0° and 30°, it can be said that the reflection angle for vertically polarized waves can be changed.

[0258] 35 shows an example of measuring vertically polarized waves, but it can be assumed that the reflectarray of this embodiment can also be used for horizontally polarized waves to orient the directivity of radio waves from the reflectarray in a desired direction. It can also be assumed that the angles for vertically polarized waves and horizontally polarized waves can be changed while reducing the angle region where a reduction in the beam scanning angle occurs due to the occurrence of grating lobes.

[0259] (Modified example of reflectarray) In the first to fourth embodiments, the reflectarray included in the wireless communication device has been described as a reflector capable of changing the reflection angle, but the reflectarray of the present invention may be a fixed reflectarray that reflects radio waves in a direction other than specular reflection. In this case, the reflectarray also has a plurality of cells regularly arranged. Each of the plurality of cells has at least two main resonant elements and at least one parasitic resonant element, and the parasitic resonant element is coupled to two or more adjacent main resonant elements.

[0260] The reflectarray and wireless communication device according to exemplary embodiments of the present invention have been described above. However, the present invention is not limited to the specifically disclosed embodiments, and various modifications and changes are possible without departing from the scope of the claims.

[0261] This international application claims priority based on Japanese Patent Application No. 2021-114605, filed on July 9, 2021, and Japanese Patent Application No. 2022-011317, filed on January 27, 2022, and the entire contents of Nos. 2021-114605 and 2022-011317 are incorporated herein by reference. [Explanation of symbols]

[0262] 1, 2, 3, 4 Reflectarray 5. Control section 10, 10α, 10A, 10B, 10C, 20, 20C cells 100 Wireless communication equipment 11, 11α, 11D, 11E, 11F board 111 first substrate 112, 112α Second substrate 12 Conductor (conductor pattern) 14 Ground plane 21, 22, 23, 24, 21C, 22C, 23C, 24C Main resonator element 211, 221, 231, 241 One side of the resonator element 30, 30A, 30B Parasitic resonant elements 30-1, 30-2, 30-1C, 30-2C Parasitic resonant elements 33-1, 33-2, 33-1C, 33-2C Parasitic resonant elements 31, 32, 31A, 32A, 32B, 32B element parts 311, 321, 311C, 321C 1st element 312, 322, 312B, 322B Second element 313, 323, 313A, 323A 3rd element 34, 35, 34C, 35C element parts 341, 351, 341C, 351C First element 342, 352 Second element 343, 353 Third Element 41, 41-1, 41-2, PIN diode (electrical switch) 42, 43 RF choke 44-1, 44-2, PIN diode (electrical switch) 45, 45 RF choke 50 cells 201 Main resonator element on one end (main resonator element, reflector element) 202 Main resonator element on the other end (main resonator element, reflector element) 202-1 Main resonator element at the other end of one horizontal subarray 201-2 Main resonator element at one end of the second horizontal subarray 301, 302 Parasitic resonant element 301-1 Parasitic resonant elements of one horizontal subarray 301-2 Parasitic resonators of the two horizontal subarrays 302-1 Parasitic resonant element of one vertical subarray 302-2 Parasitic resonators in the two vertical subarrays 401, 402 PIN diode (electrical switch) 401-1 PIN diodes in one horizontal subarray 401-2 PIN diodes in the second horizontal subarray 402-1 PIN diodes in one vertical subarray 402-2 PIN diodes in the second vertical subarray XS horizontal sub-array XSA, XSB lateral sub-arrays XS1 horizontal sub-array (one horizontal sub-array) XS2 horizontal sub-array (second horizontal sub-array) YS vertical sub-array YSA, YSB vertical sub-arrays YS1 vertical sub-array (one vertical sub-array) YS2 horizontal sub-array (second vertical sub-array)

Claims

1. A reflectarray that can set the reflection angle of radio waves to an angle other than specular reflection, A plurality of cells arranged in an array, Each of the plurality of cells has at least two main resonant elements and one parasitic resonant element coupled to the at least two main resonant elements, The parasitic resonator element is capable of adjusting a resonant frequency, and is coupled to the at least two adjacent main resonator elements to adjust the resonant frequency of the main resonator element, thereby adjusting the reflection phase of the reflectarray surface; The element spacing of the main resonance element is ½λ 0 ±20%, where λ 0 is the free space wavelength of the frequency of the radio wave. Reflect array.

2. The main resonance element resonates at a main resonance frequency when used alone, the parasitic resonant element resonates at a first parasitic resonant frequency or a second parasitic resonant frequency when used alone; In the cell, when the resonant frequency of one parasitic resonant element is set to the first parasitic resonant frequency, the parasitic resonant element couples with two or more adjacent main resonant elements to create a first state; In the cell, when the resonant frequency of one parasitic resonant element is set to the second parasitic resonant frequency, the parasitic resonant element couples with two or more adjacent main resonant elements to create a second state; The absolute value of the difference between the reflection phase in the first state and the reflection phase in the second state at the frequency of the radio wave is 180°±45°. The reflect array according to claim 1 .

3. a fundamental mode of the first parasitic resonance frequency and a fundamental mode of the second parasitic resonance frequency are lower than a main resonance frequency of the element alone; One of the higher modes of the first parasitic resonance frequency has a value that is the same as or close enough to the main resonance frequency of the element alone so that they can interact with each other. The reflect array according to claim 2 .

4. When the deviation between the frequency of the incident radio wave and the main resonant frequency of the element unit is within ±20% of the main resonant frequency of the element unit, The absolute value of the difference between the reflection phase in the first state and the reflection phase in the second state is 180°±45°, and the angle at which the radio wave is reflected can be changed. The reflect array according to claim 2 or 3.

5. The parasitic resonant element is electrically controlled to adjust the resonant frequency to the first parasitic resonant frequency or the second parasitic resonant frequency. The reflect array according to claim 2 .

6. The parasitic resonant element can adjust the resonant frequency to the first parasitic resonant frequency or the second parasitic resonant frequency by turning on / off an electric switch that is a PIN diode, an FET, or a transistor. The reflect array according to claim 5 .

7. When the electrical control of the parasitic resonant element is ON, the resonant frequency of the parasitic resonant element that is closest to the resonant frequency of the main resonant element is set as a first parasitic resonant frequency of the element alone; When the electrical control of the parasitic resonant element is OFF, if the resonant frequency of the parasitic resonant element that is closest to the resonant frequency of the main resonant element is set as the second parasitic resonant frequency of the element alone, |First parasitic resonance frequency of the element alone−Main resonance frequency of the element alone|<|Second parasitic resonance frequency of the element alone−Main resonance frequency of the element alone|, In the first state, the first parasitic resonant frequency of the element alone and the main resonant frequency of the element alone interact to form two spaced apart reconfiguration frequencies. The reflect array according to claim 2 or 3.

8. A first parasitic resonance frequency of the element alone and a main resonance frequency of the element alone are |First parasitic resonance frequency of the element alone−Main resonance frequency of the element alone| / Main resonance frequency of the element alone≦3% The relationship is The reflect array according to claim 7 .

9. the plurality of cells are regularly arranged, Each of the plurality of cells has two main resonant elements and one parasitic resonant element provided between the two main resonant elements. The reflect array according to claim 1 .

10. Each of the plurality of cells includes four main resonance elements arranged two by two in the vertical and horizontal directions, and four parasitic resonance elements sandwiched between adjacent main resonance elements, the parasitic resonator elements are provided adjacent to each of the four main resonator elements in two directions orthogonal to each other, a parasitic resonator element sandwiched between two main resonator elements arranged vertically couples the two adjacent main resonator elements arranged vertically, A parasitic resonator element sandwiched between two main resonator elements arranged side by side couples the adjacent two main resonator elements arranged side by side, The reflect array can change the reflection angle for vertically polarized waves and horizontally polarized waves. The reflect array according to claim 1 .

11. each of the plurality of cells includes two main resonance elements and one parasitic resonance element coupled to the two main resonance elements, the main resonance element, the parasitic resonance element, and the main resonance element being arranged in this order in a first direction; the plurality of cells are provided in the first direction and in a second direction perpendicular to the first direction, the main resonance elements are arranged at equal intervals in the first direction, The plurality of cells are arranged in a staggered pattern so that the positions in the first direction of a main resonance element on the other end side of one cell in the first direction and a main resonance element on one end side of a second cell adjacent to the one cell in the second direction are aligned with each other. The reflect array according to claim 1 .

12. The reflect array is a plurality of horizontal subarrays each having two main resonance elements and one parasitic resonance element coupled to the two main resonance elements, such that a main resonance element, a parasitic resonance element, and another main resonance element are arranged in a horizontal direction; a plurality of vertical subarrays each having two main resonance elements and one parasitic resonance element coupled to the two main resonance elements, such that a main resonance element, a parasitic resonance element, and another main resonance element are arranged in a vertical direction; The main resonance elements are arranged at equal intervals in the vertical and horizontal directions, the plurality of horizontal subarrays are arranged in a staggered manner so that a main resonance element at the other end of one horizontal subarray in the horizontal direction and a main resonance element at one end of a second horizontal subarray adjacent to the one horizontal subarray in the vertical direction are aligned in the horizontal direction; the parasitic resonant element of the vertical subarray is provided adjacent to a main resonant element of one horizontal subarray at the other end of the horizontal direction and a main resonant element of the second horizontal subarray at one end of the horizontal direction, so that the horizontal subarrays are arranged in a staggered pattern; The reflect array can change the reflection angle for vertically polarized waves and horizontally polarized waves. The reflect array according to claim 1 .

13. The main resonator element has an effective wavelength of the radio wave frequency on the substrate of λ ｇ Then, 1 / 2λ ｇ ±10% of one side The reflect array according to claim 1 .

14. The main resonance element has a rectangular shape having a predetermined area or a rectangular shape with a part cut out. The reflect array according to claim 1 .

15. The parasitic resonant element is a first element that is parallel to one side of an adjacent main resonance element and is not in contact with the main resonance element; a second element having one end in contact with the first element and extending in a direction away from the main resonator element; a third element that is in contact with the other end of the second element and is substantially parallel to the first element, and a PIN diode is connected between the third elements of the two element parts of the parasitic resonant element; When the PIN diode is ON, the two element parts are electrically connected to each other, and the two connected element parts resonate at a first parasitic resonance frequency, thereby entering a first state; When the PIN diode is OFF, the two element parts are electrically disconnected, and one element part resonates at a second parasitic resonance frequency, thereby entering a second state. The reflect array according to claim 1 .

16. The distance between one side of the main resonator element and the first element of the parasitic resonator element is 1 / 10λ, where λg is the effective wavelength of the radio wave frequency on the substrate. ｇ is The reflect array according to claim 15.

17. In the parasitic resonator element, an RF choke is provided on both sides of the PIN diode and at one end of each third element of the two element parts. The reflect array according to claim 15 or 16.

18. the main resonator element and the parasitic resonator element are provided on a first surface of a substrate; A ground plane is provided on the surface of the substrate opposite to the first surface. The reflect array according to claim 1 .

19. The frequency band of the radio waves incident on the reflectarray is 0.3 GHz to 100 GHz. The reflect array according to claim 1 .

20. A reflectarray that reflects radio waves in a direction other than specular reflection, A plurality of cells are regularly arranged, Each of the plurality of cells has at least two main resonant elements and at least one parasitic resonant element, The parasitic resonator element is capable of adjusting a resonant frequency, and is coupled to the at least two adjacent main resonator elements to adjust the resonant frequency of the main resonator element, thereby adjusting the reflection phase of the reflectarray surface; The element spacing of the main resonance element is ½λ 0 ±20%, where λ 0 is the free space wavelength of the frequency of the radio wave. Reflect array.

21. The reflect array according to claim 1; a control unit that receives a reflection direction instruction and controls the reflection angles of the plurality of cells of the reflect array, respectively; Wireless communication equipment.

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