Method for adjusting radio wave reflecting device

Abstract

This adjustment method for a radio wave reflection device is an adjustment method for a radio wave reflection device that includes: a first radio wave reflection plate; and a second radio wave reflection plate adjacent to the first radio wave reflection plate. The method includes transmitting a radio wave to a radio wave reflection surface of the radio wave reflection device, and measuring the intensity of a radio wave reflected by a reception antenna arranged in a direction of a predetermined angle with respect to the radio wave reflection surface. In the measurement, a phase difference setting ΔΦ is applied to the first radio wave reflection plate, the phase difference setting ΔΦ + a phase correction amount ΔΦ' is applied to the second radio wave reflection plate, and the phase correction amount ΔΦ' corresponding to a peak position of the reception radio wave intensity of the reception antenna is acquired by sweeping the phase correction amount ΔΦ'.

Description

How to adjust a radio wave reflector

[0001] One embodiment of the present invention relates to a method for adjusting a radio wave reflecting device having a radio wave reflector made of a liquid crystal material.

[0002] A phased array antenna device has the characteristic that when a high-frequency signal is applied to some or all of multiple antenna elements, the amplitude and phase of each high-frequency signal can be controlled to control the radiation directivity of the antenna while keeping the antenna orientation fixed in one direction.

[0003] As an example, a liquid crystal metasurface reflector is known that can change the reflection direction of radio waves by utilizing the dielectric anisotropy of liquid crystal. For example, Patent Document 1 discloses a metasurface that applies a voltage to a radio wave reflection element containing liquid crystal to change the orientation of the liquid crystal molecules in the radio wave reflection element, thereby adjusting the reflection phase and controlling the direction in which radio waves are reflected and the direction in which reflected radio waves are suppressed.

[0004] Japanese Patent Application Laid-Open No. 2021-175054

[0005] It is desirable for radio wave reflectors to be large in order to increase the reflection strength of radio waves. However, the larger the size, the higher the costs for manufacturing, transporting, and installing, which is undesirable. Therefore, it is effective to use them in tiling, where multiple radio wave reflectors are installed in combination to increase the size when in use.

[0006] However, the frame area of ​​the radio wave reflector where no radio wave reflecting element is arranged and the gap between two radio wave reflectors become ineffective areas. The size of this ineffective area varies depending on the positional deviation of the radio wave reflector and manufacturing variations in the size of the frame area. Therefore, when combining radio wave reflectors into a single large radio wave reflecting device, the pitch of the radio wave reflecting elements is not constant within the surface, which can impair the reflection strength of the radio wave reflecting device.

[0007] A method for adjusting a radio wave reflecting device according to one embodiment of the present invention is a method for adjusting a radio wave reflecting device that includes a first radio wave reflecting plate and a second radio wave reflecting plate adjacent to the first radio wave reflecting plate, and includes transmitting radio waves to the radio wave reflecting surface of the radio wave reflecting device and measuring the intensity of the radio waves reflected by a receiving antenna arranged at a predetermined angle relative to the radio wave reflecting surface, and during the measurement, applying a phase difference setting ΔΦ to the first radio wave reflecting plate and applying the phase difference setting ΔΦ + phase correction amount ΔΦ' to the second radio wave reflecting plate, and sweeping the phase correction amount ΔΦ' to obtain the phase correction amount ΔΦ' corresponding to the peak position of the received radio wave intensity of the receiving antenna.

[0008] 1 is a plan view showing the configuration of a radio wave reflector according to one embodiment of the present invention. FIG. 2 is an enlarged plan view showing the configuration of a radio wave reflector according to one embodiment of the present invention. FIG. 3 is a plan view showing the configuration of a radio wave reflecting device according to one embodiment of the present invention. FIG. 4 is a cross-sectional end view showing an example of a thin film transistor of a radio wave reflector according to a modified example of the present invention. FIG. 5 is a diagram showing the relationship between the voltage applied to liquid crystal and the phase according to one embodiment of the present invention. FIG. 6 is a top view showing the configuration of a radio wave reflecting device according to one embodiment of the present invention. FIG. 7 is a diagram showing a phase distribution according to a reference example of the present invention. FIG. 8 is a diagram showing a reflection pattern according to a reference example of the present invention. FIG. 9 is a diagram showing a phase distribution according to a comparative example of the present invention. FIG. 10 is a diagram showing a reflection pattern according to a comparative example of the present invention. FIG. 11 is a diagram showing radio wave intensity when the phase correction amount according to an example of the present invention is swept. FIG. 12 is a diagram showing a phase distribution according to an example of the present invention. FIG. 13 is a diagram showing a reflection pattern according to an example of the present invention.

[0009] Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention can be implemented in many different forms, and should not be construed as being limited to the description of the embodiments exemplified below. For clarity of explanation, the drawings may show the width, thickness, shape, etc. of each part schematically compared to the actual form, but these are merely examples and do not limit the interpretation of the present invention. Furthermore, in this specification and each drawing, elements similar to those previously described with reference to the previous drawings are designated by the same reference numerals (or reference numerals with a, b, etc. suffixed thereto), and detailed descriptions may be omitted as appropriate. Furthermore, the letters "first" and "second" attached to each element are convenient labels used to distinguish each element and have no further meaning unless otherwise specified.

[0010] In this specification, when a certain component or region is referred to as being "above (or below)" another component or region, unless otherwise specified, this includes not only the case where it is directly above (or directly below) the other component or region, but also the case where it is above (or below) the other component or region, i.e., the case where another component is included between the component or region and above (or below) the other component or region. In the following description, unless otherwise specified, in a cross-sectional view, the upper side relative to the normal position in the drawing will be referred to as "above" or "upper side," and the surface seen from "above" or "upper side" will be referred to as the "upper surface" or "upper surface side," and the opposite will be referred to as "below," "below," "lower surface" or "lower surface side."

[0011] [Configuration of Radio Wave Reflector] Fig. 1A shows a plan view of a radio wave reflector according to one embodiment of the present invention. Fig. 1B shows an enlarged plan view of a reflecting element of the radio wave reflector according to one embodiment of the present invention. The radio wave reflector 100 is provided on a first surface of an array substrate 110 with a reflective area (radio wave reflecting surface) 102 that reflects radio waves and a peripheral area 104 that surrounds the reflective area 102. In the reflective area 102, which is rectangular in plan view, a plurality of reflective elements (radio wave reflecting elements) 10 are spaced apart at the same interval w2 as adjacent reflective elements 10, and are arranged in an array at the same period (pitch) d in a first direction (X direction) parallel to a first side A of the array substrate 110 and in a second direction (Y direction) perpendicular to the first direction.

[0012] The reflective element 10 includes a first electrode 150, a liquid crystal layer 130, and a second electrode 170. The plurality of first electrodes 150 are formed on a first surface of the array substrate 110. The plurality of second electrodes 170 are formed on a first surface of the counter substrate 120. The first electrode 150 and the second electrode 170 are spaced apart and arranged opposite each other in a third direction (Z direction) perpendicular to the first direction (X direction) and the second direction (Y direction). The liquid crystal layer 130 is arranged in the region between the spaced first electrode 150 and the second electrode 170. The liquid crystal layer 130 and the second electrode 170 are arranged in common to the plurality of reflective elements 10. The plurality of second electrodes 170 are patch electrodes in which adjacent electrodes are connected to each other by wiring. One first electrode 150 is arranged on each of the plurality of reflective elements 10, and adjacent electrodes are arranged with a gap therebetween. The first electrode 150 is a liquid crystal control electrode that defines one unit of the reflective element 10 .

[0013] The radio wave reflector 100 is a device that scatters radio waves incident on its incident surface in a predetermined direction, with the counter substrate 120 disposed on the incident surface side and the array substrate 110 disposed on the back side of the incident surface. That is, the second electrode 170 is disposed on the incident surface, and the first electrode 150 is disposed on the back side of the second electrode 170 with the liquid crystal layer 130 sandwiched therebetween.

[0014] In this embodiment, the plurality of first electrodes 150 are shown as squares each having the same width w1 in the first direction (X direction) and the second direction (Y direction). However, the present invention is not limited to this, and the plurality of first electrodes 150 may have any shape as long as they are symmetrical in the first direction (X direction) and the second direction (Y direction), and may be, for example, polygonal or circular.

[0015] The multiple first electrodes 150 are arranged at equal intervals w2 in a first direction (X-axis direction). The multiple first electrodes 150 are arranged at equal intervals w2 in a second direction (Y-axis direction) perpendicular to the first direction. The intervals w2 between the multiple first electrodes 150 aligned in the first direction (X-axis direction) are substantially the same as the intervals w2 between the multiple first electrodes 150 aligned in the second direction (Y-axis direction).

[0016] The multiple first electrodes 150 are arranged in an array at the same period (pitch) d in a first direction (X-axis direction). The multiple first electrodes 150 are arranged in an array at the same period (pitch) d in a second direction (Y-axis direction) perpendicular to the first direction. The period (pitch) d of the multiple first electrodes 150 aligned in the first direction (X-axis direction) is approximately the same as the period (pitch) d of the multiple first electrodes 150 aligned in the second direction (Y-axis direction). The period (pitch) d of the first electrodes 150 is the sum of the width w1 of the first electrodes 150 and the spacing w2 between the first electrodes 150.

[0017] The period (pitch) d at which the reflecting elements 10 are arranged is preferably in the range of 1 / 3 to 1 / 2 of the wavelength of the radio wave so as to obtain the maximum reflected power.

[0018] In the reflective region 102, the multiple first electrodes 150 arranged along the second direction (Y-axis direction) are electrically connected by bias signal lines 160. The bias signal lines 160 are drawn from a first end of the reflective region 102 to the peripheral region 104 and are electrically connected via wiring to a drive circuit 180 that drives the reflective elements 10. The drive circuit 180 outputs a bias signal to the bias signal lines 160. The drive circuit 180 is mounted on a mounting section 106 arranged on a first side A (part of the peripheral region 104) of the array substrate 110. The opposing substrate 120 exposes the wiring (not shown) on the array substrate 110 and the drive circuit 180 at the mounting section 106. The mounting section 106 extends in the first direction (X-direction) along the first end of the reflective region 102 and the first side A of the array substrate 110. A flexible printed circuit board is further connected to the drive circuit 180 via a terminal (not shown).

[0019] In the reflective region 102, a plurality of first electrodes 150 arranged along a first direction (X-axis direction) are electrically connected by selection signal lines 260. The selection signal lines 260 are drawn from a first end of the reflective region 102 to the peripheral region 104 and are electrically connected via wiring to a drive circuit 280 that drives the reflective elements 10. The drive circuit 280 outputs a selection signal to the selection signal lines 260. The drive circuit 280 is mounted on a mounting section 106 arranged on a first side A (part of the peripheral region 104) of the array substrate 110. The opposing substrate 120 exposes wiring (not shown) on the array substrate 110 and the drive circuit 280 at the mounting section 106. A flexible printed circuit board is further connected to the drive circuit 280 via terminals (not shown). The drive circuit 180 and the drive circuit 280 may be integrated.

[0020] In the reflective region 102, each of the first electrodes 150 is connected to a thin film transistor (TFT) 200. The thin film transistor 200 used as a switching element has a gate connected to a selection signal line 260, one input / output terminal connected to a bias signal line 160, and the other input / output terminal connected to the first electrode 150. The switching operation (on / off state) of the thin film transistor 200 is controlled by a selection signal from the selection signal line 260, and a bias signal (bias voltage) is input from the bias signal line 160. The bias signal is input to each of the first electrodes 150 individually by the thin film transistor 200. That is, the bias signal is input to each of the first electrodes 150 arranged in a matrix form individually by the thin film transistor 200.

[0021] In the reflective area 102, a liquid crystal layer 130 is filled between the plurality of first electrodes 150 and the second electrodes 170. In the peripheral area 104, the liquid crystal layer 130 is surrounded and sealed by a seal 140.

[0022] The first surface of the array substrate 110 includes a first side A on which the mounting portion 106 is arranged, a second side B opposite to the first side A, a third side C connecting the first side A and the second side B, and a fourth side D opposite to the third side C.

[0023] 2 shows a plan view of a radio wave reflecting device according to one embodiment of the present invention. The radio wave reflecting device 1000 includes a radio wave reflecting plate 100-1, a radio wave reflecting plate 100-2, and a radio wave reflecting plate 100-3 on a radio wave reflecting surface (when not distinguishing between the radio wave reflecting plates 100-1, 100-2, and 100-3, they will be referred to as radio wave reflecting plate 100). Each of the radio wave reflecting plates 100-1, 100-2, and 100-3 has reflective areas 102-1, 102-2, and 102-3 that reflect radio waves, and peripheral areas 104-1, 104-2, and 104-3 that surround the reflective areas 102-1, 102-2, and 102-3 (here, when the reflective areas 102-1, 102-2, and 102-3 are not distinguished, they are referred to as reflective area 102, and when the peripheral areas 104-1, 104-2, and 104-3 are not distinguished, they are referred to as peripheral area 104). The reflective area 102-1 of the radio wave reflecting plate 100-1, the reflective area 102-2 of the radio wave reflecting plate 100-2, and the reflective area 102-3 of the radio wave reflecting plate 100-3 are arranged to face the same side. The reflection area 102-1 of the radio wave reflector 100-1, the reflection area 102-2 of the radio wave reflector 100-2, and the reflection area 102-3 of the radio wave reflector 100-3 are arranged substantially parallel to each other. In the reflection area 102, a plurality of reflection elements 10 are spaced apart at the same interval w2 as adjacent reflection elements 10, and are arranged in an array at the same period (pitch) d in a first direction (X direction) along a first side A of the array substrate 110 and in a second direction (Y direction) perpendicular to the first direction.

[0024] The first surface of the array substrate 110 included in the radio wave reflector 100-1 includes a first side A1 on which the mounting section 106-1 is arranged, a second side B1 opposite to the first side A1, a third side C1 connecting the first side A1 and the second side B1, and a fourth side D1 opposite to the third side C1. The first surface of the array substrate 110 included in the radio wave reflector 100-2 includes a first side A2 on which the mounting section 106-2 is arranged, a second side B2 opposite to the first side A2, a third side C2 connecting the first side A2 and the second side B2, and a fourth side D2 opposite to the third side C2. The first surface of the array substrate 110 provided on the radio wave reflector 100-3 includes a first side A3 on which the mounting section 106-3 is arranged, a second side B3 opposite to the first side A3, a third side C3 connecting the first side A3 and the second side B3, and a fourth side D3 opposite to the third side C3.

[0025] In this embodiment, the fourth side D1 of the radio wave reflector 100-1 and the third side C2 of the radio wave reflector 100-2 are disposed adjacent to each other. The fourth side D2 of the radio wave reflector 100-2 and the third side C3 of the radio wave reflector 100-3 are disposed adjacent to each other. That is, the radio wave reflectors 100-1, 100-2, and 100-3 are aligned in a first direction (X direction) along the first side A of the array substrate 110. The first side A1 of the radio wave reflector 100-1, the first side A2 of the radio wave reflector 100-2, and the first side A3 of the radio wave reflector 100-3 may be disposed on the same line in the first direction (X direction). The fourth side D1 of the radio wave reflector 100-1 and the third side C2 of the radio wave reflector 100-2 may be disposed parallel to each other. The fourth side D2 of the radio wave reflector 100-2 and the third side C3 of the radio wave reflector 100-3 may be arranged parallel to each other.

[0026] In this embodiment, the plurality of reflective elements 10 adjacent to the fourth side D2 of the radio wave reflector 100-2 and the plurality of reflective elements 10 adjacent to the third side C3 of the radio wave reflector 100-3 are spaced apart by a distance w4. The distance w4 is approximately the same as the distance w2 between the first electrodes 150, and there is no misalignment at the connection portion D2-C3 between the fourth side D2 of the radio wave reflector 100-2 and the third side C3 of the radio wave reflector 100-3. Therefore, the period (pitch) d at which the reflective elements 10 are arranged in the first direction (X direction) along the first side A from the reflective area 102-2 to the reflective area 102-3 is constant.

[0027] In this embodiment, there is a gap g in the positional deviation at the connection D1-C2 between the fourth side D1 of the radio wave reflector 100-1 and the third side C2 of the radio wave reflector 100-2. Therefore, the plurality of reflecting elements 10 adjacent to the fourth side D1 of the radio wave reflector 100-1 and the plurality of reflecting elements 10 adjacent to the third side C2 of the radio wave reflector 100-2 are separated by a distance w3. Because there is a gap g in the positional deviation at the connection D1-C2 between the radio wave reflector 100-1 and the radio wave reflector 100-2, the distance w3 is the distance w2 between the first electrodes 150 plus the gap g. Therefore, the period (pitch) at which the reflecting elements 10 are arranged in the first direction (X direction) along the first side A from the reflecting area 102-1 to the reflecting area 102-2 is not constant. At the connection D1-C2 between the radio wave reflector 100-1 and the radio wave reflector 100-2, the period (pitch) between the plurality of reflecting elements 10 adjacent to the fourth side D1 of the radio wave reflector 100-1 and the plurality of reflecting elements 10 adjacent to the third side C2 of the radio wave reflector 100-2 is d + gap g.

[0028] In this embodiment, a reflection pattern is detected when a phase difference setting ΔΦ is applied to determine the same reflection direction for two adjacent radio wave reflectors 100. Because the period (pitch) d at which the reflecting elements 10 are arranged is constant between the radio wave reflectors 100-2 and 100-3, applying a phase difference setting ΔΦ to determine the same reflection direction for the radio wave reflectors 100-2 and 100-3 results in a peak angle in the desired reflection direction. On the other hand, because the period (pitch) at which the reflecting elements 10 are arranged at the connection D1-C2 differs between the radio wave reflectors 100-1 and 100-2, applying a phase difference setting ΔΦ to determine the same reflection direction for the radio wave reflectors 100-1 and 100-2 results in a shift in the peak angle of the reflection pattern and a decrease in radio wave intensity in the desired reflection direction. The phase difference setting ΔΦ for determining the reflection direction can be calculated using the following equation 1, where d is the period (pitch) at which the reflecting elements 10 are arranged, θ is the reflection angle, and λ is the wavelength.

[0029] 2 shows a configuration in which three radio wave reflectors 100 are combined. However, the present invention is not limited to this, and additional radio wave reflectors 100 may be combined in the first direction (X direction) and / or the second direction (Y direction).

[0030] In the radio wave reflector 100, each first electrode 150 is connected to a bias signal line 160 and a selection signal line 260 via a thin film transistor 200 shown in FIG. 3. FIG. 3 is a cross-sectional view showing an example of the thin film transistor 200. The thin film transistor 200 has a structure in which, for example, an undercoat layer 1510, a gate electrode 1530, a bottom gate insulating film 1550, an oxide semiconductor layer 1570, a first connection wiring layer 1590, a top gate insulating film 1610, a bottom gate electrode 1630, a passivation film 1650, a second connection wiring layer 1670, a signal line 1690, and an insulating film 1710 are sequentially stacked on the array substrate 110. The thin film transistor 200 has an overcoat layer 1730, an insulating film 1750, a first electrode 150, a first alignment film 112a, a liquid crystal layer 130, a second alignment film 112b, a second electrode 170, and an opposing substrate 120 sequentially stacked thereon.

[0031] The undercoat layer 1510 may be composed of, for example, a silicon oxide film. The bottom gate insulating film 1550 may be composed of, for example, a stacked structure of a silicon nitride film and a silicon oxide film. The gate electrode 1530 may be composed of, for example, molybdenum, tungsten, or an alloy thereof. The top gate insulating film 1610 may be composed of, for example, a silicon oxide film. Furthermore, the first connection wiring layer 1590 and the second connection wiring layer 1670 may be composed of, for example, a Ti / Al / Ti stacked structure or a Mo / Al / Mo stacked structure. The passivation film 1650 may be composed of, for example, a silicon nitride film. The insulating film 1710 may be composed of, for example, a silicon oxide film or a silicon nitride film. The first electrode 150 may be composed of, for example, a Ti / Al / Ti stacked structure or a Mo / Al / Mo stacked structure. The second electrode 170 may be composed of, for example, molybdenum, tungsten, or an alloy thereof.

[0032] 3, the thin film transistor 200 is shown as a dual-gate TFT using an oxide semiconductor, but amorphous silicon or low-temperature polysilicon (LTPS) may also be used. Also, although an example of vertical electric field driving is shown in FIG. 3, horizontal electric field driving may also be used.

[0033] The radio wave reflecting device 1000 further includes a control unit (not shown) that controls the potential difference between each first electrode 150 and each second electrode 170 via each thin film transistor 200. The control unit controls the voltage applied to each first electrode 150 to control the potential difference between each first electrode 150 and each second electrode 170, thereby driving each liquid crystal layer 130 and changing the dielectric constant of the liquid crystal molecules depending on their orientation. Independently changing the dielectric constant of each liquid crystal layer 130 changes the phase of the radio wave reflected by each reflecting element 10, thereby changing the direction of travel of the irradiated radio wave. Figure 4 shows the relationship between the applied voltage and phase of the liquid crystal according to one embodiment of the present invention. This mechanism allows the radio wave reflector 100 to reflect radio waves at a reflection angle different from the angle of incidence.

[0034] [Method for Adjusting the Radio Wave Reflecting Device] Figure 5 shows a top view of a radio wave reflecting device according to one embodiment of the present invention. In this embodiment, there is a positional gap g at the connection D1-C2 between the radio wave reflecting plate 100-1 and the radio wave reflecting plate 100-2. Therefore, the period (pitch) at which the reflecting elements 10 are arranged in the first direction (X direction) along the first side A from the reflection area 102-1 to the reflection area 102-2 is not constant. Because the period (pitch) at which the reflecting elements 10 are arranged at the connection D1-C2 differs between the radio wave reflecting plate 100-1 and the radio wave reflecting plate 100-2, applying a phase difference setting ΔΦ to determine the same reflection direction to the radio wave reflecting plate 100-1 and the radio wave reflecting plate 100-2 results in a shift in the peak angle of the reflection pattern and a decrease in radio wave intensity in the intended reflection direction. For this reason, the reflection angles of the plurality of reflection elements 10 arranged on the radio wave reflector 100-2 must be corrected by the misalignment gap g of the connection portions D1-C2 relative to the plurality of reflection elements 10 arranged on the radio wave reflector 100-1. The reflection angle is determined by the amount of change in the phase of the reflected wave, and the amount of change in the phase of the reflected wave can be controlled by controlling the potential difference between the first electrode 150 and the second electrode 170 using the control unit. In the radio wave reflector 100, each first electrode 150 is connected to a selection signal line 260 via a thin film transistor 200 shown in FIG. 3 and is controlled individually.

[0035] As shown in FIG. 5, radio waves transmitted from a transmitting antenna 1 are reflected by a radio wave reflecting device 1000 (in this case, radio wave reflecting plates 100-1 and 100-2) and received by a receiving antenna 2. The phase of the radio waves reflected by the radio wave reflecting plates 100-1 and 100-2 changes due to a positional gap g at the connection points D1-C2 between the radio wave reflecting plates 100-1 and 100-2, resulting in a shift in the peak angle of the reflection pattern (in the direction of the dotted arrow) and a decrease in radio wave intensity in the intended reflection direction. In the method for adjusting the radio wave reflecting device according to this embodiment, in order to determine a phase difference setting that takes into account the gap g, the control unit sweeps the phase difference settings of the multiple reflecting elements 10 arranged on the radio wave reflecting plate 100-2 as a parameter. By detecting the change in radio wave intensity in the target reflection direction when sweeping the phase correction amount ΔΦ' relative to the phase difference setting ΔΦ of the multiple reflecting elements 10 arranged on the radio wave reflecting plate 100-1, it is possible to obtain the phase difference setting (phase difference setting ΔΦ of the multiple reflecting elements 10 arranged on the radio wave reflecting plate 100-1 + phase correction amount ΔΦ') corresponding to the peak position of the radio wave intensity. Here, the gap g can be calculated by the following equation 2 when the phase correction amount ΔΦ', the period (pitch) of the multiple reflecting elements 10 aligned in the first direction (X-axis direction) is d, the reflection angle θ is θ, and the wavelength λ is λ.

[0036] Furthermore, by determining the gap g, the phase correction amount ΔΦ′ at another reflection angle θ can be calculated by the following equation 3.

[0037] That is, in the method for adjusting the radio wave reflecting device according to this embodiment, as long as the positional relationship between the transmitting antenna 1, the receiving antenna 2, and the radio wave reflecting device 1000 is known, it is possible to suppress a decrease in reflection intensity due to positional misalignment by remotely obtaining the phase correction amount ΔΦ' without measuring the positional misalignment amount (gap g) on-site even after the radio wave reflector 100 has been installed. Furthermore, by calculating the positional misalignment amount (gap g) from the phase correction amount ΔΦ', it is also possible to obtain the phase correction amount ΔΦ' at another reflection angle θ, thereby simplifying the control of the direction of radio waves.

[0038] In this embodiment, a method for adjusting the positional misalignment of two adjacent radio wave reflectors 100 in a first direction (X direction) has been described. However, this is not a limitation, and the positional misalignment of two adjacent radio wave reflectors 100 in a second direction (Y direction) can also be adjusted in a similar manner. In this embodiment, a method for adjusting a positive positional misalignment has been described. However, this is not a limitation, and a negative positional misalignment caused by an external dimensional error of the radio wave reflector 100 or the like can also be similarly adjusted by subtracting the phase correction amount. Furthermore, by performing the same adjustment on adjacent radio wave reflectors 100 in all of the radio wave reflecting devices 1000, the phases of the reflected waves of the multiple radio wave reflectors 100 in the radio wave reflecting device 1000 can be aligned.

[0039] [Reference Example] The phase distribution of the radio wave reflector 100-2 and the radio wave reflector 100-3 when the number of reflecting elements 10 is 24x2, the period (pitch) d of the reflecting elements 10 is 3.7 mm, the frequency is 28 GHz, the wavelength λ is 10.7, and the reflection angle θ is 45° is shown in Fig. 6, and the reflection pattern is shown in Fig. 7. Even when the phase difference is constant, the peak angle is 45.0°, and the radio wave intensity at 45° is 0.00 dB, and it can be seen that there is no positional misalignment at the connection D2-C3 of the radio wave reflector 100-2 and the radio wave reflector 100-3.

[0040] [Comparative Example] The phase distribution of the radio wave reflector 100-1 and the radio wave reflector 100-2 when the number of reflecting elements 10 is 24 x 2, the period (pitch) d of the reflecting elements 10 is 3.7 mm, the frequency is 28 GHz, and the reflection angle θ is 45° is shown in Fig. 8, and the reflection pattern is shown in Fig. 9. When the phase difference is constant, the peak angle is 44.1°, and the radio wave intensity at 45° is -0.66 dB, and it can be seen that there is a positional deviation at the connection part D1-C2 of the radio wave reflector 100-1 and the radio wave reflector 100-2.

[0041] [Example] Figure 10 shows the radio wave intensity at a reflection angle θ = 45° when the phase correction amount ΔΦ' is added (swept) in 10° increments in a comparative example. As a result of sweeping the phase correction amount ΔΦ', it was found that the phase correction amount ΔΦ' corresponding to the peak position of the radio wave intensity was approximately 44° (arrow). From Equation 2, it can be seen that there is a positional deviation (gap g) of 1.85 mm at the connection portion D1-C2 between the radio wave reflector 100-1 and the radio wave reflector 100-2. Figure 11 shows the phase distribution taking into account the positional deviation (gap g) between the radio wave reflector 100-1 and the radio wave reflector 100-2 when the number of reflecting elements 10 = 24 x 2, the period (pitch) d of the reflecting elements 10 = 3.7 mm, the frequency = 28 GHz, and the reflection angle θ = 45°, and Figure 12 shows the reflection pattern. By adding a phase correction amount ΔΦ' at the connection D1-C2 (between element numbers 24 and 25) between radio wave reflector 100-1 and radio wave reflector 100-2, the peak angle was 45.0 deg, and the radio wave intensity at 45° was 0.00 dB, and even if there was a positional misalignment at the connection D1-C2 between radio wave reflector 100-1 and radio wave reflector 100-2, the decrease in reflection intensity could be suppressed.

[0042] REFERENCE SIGNS LIST 1 transmitting antenna, 2 receiving antenna, 10 reflecting element, 100 radio wave reflector, 102 reflecting area, 104 peripheral area, 110 array substrate, 120 opposing substrate, 130 liquid crystal layer, 140 seal, 150 first electrode, 160 bias signal line, 170 second electrode, 180 driving circuit, 190 wiring, 260 selection signal line, 280 driving circuit, 1000 radio wave reflecting device

Claims

1. A method for adjusting a radio wave reflecting device including a first radio wave reflector and a second radio wave reflector adjacent to the first radio wave reflector, comprising: transmitting radio waves to the radio wave reflecting surface of the radio wave reflecting device; and measuring the strength of the radio waves reflected by a receiving antenna arranged at a predetermined angle to the radio wave reflecting surface; and during the measurement, applying a phase difference setting ΔΦ to the first radio wave reflector; applying the phase difference setting ΔΦ + phase correction amount ΔΦ' to the second radio wave reflector; and acquiring the phase correction amount ΔΦ' corresponding to the peak position of the radio wave strength received by the receiving antenna by sweeping the phase correction amount ΔΦ'.

2. A method for adjusting a radio wave reflecting device according to claim 1, wherein each of the first radio wave reflector and the second radio wave reflector includes a plurality of periodically arranged radio wave reflecting elements, and when the phase correction amount ΔΦ' is ΔΦ, the period of the plurality of reflecting elements is d, the reflection angle is θ, and the wavelength is λ, the gap g between the radio wave reflecting elements of the first radio wave reflector and the radio wave reflecting elements of the second radio wave reflector is calculated using the following formula:

3. The method for adjusting a radio wave reflecting device according to claim 2, wherein the phase correction amount ΔΦ' for an angle different from the reflection angle θ is calculated using the following formula:

4. A method for adjusting a radio wave reflecting device according to claim 2, wherein each of the plurality of radio wave reflecting elements includes a first electrode, a second electrode, and a liquid crystal layer disposed between the first electrode and the second electrode.

5. The method for adjusting a radio wave reflecting device according to claim 4, wherein the plurality of radio wave reflecting elements include transistors.

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