A terahertz wave beam steerer based on a huygens super-surface

Abstract

The application claims a terahertz beam deflector based on a Huygens super surface, relates to the technical field of terahertz, and is composed of five resonant units with different shapes and sizes in the horizontal direction, and the units are periodically arranged in the vertical direction. Each resonant unit comprises a dielectric substrate PI (polyimide) and a metal structure. The metal structure in each resonant unit is composed of multiple metal strips, and a metal opening is designed between specific metal strips in each group of metal structures. The terahertz beam deflector based on the Huygens super surface has the advantages that the incident terahertz waves can be refracted and deflected, and the transmission coefficient is relatively high. The structure is simple, the manufacturing process is mature, and the terahertz beam deflector has important application prospects in the fields of terahertz components, terahertz sensors and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of terahertz, in particular to a terahertz beam steering device based on a Huygens super surface. BACKGROUND

[0002] Terahertz (THz) technology has broad application prospects in medical imaging, sensing and detection, wireless communication and other fields. Terahertz technology is internationally recognized as a cutting-edge technology. In recent years, with the development of terahertz imaging technology, there is an urgent need for technology that is 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 terahertz waves, so it has high practical value in the field of terahertz sensing and detection.

[0003] After searching, the application publication number CN116706555A, a feed line horizontal and vertical distribution adjustable Huygens super surface, belongs to the field of adjustable Huygens super surface feed, including: a dielectric layer; an upper metal layer including a first upper horizontal rod, a first lower horizontal rod, and a first vertical rod connecting the first upper horizontal rod and the first lower horizontal rod, a first PIN tube is arranged in the first vertical rod; a lower metal layer including a second upper horizontal rod, a second lower horizontal rod, a second vertical rod connecting the second upper horizontal rod and the second lower horizontal rod, a first horizontal feed line, and a first vertical feed line, a second PIN tube is arranged in the second vertical rod; the upper metal layer structure and the lower metal layer structure are arranged on both sides of the dielectric layer respectively; a metal via hole is connected to the first lower horizontal rod at the top and the second upper horizontal rod at the bottom. The center frequency of the present application is 9.4GHz, and the metal via hole is used to connect the upper and lower metal layers and the feed line horizontally and vertically across the entire super surface, which is expected to simplify the feed network of the Huygens super surface array, and has the characteristics of simple feed network.

[0004] The above-mentioned patent specifically relates to an adjustable Huygens super surface with horizontal and vertical distribution of feed lines, which has a relatively complex structure and process, and a high manufacturing cost. The design structure of the present application is relatively simple, the manufacturing process is more mature, and fewer process flows are required. The via hole process in the above-mentioned patent is not required, the manufacturing cost is low, and the abnormal refraction angle can be adjusted by directly modifying the surface structure size. At the same time, the front and back surfaces are designed in a rotational symmetry, which is convenient for subsequent optimization. The center frequency of the above-mentioned patent is 9.4GHz, while the working frequency of the present application is 0.8618THz, which is much higher than that of the above-mentioned patent, and is more in line with the development of technology. The transmission amplitude of the above-mentioned patent is greater than-3dB in most frequency bands, while the transmission amplitude of the present application is-1.47bB at the working frequency, which has a higher transmission amplitude and smaller energy loss, and is conducive to reducing errors. SUMMARY

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

[0006] A terahertz beam steering device, wherein the terahertz beam steering device is composed of five first resonant units to fifth resonant units of the same shape but different sizes in the horizontal direction, and the same units are periodically arranged in the vertical direction. In a periodic array, there is a dielectric substrate (1) and a front metal pattern (2) and a back metal pattern (3).

[0007] In this design, a one-dimensional array with a phase difference in space is constructed using individual resonant units as the unit. The phase of each resonant unit changes with the array, enabling the array to achieve efficient anomalous refraction of single-polarized terahertz waves. Furthermore, the electromagnetic response of the Huygens metasurface is related to the geometric parameters of the metal pattern on the surface of the first to fifth resonant units. Therefore, the phase can be adjusted by changing the shape of the surface metal pattern by adjusting only the geometric parameters of the vertical metal rod, 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 energy of the incident terahertz wave from the front incident end to the back exit end.

[0009] In the first resonant unit to the fifth resonant unit, each resonant unit includes a dielectric substrate (1) and two sets of metal structures. These two sets of metal structures are attached to the front and back of the dielectric substrate (1) respectively, and the two sets of metal structures satisfy rotational symmetry about the center of the dielectric substrate (1). The metal structures include a first set of metal structures and a second set of metal structures. The first set 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. A metal opening is provided between the second metal rod (5), the third metal rod (6), and the fourth metal rod (7). The first metal rod (4) and the second metal rod (5) are arranged in parallel, and the third metal rod (6) and the fourth metal rod (7) are arranged perpendicularly between the first metal rod (4) and the second metal rod (5), and the third metal rod (6) and the fourth metal rod (7) are arranged in parallel. The lengths of the first metal rod (4) and the second metal rod (5) are the same as the length of the dielectric substrate (1).

[0010] The second group of metal structures includes four metal rods, i.e., a fifth metal rod (8), a sixth metal rod (9), a seventh metal rod (10), and an eighth metal rod (11), and a metal opening is arranged between the sixth metal rod (9), the seventh metal rod (10), and the eighth metal rod (11); the fifth metal rod (8) and the sixth metal rod (9) are arranged in parallel, the seventh metal rod (10) and the eighth metal rod (11) are arranged perpendicularly between the fifth metal rod (8) and the sixth metal rod (9), and the seventh metal rod (10) and the eighth metal rod (11) are arranged in parallel; and the lengths of the fifth metal rod (8) and the sixth metal rod (9) are the same as the length of the dielectric substrate (1).

[0011] Further, 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 resonant unit; in the first resonant 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 40 um; in the second resonant 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 um; in the third resonant 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 52.54 um; in the fourth resonant 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 resonant 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; and the shape of the dielectric substrate in each resonant unit is a square with a side length of 224 um.

[0012] Further, the widths of the metal rods in the metal structure are all 19 um, the left side of the third metal rod (6) and the eighth metal rod (11) is 46.5 um away from the left side of the substrate, the right side of the fourth metal rod (7) and the seventh metal rod (10) is 46.5 um away from the right side of the substrate, the width between the third metal rod (6) and the fourth metal rod (7) is 93 um, the width between the seventh metal rod (10) and the eighth metal rod (11) is 93 um, the lengths of the first metal rod (4), the second metal rod (5), the fifth metal rod (8), and the sixth metal rod (9) are all 224 um, the first metal rod (4) is 31 um away from the top edge of the dielectric substrate, the sixth metal rod (9) is 31 um away from the bottom edge of the dielectric substrate, the distances between the third metal rod (6), the fourth metal rod (7), and the second metal rod (5) and between the seventh metal rod (10), the eighth metal rod (11), and the fifth metal rod (8) are all 2 um.

[0013] Further, the medium substrate (1) is a PI polyimide substrate, the dielectric constant is 3.9, the thickness is 46um, and the period length is 1120um.

[0014] Further, the material of each group of metal structures is copper, the conductivity is 5.71*10 7 S / m, and the thickness is 0.2um.

[0015] Further, at a frequency of 0.8618THz, the terahertz beam deflector has a maximum value at a theta angle of 17° in a far-field diagram, indicating that the present application realizes abnormal refraction at an angle of 17° when the normal incidence is perpendicular to the xoy plane in the CST simulation. The theta angle represents the included angle between the normal direction of the outgoing wave and the negative half of the Z axis.

[0016] Advantages and beneficial effects of the present application are as follows:

[0017] 1. The present application has a higher transmission coefficient at the working frequency point, and the loss is smaller than that of the traditional terahertz beam deflector, and the influence on subsequent work is smaller.

[0018] 2. The present application has a large phase change amount with the change of the length of the specific metal rod at the working frequency, so the present application can set the corresponding length of the metal rod according to the required deflection angle, and is convenient to control.

[0019] 3. The metal layer pattern in the present application is simple in geometry, the processing technology is mature, the manufacturing cost is low, and it is easy to integrate.

[0020] 4. The material property of the present application is flexible, and has high universality.

[0021] The application adopts flexible materials, and has higher applicability; the application adopts double-layer Huygens super surfaces for design, and adopts positive and reverse two-side rotationally symmetrical design, so that the steps are simpler when parameters are modified according to requirements; the application sets a metal opening with a length of 2 um between the vertical metal rod and the second metal rod (5) and the fifth metal rod (8), and the opening has the performance most meeting the requirements when the length is 2 um; in the application, the first metal rod (4) and the sixth metal rod (9) do not change positions when the surface metal structure size of the first resonance unit to the fifth resonance unit is changed, that is, only the size of the vertical metal rod needs to be changed, the relative positions of the first metal rod (4), the sixth metal rod (9), the second metal rod (5) and the fifth metal rod (8) and the vertical metal rod are unchanged, so that the design of the first resonance unit to the fifth resonance unit can be realized, and the first resonance unit to the fifth resonance unit is one-dimensionally combined, and the size of the transverse metal rod in the first resonance unit to the fifth resonance unit is consistent with the base length and is 224 um, so that the horizontal polarization can be excluded after the first resonance unit to the fifth resonance unit is one-dimensionally combined into an array, and therefore the application can realize single-polarization abnormal refraction of terahertz waves. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a front view of an array formed by the Huygens super surface-based terahertz wave beam steering device according to the preferred embodiment of the application;

[0023] Figure 2 is a back view of the array formed by the application;

[0024] Figure 3 is a front view of a resonance unit of the application;

[0025] Figure 4 is a back view of the resonance unit of the application;

[0026] Figure 5 is a right view of the application;

[0027] Figure 6 is a normalized far field diagram of the array of the application at a working frequency point.

[0028] Markings in the drawings and corresponding part names:

[0029] 1-medium base, 2-front metal pattern of a single period array, 3-back metal pattern of a single period array, 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

[0030] The technical solutions of the embodiments of the present invention will be clearly and thoroughly described below with reference to the accompanying drawings. The described embodiments are merely some embodiments of the present invention.

[0031] The technical solution of the present invention to solve the above-mentioned technical problems is:

[0032] like Figures 1 to 6 As shown, a terahertz beam steering device based on a Huygens metasurface is characterized in that: the terahertz beam steering device based on a Huygens metasurface consists of five resonant units of different shapes and sizes in the horizontal direction, and the units are arranged periodically in the vertical direction. In a periodic array, there is a dielectric substrate 1 and a front metal pattern 2 and a back metal pattern 3.

[0033] In the five resonant units, each resonant unit includes a dielectric substrate 1 and two sets of metal structures. These two sets of metal structures are attached to the front and back sides of the dielectric substrate 1, respectively, and the two sets of metal structures satisfy rotational symmetry about the center of the dielectric substrate 1. The characteristics of different resonant units are as follows: 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 resonant unit. In the first resonant 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 40 μm. In the second resonant 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. 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 52.54 μm. In the fourth resonant 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 μm. In the fifth resonant 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 μm. The dielectric substrate of each unit is a square with a side length of 224 μm.

[0034] Each resonant unit includes a dielectric substrate 1 and two sets of metal structures. The metal structures include a first set of metal structures and a second set of metal structures. The first set of metal structures includes four metal rods: a first metal rod 4, a second metal rod 5, a third metal rod 6, and a fourth metal rod 7. A metal opening is provided between the second metal rod 5, the third metal rod 6, and the fourth metal rod 7. The second set of metal structures includes four metal rods: a fifth metal rod 8, a sixth metal rod 9, a seventh metal rod 10, and an eighth metal rod 11. A metal opening is provided between the sixth metal rod 9, the seventh metal rod 10, and the eighth metal rod 11.

[0035] Each of the resonant units is characterized in that: the metal rod width in the metal structure is 19 um, the third metal rod 6 and the eighth metal rod 11 are 46.5 um away from the left side of the base, the fourth metal rod 7 and the seventh metal rod 10 are 46.5 um away from the right side of the base, the width between the third metal rod 6 and the fourth metal rod 7 is 93 um, the width between the seventh metal rod 10 and the eighth metal rod 11 is 93 um, the length of the first metal rod 4, the second metal rod 5, the fifth metal rod 8 and the sixth metal rod 9 is 224 um, and the first metal rod 4 is 31 um away from the top edge of the dielectric substrate, the sixth metal rod 9 is 31 um away from the bottom edge of the dielectric substrate, and the distance between the third metal rod 6, the fourth metal rod 7 and the second metal rod 5 and the distance between the seventh metal rod 10, the eighth metal rod 11 and the fifth metal rod 8 are both 2 um.

[0036] In the embodiment, the dielectric substrate 1 is a PI polyimide substrate, the dielectric constant is 3.9, the thickness is 46 um, and the period length is 1120 um.

[0037] The material of each group of metal structures is copper, the electrical conductivity is 5.71*10 7 S / m, and the thickness is 0.2 um.

[0038] At a frequency of 0.8618 THz, the transmission coefficient of the first resonant unit is-1.47 dB, the transmission coefficient of the second resonant unit is-0.94 dB, the transmission coefficient of the third resonant unit is-1.22 dB, the transmission coefficient of the fourth resonant unit is-1.32 dB, and the transmission coefficient of the fifth resonant unit is-1.45 dB, which shows that the transmission coefficient of the application is high.

[0039] At a frequency of 0.8618 THz, the transmission phase of the first resonant unit is-123.87°, the transmission phase of the second resonant unit is-201.2°, the transmission phase of the third resonant unit is-266.4°, the transmission phase of the fourth resonant unit is-349.74°, and the transmission phase of the fifth resonant unit is-423.74°, so that the transmission phase difference between one period of the application reaches 299.87°, close to 300°, and has a large transmission phase difference, which can be flexibly designed and changed according to actual needs.

[0040] As shown in Figure 6 For the wave perpendicular to the xoy plane and the normal incidence, at a frequency of 0.8618 THz, there is a maximum value at the Theta angle, that is, the included angle between the outgoing wave direction and the negative half of the Z axis is 17°, that is, for the wave perpendicular to the xoy plane and the normal incidence, the abnormal refraction of 17° is realized in the CST simulation.

[0041] The terahertz beam deflector based on the Huygens super surface provided by the present application can realize a higher transmission coefficient, ensure that the array has a larger phase variation, and design the refraction angle, the design of the refraction angle is flexible, the structure is simple, the process is mature, the manufacturing is easy, the price is low, and the application prospect in the future terahertz wave system is good.

[0042] The system, device, module or unit illustrated in the above embodiments can be specifically implemented by a computer chip or entity, or by a product having certain functions.

[0043] It should be further understood that the terms “comprising” or “including” or any other variation thereof are intended to cover non-exclusive inclusions, so that the process, method, product or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, product or equipment. Without more limitations, the element defined by the statement “including one” does not exclude the presence of other identical elements in the process, method, product or equipment including the element.

[0044] The above embodiments should be understood as only for illustrating the present application but not for limiting the protection scope of the present application. After reading the content of the present application, the skilled in the art can make various changes or modifications to the present application, and these equivalent changes and modifications also fall within the scope defined by the claims of the present application.

Claims

1. A terahertz beam steering system based on a Huygens metasurface, characterized in that, The terahertz beam steering unit consists of five identical-shaped but different-sized first-fifth resonant units in the horizontal direction and identical units arranged periodically in the vertical direction. In one periodic array, there is a dielectric substrate (1) and a front metal pattern (2) and a back metal pattern (3). In this design, a one-dimensional array with a phase difference in space is constructed using individual resonant units as the unit. The phase of each resonant unit changes with the array, enabling the array to achieve efficient anomalous refraction of single-polarized terahertz waves. The phase is adjusted by changing the shape of the surface metal pattern by only adjusting the geometric parameters of the vertical metal rod, 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 energy of the incident terahertz wave from the front incident end to the back exit end. In the first resonant unit to the fifth resonant unit, each resonant unit includes a dielectric substrate (1) and two sets of metal structures. These two sets of metal structures are attached to the front and back sides of the dielectric substrate (1) respectively, and the two sets of metal structures satisfy rotational symmetry about the center of the dielectric substrate (1). The metal structures include a first set of metal structures and a second set of metal structures. The first set 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. A metal opening is provided between the second metal rod (5), the third metal rod (6), and the fourth metal rod (7). The first metal rod (4) and the second metal rod (5) are arranged in parallel. The third metal rod (6) and the fourth metal rod (7) are arranged vertically between the first metal rod (4) and the second metal rod (5), and the third metal rod (6) and the fourth metal rod (7) are arranged in parallel. The lengths of the first metal rod (4) and the second metal rod (5) are the same as the length of the dielectric substrate (1). The positions of each first metal rod (4) and the sixth metal rod (9) are the same. The positions of the first metal rod (4) and the sixth metal rod (9) do not change when the surface metal structure size of the first resonant unit to the fifth resonant unit is changed. The first metal rod (4) is close to the upper surface of the dielectric substrate (1). The second group of metal structures includes four metal rods: the fifth metal rod (8), the sixth metal rod (9), the seventh metal rod (10), and the eighth metal rod (11). Metal openings are provided between the sixth metal rod (9), the seventh metal rod (10), and the eighth metal rod (11). The fifth metal rod (8) and the sixth metal rod (9) are arranged in parallel, and the seventh metal rod (10) and the eighth metal rod (11) are arranged perpendicularly between the fifth metal rod (8) and the sixth metal rod (9). The seventh metal rod (10) and the eighth metal rod (11) are arranged in parallel. The lengths of the fifth metal rod (8) and the sixth metal rod (9) are the same as the length of the dielectric substrate (1). The sixth metal rod (9) is close to the lower surface of the dielectric substrate (1). The dielectric substrate of each resonant unit is a square with a side length of 224 μm. The distances between the third metal rod (6), the fourth metal rod (7) and the second metal rod (5), as well as the distances between the seventh metal rod (10), the eighth metal rod (11) and the fifth metal rod (8), are all 2 μm.

2. A terahertz beam steering system based on a Huygens metasurface according to claim 1, characterized in that, The lengths of the third metal rod (6), fourth metal rod (7), seventh metal rod (10), and eighth metal rod (11) vary in each resonant unit. In the first resonant unit, the lengths of the third metal rod (6), fourth metal rod (7), seventh metal rod (10), and eighth metal rod (11) are all 40 μm. In the second resonant unit, the lengths of the third metal rod (6), fourth metal rod (7), seventh metal rod (10), and eighth metal rod (11) are all 49.16 μm. In the third resonant unit, the lengths of the third metal rod (6), fourth metal rod (7), seventh metal rod (10), and eighth metal rod (11) are all 52.54 μm. In the fourth resonant unit, the lengths of the third metal rod (6), fourth metal rod (7), seventh metal rod (10), and eighth metal rod (11) are all 57.54 μm. In the fifth resonant unit, the lengths of the third metal rod (6), fourth metal rod (7), seventh metal rod (10), and eighth metal rod (11) are all 104.69 μm.

3. A terahertz beam steering system based on a Huygens metasurface according to claim 2, characterized in that, The width of the metal rods in the metal structure is 19um. The left side of the third metal rod (6) and the eighth metal rod (11) is 46.5um from the left side of the base. The right side of the fourth metal rod (7) and the seventh metal rod (10) is 46.5um from the right side of the base. The width between the third metal rod (6) and the fourth metal rod (7) is 93um. The width between the seventh metal rod (10) and the eighth metal rod (11) is 93um. The length of the first metal rod (4), the second metal rod (5), the fifth metal rod (8), and the sixth metal rod (9) is 224um. The first metal rod (4) is 31um from the top edge of the medium base, and the sixth metal rod (9) is 31um from the bottom edge of the medium base.

4. A terahertz beam steering system based on a Huygens metasurface according to claim 2, characterized in that, The dielectric substrate (1) is a PI polyimide substrate with a dielectric constant of 3.9, a thickness of 46 μm, and a period length of 1120 μm.

5. A terahertz beam steering system based on a Huygens metasurface according to claim 1, characterized in that, Each group of metal structures is made of copper, with an electrical conductivity of 5.71 × 10⁻⁶. 7 S / m, thickness is 0.2um.

6. A terahertz beam steering system based on a Huygens metasurface according to claim 1, characterized in that, At a frequency of 0.8618 THz, the terahertz beam steering has a maximum value when the theta angle in the far-field diagram is 17°, where 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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