Reception power measurement method, power reflection efficiency calculation method, reception power measurement program, and power reflection efficiency calculation program

Abstract

Provide is a reception power measurement method capable of appropriately measuring reception power of an electromagnetic wave reflection device having a metasurface or a regular reflection surface.　In this reception power measurement method: a radio wave of a prescribed band selected from a frequency band of 1 MHz to 300 GHz is transmitted from a transmission antenna in a radio wave dark room where a VNA, which is connected to transmission and reception antennas in which the relative position thereof is fixed, is disposed, whereby said radio wave is incident on an electromagnetic wave reflection device at a first designated incident angle; a reflected wave is received by the reception antenna disposed in the direction of a first designated reflection angle with respect to the electromagnetic wave reflection device, whereby a first reception power in a designated frequency range is measured by the VNA; the radio wave of the prescribed band is transmitted from the transmission antenna in the radio wave dark room so as to be incident on a reflection plate, which has a metal reflection surface, at a second designated incident angle; and a reflected wave is received by the reception antenna disposed in the direction of a second designated reflection angle with respect to the reflection plate having the metal reflection surface, whereby a second reception power in the designated frequency range is measured by the VNA.

Description

Method for measuring received power, method for calculating power reflection efficiency, program for measuring received power, and program for calculating power reflection efficiency

[0001] The present disclosure relates to a method for measuring received power, a method for calculating power reflection efficiency, a program for measuring received power, and a program for calculating power reflection efficiency.

[0002] While the fifth-generation (hereinafter referred to as "5G") mobile communication standard promises high-speed, high-capacity communications, it uses radio waves with strong directionality, which can create areas where radio waves are difficult to reach. In places with many metal machines, such as factories, or in urban areas with many reflections from walls and street trees, a means is needed to deliver radio waves to the desired terminal devices and wireless devices. Similar requirements exist in places where non-line-of-sight (NLOS) spots occur, such as medical settings, event venues, and large commercial facilities. The next-generation sixth-generation standard is also expected to use the terahertz or sub-terahertz band, and similar requirements exist.

[0003] In recent years, artificial reflective surfaces known as "metasurfaces" have been developed. Metasurfaces are formed with periodic structures or patterns that are smaller than the wavelength and are designed to reflect radio waves in a desired direction (see, for example, Non-Patent Document 1). Because metasurfaces can achieve a desired reflection angle while maintaining a planar configuration, they function effectively as reflectors even in environments where there is not enough space to install multiple reflective panels. Configurations have been proposed in which wireless transmission systems including electromagnetic wave reflecting devices with metasurfaces or regular reflective surfaces are introduced into production lines in factories and plants (see, for example, Patent Documents 1 and 2).

[0004] International Publication No. 2021 / 199503 International Publication No. 2021 / 199504

[0005] Diaz-Rubio et al., Sci. Adv. 2017: 3: e1602714 1

[0006] Incidentally, when introducing a conventional wireless transmission system, the layout of the electromagnetic wave reflector and base stations will be designed based on the power reflection efficiency of the electromagnetic wave reflector having a metasurface or a regular reflection surface, so it is necessary to properly evaluate the power reflection efficiency. Moreover, not only when introducing a conventional wireless transmission system, but also when installing an electromagnetic wave reflector having a metasurface or a regular reflection surface, it is necessary to properly evaluate the power reflection efficiency.

[0007] However, there is no established method for evaluating the power reflection efficiency of an electromagnetic wave reflector with a metasurface or regular reflecting surface. Furthermore, to evaluate the power reflection efficiency, it is necessary to properly evaluate the received power at the electromagnetic wave reflector.

[0008] Therefore, the object is to provide a method for measuring received power that can appropriately measure the received power in an electromagnetic wave reflecting device having a metasurface or a regular reflecting surface, and a method for calculating power reflection efficiency that can appropriately calculate the power reflection efficiency in an electromagnetic wave reflecting device having a metasurface or a regular reflecting surface.

[0009] A method for measuring received power according to an embodiment of the present disclosure includes the following steps: a first step of transmitting radio waves in a predetermined band selected from a frequency band of 1 MHz to 300 GHz inclusive from the transmitting antenna inside an anechoic chamber in which a transmitting antenna and a receiving antenna whose relative positions are fixed are placed, and causing the radio waves to be incident on an electromagnetic wave reflecting device at a first specified angle of incidence; a second step of receiving, with the receiving antenna arranged in a direction at the first specified angle of reflection with respect to the electromagnetic wave reflecting device, the reflected waves of the radio waves that were incident on the electromagnetic wave reflecting device in the first step, and measuring a first received power in the specified frequency range with the vector network analyzer; a third step of transmitting radio waves in the predetermined band from the transmitting antenna inside the anechoic chamber, and causing the reflected waves to be incident on a reflector having a metal reflecting surface at a second specified angle of incidence; and a fourth step of receiving, with the receiving antenna arranged in a direction at the second specified angle of reflection with respect to the reflector having the metal reflecting surface, the reflected waves of the radio waves that were incident on the metal reflecting surface in the third step, and measuring a second received power in the specified frequency range with the vector network analyzer.

[0010] It is possible to provide a method for measuring received power that can appropriately measure the received power in an electromagnetic wave reflecting device having a metasurface or a regular reflecting surface, and a method for calculating power reflection efficiency that can appropriately calculate the power reflection efficiency in an electromagnetic wave reflecting device having a metasurface or a regular reflecting surface.

[0011] 1 is a diagram showing an example of the configuration of an electromagnetic wave reflecting device 60 using a reflective panel 10 of an embodiment. FIG. 2 is a diagram showing an example of the configuration of an electromagnetic wave reflecting fence 100 in which electromagnetic wave reflecting devices 60-1, 60-2, and 60-3 are connected. FIG. 3 is a diagram showing an example of the layer structure of the reflective panel 10. FIG. 4 is a diagram showing an example of the layer structure of the reflective panel 10A. FIG. 5 is a diagram showing an example of the configuration of a unit cell 20 of a conductive pattern 15 composed of a hollow pattern 151. FIG. 6 is a diagram showing an example of a measuring device arranged in an anechoic chamber 101. FIG. 7 is a diagram explaining an example of a method for calculating power reflection efficiency of an embodiment. FIG. 8 is a diagram explaining an example of a method for calculating power reflection efficiency of an embodiment. FIG. 9 is a flowchart showing an example of processing in a method for measuring received power and a method for calculating power reflection efficiency of an embodiment. FIG. 10 is a diagram showing an example of measurement results of the distance from a transmitting antenna 115Tx to the electromagnetic wave reflecting device 60A on the path of an incident wave and the distance from the electromagnetic wave reflecting device 60A to a receiving antenna 115Rx on the path of a reflected wave in a case where the correction value is 1 or less and a slight deviation in the measurement distance does not result in a large change. 9A is a diagram showing an example of measurement results of the distance from the transmitting antenna 115Tx to the electromagnetic wave reflecting device 60A on the path of the incident wave and the distance from the electromagnetic wave reflecting device 60A to the receiving antenna 115Rx on the path of the reflected wave, when the correction value is 1 or less and a slight deviation in the measurement distance does not result in a large change, for the electromagnetic wave reflecting device 60A. FIG. 9B is a diagram showing an example of the configuration of the reflecting surface of the electromagnetic wave reflecting device 60A. FIG. 9C is a diagram showing an example of the result of fitting a quadratic curve to the result of FIG.

[0012] Hereinafter, embodiments of the present disclosure will be described, in which the received power measurement method, the power reflection efficiency calculation method, the received power measurement program, and the power reflection efficiency calculation program are applied. In the following, the same elements are denoted by the same reference numerals, and duplicated descriptions may be omitted.

[0013] Before describing the method for measuring received power, the method for calculating power reflection efficiency, the program for measuring received power, and the program for calculating power reflection efficiency of the present disclosure, we will first explain the configuration of an electromagnetic wave reflecting device having a metasurface or a regular reflecting surface that is included in a wireless transmission system that can be used outdoors or indoors. In addition to such an electromagnetic wave reflecting device, the wireless transmission system also includes a base station, and establishes a wireless communication area in an outdoor or indoor facility.

[0014] In the following description, the XYZ coordinate system is defined. The direction parallel to the X axis (X direction), the direction parallel to the Y axis (Y direction), and the direction parallel to the Z axis (Z direction) are perpendicular to one another. For ease of explanation, the -Z direction may be referred to as the lower side or bottom, and the +Z direction may be referred to as the upper side or top. Planar view refers to viewing from the XY plane. In the following description, the length, width, thickness, etc. of each part may be exaggerated to make the configuration easier to understand. Terms such as parallel, right angle, orthogonal, horizontal, vertical, and up and down may be misaligned to the extent that they do not impair the effects of the embodiments.

[0015] In an embodiment, an electromagnetic wave reflecting device is used to reduce blind zones in a wireless transmission system used indoors and outdoors. In this specification, a "blind zone" refers to an area where the reception power is reduced by 10 dB or more due to the influence of an obstruction compared to the surrounding reception environment without obstructions. Generally, electromagnetic waves below 3 THz are called radio waves, but in this specification, communication waves transmitted from a base station are called "radio waves," and electromagnetic waves in general are called "electromagnetic waves."

[0016] Blind zones include not only two-dimensional areas but also three-dimensional spaces. When production equipment, sensors, or mobile communication terminals with wireless communication capabilities are located in a blind zone, it becomes difficult to send and receive signals between them and base stations. Therefore, electromagnetic wave reflectors can be introduced to reduce the blind zone and improve the radio wave environment.

[0017] 1 is a diagram showing an example of the configuration of an electromagnetic wave reflecting device 60 using a reflective panel 10 according to an embodiment. The electromagnetic wave reflecting device 60 includes the reflective panel 10 and a frame 50 that holds the reflective panel 10. In the coordinate system shown in FIG. 1 , when the electromagnetic wave reflecting device 60 is installed, the width or horizontal direction of the reflective panel 10 is defined as the X direction, the height or vertical direction is defined as the Y direction, and the thickness direction is defined as the Z direction. The reflective panel 10 reflects electromagnetic waves in the gigahertz to terahertz bands, such as microwaves, millimeter waves, and submillimeter waves, and reflects electromagnetic waves of 1 MHz or more and 300 GHz or less, for example.

[0018] The radio waves transmitted and received by a base station in a wireless transmission system including the electromagnetic wave reflecting device 60 are preferably, for example, radio waves in the 1 MHz to 300 GHz frequency band, which includes the Sub-6 frequency band and millimeter wave band of fifth-generation mobile communication systems (5G). Currently, the Sub-6 frequency band and the 28 GHz band included in the millimeter wave band are used, and the next-generation 6G mobile communication standard is expected to expand to the sub-terahertz band. Using such high-frequency bands significantly expands the communication bandwidth, enabling large-volume data communication with low latency.

[0019] The radio waves transmitted and received by the base station may be Long Term Evolution (LTE), LTE-Advanced (LTE-A), Ultra Mobile Broadband (UMB), or Citizens Broadband Radio Service (CBRS). The radio waves transmitted and received by the base station may be IEEE 802.11 (Wi-Fi (registered trademark)), IEEE 802.16 (WiMAX (registered trademark)), IEEE 802.20, Ultra Wideband (UWB), Bluetooth (registered trademark), Low Power Wide Area (LPWA), or the like.

[0020] The reflective panel 10 may have a specular reflective surface where the incident angle and the outgoing angle of the electromagnetic wave are equal, or may have a metasurface where the reflection direction is controlled. The reflective panel 10 may be configured by combining a specular reflective surface and a metasurface. The metasurface may not only provide a non-specular reflective surface that reflects the incident electromagnetic wave in a direction different from the incident angle, but may also be designed to control the diffusion state of the electromagnetic wave.

[0021] The metasurface of the reflective panel 10 reflects both horizontally and vertically polarized waves in controlled directions. Horizontally polarized waves are waves that oscillate parallel to the ground or transversely to the propagation direction. Vertically polarized waves are waves that oscillate perpendicular to the ground or longitudinally to the propagation direction. By forming the conductor pattern that makes up the metasurface as a hollow rectangle, both horizontally and vertically polarized waves can be reflected in controlled directions.

[0022] The frame 50 supports two sides of the reflective panel 10 along the height direction when the reflective panel 10 is installed. In addition to the frame 50, a top frame 57 that supports the upper end of the reflective panel 10 and a bottom frame 58 that supports the lower end may be provided. In this case, the frame 50, the top frame 57, and the bottom frame 58 form a frame that supports the entire periphery of the reflective panel 10. The frame 50 may be referred to as a "side frame" based on its position relative to the top frame 57 and the bottom frame 58. Legs 56 that support the frame 50 may be provided. As shown in FIG. 1 , it is desirable to provide the legs 56 when the electromagnetic wave reflecting device 60 is to be freestanding on the installation surface, but the legs 56 are not required. The legs 56 may be provided with casters to make the reflective panel 10 mobile, or the reflective panel 10 may be installed on a wall or hung from a ceiling without the legs 56.

[0023] Fig. 2 is a diagram showing an example of the configuration of an electromagnetic wave reflecting fence 100 in which electromagnetic wave reflecting devices 60-1, 60-2, and 60-3 are connected together. In Fig. 2, three electromagnetic wave reflecting devices 60-1, 60-2, and 60-3 (hereinafter, sometimes collectively referred to as "electromagnetic wave reflecting devices 60") are connected together to form the electromagnetic wave reflecting fence 100, but there is no particular limit to the number of electromagnetic wave reflecting devices 60 that can be connected together.

[0024] The electromagnetic wave reflecting devices 60-1, 60-2, and 60-3 each have a reflecting panel 10-1, 10-2, and 10-3, respectively. Adjacent reflecting panels are held together by a frame 50, resulting in an electromagnetic wave reflecting fence 100 connected in the X direction. Each of the reflecting panels 10-1, 10-2, and 10-3 (hereinafter sometimes collectively referred to as "reflecting panel 10") has, at least in part, a reflecting surface formed from a hollow rectangular conductive pattern. This allows both horizontally polarized and vertically polarized radio waves to be reflected in controlled directions.

[0025] <Layer structure of reflective panel 10> Fig. 3 is a diagram showing an example of the layer structure of the reflective panel 10. The layer structure shown in Fig. 3 is a layer structure in an XZ cross section of the reflective panel 10, and the stacking direction is the thickness direction (Z direction) of the reflective panel 10. Fig. 3 shows a cross section of the reflective panel 10 as seen from the bottom side (-Y direction side) as an example.

[0026] The reflective panel 10 has a dielectric layer 11, a periodic conductive pattern 15 provided on one surface 11A of the dielectric layer 11, and a ground layer 12 provided on the other surface 11B of the dielectric layer 11. The conductive pattern 15 forms the reflective surface of the reflective panel 10 and reflects electromagnetic waves in the range of 1 MHz to 300 GHz in a predetermined direction.

[0027] The conductive pattern 15 includes a periodic arrangement of a plurality of hollow patterns 151. The specific shape of the hollow patterns 151 will be described later with reference to FIG. 5 . The hollow patterns are formed of, for example, a good conductor such as Ag, Cu, Ni, or Al, and have a thickness of, for example, 0.01 mm or more and 0.05 mm or less. If the thickness is less than 0.01 mm, the surface resistivity becomes high, making it difficult to maintain high reflection efficiency. If the thickness is greater than 0.05 mm, it becomes difficult to maintain the flatness of the reflection surface. The surface of the conductive pattern 15 may be protected with a transparent film having a dielectric constant and dielectric loss tangent equivalent to those of the dielectric layer 11.

[0028] The hollow pattern 151 is bonded to the dielectric layer 11 by, for example, an adhesive layer 13. The adhesive layer 13 is not applied to the entire surface of the dielectric layer 11, but is applied in an amount necessary to stably support the hollow pattern 151. This is to minimize the effect of the adhesive layer 13 on the dielectric constant of the dielectric layer 11. The area occupied by the adhesive layer 13 does not need to be exactly the same as the area occupied by the conductive pattern 15, and may vary slightly as long as the hollow pattern 151 can be stably bonded to the dielectric layer 11. For example, if the area occupancy of the conductive pattern 15 with respect to the dielectric layer 11 is 10.0% or more and 45.0% or less, the area occupancy of the adhesive layer 13 with respect to the dielectric layer 11 is 9.0% or more and 50.0% or less.

[0029] If the area occupation ratio of the conductive pattern 15 is less than 10.0%, it becomes difficult to achieve the desired reflection characteristics and reflection efficiency. If the area occupation ratio of the conductive pattern 15 exceeds 45.0%, it becomes difficult to maintain the transparency of the reflective panel 10. However, in applications that do not require transparency, the area occupation ratio of the conductive pattern 15 may be set to more than 45.0% to prioritize reflection efficiency.

[0030] The adhesive layer 13 is made of a material capable of bonding the conductive pattern 15 to the dielectric layer 11, and may be made of a thermoplastic resin such as vinyl acetate resin, acrylic resin, cellulose resin, or silicone resin. The thickness of the adhesive layer 13 is such that the conductive pattern 15 can be stably bonded to the dielectric layer 11, and is, for example, 0.002 mm or more and 0.050 mm or less. From the viewpoint of ensuring adhesive strength, the thickness is desirably 0.010 mm or more and 0.050 mm or less.

[0031] The dielectric layer 11 is an insulating polymer film made of polycarbonate, cycloolefin polymer (COP), polyethylene terephthalate (PET), fluororesin, or the like, and has a thickness of approximately 0.3 mm to 1.0 mm. The dielectric layer 11 may be made of any material having a relative permittivity and dielectric loss tangent suitable for achieving the target reflection characteristics.

[0032] The ground layer 12 may be made of the same material as the conductive pattern 15, or may be made of a different conductive material. The ground layer 12 forms a predetermined parasitic capacitance between the conductive pattern 15 and the ground layer 12. The amount of phase delay is determined by the parasitic capacitance formed between the conductive pattern 15 and the ground layer 12.

[0033] FIG. 4 shows an example of the layer structure of the reflective panel 10A. This layer structure has the layer structure of FIG. 3 sandwiched between two dielectric substrates 21 and 22. The dielectric substrate 21 is bonded to the ground layer 12 by an adhesive layer 23. The dielectric substrate 22 is bonded to the conductive pattern 15 side of the dielectric layer 11 by an adhesive layer 24. The dielectric substrates 21 and 22 are transparent to electromagnetic waves in the gigahertz to terahertz bands, specifically, electromagnetic waves in the range of 1 MHz to 3 THz, for example, 1 MHz to 300 GHz. The dielectric substrates 21 and 22 are preferably formed as the outermost layers of the reflective panel 10A from a material with excellent impact resistance, durability, and transparency. The dielectric substrates 21 and 22 can be made of polycarbonate, acrylic resin, PET, or the like. The thickness of the dielectric substrates 21 and 22 can be selected appropriately depending on the installation location, for example, between 1.0 mm and 10.0 mm. The dielectric substrates 21 and 22 may have the same thickness or different thicknesses.

[0034] The adhesive layer 23 protects the surface of the ground layer 12 and adheres and holds the dielectric substrate 21. The adhesive layer 24 protects the surface of the conductive pattern 15 and adheres and holds the dielectric substrate 22. The adhesive layers 23 and 24 are preferably durable and moisture-resistant, and may be made of, for example, ethylene-vinyl acetate (EVA) copolymer or cycloolefin polymer (COP). The thickness of the adhesive layers 23 and 24 is appropriately determined in the range of 10 μm to 400 μm so as to be able to bond the dielectric substrates 21 and 22.

[0035] By covering the conductive pattern 15 with the adhesive layer 24 and then bonding the dielectric substrate 22, the intrusion of moisture and air into the surface of the conductive pattern 15 is suppressed, and deterioration of the reflective surface is suppressed. By covering the ground layer 12 with the adhesive layer 23 and then bonding the dielectric substrate 21, the intrusion of moisture and air into the surface of the ground layer 12 is suppressed, and surface deterioration of the ground layer 12 is suppressed. This keeps the capacitance between the ground layer 12 and the conductive pattern 15 constant, and allows the designed magnitude of phase delay to be maintained. In other words, the reflection efficiency of radio waves in the designed direction can be maintained.

[0036] <Configuration Example of Hollow Pattern> FIG. 5 is a diagram showing an example of the configuration of a unit cell 20 of a conductive pattern 15 formed by a hollow pattern 151. As shown in FIG.

[0037] In the example shown in FIG. 5 , the unit cell 20 has six hollow patterns 151 a, 151 b, 151 c, 151 d, 151 e, and 151 f. The width W1 and length L of the hollow patterns 151 a to 151 f correspond to the width (X) and height (Z) directions of the reflective panel 10 in FIG. 2A , respectively. The hollow patterns 151 a to 151 f have the same width W1 and different lengths L, but their central axes are aligned (the Y coordinate position of the central axis is constant). The pitch or spacing G in the X direction is constant. The shape and size of the hollow patterns 151 a to 151 f control the phase of reflection, and the reflected waves are superimposed to form a reflected beam in the desired direction. In this example, the unit cell 20 is designed to reflect the reflected wave beam of electromagnetic waves incident perpendicularly (at an incident angle of 0°) in a direction 50° from the normal.

[0038] Hollow patterns 151a, 151b, 151c, 151d, 151e, and 151f (hereinafter sometimes collectively referred to as "hollow patterns 151") are hollowed out with a width W2. The hollow patterns have a rectangular annular shape when viewed in the XZ plane. The width of the vertical line segments is half the difference between the outer width W1 and the inner width W2 of each hollow pattern 151. Similarly, the thickness of the horizontal line segments of hollow pattern 151 is determined according to the area of ​​the hollowed out portion. The vertical and horizontal line segments of hollow pattern 151 enable reflection of both vertically polarized and horizontally polarized radio waves.

[0039] The corners of the outer edge of the hollow pattern 151 may be right angles without any curvature, or may be curved with a curvature radius R1. In the case of a right angle, the curvature radius R1 = 0.0 mm. The corners of the inner periphery of the hollow pattern 151 are curved with a curvature radius R2. The curvature radius R1 is the same as or smaller than R2. By rounding the corners of the hollow pattern 151, particularly the corners on the inner edge side, with a predetermined curvature radius, current concentration is prevented and reflection efficiency is maintained. Specifically, by rounding the corners on the inner edge side of the hollow pattern 151 with a curvature radius R2 that is between 1 / 10 and 1 / 2 of the width W1, current concentration is suppressed while enabling response to both vertically polarized waves and horizontally polarized waves.

[0040] The conductive pattern 15 is a periodic pattern in which unit cells 20 are repeatedly arranged in the X and Z directions. By providing a reflective surface formed by the conductive pattern 15 on at least a part of the reflective panel 10, it becomes possible to reflect both horizontally polarized and vertically polarized electromagnetic waves that are incident in controlled directions.

[0041] <Method of Measuring Received Power and Method of Calculating Power Reflection Efficiency According to the Embodiment> First, an example of a measuring device for measuring the received power of the electromagnetic wave reflecting device 60 will be described with reference to FIG.

[0042] <Measurement Equipment> Fig. 6 is a diagram showing an example of measurement equipment placed in the anechoic chamber 101. Here, a VNA (Vector Network Analyzer) 110 is used as the measurement equipment. A transmitting antenna 115Tx and a receiving antenna 115Rx are connected to the VNA 110 via a cable 110A. The transmitting antenna 115Tx is directed toward the electromagnetic wave reflecting device 60, and the receiving antenna 115Rx is placed in the reflection direction of the electromagnetic wave reflecting device 60.

[0043] A PC (Personal Computer) 120 is also connected to the VNA 110. The PC 120 may be located inside the anechoic chamber 101, but in FIG. 6 it is located outside the anechoic chamber 101 as an example.

[0044] As an example, the electromagnetic wave reflecting device 60, the transmitting antenna 115Tx, and the receiving antenna 115Rx are placed on a tripod or the like at a predetermined height above the floor of the anechoic chamber 101. When performing measurements, the relative positions of the transmitting antenna 115Tx and the receiving antenna 115Rx are fixed. The position of the electromagnetic wave reflecting device 60 relative to the transmitting antenna 115Tx and the receiving antenna 115Rx is also fixed.

[0045] Note that, when changing the angle of the electromagnetic wave reflecting device 60 relative to the transmitting antenna 115Tx and the receiving antenna 115Rx depending on whether the electromagnetic wave reflecting device 60 is a metasurface that performs non-specular reflection or a reflecting device that performs specular reflection, the angle of the electromagnetic wave reflecting device 60 may be changed while the transmitting antenna 115Tx and the receiving antenna 115Rx are fixed, or the position (orientation) of the transmitting antenna 115Tx and the receiving antenna 115Rx may be changed while the angle of the electromagnetic wave reflecting device 60 is fixed. Also, the positions (orientations) of both the electromagnetic wave reflecting device 60 and the transmitting antenna 115Tx and the receiving antenna 115Rx may be changed.

[0046] <VNA 110> The VNA 110 includes a transmission circuit unit that transmits a transmission signal to a transmission antenna 115Tx, a reception circuit unit that measures the power (reception power) of a reception signal received by a reception antenna 115Rx, as well as a processing unit 111 and a memory 112. The transmission circuit unit and reception circuit unit of the VNA 110 are omitted in Fig. 6.

[0047] Here, we will explain a configuration in which a transmitting antenna 115Tx and a receiving antenna 115Rx are connected to one VNA 110, but the VNA 110 may also be separated into a VNA connected to the transmitting antenna 115Tx and a VNA connected to the receiving antenna 115Rx, and the two VNAs may be connected by an optical cable or the like so that they operate in cooperation with each other.

[0048] The VNA 110 incorporates a computer system that implements a processing unit 111 and a memory 112. The computer system is implemented by a computer including a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), an input / output interface, an internal bus, etc. The processing unit 111 represents, as a functional block, the functions of a program executed by the computer system of the VNA 110. The memory 112 functionally represents the memory of the computer system of the VNA 110.

[0049] The processing unit 111 controls the transmitting circuit unit and the receiving circuit unit of the VNA 110 to perform a process of causing the transmitting antenna 115Tx to emit radio waves and a process of measuring the received power of the radio waves received by the receiving antenna 115Rx. This process is realized by the received power measurement method of the embodiment.

[0050] In the process of causing the transmitting antenna 115Tx to emit radio waves, the processing unit 111 controls the transmitting circuit unit to cause the transmitting antenna 115Tx to transmit radio waves in a predetermined band selected from a frequency band of 1 MHz to 300 GHz. The predetermined band is selected by an operator of the PC 120 inputting the desired band into the PC 120, which then transmits data representing the predetermined band to the VNA 110. Note that the predetermined band may also be selected directly by the VNA 110 without going through the PC 120.

[0051] In the process of measuring the received power, the processing unit 111 controls the receiving circuit unit to scan the frequencies of the received power within a specified frequency range and measure the received power at the electromagnetic wave reflecting device 60. By utilizing the time domain function, the processing unit 111 can distinguish between the reflected wave at the electromagnetic wave reflecting device 60, the reflected wave at the inner wall of the anechoic chamber 101, and the direct wave.

[0052] The wave reflected by the electromagnetic wave reflecting device 60 is a radio wave that is transmitted from the transmitting antenna 115Tx, reflected by the electromagnetic wave reflecting device 60, and reaches the receiving antenna 115Rx. The wave reflected by the inner wall of the anechoic chamber 101 is a radio wave that is transmitted from the transmitting antenna 115Tx, reflected by the inner wall of the anechoic chamber 101, and reaches the receiving antenna 115Rx. The direct wave is a radio wave that is transmitted from the transmitting antenna 115Tx and directly reaches the receiving antenna 115Rx.

[0053] Furthermore, in the method for calculating the power reflection efficiency of the embodiment, the power reflection coefficient is calculated based on the received power, but this processing may be performed by either the processing unit 111 of the VNA 110 or the processing unit 121 of the PC 120, or may be performed jointly by the processing units 111 and 121. Here, as an example, a form in which the processing unit 111 of the VNA 110 calculates the power reflection coefficient based on the received power will be described. That is, here, as an example, a form in which the processing unit 111 of the VNA 110 executes the calculation processing according to the method for calculating the power reflection efficiency will be described in detail with reference to FIGS. 6 to 8.

[0054] <Memory 112> The memory 112 stores programs, data, and the like required for the processing unit 111 of the VNA 110 to execute calculation processing according to the method for calculating the power reflection efficiency.

[0055] <PC 120> The PC 120 incorporates a computer system that realizes a processing unit 121 and a memory 122. The computer system is realized by a computer including a CPU, RAM, ROM, an input / output interface, an internal bus, etc. The processing unit 121 represents, as a functional block, the functions of a program executed by the computer system of the PC 120. The memory 122 functionally represents the memory of the computer system of the PC 120.

[0056] As described above, in this embodiment, the processing unit 111 of the VNA 110 executes the calculation process using the method for calculating the power reflection efficiency, but the processing unit 121 of the PC 120 may execute the calculation process using the method for calculating the power reflection efficiency, or the processing units 111 and 121 may share the responsibility of executing the calculation process using the method for calculating the power reflection efficiency. The memory 122 stores programs, data, etc. required for the processing unit 121 to execute the processing.

[0057] 7A and 7B are diagrams illustrating an example of a method for calculating the power reflection efficiency according to an embodiment. The XYZ coordinate system shown in FIGS. 1 to 5 is used in common.

[0058] 7A and 7B show a simplified positional relationship on a two-dimensional plane between the transmitting antenna 115Tx, the receiving antenna 115Rx, and the electromagnetic wave reflecting device 60. Hereinafter, the electromagnetic wave reflecting device 60 having a metasurface may be referred to as the electromagnetic wave reflecting device 60A, and the electromagnetic wave reflecting device 60 having a regular reflecting surface may be referred to as the electromagnetic wave reflecting device 60B. When there is no need to distinguish between the electromagnetic wave reflecting devices 60A and 60B, they will simply be referred to as the electromagnetic wave reflecting device 60.

[0059] Furthermore, when calculating the reflection efficiency of the electromagnetic wave reflecting devices 60A and 60B, a reflection coefficient calculated from the received power measured by the electromagnetic wave reflecting device 60 made of a perfect conductor is used. Hereinafter, the electromagnetic wave reflecting device 60 made of a perfect conductor will be referred to as the electromagnetic wave reflecting device 60C. The electromagnetic wave reflecting device 60C is an example of a reflector having a metal reflecting surface. The electromagnetic wave reflecting device 60C may have any reflecting surface as long as it is a flat metal surface, and as an example, an aluminum metal plate may be used as the electromagnetic wave reflecting device 60C. Note that, since the reflecting surface is only required to be a flat metal surface, a reflector in which aluminum foil is attached to a resin substrate or the like may also be used as the electromagnetic wave reflecting device 60C.

[0060] Fig. 7A shows an electromagnetic wave reflecting device 60A having a metasurface, and Fig. 7B shows an electromagnetic wave reflecting device 60B having a regular reflecting surface. In addition, electromagnetic wave reflecting device 60C, which is made of a perfect conductor, performs specular reflection like electromagnetic wave reflecting device 60B, and is therefore referred to as electromagnetic wave reflecting device 60B (60) or 60C in Fig. 7B.

[0061] <Details of the Calculation Method of Power Reflection Efficiency in the Embodiment> As shown in FIG. 7A , in the case of an electromagnetic wave reflecting device 60A, for example, the angles and distances of the electromagnetic wave reflecting device 60A, the transmitting antenna 115Tx, and the receiving antenna 115Rx are set in advance so that the transmitting antenna 115Tx is positioned in a direction in which the incident angle is 0 degrees, and the receiving antenna 115Rx is positioned in a direction in which the reflection angle is θ degrees when a radio wave is incident at an incident angle of 0 degrees. The angle θ is the angle formed by the transmitting antenna 115Tx and the receiving antenna 115Rx with respect to the electromagnetic wave reflecting device 60A. In FIG. 7A , the normal to the reflecting surface is indicated by a dashed line. The distance between the electromagnetic wave reflecting device 60A and the transmitting antenna 115Tx on the path of the incident wave is equal to the distance between the electromagnetic wave reflecting device 60A and the receiving antenna 115Rx on the path of the reflected wave. As an example, in FIG. 7A , the normal to the reflecting surface of the electromagnetic wave reflecting device 60A is oriented horizontally. The incident angle does not have to be 0 degrees. The electromagnetic wave reflecting device 60A reflects the radio wave in a direction shifted by θ degrees from the incident angle.

[0062] Furthermore, when measuring the received power of the electromagnetic wave reflecting device 60C under the same reflection conditions as the electromagnetic wave reflecting device 60A, as shown in FIG. 7B , the positions of the transmitting antenna 115Tx and the receiving antenna 115Rx are not changed, and the angle of the electromagnetic wave reflecting device 60C is adjusted so that the direction of the normal to the reflecting surface of the electromagnetic wave reflecting device 60C passes through the center of the angle θ in FIG. 7A . As a result, the incident angle and reflection angle of the electromagnetic wave reflecting device 60C are φ degrees, and θ = 2φ holds. The angle 2φ is the angle formed by the transmitting antenna 115Tx and the receiving antenna 115Rx with respect to the electromagnetic wave reflecting device 60C. The distance between the electromagnetic wave reflecting device 60A and the transmitting antenna 115Tx on the path of the incident wave is equal to the distance between the electromagnetic wave reflecting device 60A and the receiving antenna 115Rx on the path of the reflected wave.

[0063] The same reflection conditions mean that the angle θ in Figure 7A and the sum (2φ) of the incident angle φ and reflection angle φ in Figure 7B are the same, and the distance between the electromagnetic wave reflecting device 60A in Figure 7A and the transmitting antenna 115Tx and receiving antenna 115Rx are the same as the distance between the electromagnetic wave reflecting device 60C in Figure 7B and the transmitting antenna 115Tx and receiving antenna 115Rx.

[0064] In this way, under the same reflection conditions, the received power P1 of the reflected wave reflected by the electromagnetic wave reflection device 60A and the received power P2 of the reflected wave reflected by the electromagnetic wave reflection device 60C are measured, and the power reflection coefficient Γ1 is calculated from the received power P1, and the power reflection coefficient Γ2 is calculated from the received power P2.

[0065] Then, using the power reflection coefficients Γ1 and Γ2 calculated for the electromagnetic wave reflecting devices 60A and 60C under the same reflection conditions, the power reflection coefficient Γ1 is divided by the power reflection coefficient Γ2 to calculate the power reflection efficiency H of the electromagnetic wave reflecting device 60A. In this way, the power reflection coefficient Γ1 of the electromagnetic wave reflecting device 60A is normalized by the power reflection coefficient Γ2 of the electromagnetic wave reflecting device 60C, which is made up of a perfect conductor, to calculate the power reflection efficiency H of the electromagnetic wave reflecting device 60A.

[0066] The electromagnetic wave reflection device 60C, which is made of a perfect conductor, performs specular reflection, so the angle of incidence and the angle of reflection are equal, but the electromagnetic wave reflection device 60A with a metasurface has different angles of incidence and reflection, so it is necessary to correct the power reflection efficiency H (=Γ1 / Γ2) calculated from the power reflection coefficients Γ1 and Γ2 calculated for the electromagnetic wave reflection devices 60A and 60C under the same reflection conditions. The power reflection efficiency H of the electromagnetic wave reflection device 60A with a metasurface is the value obtained by dividing Γ1 / Γ2 by the correction value.

[0067] The reflected electric field on an ideal metasurface with no reflection loss is E ＭＲ , the reflected electric field at a reflecting surface made of a perfect conductor is E ＰＥＣ Then, the correction value ε ｐ Ha | E ＭＲ / E ＰＥＣ | ２ It can be expressed as:

[0068] |EＭＲ / E ＰＥＣ | is expressed by the following formula (1) or (2).

[0069]

[0070]

[0071] Here, θ is the incident angle to the metasurface, and φ is the reflection angle for the corresponding regular reflection. If the reflection angle of the metasurface is θ = 50° or θr = 50°, the incident angle is θi = 0°, and the reflection angle for regular reflection is φ = 25°, then the correction value ε ｐ is 0.7826.

[0072] 7A and 7B, a method for determining the power reflection efficiency H of the electromagnetic wave reflection device 60A having a metasurface has been described. In the case of the electromagnetic wave reflection device 60B having a regular reflecting surface, the measurement of the received power and the calculation of the power reflection coefficient Γ2 based on the received power are performed under the reflection condition where both the incident angle and the reflection angle are φ, as shown in FIG. 7B. Therefore, correction based on differences in radar cross section, as in the case of the electromagnetic wave reflection device 60A having a metasurface, is not required.

[0073] Under the same reflection conditions, the received power P1 of the reflected wave reflected by the electromagnetic wave reflecting device 60B and the received power P2 of the reflected wave reflected by the electromagnetic wave reflecting device 60C are measured, and the power reflection coefficient Γ1 is calculated from the received power P1, and the power reflection coefficient Γ2 is calculated from the received power P2. Then, by using the power reflection coefficients Γ1 and Γ2 calculated for the electromagnetic wave reflecting devices 60A and 60C under the same reflection conditions, the power reflection coefficient Γ1 is divided by the power reflection coefficient Γ2, and the power reflection efficiency H (=Γ1 / Γ2) of the electromagnetic wave reflecting device 60B can be calculated.

[0074] <Flowchart> Figure 8 is a flowchart showing an example of the process of the method for measuring received power and the method for calculating power reflection efficiency according to the embodiment. Here, as an example, the processing unit 111 of the VNA 110 executes the process shown in Figure 8. The process shown in Figure 8 is executed by the processing unit 111 executing a program for measuring received power and a program for calculating power reflection efficiency that implement the method for measuring received power and the method for calculating power reflection efficiency.

[0075] The processing unit 111 controls the transmission circuit unit to transmit radio waves in a predetermined band selected from a frequency band of 1 MHz to 300 GHz from the transmitting antenna 115Tx, and cause the radio waves to be incident on the electromagnetic wave reflecting device 60 (60A or 60B) at a first specified incident angle (step S1). For the electromagnetic wave reflecting device 60A, the first specified incident angle is, for example, 0 degrees, and for the electromagnetic wave reflecting device 60B, the first specified incident angle is an incident angle (φ) determined by the relative positions of the transmitting antenna 115Tx and the receiving antenna 115Rx. The incident angle determined by the relative positions of the transmitting antenna 115Tx and the receiving antenna 115Rx is an angle specified by the design of the electromagnetic wave reflecting device 60B. Step S1 is an example of process 1.

[0076] The receiving antenna 115Rx, which is arranged in the direction of the first designated reflection angle relative to the electromagnetic wave reflecting device 60 (60A or 60B), receives the reflected wave of the radio wave incident on the electromagnetic wave reflecting device 60 (60A or 60B) in the first step, and the processing unit 111 measures the received power P1 in the designated frequency range (step S2). Step S2 is an example of step 2. The received power P1 is an example of the first received power. In the case of the electromagnetic wave reflecting device 60A, the first designated reflection angle is the reflection angle θ designated by the design of the electromagnetic wave reflecting device 60A, and in the case of the electromagnetic wave reflecting device 60B, it is an angle equal to the incident angle in step S1. The designated frequency range is a frequency band including multiple measurement points using the time domain function and can be set in the VNA 110. As an example, if the predetermined band selected from the frequency band of 1 MHz to 300 GHz is 28 GHz, the specified frequency range is 22 GHz to 40 GHz, and the multiple measurement points are multiple frequencies set at 10 MHz intervals within the range from 22 GHz to 40 GHz.

[0077] The processing unit 111 controls the transmission circuit unit to transmit radio waves in the same predetermined band as in step S1 from the transmission antenna 115Tx, and causes the radio waves to be incident on the electromagnetic wave reflecting device 60C at a second specified angle of incidence (step S3). If the electromagnetic wave reflecting device 60A is used in step S1, the second specified angle of incidence is half the reflection angle θ specified by the design of the electromagnetic wave reflecting device 60A, and if the electromagnetic wave reflecting device 60B is used in step S1, the second specified angle of incidence is equal to the first specified angle of incidence for the electromagnetic wave reflecting device 60B in step S1. Step S3 is an example of process 1.

[0078] The receiving antenna 115Rx, which is arranged in the direction of the second designated reflection angle relative to the electromagnetic wave reflecting device 60C, receives the reflected wave of the radio wave incident on the electromagnetic wave reflecting device 60C in the third step, and the processing unit 111 measures the received power P2 in the designated frequency range (step S4). Step S4 is an example of step 4. The received power P2 is an example of the second received power. The second designated reflection angle is an angle that is half the reflection angle θ of the electromagnetic wave reflecting device 60A when the electromagnetic wave reflecting device 60A is used in step S2, and is an angle that is equal to the first designated reflection angle for the electromagnetic wave reflecting device 60B in step S2 when the electromagnetic wave reflecting device 60B is used in step S2.

[0079] Regarding the processing of steps S1 to S4, the processing of steps S1 and S2 may be executed after the processing of steps S3 and S4.

[0080] The position of the electromagnetic wave reflecting device 60 (60A or 60B) relative to the transmitting antenna 115Tx and the receiving antenna 115Rx in steps S1 and S2 is the same as the position of the electromagnetic wave reflecting device 60C relative to the transmitting antenna 115Tx and the receiving antenna 115Rx in steps S3 and S4. Note that the positions of the electromagnetic wave reflecting devices 60A and 60B in steps S1 and S2 are, for example, the positions of the centers of gravity of the electromagnetic wave reflecting devices 60A and 60B.

[0081] The processing unit 111 calculates the power reflection coefficient Γ1 of the electromagnetic wave reflecting device 60 (60A or 60B) and the power reflection coefficient Γ2 of the electromagnetic wave reflecting device 60C based on the received powers P1 and P2 (step S5). The power reflection coefficient Γ1 is calculated as a reflection coefficient of the S-parameters based on the received power P1, and the power reflection coefficient Γ2 is calculated as a reflection coefficient of the S-parameters based on the received power P2. Step S5 is an example of a fifth step. The power reflection coefficient Γ1 is an example of a first power reflection coefficient, and the power reflection coefficient Γ2 is an example of a second power reflection coefficient.

[0082] The processing unit 111 calculates the power reflection efficiency H of the electromagnetic wave reflection device 60 (60A or 60B) by dividing the power reflection coefficient Γ1 by the power reflection coefficient Γ2 (step S6). Step S6 is an example of the sixth step. In step S6, the power reflection efficiency H is calculated as Γ1 / Γ2.

[0083] In the case of the electromagnetic wave reflection device 60B, the angle of incidence and the angle of reflection are equal in regular reflection, so no correction is required. Therefore, the power reflection efficiency H (=Γ1 / Γ2) calculated in step S6 is the power reflection efficiency of the electromagnetic wave reflection device 60B.

[0084] In the case of the electromagnetic wave reflecting device 60B, correction is necessary, so the processing unit 111 executes step S7.

[0085] The processing unit 111 converts the power reflection efficiency H (=Γ1 / Γ2) calculated in step S6 for the electromagnetic wave reflection device 60A into a correction value |EMR / EPEC| ２ The power reflection efficiency H (=Γ1 / Γ2) of the electromagnetic wave reflection device 60A is corrected by dividing by (Step S7). Step S7 is an example of a seventh step.

[0086] With this, the processing unit 111 ends the series of processes (END).

[0087] <Experimental Results (Part 1)> Here, examples 1 to 7 will be described as experimental results (Part 1).

[0088] Example 1: Example 1 is Example 1. An anechoic chamber 101 was used, measuring 5.0 m in length, 5.0 m in width, and 3.0 m in height. Inside the anechoic chamber 101, a high-frequency signal at a specified frequency between 22.0 GHz and 40.0 GHz was output from VNA 110. The signal propagated through space via transmitting antenna 115Tx, incident at an angle of +25° on a 5.0 mm thick aluminum plate (electromagnetic wave reflecting device 60C) made of a perfect conductor. The reflected wave was received at a -25° angle by receiving antenna 115Rx. The received power P2 at 28.0 GHz was measured at the terminal of VNA 110 connected to receiving antenna 115Rx. The aluminum plate measured 0.2 m x 0.2 m in size (length in the X direction x length in the Y direction). The distance from transmitting antenna 115Tx to the aluminum plate along the incident wave path was 1.5 m, and the distance from the aluminum plate to receiving antenna 115Rx along the reflected wave path was 1.5 m. The received power P2 was −29.7 dB, and the power reflection coefficient Γ2 was 0.00108.

[0089] Next, the electromagnetic wave was incident at an angle of +25° on the electromagnetic wave reflecting device 60B, which had a regular reflecting surface 5.0 mm thick, via the transmitting antenna 115Tx and propagated through space. The reflected wave was received at a -25° angle by the receiving antenna 115Rx, and the received power P1 at 28.0 GHz was measured at the terminal of the VNA 110 connected to the receiving antenna 115Rx. The size (length in the X direction x length in the Y direction) of the electromagnetic wave reflecting device 60B was 0.2 m x 0.2 m, the distance from the transmitting antenna 115Tx to the electromagnetic wave reflecting device 60B on the incident wave path was 1.5 m, and the distance from the electromagnetic wave reflecting device 60B to the receiving antenna 115Rx on the reflected wave path was 1.5 m. The received power P1 was -29.8 dB, and the power reflection coefficient Γ1 was 0.00105. The ratio Γ1 / Γ2 was 98.1%. This was consistent with the results of a prior electromagnetic field analysis.

[0090] Example 2: Example 2 is Example 2. An anechoic chamber 101 was used, measuring 5.0 m in length, 5.0 m in width, and 3.0 m in height. Inside the anechoic chamber 101, a high-frequency signal at a specified frequency between 22.0 GHz and 40.0 GHz was output from VNA 110. The signal propagated through space via transmitting antenna 115Tx, incident at an angle of +25° on a 5.0 mm thick aluminum plate (electromagnetic wave reflecting device 60C) made of a perfect conductor. The reflected wave was received at a -25° angle by receiving antenna 115Rx. The received power P2 at 28.0 GHz was measured at the terminal of VNA 110 connected to receiving antenna 115Rx. The aluminum plate measured 0.2 m x 0.2 m in size (length in the X direction x length in the Y direction). The distance from transmitting antenna 115Tx to the aluminum plate along the incident wave path was 1.5 m, and the distance from the aluminum plate to receiving antenna 115Rx along the reflected wave path was 1.5 m. The received power P2 was −29.7 dB, and the power reflection coefficient Γ2 was 0.00108.

[0091] Next, radio waves were incident on the electromagnetic wave reflecting device 60A, which had a 5.0 mm-thick metasurface, via the transmitting antenna 115Tx and propagated through space at an incident angle of 0°. The reflected waves were received by the receiving antenna 115Rx at a +50° angle. The received power at 28.0 GHz was measured at the terminal of the VNA 110 connected to the receiving antenna 115Rx. The size (length in the X direction x length in the Y direction) of the electromagnetic wave reflecting device 60A was 0.2 m x 0.2 m. The distance from the transmitting antenna 115Tx to the electromagnetic wave reflecting device on the incident wave path was 1.5 m, and the distance from the electromagnetic wave reflecting device to the receiving antenna 115Rx on the reflected wave path was 1.5 m. The received power P1 was -30.8 dB, and the power reflection coefficient Γ1 was 0.00082. The ratio Γ1 / Γ2 was 75.9%. Since the correction value was 0.96, the corrected power reflection efficiency was 79.1%. This was consistent with the results of a preliminary electromagnetic field analysis.

[0092] Example 3: Example 3 is Example 3. An anechoic chamber 101 was used, measuring 5.0 m in length, 5.0 m in width, and 3.0 m in height. Inside the anechoic chamber 101, a high-frequency signal at a specified frequency between 22.0 GHz and 40.0 GHz was output from VNA 110. The signal propagated through space via transmitting antenna 115Tx, incident at an angle of +15° on a 5.0 mm thick aluminum plate (electromagnetic wave reflecting device 60C) made of a perfect conductor. The reflected wave was received at an angle of -15° by receiving antenna 115Rx. The received power P2 at 28.0 GHz was measured at the terminal of VNA 110 connected to receiving antenna 115Rx. The aluminum plate measured 0.3 m x 0.3 m in size (length in the X direction x length in the Y direction). The distance from transmitting antenna 115Tx to the aluminum plate along the incident wave path was 3.0 m, and the distance from the aluminum plate to receiving antenna 115Rx along the reflected wave path was 3.0 m. The received power P2 was −29.7 dB, and the power reflection coefficient Γ2 was 0.00108.

[0093] Next, radio waves were incident on the electromagnetic wave reflecting device 60A, which has a 5.0 mm-thick metasurface, via the transmitting antenna 115Tx and propagated through space at an incident angle of 0°. The reflected waves were received by the receiving antenna 115Rx at a +30° angle. The received power P1 at 28.0 GHz was measured at the terminal of the VNA 110 connected to the receiving antenna 115Rx. The size (length in the X direction x length in the Y direction) of the electromagnetic wave reflecting device 60A was 0.3 m x 0.3 m. The distance from the transmitting antenna 115Tx to the electromagnetic wave reflecting device 60A on the incident wave path was 1.5 m, and the distance from the electromagnetic wave reflecting device 60A to the receiving antenna 115Rx on the reflected wave path was 1.5 m. The received power P1 was -30.2 dB, and the power reflection coefficient Γ1 was 0.00095. The ratio Γ1 / Γ2 was 88.0%. The correction value was 0.98, and the power reflection efficiency after correction was 89.8%, which was consistent with the results of the electromagnetic field analysis performed in advance.

[0094] Example 4: Example 4 is Example 4. An anechoic chamber 101 was used, measuring 5.0 m in length, 5.0 m in width, and 3.0 m in height. A high-frequency signal at a specified frequency between 22.0 GHz and 40.0 GHz was output from VNA 110 within anechoic chamber 101. The signal propagated through space via transmitting antenna 115Tx and incident at an angle of +15° onto a 5.0 mm thick aluminum plate (electromagnetic wave reflecting device 60C) made of a perfect conductor. The reflected wave was received at a -15° angle by receiving antenna 115Rx. The received power at 28.0 GHz was measured at the terminal of VNA 110 connected to receiving antenna 115Rx. The aluminum plate measured 0.5 m x 0.2 m in size (length in the X direction x length in the Y direction). The distance from transmitting antenna 115Tx to the aluminum plate along the incident wave path was 8.0 m, and the distance from the aluminum plate to receiving antenna 115Rx along the reflected wave path was 8.0 m. The received power P2 was −29.7 dB, and the power reflection coefficient Γ2 was 0.00108.

[0095] Next, radio waves were incident on the electromagnetic wave reflecting device 60A, which has a 5.0 mm-thick metasurface, via the transmitting antenna 115Tx and propagated through space at an incident angle of 0°. The reflected waves were received by the receiving antenna 115Rx at a +45° angle. The received power at 28.0 GHz was measured at the terminal of the VNA 110 connected to the receiving antenna 115Rx. The size (length in the X direction x length in the Y direction) of the electromagnetic wave reflecting device 60A was 0.2 m x 0.2 m. The distance from the transmitting antenna 115Tx to the electromagnetic wave reflecting device 60A on the incident wave path was 1.5 m, and the distance from the electromagnetic wave reflecting device 60A to the receiving antenna 115Rx on the reflected wave path was 1.5 m. The received power P1 was -30.5 dB, and the power reflection coefficient Γ1 was 0.00089. The ratio of Γ1 / Γ2 was 82.4%, but the correction value was 0.99, so the power reflection efficiency after correction was 83.2%, which was consistent with the results of the electromagnetic field analysis performed in advance.

[0096] Example 5: Example 5 corresponds to Comparative Example 1. An anechoic chamber 101 measuring 5.0 m in length, 5.0 m in width, and 3.0 m in height was used. A high-frequency signal at a specified frequency between 22.0 GHz and 40.0 GHz was output from VNA 110 within anechoic chamber 101. The signal was incident on a 5.0 mm thick aluminum plate (electromagnetic wave reflection device 60C) made of a perfect conductor at an angle of +25.0° via transmitting antenna 115Tx. The reflected wave was received at a direction of -25.0° via receiving antenna 115Rx. The received power at 28.0 GHz was measured at the terminal of VNA 110 connected to receiving antenna 115Rx. The aluminum plate measured 0.3 m x 0.3 m in size (length in the X direction x length in the Y direction). The distance from transmitting antenna 115Tx to the aluminum plate along the incident wave path was 1.0 m, and the distance from the aluminum plate to receiving antenna 115Rx along the reflected wave path was 1.0 m. The received power was −29.5 dB, and the power reflection coefficient Γ2 was 0.00112.

[0097] Next, radio waves were incident on the electromagnetic wave reflecting device 60A, which has a 5.0 mm-thick metasurface, via the transmitting antenna 115Tx and propagated through space at an incident angle of 0°. The reflected waves were received by the receiving antenna 115Rx at a +50° angle. The received power at 28.0 GHz was measured at the terminal of the VNA 110 connected to the receiving antenna 115Rx. The size of the electromagnetic wave reflecting device (length in the X direction x length in the Y direction) was 0.3 m x 0.3 m. The distance from the transmitting antenna 115Tx to the electromagnetic wave reflecting device on the incident wave path was 0.3 m, and the distance from the electromagnetic wave reflecting device to the receiving antenna 115Rx on the reflected wave path was 0.3 m. The received power was -30.5 dB, and the power reflection coefficient was 0.00089 (Γ2). The ratio of Γ1 / Γ2 was 63.4%, but the correction value was 2.12, which exceeds 1 and therefore cannot be corrected. Furthermore, the results did not match those of the electromagnetic field analysis that was conducted in advance.

[0098] Example 6: Example 6 corresponds to Comparative Example 2. An anechoic chamber 101 measuring 5.0 m in length, 5.0 m in width, and 3.0 m in height was used. A high-frequency signal at a specified frequency between 22.0 GHz and 40.0 GHz was output from VNA 110 within anechoic chamber 101. The signal propagated through space via transmitting antenna 115Tx and incident at an angle of +25° onto a 5.0 mm thick aluminum plate (electromagnetic wave reflecting device 60C) made of a perfect conductor. The reflected wave was received at an angle of -25° by receiving antenna 115Rx. The received power at 28.0 GHz was measured at the terminal of VNA 110 connected to receiving antenna 115Rx. The aluminum plate measured 0.5 m x 0.2 m in size (length in the X direction x length in the Y direction). The distance from transmitting antenna 115Tx to the aluminum plate along the incident wave path was 2.9 m, and the distance from the aluminum plate to receiving antenna 115Rx along the reflected wave path was 2.9 m. The received power was −29.5 dB, and the power reflection coefficient Γ2 was 0.00112.

[0099] Next, radio waves were incident on the electromagnetic wave reflecting device 60A, which has a 5.0 mm-thick metasurface, via the transmitting antenna 115Tx and propagated through space at an incident angle of 0°. The reflected waves were received by the receiving antenna 115Rx at a +50° angle. The received power at 28.0 GHz was measured at the terminal of the VNA 110 connected to the receiving antenna 115Rx. The size of the electromagnetic wave reflecting device 60A (length in the X direction x length in the Y direction) was 0.3 m x 0.3 m. The distance from the transmitting antenna 115Tx to the electromagnetic wave reflecting device 60A on the incident wave path was 0.3 m, and the distance from the electromagnetic wave reflecting device 60A to the receiving antenna 115Rx on the reflected wave path was 0.3 m. The received power P1 was -30.9 dB, and the power reflection coefficient Γ1 was 0.00081. The ratio of Γ1 / Γ2 was 72.3%, and the correction value was 2.12, which exceeded 1 and made correction impossible. In addition, this did not match the results of the electromagnetic field analysis that was performed in advance.

[0100] Example 7: Example 7 corresponds to Comparative Example 3. An anechoic chamber 101 measuring 5.0 m in length, 5.0 m in width, and 3.0 m in height was used. A high-frequency signal at a specified frequency between 22.0 GHz and 40.0 GHz was output from VNA 110 within anechoic chamber 101. The signal propagated through space via transmitting antenna 115Tx and incident at an angle of +30° onto a 5.0 mm thick aluminum plate (electromagnetic wave reflecting device 60C) made of a perfect conductor. The reflected wave was received at an angle of -30° by receiving antenna 115Rx. The received power at 28.0 GHz was measured at the terminal of VNA 110 connected to receiving antenna 115Rx. The aluminum plate measured 0.5 m x 0.2 m in size (length in the X direction x length in the Y direction). The distance from transmitting antenna 115Tx to the aluminum plate along the incident wave path was 2.0 m, and the distance from the aluminum plate to receiving antenna 115Rx along the reflected wave path was 2.0 m. The received power P2 was −29.5 dB, and the power reflection coefficient Γ2 was 0.00112.

[0101] Next, radio waves were incident on the electromagnetic wave reflecting device 60A, which had a 5.0 mm-thick metasurface, via the transmitting antenna 115Tx and propagated through space at an incident angle of 0°. The reflected waves were received at a +60° angle by the receiving antenna 115Rx. The received power at 28.0 GHz was measured at the terminal of the VNA 110 connected to the receiving antenna 115Rx. The size (length in the X direction x length in the Y direction) of the electromagnetic wave reflecting device 60A was 0.5 m x 0.2 m. The distance from the transmitting antenna 115Tx to the electromagnetic wave reflecting device 60A on the incident wave path was 0.3 m, and the distance from the electromagnetic wave reflecting device 60A to the receiving antenna 115Rx on the reflected wave path was 0.3 m. The received power was -30.5 dB, and the power reflection coefficient Γ1 was 0.00089. The ratio of Γ1 / Γ2 was 63.4%, resulting in a correction value of 2.02, which exceeded 1 and prevented correction. Furthermore, the results did not match those of the electromagnetic field analysis that was conducted in advance.

[0102] <Experimental Results (Part 2)> In addition to Examples 2 to 7, the electromagnetic wave reflecting device 60A having a metasurface was set to various sizes (length in the X direction × length in the Y direction), and the distance between the transmitting antenna 115Tx and the electromagnetic wave reflecting device 60A on the path of the incident wave and the distance between the electromagnetic wave reflecting device 60A and the receiving antenna 115Rx on the path of the reflected wave were measured when the correction value was 1 or less and a slight deviation in the measurement distance did not result in a large change. The results shown in Figures 9A and 9B were obtained.

[0103] 9A and 9B show examples of measurement results for the electromagnetic wave reflecting device 60A, showing the distance from the transmitting antenna 115Tx to the electromagnetic wave reflecting device 60A on the path of the incident wave and the distance from the electromagnetic wave reflecting device 60A to the receiving antenna 115Rx on the path of the reflected wave, when the correction value is 1 or less and a slight deviation in the measurement distance does not result in a significant change. The phrase "no significant change" means that the deviation in the measurement distance is small enough to practically prevent calculation of the power reflection efficiency. FIG. 9C shows an example of the configuration of the reflecting surface of the electromagnetic wave reflecting device 60A. The rectangular reflecting surface of the electromagnetic wave reflecting device 60A has a length (width) of X (m) in the X direction and a length (width) of Y (m) in the Y direction. In FIG. 9C, the transmitting antenna 115Tx is positioned in a direction with an incident angle of 0 degrees relative to the electromagnetic wave reflecting device 60A, and the receiving antenna 115Rx is positioned in a direction with a reflection angle of θ degrees when radio waves are incident at an incident angle of 0 degrees. As an example, the reflection angle θ takes a positive value in the direction indicated by the arrow in FIG. 9C and a negative value in the opposite direction.

[0104] 9A shows an example of the measurement results of the distance L (see FIG. 9C ) between the electromagnetic wave reflecting device 60A and the transmitting antenna 115Tx and receiving antenna 115Rx when the lengths of the electromagnetic wave reflecting device 60A in the X and Y directions are the same, the correction value is 1 or less, and a slight deviation in the measurement distance does not result in a large change. The distance L is the measurement result of the distance from the transmitting antenna 115Tx to the electromagnetic wave reflecting device 60A on the path of the incident wave and the distance from the electromagnetic wave reflecting device 60A to the receiving antenna 115Rx on the path of the reflected wave when the correction value is 1 or less and a slight deviation in the measurement distance does not result in a large change.

[0105] When the length of the electromagnetic wave reflection device 60A in the X and Y directions was 0.3 m, the distance L was 2.85 m or more. That is, when the length of the electromagnetic wave reflection device 60A in the X and Y directions was 0.3 m, if the distance L was less than 2.85 m, the correction value was greater than 1, and even a slight deviation in the measurement distance, taking into account the installation accuracy and angle of the antenna and sample, could result in a correction value that was much smaller than the actual appropriate correction value. However, if the distance L was 2.85 m or more, the correction value was 1 or less, and even a slight deviation in the measurement distance did not result in a large change.

[0106] When the length of the electromagnetic wave reflection device 60A in the X and Y directions was increased from 0.3 m to 1.0 m, the distance L increased from 2.85 m to 31.5 m. In other words, when the length of the electromagnetic wave reflection device 60A in the X and Y directions was 1.0 m, if the distance L was less than 31.5 m, the correction value was greater than 1, and even a slight deviation in the measured distance could result in a correction value that was much smaller than the actual appropriate correction value. However, if the distance L was 31.5 m or greater, the correction value was 1 or less, and even a slight deviation in the measured distance did not result in a large change.

[0107] FIG. 9B shows an example of the measurement results of the distance L between the electromagnetic wave reflecting device 60A and the transmitting antenna 115Tx and the receiving antenna 115Rx when the lengths in the X direction and the Y direction of the electromagnetic wave reflecting device 60A are made the same or different, the correction value is 1 or less, and even if the measurement distance deviates slightly, there is no significant change.

[0108] When the length of the electromagnetic wave reflecting device 60A in the X direction is 0.2 m and the length in the Y direction is 0.4 m, the correction value is 1 or less, and even a slight deviation in the measurement distance does not result in a large change, and the distance L between the electromagnetic wave reflecting device 60A and the transmitting antenna 115Tx and the receiving antenna 115Rx is 1.3 m. In other words, when the length of the electromagnetic wave reflecting device 60A in the X direction is 0.2 m and the length in the Y direction is 0.4 m, if the distance L is less than 1.30 m, the correction value is greater than 1, and even a slight deviation in the measurement distance can result in the correction value being much smaller than the actual appropriate correction value, but if the distance L is 1.30 m or more, the correction value is 1 or less, and even a slight deviation in the measurement distance does not result in a large change.

[0109] When the length of the electromagnetic wave reflection device 60A in the X direction is 0.4 m and the length in the Y direction is 0.2 m, if the distance L is less than 5.00 m, the correction value is greater than 1, and if the distance L is 5.00 m or greater, the correction value is 1 or less, and even if the measurement distance is slightly deviated, there is no significant change. The distance L in this case is about four times longer than the distance L when the length of the electromagnetic wave reflection device 60A in the X direction is 0.2 m and the length in the Y direction is 0.4 m.

[0110] Furthermore, when the length of the electromagnetic wave reflection device 60A in the X direction is 0.2 m and the length in the Y direction is 0.2 m, if the distance L is less than 1.30 m, the correction value is greater than 1, and even a slight deviation in the measured distance can result in a correction value that is much smaller than the actual appropriate correction value, but if the distance L is 1.30 m or more, the correction value is 1 or less, and even a slight deviation in the measured distance does not result in a large change. The distance L in this case was the same as the distance L when the length of the electromagnetic wave reflection device 60A in the X direction is 0.2 m and the length in the Y direction is 0.4 m.

[0111] Furthermore, when the length of the electromagnetic wave reflection device 60A in the X direction is 0.4 m and the length in the Y direction is 0.4 m, if the distance L is less than 5.00 m, the correction value is greater than 1, and even a slight deviation in the measured distance can result in a correction value that is much smaller than the actual appropriate correction value, but if the distance L is 5.00 m or more, the correction value is 1 or less, and even a slight deviation in the measured distance does not result in a large change. The distance L in this case was the same as the distance L when the length of the electromagnetic wave reflection device 60A in the X direction is 0.4 m and the length in the Y direction is 0.2 m.

[0112] From the results of FIG. 9B, it was found that an increase in the distance L has a greater effect on the length of the electromagnetic wave reflection device 60A in the X direction than on the length in the Y direction.

[0113] Fig. 10 is a diagram showing an example of the results of fitting a quadratic curve to the results of Fig. 9A. In Fig. 10, the horizontal axis represents the length (m) of the electromagnetic wave reflection device 60A in the X and Y directions. Here, the lengths of the electromagnetic wave reflection device 60A in the X and Y directions are equal (X = Y). The vertical axis represents the distance L.

[0114] The fitted quadratic curve can be expressed by the following equation (3).

[0115]

[0116] When the lengths of the electromagnetic wave reflection device 60A in the X and Y directions are equal and both are X (m), if the distance L is equal to or greater than the distance L expressed by equation (3), the correction value will be 1 or less, and even if the measurement distance deviates slightly, there will be no significant change. Therefore, the relationship of the following equation (4) should be established between the lengths (m) of the electromagnetic wave reflection device 60A in the X and Y directions and the distance L.

[0117]

[0118] That is, when the lengths of the electromagnetic wave reflecting device 60A in the X direction and the Y direction are equal (X=Y), if the distance L between the electromagnetic wave reflecting device 60A and the transmitting antenna 115Tx and the receiving antenna 115Rx is set so that the distance L satisfies the relationship of equation (4), the power reflection efficiency H (=Γ1 / Γ2) calculated for the electromagnetic wave reflecting device 60A can be corrected, as in the results of Examples 2 to 4 of the experimental results (Part 1).

[0119] 9B , it was found that an increase in distance L had a significant effect on the length of the electromagnetic wave reflecting device 60A in the X direction, and therefore equation (4) can be considered as follows: That is, as shown in FIG. 9C , when the length (width) in the X direction of the rectangular reflecting surface of the electromagnetic wave reflecting device 60A is X (m), by setting the distance L between the electromagnetic wave reflecting device 60A and the transmitting antenna 115Tx and the receiving antenna 115Rx so that distance L satisfies the relationship of equation (4), the power reflection efficiency H (=Γ1 / Γ2) calculated for the electromagnetic wave reflecting device 60A can be corrected, as in the results of Examples 2 to 4 of Experimental Results (Part 1).

[0120] <Effects> The method of measuring the received power includes a first step (step S1) of transmitting radio waves in a predetermined band selected from a frequency band of 1 MHz to 300 GHz from the transmitting antenna 115Tx inside the anechoic chamber 101 in which the VNA 110 connected to the transmitting antenna 115Tx and the receiving antenna 115Rx, the relative positions of which are fixed, is placed, and causing the radio waves to be incident on the electromagnetic wave reflecting device 60 (60A or 60B) at a first designated incident angle; and a second step (step S2) of measuring the reflected waves of the radio waves incident on the electromagnetic wave reflecting device 60 (60A or 60B) in the first step by using the receiving antenna 115Rx, which is placed in the direction of the first designated reflection angle with respect to the electromagnetic wave reflecting device 60 (60A or 60B). The method includes a second step (step S2) of receiving a radio wave from a transmitting antenna 115Tx and measuring a first received power in a specified frequency range with the VNA 110, a third step (step S3) of transmitting radio waves in a predetermined band from the transmitting antenna 115Tx inside the anechoic chamber 101 and making the radio waves incident on the electromagnetic wave reflecting device 60C made of a perfect conductor at a second specified incident angle, and a fourth step (step S4) of receiving a reflected wave of the radio waves incident on the electromagnetic wave reflecting device 60C in the third step with the receiving antenna 115Rx arranged in the direction of the second specified reflection angle with respect to the electromagnetic wave reflecting device 60C made of a perfect conductor, and measuring a second received power in the specified frequency range with the VNA 110. Therefore, the received power can be measured under the same reflection conditions for the electromagnetic wave reflecting device 60 (60A or 60B) having a metasurface or a regular reflecting surface and the electromagnetic wave reflecting device 60C made of a perfect conductor using the VNA 110.

[0121] Therefore, it is possible to provide a received power measurement method that can appropriately measure the received power in an electromagnetic wave reflection device 60 having a metasurface or a regular reflection surface. Also, it is possible to provide a received power measurement program that can appropriately measure the received power in an electromagnetic wave reflection device 60 having a metasurface or a regular reflection surface.

[0122] Furthermore, the angle formed by the transmitting antenna 115Tx and the receiving antenna 115Rx with respect to the electromagnetic wave reflecting device 60 (60A or 60B) in the first step (step S1) and the second step (step S2) may be equal to the angle formed by the transmitting antenna 115Tx and the receiving antenna 115Rx with respect to the electromagnetic wave reflecting device 60C made of a perfect conductor in the third step (step S3) and the fourth step (step S4). Therefore, the received power can be measured more reliably using the VNA 110 under the same reflection conditions.

[0123] The method for calculating the power reflection efficiency includes a fifth step (step S5) of calculating a first power reflection coefficient Γ1 of the electromagnetic wave reflecting device 60 (60A or 60B) and a second power reflection coefficient Γ2 of the electromagnetic wave reflecting device 60C constituted by the perfect conductor based on any of the above-described methods for measuring received power, the first received power P1, and the second received power P2, and a sixth step (step S6) of calculating the power reflection efficiency Γ1 / Γ2 of the electromagnetic wave reflecting device 60 (60A or 60B) by dividing the first power reflection coefficient Γ1 by the second power reflection coefficient Γ2. Therefore, the power reflection efficiency Γ1 / Γ2 of the electromagnetic wave reflecting device 60 (60A or 60B) can be calculated using the VNA 110. Furthermore, by executing a power reflection efficiency calculation program, the power reflection efficiency Γ1 / Γ2 of the electromagnetic wave reflecting device 60 (60A or 60B) can be calculated using the VNA 110.

[0124] Furthermore, the electromagnetic wave reflecting device 60 is an electromagnetic wave reflecting device 60B that performs specular reflection, and the first designated angle of incidence, the first designated angle of reflection, the second designated angle of incidence, and the second designated angle of reflection may all be equal. Therefore, using the VNA 110, it is possible to more reliably calculate the power reflection efficiency Γ1 / Γ2 of the electromagnetic wave reflecting device 60 (60A or 60B) under the same reflection conditions.

[0125] Furthermore, the electromagnetic wave reflecting device 60 is an electromagnetic wave reflecting device 60A that performs non-specular reflection, and the sum of the first designated angle of incidence and the first designated angle of reflection may be equal to the sum of the second designated angle of incidence and the second designated angle of reflection. Therefore, using the VNA 110, it is possible to more reliably calculate the power reflection efficiency Γ1 / Γ2 of the electromagnetic wave reflecting device 60A under the same reflection conditions.

[0126] Furthermore, the correction value |EMR / EPEC| obtained based on the reflected electric field EMR at an ideal metasurface with no reflection loss and the reflected electric field EPEC at a reflection surface made of a perfect conductor is ２ Using this, the power reflection efficiency Γ1 / Γ2 of the electromagnetic wave reflection device 60A that performs non-specular reflection is calculated as the correction value |EMR / EPEC| ２ The method may further include a seventh step (step S7) of correcting the power reflection efficiency Γ1 / Γ2 of the electromagnetic wave reflection device 60A that performs non-specular reflection by dividing by Γ1 / Γ2. Therefore, it is possible to appropriately correct the power reflection efficiency Γ1 / Γ2 of the electromagnetic wave reflection device 60A that has different angles of incidence and reflection using the VNA 110.

[0127] Furthermore, the reflecting surface of the electromagnetic wave reflecting device 60A that performs non-specular reflection is a rectangle with a width of X (m), and the distance on the path of the incident wave between the electromagnetic wave reflecting device 60A that performs non-specular reflection and the transmitting antenna 115Tx is equal to the distance on the path of the reflected wave between the electromagnetic wave reflecting device 60A that performs non-specular reflection and the receiving antenna 115Rx, both of which are L (m).The condition for the distance L when the correction value is 1 or less may be expressed by the following equation (5).

[0128]

[0129] By setting the length X (m) of the reflecting surface of the electromagnetic wave reflecting device 60A that performs non-specular reflection and the distance L so as to satisfy equation (5), the correction value becomes 1 or less, and even if the measurement distance deviates slightly, there is no significant change, and the power reflection efficiency H (=Γ1 / Γ2) calculated for the electromagnetic wave reflecting device 60A can be corrected.

[0130] The above describes exemplary methods for measuring received power and calculating power reflection efficiency according to the present disclosure. However, the present disclosure is not limited to the specifically disclosed embodiments, and various modifications and variations are possible without departing from the scope of the claims.

[0131] This international application claims priority based on Japanese Patent Application No. 2023-203013, filed on November 30, 2023, the entire contents of which are incorporated herein by reference.

[0132] 10, 10-1, 10-2, 10A Reflection panel 15 Conductive pattern 60, 60-1, 60-2, 60-3 Electromagnetic wave reflection device 60A Electromagnetic wave reflection device 60B Electromagnetic wave reflection device 60C Electromagnetic wave reflection device 100 Electromagnetic wave reflection fence 101 Radio wave anechoic chamber 110 VNA 111 Processing unit 112 Memory 115Tx Transmitting antenna 115Rx Receiving antenna 120 PC 121 Processing unit 122 Memory

Claims

1. A method for measuring received power comprising: a first step of transmitting radio waves of a predetermined band selected from a frequency band of 1 MHz to 300 GHz inclusive from the transmitting antenna inside an anechoic chamber in which a transmitting antenna and a receiving antenna whose relative positions are fixed are placed, and causing the transmitting antenna to transmit radio waves in a predetermined band selected from a frequency band of 1 MHz to 300 GHz inclusive, and causing the transmitting antenna to transmit the radio waves to an electromagnetic wave reflecting device at a first specified angle of incidence; a second step of receiving the reflected waves of the radio waves that were incident on the electromagnetic wave reflecting device in the first step with the receiving antenna placed in a direction of a first specified angle of reflection with respect to the electromagnetic wave reflecting device, and measuring a first received power in the specified frequency range with the vector network analyzer; a third step of transmitting radio waves of the predetermined band from the transmitting antenna inside the anechoic chamber, and causing the radio waves to be incident on a reflector having a metal reflecting surface at a second specified angle of incidence; and a fourth step of receiving the reflected waves of the radio waves that were incident on the metal reflecting surface in the third step with the receiving antenna placed in a direction of a second specified angle of reflection with respect to the reflector having the metal reflecting surface, and measuring a second received power in the specified frequency range with the vector network analyzer.

2. A method for measuring received power as described in claim 1, wherein the angles formed by the transmitting antenna and the receiving antenna with respect to the electromagnetic wave reflecting device in the first and second steps are equal to the angles formed by the transmitting antenna and the receiving antenna with respect to the reflector having the metal reflecting surface in the third and fourth steps.

3. A method for calculating power reflection efficiency comprising: a method for measuring received power as claimed in claim 1 or 2; a fifth step of calculating a first power reflection coefficient Γ1 of the electromagnetic wave reflecting device and a second power reflection coefficient Γ2 of the reflector having the metal reflecting surface based on the first received power A and the second received power B; and a sixth step of calculating the power reflection efficiency Γ1 / Γ2 of the electromagnetic wave reflecting device by dividing the first power reflection coefficient Γ1 by the second power reflection coefficient Γ2.

4. The method of calculating power reflection efficiency described in claim 3, wherein the electromagnetic wave reflecting device is a reflecting device that performs specular reflection, and the first specified angle of incidence, the first specified angle of reflection, the second specified angle of incidence, and the second specified angle of reflection are all equal.

5. A method for calculating power reflection efficiency as described in claim 3, wherein the electromagnetic wave reflecting device is a reflecting device that performs non-specular reflection, and the sum of the first specified angle of incidence and the first specified angle of reflection is equal to the sum of the second specified angle of incidence and the second specified angle of reflection.

6. Correction value |EMR / EPEC| calculated based on the reflected electric field EMR at an ideal metasurface with no reflection loss and the reflected electric field EPEC at a reflecting surface composed of a perfect conductor ２ Using the above, the power reflection efficiency Γ1 / Γ2 of the electromagnetic wave reflection device performing non-specular reflection is adjusted to the correction value |EMR / EPEC| ２ 6. The method for calculating the power reflection efficiency according to claim 5, further comprising a seventh step of correcting the power reflection efficiency Γ1 / Γ2 of the electromagnetic wave reflecting device performing non-specular reflection by dividing by Γ1 / Γ2.

7. A method for calculating power reflection efficiency as described in claim 6, wherein the reflecting surface of the electromagnetic wave reflecting device that performs non-specular reflection is a rectangle with a width of X (m), the distance on the path of the incident wave between the electromagnetic wave reflecting device that performs non-specular reflection and a transmitting antenna is equal to the distance on the path of the reflected wave between the electromagnetic wave reflecting device that performs non-specular reflection and a receiving antenna, both of which are L (m), and the condition for the distance L when the correction value is 1 or less is expressed by the following equation (1).

8. A program for measuring received power, executed by a computer, comprising: a first step of transmitting radio waves of a predetermined band selected from a frequency band of 1 MHz to 300 GHz inclusive from the transmitting antenna inside an anechoic chamber in which a transmitting antenna and a vector network analyzer connected to a receiving antenna whose relative positions are fixed are placed, and causing the transmitting antenna to transmit radio waves of a predetermined band selected from a frequency band of 1 MHz to 300 GHz inclusive and causing the transmitting antenna to transmit the radio waves to an electromagnetic wave reflecting device at a first specified angle of incidence; a second step of receiving the reflected waves of the radio waves that were incident on the electromagnetic wave reflecting device in the first step with the receiving antenna placed in a direction of a first specified reflection angle with respect to the electromagnetic wave reflecting device, and measuring a first received power in the specified frequency range with the vector network analyzer; a third step of transmitting radio waves of the predetermined band from the transmitting antenna inside the anechoic chamber, and causing the radio waves to be incident on a reflector having a metal reflecting surface at a second specified angle of incidence; and a fourth step of receiving the reflected waves of the radio waves that were incident on the metal reflecting surface in the third step with the receiving antenna placed in a direction of a second specified reflection angle with respect to the reflector having the metal reflecting surface, and measuring a second received power in the specified frequency range with the vector network analyzer.

9. A program for calculating power reflection efficiency, which is executed by a computer, includes the following steps: a program for measuring received power as claimed in claim 8; a fifth step for calculating a first power reflection coefficient Γ1 of the electromagnetic wave reflecting device and a second power reflection coefficient Γ2 of the reflector having the metal reflecting surface based on the first received power A and the second received power B; and a sixth step for calculating the power reflection efficiency Γ1 / Γ2 of the electromagnetic wave reflecting device by dividing the first power reflection coefficient Γ1 by the second power reflection coefficient Γ2.