Terahertz beam diverter based on Huygens metasurface

Abstract

The invention requests to protect a terahertz wave beam steering gear based on a Huygens metasurface, which relates to the technical field of terahertz, and is composed of five resonance units with different shapes and sizes in the horizontal direction, and the same units are periodically arranged in the vertical direction. Each resonance unit comprises a dielectric substrate PI (polyimide) and a metal structure. The metal structure in one resonance unit is composed of a plurality of metal strips, and a metal opening is designed between the specific metal strips in each group of metal structure. According to the terahertz wave beam steering device based on the Huygens metasurface, incident terahertz waves can be refracted and steered, and the terahertz wave beam steering device has a high transmission coefficient. The terahertz sensor is simple in structure and mature in manufacturing process, and has important application prospects in the fields of terahertz components, terahertz sensing and the like.

Description

Technical Field

[0001] The present invention relates to the field of terahertz technology, and in particular to a terahertz beam steering device based on Huygens metasurface. Background Art

[0002] Terahertz (THz) technology has broad application prospects in many fields such as medical imaging, sensor detection, wireless communication, etc. Terahertz technology is recognized as a cutting-edge scientific and technological field internationally. In recent years, with the development of terahertz imaging technology, there is an urgent need for updated technologies that are conducive to terahertz single-pixel imaging. Traditional terahertz single-pixel imaging has problems such as slow imaging speed and high integration difficulty. The terahertz beam steering device can improve the efficiency of terahertz imaging by changing the propagation direction of the terahertz wave. Therefore, in the field of terahertz sensing and detection, the terahertz beam steering device has extremely high practical value.

[0003] After searching, the application publication number CN116706555A, an adjustable Huygens metasurface with horizontal and vertical distribution of feed lines, belongs to the feeding field of adjustable Huygens metasurface, including: a dielectric layer; an upper metal layer, including a first upper crossbar, a first lower crossbar, and a first vertical bar connecting the first upper crossbar and the first lower crossbar, wherein a first PIN tube is arranged in the first vertical bar; a lower metal layer, including a second upper crossbar, a second lower crossbar, a second vertical bar connecting the second upper crossbar and the second lower crossbar, a first horizontal feed line and a first vertical feed line, wherein a second PIN tube is arranged in the second vertical bar; the upper metal structure and the lower metal structure are respectively arranged on both sides of the dielectric layer; the metal via is connected to the first lower crossbar on the upper side and the second upper crossbar on the lower side. The central frequency of the present invention is 9.4GHz, and the use of metal vias to connect the upper and lower metal layers and the feed lines to cross the entire metasurface horizontally and vertically is expected to simplify the feeding network of the Huygens metasurface array, and has the characteristics of a simple feeder network.

[0004] The above patent specifically involves an adjustable Huygens metasurface with horizontal and vertical distribution of feed lines, whose structure and process are relatively complex and the production cost is high; the design structure of this patent is relatively simple, the production process is more mature, fewer process flows are required, and there is no need to carry out processes such as vias in the above patent. The production cost is low, and the adjustment of the abnormal refraction angle can be achieved by directly modifying the surface structure size. At the same time, the front and back sides adopt a rotationally symmetrical design to facilitate subsequent optimization. The center frequency of the above patent is 9.4GHz, while the operating frequency of the present invention is 0.8618THz, which is much higher than the operating frequency of the above patent and is more in line with the development of technology; the transmission amplitude of the above patent is greater than -3dB in most frequency bands, while the transmission amplitude of this patent is as low as -1.47bB at the operating frequency, with a higher transmission amplitude and less energy loss, which is conducive to reducing errors. Summary of the invention

[0005] The present invention aims to solve the above problems of the prior art. A terahertz beam steering device based on Huygens metasurface is proposed. The technical solution of the present invention is as follows:

[0006] A terahertz beam steering device based on a Huygens metasurface, wherein the terahertz beam steering device is composed of five first resonance units to fifth resonance units of different shapes and sizes in the horizontal direction, and the same units are periodically arranged in the vertical direction, and a periodic array includes a dielectric substrate (1) and a front metal pattern (2) and a back metal pattern (3);

[0007] Among them, a one-dimensional array with a phase difference in space is constructed with a single resonance unit as a unit. The phase of each resonance unit changes with the array, so that the array can achieve efficient anomalous refraction of single-polarized terahertz waves. In addition, the electromagnetic response of the Huygens metasurface is related to the geometric parameters of the metal pattern on the surface of the first resonance unit to the fifth resonance unit. Therefore, the phase can be adjusted by changing the shape of the metal pattern on the surface by adjusting only the geometric parameters of the vertical metal strips, thereby changing the angle of anomalous refraction of terahertz waves.

[0008] The dielectric substrate (1) is used to filter the incident wave, and the front metal pattern (2) and the back metal pattern (3) can transfer the incident terahertz wave energy from the incident end to the output end.

[0009] Furthermore, any one of the first to fifth resonance units comprises a dielectric substrate (1) and two groups of metal structures, the two groups of metal structures are respectively attached to the front and back surfaces of the dielectric substrate (1), and the two groups of metal structures satisfy rotational symmetry about the center of the dielectric substrate (1); the metal structure comprises a first group of metal structures and a second group of metal structures, the first group of metal structures comprises a first metal rod (4), a second metal rod (5), a third metal rod (6), and a fourth metal rod (7), a total of four metal rods, and metal openings are provided between the metal rods (5) and the metal rods (6) and the metal rods (7); the second group of metal structures comprises a fifth metal rod (8), a sixth metal rod (9), a seventh metal rod (10), and an eighth metal rod (11), a total of four metal rods, and metal openings are provided between the metal rods (9) and the metal rods (10) and the metal rods (11).

[0010] Furthermore, the lengths of the third metal rod (6), the fourth metal rod (7), the seventh metal rod (10), and the eighth metal rod (11) are different in each resonance unit. In the first resonance unit, the lengths of the third metal rod (5), the fourth metal rod (7), the seventh metal rod (10), and the eighth metal rod (11) are all 40 μm. In the second resonance unit, the lengths of the third metal rod (6), the fourth metal rod (7), the seventh metal rod (10), and the eighth metal rod (11) are all 49.16 μm. In the third resonance unit; 6), the lengths of the fourth metal rod (7), the seventh metal rod (10), and the eighth metal rod (11) are all 52.54 um. In the fourth resonance unit, the lengths of the third metal rod (6), the fourth metal rod (7), the seventh metal rod (10), and the eighth metal rod (11) are all 57.54 um. In the fifth resonance unit, the lengths of the third metal rod (6), the fourth metal rod (7), the seventh metal rod (10), and the eighth metal rod (11) are all 104.69 um. The shape of the dielectric substrate of each resonance unit is a square with a side length of 224 um.

[0011] Furthermore, the width of the metal rods in the metal structure is 19 um. The left sides of the metal rods (6) and (11) are 46.5 um away from the left side of the substrate. The right sides of the metal rods (7) and (10) are 46.5 um away from the right side of the substrate. The width between the metal rods (6) and (7) is 93 um. The width between the metal rods (10) and (11) is 93 um. The length of the metal rods (4) (5) (8) (9) is 224 um. The distance between the metal rods (4) and (9) is 31 um from the top edge of the dielectric substrate. The distance between the metal rods (6) and (7) and the metal rods (5) and the distance between the metal rods (10) and (11) and the metal rods (8) are all 2 um.

[0012] Furthermore, the dielectric substrate (1) is a PI polyimide substrate with a dielectric constant of 3.9, a thickness of 46 um, and a period length of 1120 um.

[0013] Furthermore, each group of metal structures is made of copper with an electrical conductivity of 5.71×10 7 S / m, thickness is 0.2um.

[0014] Furthermore, when the frequency is 0.8618 THz, the terahertz beam steering device has a maximum value when the theta angle is at 17° in the far field diagram, indicating that in the CST simulation, the present invention realizes the anomalous refraction at an angle of 17° when the incident light is perpendicular to the xoy plane. The theta angle represents the angle between the normal direction of the outgoing wave and the negative half axis of the Z axis.

[0015] The advantages and beneficial effects of the present invention are as follows:

[0016] 1. The present invention has a higher transmission coefficient at the working frequency point, has less loss than the traditional terahertz beam steering device, and has less impact on subsequent work;

[0017] 2. The present invention has a large phase change when the working frequency changes with the change of the length of the specific metal strip. Therefore, the present invention can set the corresponding metal strip length according to the required steering angle, which is convenient for regulation;

[0018] 3. The metal layer in the present invention has simple geometric patterns, mature processing technology, low manufacturing cost and easy integration; 4. The material properties of the present invention are flexible and have high versatility.

[0019] The present invention adopts flexible materials and has high applicability; the present invention adopts a double-layer Huygens metasurface for design, and the present invention adopts a rotationally symmetrical design on both the front and back sides, so that the steps are simpler when modifying parameters according to requirements; the present invention sets a metal opening with a length of 2 μm between the vertical metal strip and the second metal strip (5) and the fifth metal strip (8), and it is tested that the performance of the opening when the length is 2 μm best meets the requirements; in the present invention, the positions of the first metal strip (4) and the sixth metal strip (9) do not change when the surface metal structure size of the first resonance unit to the fifth resonance unit is changed, that is, only the length of the vertical metal strip needs to be changed. The dimensions are changed to ensure that the relative positions of the first metal strip (4), the sixth metal strip (9), the second metal strip (5) and the fifth metal strip (8) with the vertical metal strip remain unchanged, so that the design of the first resonance unit-the fifth resonance unit can be realized, and then the first resonance unit-the fifth resonance unit are combined in one dimension. At the same time, the dimensions of the transverse metal strips in the first resonance unit-the fifth resonance unit are consistent with the side length of the substrate, both of which are 224 μm. After the first resonance unit-the fifth resonance unit are combined in one dimension into an array, the polarization in the horizontal direction can be eliminated. Therefore, the present invention can realize the single-polarization anomalous refraction of terahertz waves. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a front schematic diagram of an array formed by a terahertz beam steering device based on a Huygens metasurface according to a preferred embodiment of the present invention;

[0021] Figure 2 A schematic diagram of the reverse side of the array formed by the present invention;

[0022] Figure 3 It is a front view of the resonance unit of the present invention;

[0023] Figure 4 It is a rear front view of the resonance unit of the present invention;

[0024] Figure 5 It is a right side view of the present invention;

[0025] Figure 6 It is the normalized far-field diagram of the array of the present invention at the operating frequency point.

[0026] Marks and corresponding parts names in the attached drawings:

[0027] 1- dielectric substrate, 2- single periodic array front metal pattern, 3- single periodic array back metal pattern, 4- first metal rod, 5- second metal rod, 6- third metal rod, 7- fourth metal rod, 8- fifth metal rod, 9- sixth metal rod, 10- seventh metal rod, 11- eighth metal rod. DETAILED DESCRIPTION

[0028] The following will describe the technical solutions in the embodiments of the present invention in detail in conjunction with the accompanying drawings in the embodiments of the present invention. The described embodiments are only part of the embodiments of the present invention.

[0029] The technical solution of the present invention to solve the above technical problems is:

[0030] like Figures 1 to 6 As shown, a terahertz beam steering device based on Huygens metasurface is characterized in that: the terahertz beam steering device based on Huygens metasurface is composed of five resonant units with different shapes and sizes in the horizontal direction, and the vertical direction is a periodic arrangement of identical units. One periodic array includes a dielectric substrate 1, a front metal pattern 2, and a back metal pattern 3.

[0031] Among the five resonance units, any one of the resonance units includes a dielectric substrate 1 and two groups of metal structures, which are respectively attached to the front and back sides of the dielectric substrate 1, and the two groups of metal structures satisfy rotational symmetry about the center of the dielectric substrate 1; the characteristics of different resonance units are that the lengths of the third metal rod 6, the fourth metal rod 7, the seventh metal rod 10, and the eighth metal rod 11 are different in each resonance unit. In the first resonance unit, the lengths of the third metal rod 5, the fourth metal rod 7, the seventh metal rod 10, and the eighth metal rod 11 are all 40um, and in the second resonance unit, the lengths of the third metal rod 6, the fourth metal rod 7, the seventh metal rod 10, and the eighth metal rod 11 are all 49.16um. In the third resonance unit. The lengths of the third metal rod 6, the fourth metal rod 7, the seventh metal rod 10, and the eighth metal rod 11 are all 52.54um. In the fourth resonance unit, the lengths of the third metal rod 6, the fourth metal rod 7, the seventh metal rod 10, and the eighth metal rod 11 are all 57.54um. In the fifth resonance unit, the lengths of the third metal rod 6, the fourth metal rod 7, the seventh metal rod 10, and the eighth metal rod 11 are all 104.69um, and the shape of each unit dielectric substrate is a square with a side length of 224um.

[0032] Each resonant unit includes a dielectric substrate 1 and two groups of metal structures, wherein the metal structures include a first group of metal structures and a second group of metal structures, wherein the first group of metal structures includes a first metal rod 4, a second metal rod 5, a third metal rod 6, and a fourth metal rod 7, a total of four metal rods, and metal openings are provided between the metal rod 5 and the metal rod 6 and the metal rod 7, and the second group of metal structures includes a fifth metal rod 8, a sixth metal rod 9, a seventh metal rod 10, and an eighth metal rod 11, a total of four metal rods, and metal openings are provided between the metal rod 9 and the metal rod 10 and the metal rod 11.

[0033] Each resonant unit is characterized in that: the width of the metal rods in the metal structure is 19um, the left sides of metal rods 6 and 11 are 46.5um away from the left side of the substrate, the right sides of metal rods 7 and 10 are 46.5um away from the right side of the substrate, the width between metal rods 6 and 7 is 93um, the width between metal rods 10 and 11 is 93um, the length of metal rods 4, 5, 8, and 9 is 224um, the distance between metal rod 4 and the top edge of the dielectric substrate is 31um, the distance between metal rods 9 and the bottom edge of the dielectric substrate is 31um, the distance between metal rods 6, 7 and metal rod 5, and the distance between metal rods 10, 11 and metal rod 8 are all 2um.

[0034] In this embodiment, the dielectric substrate 1 is a PI polyimide substrate with a dielectric constant of 3.9, a thickness of 46 um, and a period length of 1120 um.

[0035] The material of each group of metal structures is copper, and the electrical conductivity is 5.71×10 7 S / m, thickness is 0.2um.

[0036] When the frequency is 0.8618THz, the transmission coefficient of the first resonance unit is -1.47dB, the transmission coefficient of the second resonance unit is -0.94dB, the transmission coefficient of the third resonance unit is -1.22dB, the transmission coefficient of the fourth resonance unit is -1.32dB, and the transmission coefficient of the fifth resonance unit is -1.45dB, indicating that the transmission coefficient of the present invention is relatively high.

[0037] When the frequency is 0.8618 THz, the transmission phase of the first resonance unit is -123.87°, the transmission phase of the second resonance unit is -201.2°, the transmission phase of the third resonance unit is -266.4°, the transmission phase of the fourth resonance unit is -349.74°, and the transmission phase of the fifth resonance unit is -423.74°. It can be obtained that the transmission phase difference between one cycle of the present invention reaches 299.87°, which is close to 300°. It has a large transmission phase difference and can be flexibly designed according to actual needs.

[0038] like Figure 6As shown, for the wave with normal incidence perpendicular to the xoy plane, at a frequency of 0.8618 THz, there is a maximum value at the Theta angle, that is, when the angle between the outgoing wave direction and the negative semi-axis of the Z axis is 17°, that is, for the wave with normal incidence perpendicular to the xoy plane, an anomalous refraction with an angle of 17° is achieved in the CST simulation.

[0039] The terahertz beam steering device based on Huygens metasurface provided in the example of the present invention can achieve a higher transmission coefficient while ensuring that the array has a larger phase change, so as to design the refraction angle. The present invention is more flexible in designing the refraction angle, has a simple structure, mature technology, is easy to manufacture, and is low in price, and has good application prospects in future terahertz wave systems.

[0040] The systems, devices, modules or units described in the above embodiments may be implemented by computer chips or entities, or by products with certain functions.

[0041] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0042] The above embodiments should be understood to be only used to illustrate the present invention and not to limit the protection scope of the present invention. After reading the contents of the present invention, technicians can make various changes or modifications to the present invention, and these equivalent changes and modifications also fall within the scope defined by the claims of the present invention.

Claims

1. A terahertz beam steering device based on Huygens metasurface, characterized in that: The terahertz beam steering device is composed of five first resonant units to fifth resonant units of different shapes and sizes in the horizontal direction, and the same units are periodically arranged in the vertical direction. A periodic array includes a dielectric substrate (1) and a front metal pattern (2) and a back metal pattern (3); Among them, a one-dimensional array with a phase difference in space is constructed with a single resonance unit as a unit, and the phase of each resonance unit changes with the array, so that the array can achieve efficient anomalous refraction of single-polarized terahertz waves; and the electromagnetic response of the Huygens metasurface is related to the geometric parameters of the metal pattern on the surface of the first resonance unit to the fifth resonance unit, so the phase can be adjusted by changing the shape of the metal pattern on the surface by adjusting only the geometric parameters of the vertical metal strips, thereby changing the angle of anomalous refraction of terahertz waves; The dielectric substrate (1) is used to filter the incident wave, and the front metal pattern (2) and the back metal pattern (3) can transfer the incident terahertz wave energy from the front incident end to the back output end.

2. A terahertz beam steering device based on Huygens metasurface according to claim 1, characterized in that: In the first to fifth resonance units, any one of the resonance units comprises a dielectric substrate (1) and two groups of metal structures, the two groups of metal structures are respectively attached to the front and back surfaces of the dielectric substrate (1), and the two groups of metal structures satisfy rotational symmetry about the center of the dielectric substrate (1); the metal structure comprises a first group of metal structures and a second group of metal structures, the first group of metal structures comprises a first metal rod (4), a second metal rod (5), a third metal rod (6), and a fourth metal rod (7), a total of four metal rods, and metal openings are provided between the metal rods (5) and the metal rods (6) and the metal rods (7); the second group of metal structures comprises a fifth metal rod (8), a sixth metal rod (9), a seventh metal rod (10), and an eighth metal rod (11), a total of four metal rods, and metal openings are provided between the metal rods (9) and the metal rods (10) and the metal rods (11).

3. A terahertz beam steering device based on Huygens metasurface according to claim 2, characterized in that: The lengths of the third metal rod (6), the fourth metal rod (7), the seventh metal rod (10), and the eighth metal rod (11) are different in each resonance unit. In the first resonance unit, the lengths of the third metal rod (5), the fourth metal rod (7), the seventh metal rod (10), and the eighth metal rod (11) are all 40 μm. In the second resonance unit, the lengths of the third metal rod (6), the fourth metal rod (7), the seventh metal rod (10), and the eighth metal rod (11) are all 49.16 μm. In the third resonance unit; The lengths of the fourth metal rod (7), the seventh metal rod (10), and the eighth metal rod (11) are all 52.54 um. In the fourth resonance unit, the lengths of the third metal rod (6), the fourth metal rod (7), the seventh metal rod (10), and the eighth metal rod (11) are all 57.54 um. In the fifth resonance unit, the lengths of the third metal rod (6), the fourth metal rod (7), the seventh metal rod (10), and the eighth metal rod (11) are all 104.69 um. The shape of the dielectric substrate of each resonance unit is a square with a side length of 224 um.

4. The terahertz beam steering device based on Huygens metasurface according to claim 3, characterized in that: The width of the metal rods in the metal structure is 19 um. The left sides of the metal rods (6) and (11) are 46.5 um away from the left side of the substrate. The right sides of the metal rods (7) and (10) are 46.5 um away from the right side of the substrate. The width between the metal rods (6) and (7) is 93 um. The width between the metal rods (10) and (11) is 93 um. The length of the metal rods (4) (5) (8) (9) is 224 um. The distance between the metal rods (4) and (9) is 31 um from the top edge of the dielectric substrate. The distance between the metal rods (6) and (7) and the metal rods (5) and the distance between the metal rods (10) and (11) and the metal rods (8) are all 2 um.

5. The terahertz beam steering device based on Huygens metasurface according to claim 3, characterized in that: The dielectric substrate (1) is a PI polyimide substrate with a dielectric constant of 3.9, a thickness of 46 um, and a period length of 1120 um.

6. The terahertz beam steering device based on Huygens metasurface according to claim 1, characterized in that: The metal structure of each group is made of copper, with an electrical conductivity of 5.71×10 7 S / m, thickness is 0.2um.

7. The terahertz beam steering device based on Huygens metasurface according to claim 1, characterized in that: When the frequency is 0.8618 THz, the terahertz beam steering device has a maximum value when the theta angle is at 17° in the far field diagram, indicating that in the CST simulation, the present invention realizes the anomalous refraction with an angle of 17° when incident perpendicular to the xoy plane. The theta angle represents the angle between the normal direction of the outgoing wave and the negative half axis of the Z axis.

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