Transparent metasurface-loaded antenna and transparent metasurface plate

Abstract

To provide a transparent metasurface plate and a variable-directivity antenna that can reduce losses in transmission lines and reduce costs by standardizing components compared to conventional methods.SOLUTION: A transparent metasurface-loaded antenna includes a transparent metasurface plate and an antenna portion arranged parallel to the transparent metasurface plate. The transparent metasurface plate has a plurality of transmitting elements and converts an approximately plane wave incident from one surface into a directional electromagnetic wave having directivity in a predetermined direction within one plane. The transmitting elements transmit the incident approximately plane wave with a predetermined phase difference. The transparent metasurface plate has transmitting elements differing by a predetermined phase difference. The antenna portion is a plane wave antenna that emits an approximately plane wave.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a transmission type metasurface-loaded antenna and a transmission type metasurface plate, and more particularly to a variable directivity antenna and a spatial phase shifter using a transmission type metasurface plate and a plane wave excitation element. [Background technology]

[0002] In order to shape the directivity of an array antenna, a method is used in which an array is formed using a distribution circuit and a phase difference and an amplitude difference are generated. In conventional sector antennas, a reflector is installed on the back surface to obtain sector directivity, and a distribution circuit and amplitude ratio control are used to narrow the vertical directivity and increase the gain, thereby obtaining vertical directivity with suppressed side lobes. In Prior Art 1, an excitation wave from a spherical wave source, a horn, or the like is directly converted into a plane wave with a phase gradient. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] Naser Ojaroudi Parchin, et. al., “Recent Developments of Reconfigurable Antennas for Current and Future Wireless Communication Systems” MDPI, Electronics 8(2), 128, January 2019 Summary of the Invention [Problem to be solved by the invention]

[0004] The structure becomes large due to the transmission loss of the distribution circuit, the complexity of the design, and the need to install a reflector to obtain sector directivity. A phase difference circuit is required to generate tilt, but phase shifters in the millimeter wave band consume power. Direct control from spherical waves is difficult because the phase difference within the same plane is too large. When high gain is required, it becomes necessary to place the distribution circuits in layers, so the antenna design must take into account the circuit routing method, transmission loss due to the circuit length, etc. The larger the array scale, the greater the loss, and the lower the radiation efficiency. For example, in the conventional configuration where phase difference feeding and excitation amplitude are controlled by a distributor to generate directivity, when generating phase difference and amplitude ratio in a transmission line, it is necessary to adjust the directivity by the circuit length. This causes loss, for example, transmission line loss of about 4 dB. In addition, the laminated structure and feeding circuit are complicated. In directivity shaping using a transmit array, the wave source is considered to be a spherical wave, and the phase of the wave source and the transmission phase of the transmit array are shaped as the directivity. Because the wave source is a spherical wave, it is necessary to design it taking into account the positional relationship with the excitation source and the path length difference. In the millimeter wave band, sensitive phase design is required, and design flexibility is required. In Prior Art 1, since an excitation wave from a spherical wave source or a horn is directly converted into a plane wave with a phase gradient, a design taking into account the phase distribution of the spherical wave is required. Therefore, an object of the present invention is to provide a transparent metasurface plate and a directional variable antenna that can reduce losses in transmission lines and reduce costs by standardizing components compared to conventional methods. [Means for solving the problem]

[0005] The transmission type metasurface-loaded antenna according to claim 1 of the present invention is The antenna includes a transmission type metasurface plate and an antenna portion arranged in parallel with the transmission type metasurface plate, The transmission type metasurface plate is A device having a plurality of transmission elements, which converts a substantially plane wave incident from one surface into a directional electromagnetic wave having directivity in a predetermined direction within one plane, The transmission element transmits the incident substantially plane wave with a predetermined phase difference, The transmission type metasurface plate has transmission elements having different predetermined phase differences, The antenna unit is a transmission type metasurface-loaded antenna characterized by being a plane wave antenna that emits a substantially plane wave. Here, the term "approximately plane waves" includes quasi-plane waves. Whereas plane waves have equiphase surfaces that are in phase, quasi-plane waves are not perfect plane waves, but waves that have a phase difference of several tens of degrees. While plane waves have equiphase surfaces that appear at a certain period, quasi-plane waves that have an error of several tens of degrees at a certain period are also included in the category of approximately plane waves. The transmission type metasurface-loaded antenna according to claim 2 of the present invention is The transparent metasurface-loaded antenna described in claim 1 is characterized in that the transparent metasurface plate converts two different polarized waves incident from one side into directional electromagnetic waves each having a directivity in a predetermined direction within a single plane. The transmission type metasurface-loaded antenna according to claim 3 of the present invention comprises: The antenna section is a transmission type metasurface-loaded antenna as described in claim 1, characterized in that it has a single excitation element. The transmission type metasurface-loaded antenna according to claim 4 of the present invention comprises: 2. The transmission type metasurface-loaded antenna according to claim 1, wherein the antenna portion is a Fabry-Perot antenna. The transmission type metasurface-loaded antenna according to claim 5 of the present invention comprises: It has a movable part, The transparent metasurface-loaded antenna of claim 1 is characterized in that the movable part changes the directivity by moving the transparent metasurface plate. The transmission type metasurface-loaded antenna according to claim 6 of the present invention comprises: The antenna unit includes a plurality of excitation elements, The transmission type metasurface-loaded antenna according to claim 1, characterized in that a plurality of transmission type metasurface plates are arranged at positions corresponding to each excitation element. The transmission type metasurface-loaded antenna according to claim 7 of the present invention comprises: The transparent metasurface-loaded antenna according to claim 7, characterized in that the antenna section includes a switching section for switching between a plurality of excitation elements. The transmission type metasurface plate according to claim 8 of the present invention comprises: A transmission type metasurface plate used in the transmission type metasurface-loaded antenna according to claim 1, A plurality of transmission elements are provided. The transmission element is It transmits an incident plane wave with a predetermined phase difference, The transmission type metasurface plate has transmission elements having different predetermined phase differences, This is a transmission type metasurface plate characterized by converting a nearly plane wave incident from one surface into a directional electromagnetic wave having directivity in a specified direction within one plane. The transmission type metasurface plate according to claim 9 of the present invention comprises: The transmission element is A first substrate portion and a second substrate portion, The first substrate portion and the second substrate portion are It is formed from a dielectric substrate, are arranged parallel to each other, and It has a metal part, The transmission type metasurface plate according to claim 8, wherein the metal part forms a magnetic loop with an electric dipole. The transmission type metasurface plate according to claim 10 of the present invention comprises: The transmission type metasurface plate according to claim 8, characterized in that it has a fixing portion for fixing its position relative to the plane wave antenna. The transmission type metasurface plate according to claim 11 of the present invention comprises: The transmission type metasurface plate according to claim 9, wherein the metal portions of at least some of the transmission elements have straight line portions that are parallel to each other. The transmission type metasurface plate according to claim 12 of the present invention comprises: The metal portion of at least some of the transmission elements has a first bend at the end of a straight portion that is turned approximately 90 degrees in the same direction, and is approximately U-shaped, as described in claim 11. The transmission type metasurface plate according to claim 13 of the present invention comprises: The transmission type metasurface plate described in claim 12 is characterized in that the metal portion of at least some of the transmission elements has a second bend portion that is further turned approximately 90 degrees from the first bend portion and is approximately C-shaped. With the above configuration, the present invention makes it possible to omit the complicated power supply circuit of the phased array antenna and reduce transmission loss. In addition, by replacing the transmission type metasurface plate, i.e., the transmit array, it is possible to change the directivity, and it is possible to standardize and simplify the design even when different directivities are required. Other advantages of the present invention will be described in the detailed description of the invention. [Brief description of the drawings]

[0006] [Figure 1] 1 shows an example of the configuration of a transmission type metasurface-loaded antenna in one embodiment of the present invention. [Diagram 2] 1 shows an example of the configuration of a transmission type metasurface-loaded antenna in one embodiment of the present invention. [Diagram 3] 1 shows an example of the configuration of a transmission type metasurface-loaded antenna in one embodiment of the present invention. [Figure 4]1 shows an example of the configuration of a transmission type metasurface-loaded antenna in one embodiment of the present invention. [Diagram 5] 1 shows an example of the configuration of a transmission type metasurface-loaded antenna in one embodiment of the present invention. [Figure 6] 1 shows an example of the configuration of a transmission type metasurface-loaded antenna in one embodiment of the present invention. [Figure 7] 1 shows an example of the configuration of a transmission type metasurface-loaded antenna in one embodiment of the present invention. [Figure 8] 1 shows an example of the configuration of a transmission type metasurface-loaded antenna in one embodiment of the present invention. [Figure 9] 1 shows an example of the configuration of a transmission type metasurface-loaded antenna in one embodiment of the present invention. [Figure 10] 1 shows an example of the configuration of a transmission type metasurface plate in one embodiment of the present invention. [Figure 11] 1 shows an example of the configuration of a transmission type metasurface plate in one embodiment of the present invention. [Figure 12] 1 shows an example of the configuration of a transmission type metasurface plate in one embodiment of the present invention. [Figure 13] 1 shows an example of the configuration of a transmission type metasurface plate in one embodiment of the present invention. [Figure 14] 1 shows an example of the configuration of a transmission type metasurface plate in one embodiment of the present invention. [Figure 15] 1 shows an example of the configuration of a transmission type metasurface plate in one embodiment of the present invention. [Figure 16] 1 shows an example of the configuration of a transmission type metasurface plate in one embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] 1 and 2 show a configuration example of a transmission type metasurface-loaded antenna 1 in one embodiment of the present invention. The transmission type metasurface-loaded antenna 1 in this embodiment includes a transmission type metasurface plate 100 and an antenna section 200 arranged in parallel with the transmission type metasurface plate 100. In this description, the transmission type metasurface plate 100 may be referred to as a transmit array.

[0008] The transmission type metasurface plate 100 has a plurality of transmission elements 110, and converts a substantially plane wave incident from one surface into a directional electromagnetic wave having a directionality in a predetermined direction within one plane. That is, the transmission type metasurface plate 100 converts a substantially plane wave represented by a vertically long circle in the figure into a directional electromagnetic wave represented by a horizontally long circle in the figure. The transmission element 110 transmits an incident substantially plane wave with a predetermined phase difference. The transmission type metasurface plate 100 has transmission elements 110 that differ from each other by a predetermined phase difference.

[0009] The antenna section 200 is a plane wave antenna that emits a substantially plane wave. A plane wave or a plane wave-like antenna is used as the radiation source, and a transmit array with a phase distribution set according to the required directivity is arranged for this radiation source, so that the phase difference during transmission can be set. The phase difference to be set can be the same as when the transmission element 110 is regarded as an antenna element. Since the decrease in radiation efficiency is smaller than the loss in the transmission line, it is possible to reduce the transmission line loss. In addition, the complex power supply circuit of the phased array antenna can be omitted, and the cost can be reduced by sharing the antenna and other parts. If the radiating elements are standardized into antennas with a thin shape that allows for plane wave excitation, and this radiation directivity is configured to be shaped in the vertical and horizontal planes by a transmit array, it will be possible to reduce the transmission loss due to the distribution and phase difference circuits, while also making it possible to standardize and simplify the design, thereby improving the designability of sector antennas.

[0010] In one embodiment of the present invention, the transmissive metasurface plate 100 converts two differently polarized waves incident from one surface into directional electromagnetic waves each having a directivity in a predetermined direction within a single plane. This makes it possible to use the antenna as a dual polarized antenna by controlling the directivity of horizontally polarized waves and the directivity of vertically polarized waves, for example.

[0011] FIG. 3 shows a configuration example of a transmission type metasurface-loaded antenna 1 in one embodiment of the present invention. In this embodiment, the antenna section 200 has a single driven element 201 . This configuration makes it possible to achieve a compact design and to shape the directivity of the drive element 201 with a single element.

[0012] In this embodiment, the antenna section 200 is a Fabry-Perot antenna, but other structures such as an array antenna may be used as long as the antenna is a plane wave antenna that emits approximately plane waves. In this embodiment, a high-gain antenna such as a Fabry-Perot antenna is used as the radiating element, and an excitation wave equivalent to a plane wave is obtained very close to the antenna, that is, at a distance less than the wavelength, and the excitation wave is then incident on a transmit array that is matched to the desired directivity. In addition, by adjusting the transmitted phase distribution of the transmit array and its positional relationship with the radiating elements to match the desired vertical and horizontal directivity, it is possible to shape the directivity with the metasurface using a high-gain antenna as a wave source. In this embodiment, the directivity of the Fabry-Perot antenna is shaped by a metasurface, and a horizontal beamwidth of 10° to 60°, a vertical tilt angle of 10°, 20°, and 30°, and a voltage standing wave ratio (VSWR) of 2.0 or less are achieved for a center frequency of approximately 30 GHz.

[0013] When a point-like radiation source is used, the phase is inverted in a very small area in the transmit array, making it difficult to control the electromagnetic field. In contrast, in this embodiment, the area where the phase is close to equal is large, making it easier to control. In addition, since the wave is close to a plane wave, it becomes easier to control the phase near the driven element 201. When designing the aperture phase distribution, a two-dimensional phase distribution is required for directivity shaping, but a phase difference for beam tilt can be provided only in the vertical or horizontal direction. To widen the beam, that is, to reduce the gain, a phase difference can be provided to adjust the conical beam width in the horizontal direction, and conversely, to narrow the beam, that is, to increase the gain, a phase difference can be provided to focus the light in both the horizontal and vertical directions. By setting the focal point at the distance to the receiving area, efficient communication is possible.

[0014] 4 and 5 show a configuration example of a transmission type metasurface-loaded antenna 1 in one embodiment of the present invention. The transmission type metasurface-loaded antenna 1 in this embodiment has a movable part 300. The movable part 300 moves the transmission type metasurface plate 100 to change the directivity. By making the transmit array a movable structure, the directivity can be changed depending on the irradiation position.

[0015] 6 and 7 show a configuration example of a transmission type metasurface-loaded antenna 1 in one embodiment of the present invention. In the transmission type metasurface-loaded antenna 1 in this embodiment, the antenna section 200 includes a plurality of excitation elements 201 . A plurality of transmission type metasurface plates 100 are arranged at positions corresponding to each of the excitation elements 2019 .

[0016] A multi-beam configuration can be realized by arranging multiple transmit arrays and switching between the excitation elements 201. The antenna section 200 may also be configured to include a switching section 210 for switching between a plurality of excitation elements 201, thereby switching the directivity and intensity.

[0017] 8 and 9 show a configuration example of a transmission type metasurface-loaded antenna 1 in one embodiment of the present invention. In this embodiment, antennas loaded with a transmit array are arranged in a circle, and the transmit array can be used to form a sector antenna with beam tilt and horizontal plane directivity.

[0018] The transmission type metasurface plate 100 in one embodiment of the present invention is a transmission type metasurface plate 100 used in any of the above-mentioned transmission type metasurface-loaded antennas 1, and has a plurality of transmission elements 110 as shown in FIG. 2 . The transmission element 110 transmits an incident plane wave with a predetermined phase difference. The transmission type metasurface plate 100 has transmission elements 110 with different predetermined phase differences, and converts a substantially plane wave incident from one surface into a directional electromagnetic wave having directivity in a predetermined direction within one plane.

[0019] FIG. 10 shows an example of the configuration of a transmission type metasurface plate 100 in one embodiment of the present invention. In the transmission type metasurface plate 100 in this embodiment, the transmission element 110 has a first substrate portion 111 and a second substrate portion 112. The first substrate portion 111 and the second substrate portion 112 are formed from dielectric substrates, are arranged parallel to each other, and have a metal portion 113. The metal portion 113 forms a magnetic loop with an electric dipole.

[0020] In the transmission metasurface, the transmission element 110 forms an electric dipole and a magnetic loop. The resonant frequency is expressed as f = 1 / 2πsqrt(LC), and the resonant frequency decreases as the value of C increases. Since the mode changes to an electric dipole mode or a magnetic loop mode every time the phase changes by 90°, in this embodiment, it is possible to realize low reflection characteristics over a wide band by appropriately controlling the electric and magnetic resonant frequencies.

[0021] FIG. 11 shows an example of the configuration of a transmission type metasurface plate 100 in one embodiment of the present invention. In the transmission type metasurface plate 100 in this embodiment, the metal parts 113 of at least some of the transmission elements 110 have straight line parts 114 that are parallel to each other.

[0022] FIG. 12 shows an example of the configuration of a transmission type metasurface plate 100 in one embodiment of the present invention. In the present embodiment, the metal portion 113 of at least a portion of the transmission elements 110 of the transmission type metasurface plate 100 has a first bend portion 115 at the end of the straight portion 114 that is turned approximately 90 degrees in the same direction, and is approximately U-shaped.

[0023] FIG. 13 shows an example of the configuration of a transmission type metasurface plate 100 in one embodiment of the present invention. In the transmission type metasurface plate 100 in this embodiment, the metal portion 113 of at least a portion of the transmission elements 110 has a second bend portion 116 that is further turned approximately 90 degrees from the first bend portion 115, and is approximately C-shaped.

[0024] FIG. 14 shows an example of the configuration of a transmission type metasurface plate 100 in one embodiment of the present invention. In the transmission type metasurface plate 100 in this embodiment, the metal parts 113 of at least some of the transmission elements 110 have straight line parts 114 that are parallel to each other. With this configuration, the transmissive metasurface plate 100 converts two mutually different polarized waves incident from one surface into directional electromagnetic waves each having a directivity in a predetermined direction within one plane. This allows the plate to be used as a dual-polarized antenna by controlling the directivity of the horizontal polarized wave and the directivity of the vertical polarized wave, for example. In one embodiment of the present invention, the metal portion 113 of at least a portion of the transmission elements 110 of the transmission type metasurface plate 100 has a first bent portion 115 at the end of a straight portion 114 that is turned approximately 90 degrees in the same direction in two perpendicular directions, and is approximately U-shaped.

[0025] FIG. 15 shows an example of the configuration of a transmission type metasurface plate 100 in one embodiment of the present invention. In the present embodiment, the metal portion 113 of at least a portion of the transmission elements 110 of the transmission type metasurface plate 100 has a second bend portion 116 that is further turned approximately 90 degrees from the first bend portion 115 in two perpendicular directions, and is approximately C-shaped.

[0026] FIG. 16 shows an example of the configuration of a transmission type metasurface plate 100 in one embodiment of the present invention. The transmission type metasurface plate 100 in this embodiment has a fixing portion 400 that fixes its position relative to the plane wave antenna. With this configuration, the directivity can be changed by changing the attached elements, and flexible directivity design is possible by replacing the transmit array with one with a different transmission phase distribution.

[0027] The present invention is not limited to the above-described embodiments, and may of course be embodied in various other forms without departing from the spirit and scope of the present invention. For example, the configurations in the respective embodiments may be freely combined within a range that does not cause any contradiction. [Explanation of symbols]

[0028] 1. Transparent metasurface-loaded antenna 100 Transmissive metasurface plate 110,120,130,140 Transmitting element 111 First board part 112 Second board section 113 Metal Parts 114 Straight section 115 First bend 116 Second bend 200 Antenna section 201 Drive element 210 Switching section 300 Moving parts 400 Fixed part

Claims

1. A transmission type metasurface plate and an antenna portion arranged in parallel with the transmission type metasurface plate, The transmission type metasurface plate is A device having a plurality of transmission elements, which converts a substantially plane wave incident from one surface into a directional electromagnetic wave having directivity in a predetermined direction within one plane, The transmission element transmits an incident substantially plane wave with a predetermined phase difference, The transmission type metasurface plate has the transmission elements having different predetermined phase differences, A transparent metasurface-loaded antenna, characterized in that the antenna portion is a plane wave antenna that emits a substantially plane wave.

2. The transparent metasurface-loaded antenna of claim 1, characterized in that the transparent metasurface plate converts two different polarized waves incident from one side into directional electromagnetic waves each having a directivity in a predetermined direction within a single plane.

3. The transmission type metasurface-loaded antenna according to claim 1 , wherein the antenna section has a single excitation element.

4. The transmission type metasurface-loaded antenna according to claim 1 , wherein the antenna portion is a Fabry-Perot antenna.

5. It has a movable part, The transmission type metasurface-loaded antenna according to claim 1 , characterized in that the movable part changes the directivity by moving the transmission type metasurface plate.

6. The antenna unit includes a plurality of excitation elements, The transmission type metasurface-loaded antenna according to claim 1 , characterized in that a plurality of the transmission type metasurface plates are arranged at positions corresponding to each of the excitation elements.

7. The transmission type metasurface-loaded antenna according to claim 7, characterized in that the antenna section includes a switching section for switching between a plurality of excitation elements.

8. A transmission type metasurface plate used in the transmission type metasurface-loaded antenna according to claim 1, A plurality of transmission elements are provided. The transmission element is It transmits an incident plane wave with a predetermined phase difference, The transmission type metasurface plate has transmission elements with different predetermined phase differences, A transmission type metasurface plate characterized by converting a nearly plane wave incident from one surface into a directional electromagnetic wave having directivity in a specified direction within a single plane.

9. the transmission element has a first substrate portion and a second substrate portion; The first substrate portion and the second substrate portion are It is formed from a dielectric substrate, are arranged parallel to each other, and It has a metal part, The transmission type metasurface plate according to claim 8 , wherein the metal portion forms a magnetic loop with an electric dipole.

10. The transmission type metasurface plate according to claim 8, characterized in that it has a fixing portion for fixing its position relative to the plane wave antenna.

11. The transmission type metasurface plate according to claim 8 , characterized in that the metal parts of at least some of the transmission elements have straight line parts that are parallel to each other.

12. The metal portion of at least some of the transmission elements has a first bend at the end of the straight portion that is turned approximately 90 degrees in the same direction, and is approximately U-shaped.

13. The transmission type metasurface plate described in claim 12, characterized in that the metal portion of at least a portion of the transmission elements has a second bend portion that is further turned approximately 90 degrees from the first bend portion and is approximately C-shaped.

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