THz dual-frequency reflectarray antenna

Abstract

The present invention relates to the field of wireless communication technology and discloses a THz dual-frequency reflectarray antenna, comprising a feed source, a dielectric substrate, and a metal ground. The feed source and the metal ground are disposed on opposite sides of the dielectric substrate, respectively. A first reflectarray and a second reflectarray are disposed on the surface of the dielectric substrate near the feed source. The first reflectarray comprises a first reflector unit consisting of two concentric first metal rings arranged periodically (M×N), for reflecting signals in a first frequency band transmitted by the feed source. The second reflectarray comprises a second reflector unit consisting of two concentric second metal rings arranged periodically (M×N), for reflecting signals in a second frequency band transmitted by the feed source. The first and second reflectors are alternately arranged on the dielectric substrate. By adjusting the size of the internal metal rings in each reflector unit, a large phase compensation can be achieved within the two frequency bands, thereby obtaining the desired beam. Furthermore, the antenna has a good reflection coefficient, ensuring high gain.

Description

Technical Field

[0001] The present invention relates to the field of wireless communication technology, and in particular to a THz dual-frequency reflectarray antenna. Background Art

[0002] With the increasing popularity of 5G, research and development of the next-generation communications technology, 6G, is proceeding intensively. Leading countries in the communications sector are increasing their investment in 6G R&D. According to current R&D targets, 6G is expected to achieve communication speeds more than ten times that of 5G. In terms of related applications, 6G is expected to continue the path of 5G, covering not only personal communications but also IoT and smart industrial applications, including ultra-high-speed wireless access within factories. To support higher communication speeds, according to Shannon's law, channel capacity must be increased accordingly, which generally requires increasing communication bandwidth. The most direct way to increase communication bandwidth is to increase the carrier frequency, which is why terahertz (THz) has garnered particular attention in the 6G field. Generally speaking, terahertz (THz) refers to the frequency band with a carrier frequency between 300 GHz and 3 THz, while sub-THz (sub-THz) refers to the frequency band around 100-300 GHz. In this context, designing an array antenna for use in the sub-THz frequency band holds great promise.

[0003] Among reflectarray antennas, dual-band antennas place high demands on reflectarray unit performance. They must maintain a 360-degree phase shift range and a good reflection coefficient, while also ensuring that structural changes in the two frequency bands do not affect each other. Multi-function reflectarray antennas are more common in reconfigurable antennas and are relatively rare in millimeter-wave multi-frequency reflectarray antennas. Designing a multi-frequency reflectarray antenna that achieves multi-function multiplexing using a combination of single and multi-beams holds great promise for application in the sub-THz (terahertz) frequency band. Summary of the Invention

[0004] The purpose of the present invention is to provide a THz dual-frequency reflectarray antenna that can achieve greater phase compensation within two frequency bands to obtain the required beam, while having a good reflection coefficient to ensure that the antenna has a high gain.

[0005] To achieve the above objectives, the present invention provides a THz dual-frequency reflectarray antenna, comprising a feed source, a dielectric substrate, and a metal ground, wherein the feed source and the metal ground are respectively arranged on both sides of the dielectric substrate, and a first reflectarray and a second reflectarray are provided on a surface of the dielectric substrate on a side close to the feed source; the first reflectarray comprises M×N periodically arranged first reflective units consisting of two concentric first metal rings, configured to reflect first-frequency band signals transmitted by the feed source, and adjusting the width of the first metal ring located inside each of the first reflective units enables the first reflective units to generate a preset phase compensation value for the first-frequency band signals; the second reflectarray comprises m×n periodically arranged second reflective units consisting of two concentric second metal rings, configured to reflect second-frequency band signals transmitted by the feed source, and adjusting the width of the second metal ring located inside each of the second reflective units enables the second reflective units to generate a preset phase compensation value for the second-frequency band signals; the first reflective units and the second reflective units are alternately arranged on the dielectric substrate.

[0006] Preferably, the first reflecting unit is further provided with a first connecting line passing through the two first metal rings; the second reflecting unit is further provided with a second connecting line passing through the two second metal rings; wherein the first connecting line and the second connecting line are perpendicular to each other and are both made of metal.

[0007] Preferably, the first frequency band is 90 GHz, the first metal ring is a square ring, the side length of the first metal ring located inside is L, and the value range of L is 0.2-1 mm; the second frequency band is 140 GHz, the second metal ring is a circular ring, the radius of the second metal ring located inside is r, and the value range of r is 0.1-0.5 mm.

[0008] Preferably, the center of the first connecting line is concentric with the first metal ring, and a square metal sheet is provided at the center.

[0009] Preferably, the center of the second connecting line is concentric with the second metal ring, and a circular metal sheet is provided at the center.

[0010] Preferably, the calculation formulas for r and L are:

[0011] phase=7175.8r 3 -4798.8r 2 -276.1r+197.3 Formula (1)

[0012] phase=548.4L 3 -1045.7L 2 +558.9L-73.9 Formula (2)

[0013] Wherein, phase is the phase compensation value of each of the first reflection unit and the second reflection unit.

[0014] Preferably, the calculation formula of the phase compensation value phase of each of the first reflecting unit and the second reflecting unit is:

[0015]

[0016] Where (x0, y0, z0) is the coordinate of the feed source, (x i ,y j ) is the coordinate of the first reflecting unit and the second reflecting unit in the i-th row and the j-th column, (θ, φ) is the angle of the signal reflected by the first reflecting unit and the second reflecting unit, p0 is the phase of the central reflecting unit, d ij is the straight-line distance between the first reflecting unit, the second reflecting unit and the feed source, and λ is the wavelength of the operating frequency signal.

[0017] Preferably, for the first reflective array, θ=25°, φ=45°, 135°, 225°, 315°, and when calculating the phase compensation value of the first reflective unit, the four φ values ​​need to be substituted into the formula (3) and the four results are summed; for the second reflective array, θ=20°, φ=0°.

[0018] Preferably, M=N=20, m=n=19.

[0019] Preferably, the feed source is set to be deflected by 20°.

[0020] As described above and in practice, the THz dual-frequency reflectarray antenna of the present invention comprises a first reflectarray and a second reflectarray, each for reflecting signals in two different frequency bands, arranged on a dielectric substrate. The first reflectarray comprises a first reflector element consisting of two concentric, periodically arranged first metal rings, and the second reflectarray comprises a second reflector element consisting of two concentric, periodically arranged second metal rings. By varying the width of the metal ring located in the middle of each reflector element, its phase compensation value can be adjusted over a range exceeding 360°. By combining the phase compensation values ​​of each reflector element, a reflected electromagnetic signal with a desired phase can be obtained. In other words, by controlling the phase compensation values ​​of each reflector element, a desired reflected beam shape can be obtained, such as a single beam, dual beam, or quad beam. For a single beam, a beam focusing effect can be achieved, making it suitable for point-to-point communication; for a multi-beam, a wider range of signal coverage can be achieved, making it suitable for point-to-multipoint communication. Furthermore, the first and second reflector elements of this structural form exhibit a good reflection coefficient, which can improve the gain of the antenna. The antenna can achieve 360° phase shift characteristics and good reflection coefficient using only a single-layer dielectric substrate.

[0021] Furthermore, since this antenna is a dual-band antenna, the first and second reflective arrays are used to reflect electromagnetic signals of different frequency bands. Therefore, by varying the width of the metal ring located in the middle of each reflective unit, one reflective array can reflect a single-beam electromagnetic signal for point-to-point communication, while the other can reflect multi-beam electromagnetic signals for point-to-multipoint communication. In other words, this antenna can operate simultaneously in different application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 1 is a side view of a THz dual-frequency reflectarray antenna according to an embodiment of the present invention.

[0023] Figure 2 This is a partially enlarged view of the side of the first reflectarray, the second reflectarray, the dielectric substrate and the metal ground of the THz dual-frequency reflectarray antenna involved in one embodiment of the present invention.

[0024] Figure 3 This is a structural schematic diagram of one side surface of a dielectric substrate of a THz dual-frequency reflectarray antenna involved in an embodiment of the present invention, showing the overall structure and local amplification structure of the first reflectarray and the second reflectarray thereon.

[0025] Figure 4 This is a graph showing the relationship between the side length of the first metal ring located inside the first reflection unit of the THz dual-frequency reflectarray antenna involved in one embodiment of the present invention and the phase compensation value and reflection amplitude at different frequencies.

[0026] Figure 5 This is a relationship diagram between the radius of the second metal ring located inside the second reflection unit of the THz dual-frequency reflective array antenna involved in one embodiment of the present invention, the phase compensation value and the reflection amplitude at different frequencies.

[0027] Figure 6 This is a diagram showing the beam effect of a THz dual-frequency reflectarray antenna at 90 GHz involved in one embodiment of the present invention.

[0028] Figure 7 This is a diagram of the beam effect of the THz dual-frequency reflectarray antenna at 140 GHz involved in one embodiment of the present invention.

[0029] Figure 8 : This is the E-plane radiation pattern of the THz dual-frequency reflectarray antenna involved in one embodiment of the present invention at 90 GHz.

[0030] Figure 9 1 is the H-plane radiation pattern of the THz dual-frequency reflectarray antenna involved in one embodiment of the present invention at 90 GHz.

[0031] Figure 10 140 GHz is the E-plane radiation pattern of the THz dual-frequency reflectarray antenna involved in one embodiment of the present invention.

[0032] Figure 11 140 GHz is the H-plane radiation pattern of the THz dual-frequency reflectarray antenna involved in one embodiment of the present invention.

[0033] Figure 12 4 is a gain diagram of a THz dual-frequency reflectarray antenna according to an embodiment of the present invention.

[0034] Figure 13 FIG. 4 is a side view of a THz dual-frequency reflectarray antenna according to another embodiment of the present invention.

[0035] The reference numerals in the figures are:

[0036] 1. Feed source; 2. Dielectric substrate; 3. Metal ground; 41. First reflection unit; 42. Second reflection unit; 51. First metal ring; 52. Second metal ring; 61. First connecting line; 62. Second connecting line. DETAILED DESCRIPTION

[0037] The exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, the exemplary embodiments can be embodied in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete and will fully convey the concepts of the exemplary embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0038] In addition, the accompanying drawings are only schematic illustrations of the present disclosure and are not necessarily drawn to scale. The same reference numerals in the figures represent the same or similar parts, and their repeated description will be omitted. It should be noted that in the present disclosure, the terms "including", "configured with", and "set on" are used to express open-ended inclusion and mean that in addition to the listed elements / components / etc., there may be additional elements / components / etc.; the terms "first", "second", etc. are used only as labels and are not intended to limit the number or order of their objects; the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operate in a specific direction, and therefore should not be understood as limiting the present invention.

[0039] Unless otherwise specified or limited, the terms "mounted," "connected," and "connected" should be interpreted broadly. For example, they can refer to fixed, removable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediary; and internal communication between two components. Those skilled in the art will understand the specific meanings of these terms in the present invention based on the specific circumstances.

[0040] This embodiment discloses a THz dual-frequency reflectarray antenna. Figure 1 The side structure of the THz dual-frequency reflectarray antenna is shown. Figure 2 The side partial enlarged structure of the reflecting part of the THz dual-frequency reflective array antenna is shown, which includes the dielectric substrate 2 and the first reflective array and the second reflective array on its upper side, as well as the metal ground on its lower side. Figure 3 The structure of one side surface of the dielectric substrate of the THz dual-frequency reflectarray antenna is shown, specifically showing the overall structure and local amplification structure of the first reflectarray and the second reflectarray thereon.

[0041] Please refer to Figures 1 to 3 The THz dual-frequency reflectarray antenna includes a feed source 1, a dielectric substrate 2, and a metal ground 3. The feed source 1 and metal ground 3 are respectively arranged on either side of the dielectric substrate 2. A first reflectarray and a second reflectarray are arranged on the surface of the dielectric substrate 2 near the feed source 1. An air layer is provided between the dielectric substrate 2 and the metal ground 3. The dielectric substrate 2 is a Rogers 5880 substrate with a dielectric constant of 2.2 and a thickness of 0.254 mm. When the feed source 1 transmits an electromagnetic signal toward the dielectric substrate 2, the first and second reflectarrays reflect the electromagnetic signal at a preset angle. The metal ground 3 also reflects any electromagnetic signal that partially passes through the dielectric substrate 2 back toward the feed source 1, ensuring that the reflectarray antenna has excellent signal reflection performance.

[0042] Specifically, the first reflector array includes M×N periodically arranged first reflector units 41, each consisting of two concentric first metal rings 51. These reflectors are used to reflect the first-band signal transmitted by the feed source 1. By adjusting the width of the inner first metal ring 51 within each first reflector unit 41, the corresponding first reflector unit 41 can generate a preset phase compensation value for the first-band signal. The second reflector array includes m×n periodically arranged second reflector units 42, each consisting of two concentric second metal rings 52. These reflectors are used to reflect the second-band signal transmitted by the feed source 1. By adjusting the width of the inner second metal ring 52 within each second reflector unit 42, the corresponding second reflector unit 42 can generate a preset phase compensation value for the second-band signal. The first and second reflector units 41, 42 are arranged in an alternating pattern on the dielectric substrate 2, allowing for a larger number of reflectors to be arranged within a smaller area. Each reflector unit can receive the electromagnetic signal transmitted by the feed source 1, and both the first and second reflector arrays can reflect the signal to form a relatively smooth beam.

[0043] Because the position of the feed source 1 and the positions of the first and second reflective units 41 and 42 are fixed, the incident phase of the electromagnetic signal emitted by the feed source 1 onto each reflective unit is fixed. Therefore, by varying the width of the metal ring located in the middle of each reflective unit to adjust its phase compensation value, a reflected electromagnetic signal with a desired phase can be obtained. In other words, by controlling the phase compensation value of each reflective unit, a desired reflected beam shape, such as a single beam, dual beam, or quad beam, can be obtained. A single beam can achieve a beam focusing effect, suitable for point-to-point communication; a multi-beam can achieve wide-range signal coverage, suitable for point-to-multipoint communication. Since this antenna is a dual-band antenna, the first and second reflective arrays are respectively used to reflect electromagnetic signals in different frequency bands. Therefore, by varying the width of the metal rings located in the middle of each reflective unit, one reflective array can reflect a single-beam electromagnetic signal for point-to-point communication, while the other reflective array can reflect multi-beam electromagnetic signals for point-to-multipoint communication. In other words, this antenna can operate simultaneously in different application scenarios.

[0044] In addition, the mutual coupling between the reflective units in the first and second reflective arrays will seriously affect the phase shift function of each frequency band. Therefore, each first reflective unit 41 is provided with a first connecting line 61 that passes through the two first metal rings 51; each second reflective unit 42 is provided with a second connecting line 62 that passes through the two second metal rings 52; wherein the first connecting line 61 and the second connecting line 62 are perpendicular to each other and are both made of metal. Figure 3In this embodiment, the first connecting line 61 is along the y-axis in the figure, and the second connecting line 62 is along the x-axis in the figure. That is, the first reflector array is Y-polarized and the second reflector array is X-polarized. X-polarization and Y-polarization are naturally orthogonal, resulting in low mutual coupling and reduced interaction between the two reflector arrays. Within their respective frequency bands, structural changes in one reflector unit have little effect on the phase changes of adjacent reflector units. This dual-polarization reflector unit design significantly improves the phase accuracy and cross-polarization of the two reflector arrays, achieving the desired effects of low sidelobes and low cross-polarization.

[0045] In addition, in this embodiment, the first frequency band is 90 GHz, the first metal ring 51 is a square ring, the side length of the first metal ring 51 located inside is L, and the value range of L is 0.2-1 mm. Figure 4 , showing the relationship between L, the phase compensation value of the first reflector 41, and the reflection amplitude at 88 GHz, 89 GHz, 90 GHz, 91 GHz, and 92 GHz. The figure shows that by varying the L value within a range of 0.2-1 mm, the phase compensation value of the first reflector 41 can be varied by more than 360°, facilitating the acquisition of reflected electromagnetic waves at specific angles. Furthermore, when varying the L value within a range of 0.2-1 mm, the reflection amplitude of the first reflector 41 remains consistently greater than -0.2 dB, demonstrating excellent reflection performance.

[0046] In this embodiment, the second frequency band is 140 GHz, the second metal ring 52 is a circular ring, the radius of the second metal ring 52 located inside is r, and the value range of r is 0.1-0.5 mm. Figure 5 , showing the relationship between r and the phase compensation value and reflection amplitude of the second reflector 42 at 136 GHz, 138 GHz, 140 GHz, 142 GHz, and 144 GHz. The figure shows that by varying the r value within a range of 0.1-0.5 mm, the phase compensation value of the second reflector 42 can be varied by more than 360°, facilitating the acquisition of reflected electromagnetic waves at specific angles. Furthermore, when varying the r value within a range of 0.1-0.5 mm, the reflection amplitude of the second reflector 42 remains consistently greater than -0.2 dB, demonstrating excellent reflection performance.

[0047] Furthermore, in this embodiment, the center of the first connecting wire 61 is concentric with the first metal ring 51 and is provided with a square metal piece at the center. The center of the second connecting wire 62 is concentric with the second metal ring 52 and is provided with a circular metal piece at the center. The provision of these two metal pieces can further enhance the reflective effect of the first and second reflective arrays.

[0048] Furthermore, in this embodiment, the phase compensation value of each of the first reflecting unit 41 and the second reflecting unit 42 is phase, and its relationship with r and L is:

[0049] phase=7175.8r 3 -4798.8r 2 -276.1r+197.3 Formula (1)

[0050] phase=548.4L 3 -1045.7L 2 +558.9L-73.9 Formula (2)

[0051] After determining the required phase shift value for a particular reflective unit, the specific size of the reflective unit can be calculated based on formulas (1) and (2). Furthermore, in this embodiment, the size of the first metal ring located on the outside of the first reflective unit is a preset fixed value, and this value is the same for each first reflective unit. In actual applications, this value can be set based on the size of the dielectric substrate and the number of first reflective units. Furthermore, under the premise that this value is fixed, the phase compensation value of each first reflective unit is only related to L, so no specific numerical value is given in this embodiment. Similarly, the size of the second metal ring located on the outside of the second reflective unit is also a preset fixed value, and this value is the same for each second reflective unit. In actual applications, this value can be set based on the size of the dielectric substrate and the number of second reflective units. Furthermore, under the premise that this value is fixed, the phase compensation value of each second reflective unit is only related to L, so no specific numerical value is given in this embodiment.

[0052] During antenna design, the position of each reflective element and the incident angle of the electromagnetic signal incident on it are known. For electromagnetic signals with a specific shape of reflected beam, the reflection angle of each reflective element is also fixed. Therefore, the phase compensation value required for each reflective element can be calculated based on the requirements. Therefore, after the phase compensation value of each reflective element is determined, the L value of each first reflective element 41 and the r value of each second reflective element 42 can be calculated according to formulas (1) and (2).

[0053] Furthermore, in this embodiment, a calculation formula for the phase compensation value phase of each of the first reflecting unit 41 and the second reflecting unit 42 is given:

[0054]

[0055] In these two formulas, (x0, y0, z0) is the coordinate of feed source 1, (x i ,y j) are the coordinates of the first reflection unit 41 and the second reflection unit 42 in the i-th row and j-th column. In order to simplify the calculation, the plane where each reflection unit is located is set to the plane of Z=0 in the spatial coordinate system. (θ, φ) are the angles of the electromagnetic signals reflected by each first reflection unit 41 and the second reflection unit 42. When the required beam shape is determined, (θ, φ) are also fixed values. θ represents the angle between the reflected beam and the positive half axis of the z-axis in the spherical coordinate system; φ represents the angle between the projection of the reflected beam on the xoy plane and the positive half axis of the x-axis in the spherical coordinate system. i and j are natural numbers greater than 0. For the first reflection array, i≤M, j≤N; for the second reflection array, i≤m, j≤n. p0 is the phase of the central reflection unit, that is, the phase shift value of the first reflection unit 41 and the second reflection unit 42 in the middle. The calculation formula is:

[0056]

[0057] d ij is the straight-line distance between the first reflecting unit 41, the second reflecting unit 42, and the feed source 1. λ is the wavelength of the operating frequency signal. For the first reflecting unit 41, λ is the wavelength of the electromagnetic signal with a frequency of 90 GHz; for the second reflecting unit 42, λ is the wavelength of the electromagnetic signal with a frequency of 140 GHz.

[0058] Furthermore, in this embodiment, the first reflector array is designed to reflect electromagnetic signals in a four-beam shape, enabling better point-to-multipoint communication. The reflection angles of each first reflector unit 41 are (θ, φ), where θ = 25°, φ = 45°, 135°, 225°, and 315°. When calculating the phase compensation value of the first reflector unit, the four φ values ​​are substituted into the formula (3) and the four results are summed to obtain the final phase compensation value, phase. The second reflector array is designed to reflect electromagnetic signals in a single-beam shape, enabling stronger point-to-point communication capabilities. The reflection angles of each second reflector unit 42 are (θ, φ), where θ = 20° and φ = 0°. Based on the reflection angles of the electromagnetic signals of the first reflector unit 41 and the second reflector unit 42, combined with the above formulas (1) to (5), the L value in each first reflector unit 41 and the r value in each second reflector unit 42 can be calculated.

[0059] More specifically, in this embodiment, M = N = 20, m = n = 19. That is, the first reflective array includes 20 rows and 20 columns of first reflective units 41, and the second reflective array includes 19 rows and 19 columns of second reflective units 42. Furthermore, in this embodiment, each second reflective unit 42 is positioned midway between four adjacent first reflective units 41. Furthermore, each row of first reflective units 41 and the adjacent row of second reflective units 42 are not aligned, and each column of first reflective units 41 and the adjacent column of second reflective units 42 are not aligned. This structural form enables the arrangement of more reflective units on a smaller dielectric substrate, while also ensuring low mutual coupling between adjacent reflective units.

[0060] See Figure 6 In this type of THz reflective array antenna, the first reflective array can form a four-beam shape when radiating electromagnetic signals in the 90GHz frequency band. Figure 8 、 Figure 9 The normalized radiation patterns of the E-plane and H-plane of the antenna at 90 GHz show that the deflection angle of the four beams is ±25 degrees, the cross-polarization size is -20 dB, and the sidelobe is -15 dB. It can be seen that the antenna has better point-to-multipoint communication capability for the 90 GHz frequency band.

[0061] Please refer to Figure 7 The second reflector in this type of THz reflector antenna can form a focused single beam shape when radiating electromagnetic signals in the 140GHz frequency band. Figure 10 、 Figure 11 The normalized radiation pattern of the E-plane and H-plane of the antenna at 140GHz has a cross-polarization size of -27dB and a sidelobe of -15dB. It can be seen that the antenna has strong point-to-point communication capability in the 140GHz frequency band.

[0062] Please refer to Figure 12 The THz reflectarray antenna has a 1-dB bandwidth of 86.8-95.2 GHz at 90 GHz, with a relative bandwidth of 9.3%, and a 1-dB bandwidth of 130.8-144.1 GHz at 140 GHz, with a relative bandwidth of 9.5%. It has a wider bandwidth and higher gain.

[0063] In addition, please refer to Figure 13 In another embodiment, the feed source 1 is set to be deflected by 20°. For the reflected electromagnetic signal with a single beam shape, this setting can avoid the feed source 1 blocking the reflected signal to achieve a better communication effect.

[0064] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be included therein. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

Claims

1. A THz dual-frequency reflectarray antenna, characterized in that: It includes a feed source, a dielectric substrate and a metal ground, wherein the feed source and the metal ground are respectively arranged on both sides of the dielectric substrate, and a first reflective array and a second reflective array are arranged on a surface of the dielectric substrate close to the feed source; The first reflective array includes M×N periodically arranged first reflective units consisting of two concentric first metal rings, which are used to reflect the first frequency band signal transmitted by the feed source. Adjusting the width of the first metal ring located inside each of the first reflective units can enable the first reflective unit to generate a preset phase compensation value for the first frequency band signal. The second reflective array includes m×n periodically arranged second reflective units consisting of two concentric second metal rings, which are used to reflect the second frequency band signal transmitted by the feed source. Adjusting the width of the second metal ring located inside each second reflective unit can enable the second reflective unit to generate a preset phase compensation value for the second frequency band signal. The first reflecting units and the second reflecting units are alternately arranged on the dielectric substrate.

2. The THz dual-frequency reflectarray antenna according to claim 1, wherein: The first reflecting unit is further provided with a first connecting line running through the two first metal rings; The second reflecting unit is further provided with a second connecting line running through the two second metal rings; The first connecting line and the second connecting line are perpendicular to each other and are both made of metal.

3. The THz dual-frequency reflectarray antenna according to claim 1, wherein: The first frequency band is 90 GHz, the first metal ring is a square ring, the side length of the first metal ring located inside is L, and the value range of L is 0.2-1 mm; The second frequency band is 140 GHz, the second metal ring is a circular ring, the radius of the second metal ring located inside is r, and the value range of r is 0.1-0.5 mm.

4. The THz dual-frequency reflectarray antenna according to claim 2, wherein: The center of the first connecting line is concentric with the first metal ring, and a square metal sheet is provided at the center.

5. The THz dual-frequency reflectarray antenna according to claim 2, wherein: The center of the second connecting line is concentric with the second metal ring, and a circular metal sheet is provided at the center.

6. The THz dual-frequency reflectarray antenna according to claim 3, wherein: The calculation formulas for r and L are: phase=7175.8r 3 -4798.8r 2 -276.1r+197.3 Formula (1) phase=548.4L 3 -1045.7L 2 +558.9L-73.9 Formula (2) Wherein, phase is the phase compensation value of each of the first reflection unit and the second reflection unit.

7. The THz dual-frequency reflectarray antenna according to claim 6, wherein: The calculation formula of the phase compensation value phase of each of the first reflecting unit and the second reflecting unit is: Where (x0, y0, z0) is the coordinate of the feed source, (x i ,y j ) is the coordinate of the first reflecting unit and the second reflecting unit in the i-th row and the j-th column, (θ, φ) is the angle of the signal reflected by the first reflecting unit and the second reflecting unit, p0 is the phase of the central reflecting unit, d ij is the straight-line distance between the first reflecting unit, the second reflecting unit and the feed source, and λ is the wavelength of the operating frequency signal.

8. The THz dual-frequency reflectarray antenna according to claim 7, wherein: For the first reflective array, θ = 25°, φ = 45°, 135°, 225°, 315°, when calculating the phase compensation value of the first reflective unit, the four φ values ​​need to be substituted into the formula (3) and the four results are summed; For the second reflection array, θ=20° and φ=0°.

9. The THz dual-frequency reflectarray antenna according to any one of claims 1 to 8, wherein: M=N=20, m=n=19.

10. The THz dual-frequency reflectarray antenna according to any one of claims 1 to 8, wherein: The feed source is set to be deflected by 20°.

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