A dual-band terahertz liquid crystal phase shifter for phased antenna and manufacturing method thereof

Abstract

The present application relates to the technical field of terahertz wave regulation, in particular to a dual-band terahertz liquid crystal phase shifter for phased antenna and a manufacturing method thereof, comprising an upper dielectric substrate and a lower dielectric substrate; a liquid crystal layer is arranged between the upper dielectric substrate and the lower dielectric substrate; a resonant structure is arranged between the upper dielectric substrate and the liquid crystal layer; a metal layer is arranged between the liquid crystal layer and the lower dielectric substrate; the resonant structure comprises a patch unit; the resonant structure and the metal layer are both connected with a power supply; by applying voltage to the resonant structure and the metal layer, the deflection state of liquid crystal molecules in the region is controlled to realize phase parameter regulation of terahertz waves; by applying different voltages, different phase shifts are achieved.

Description

Technical Field

[0001] This invention relates to the field of terahertz wave modulation technology, and more specifically, to a dual-band terahertz liquid crystal phase shifter for phased antennas and its manufacturing method. Background Technology

[0002] Liquid crystals are organic compounds that exist between solid and liquid states. Due to their unique electromagnetic properties, they are widely used in electromagnetic wave modulation devices. Liquid crystal molecules, possessing both liquid fluidity and crystal anisotropy, are also widely used in electromagnetic wave modulation devices. Under the influence of an applied electric field, nematic liquid crystal molecules easily deflect, and their dielectric properties change accordingly. Therefore, electromagnetic waves can be modulated by applying electricity. Currently, single-frequency antennas are insufficient to meet the needs of modern communication, while dual-frequency antennas, capable of covering two frequency bands simultaneously, are a superior choice. However, traditional dual-frequency antennas operate at a fixed frequency, making them untunable once designed. Terahertz waves, compared to radio frequency and microwave bands, possess abundant spectral resources, stronger directivity, and higher transmission rates, demonstrating great potential in fields such as communication and radar. Existing phased array antennas cannot achieve phase modulation of dual-band terahertz waves.

[0003] The applicant discovered through a search that Chinese patent document with publication number 110739537A, published on January 31, 2020, discloses a high-density, highly integrated millimeter-wave watt-type phased array antenna T-assembly, aiming to provide a reliable, easily integrated, and low-profile T-assembly design. This invention achieves this through the following scheme: RF signals are directly fed into the T-assembly's lower cavity bottom common terminal via an RF coaxial connector, directly transitioning to the T-junction. A single chip integrates power pre-amplification, power divider network, amplitude and phase control, serial-to-parallel conversion, power management, and digital control functions. Cascaded GaAs power amplifier chips of corresponding channel numbers form a multi-channel 2.5D heterogeneous scalable subarray unit. A low-frequency signal network directly controls the T-assembly's single chip and GaAs power amplifier, achieving phase shifting, amplitude attenuation, and power amplification of multiple signals. The processed signals are sent to the filtering functional layer of the multilayer circuit board on the upper part of the T-assembly through a vertical interconnect structure of coplanar waveguide to coaxial conversion. The filtered signals are finally sent to the microstrip patch antenna for RF signal transmission. However, this device also fails to solve the aforementioned technical problems.

[0004] Therefore, in order to improve or solve at least one of the above problems, it is necessary to provide a dual-band terahertz liquid crystal phase shifter for phased antennas that can achieve phase modulation of dual-band terahertz waves and a manufacturing method thereof. Summary of the Invention

[0005] The purpose of this invention is to provide a dual-band terahertz liquid crystal phase shifter for phased antennas, capable of phase modulation of terahertz waves in both bands, and a method for manufacturing the same.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: a dual-band terahertz liquid crystal phase shifter for a phased antenna, comprising an upper dielectric substrate and a lower dielectric substrate; a liquid crystal layer is disposed between the upper dielectric substrate and the lower dielectric substrate; a resonant structure is disposed between the upper dielectric substrate and the liquid crystal layer; a metal layer is disposed between the liquid crystal layer and the lower dielectric substrate; the resonant structure includes patch units; and both the resonant structure and the metal layer are connected to a power source.

[0007] The patch unit includes a first connecting patch and a second connecting patch; the first connecting patch and the second connecting patch are arranged crosswise; one end of the first connecting patch has an upper patch and the other end of the first connecting patch has a lower patch; one end of the second connecting patch has a left patch and the other end of the second connecting patch has a right patch.

[0008] Both the upper patch and the lower patch include a first connecting segment; the first connecting segment is connected to the first connecting patch; one end of the first connecting segment is provided with a first long arm, and the other end of the first connecting segment is provided with a first short arm; both the left patch and the right patch include a second connecting segment; the second connecting segment is connected to the second connecting patch; one end of the second connecting segment is connected to a second long arm, and the other end of the second connecting segment is connected to a second short arm.

[0009] The upper and lower patches are arranged symmetrically with respect to the intersection of the first and second connecting patches; the left and right patches are arranged symmetrically with respect to the intersection of the first and second connecting patches; and a plurality of patch units are arranged periodically on the upper dielectric substrate.

[0010] The metal layer includes a metal patch; the metal patch is disposed on the lower dielectric substrate.

[0011] The resonant structure has a polyimide film on the side near the liquid crystal layer; the metal layer has a polyimide film on the side near the liquid crystal layer; and polystyrene microspheres are respectively provided at both ends of the liquid crystal layer.

[0012] Both the patch unit and the metal patch are copper patches; the liquid crystal layer is a nematic liquid crystal; both the upper dielectric substrate and the lower dielectric substrate are quartz plates.

[0013] A method for manufacturing the dual-band terahertz liquid crystal phase shifter for a phased antenna includes the following steps:

[0014] S1: Copper is plated on the upper dielectric substrate and the copper is etched into a resonant structure;

[0015] S2: Copper is plated on the lower dielectric substrate and the copper is etched into a metal layer;

[0016] S3: Fill the space between the resonant structure and the metal layer with a liquid crystal layer; connect the resonant structure and the metal layer to a power source.

[0017] In S1: the first connecting patch and the second connecting patch are arranged vertically; the upper patch and the lower patch are arranged symmetrically with respect to the intersection point of the first connecting patch and the second connecting patch by 180° rotation; the left patch and the right patch are arranged symmetrically with respect to the intersection point of the first connecting patch and the second connecting patch by 180° rotation; multiple patch units are periodically arranged on the upper dielectric substrate, with a period length of P and a period number that is a positive integer greater than 1;

[0018] In step S2, a metal patch is plated onto the lower dielectric substrate; the metal patch is recessed to the left and right by a certain interval.

[0019] In step S3, a liquid crystal layer is filled between the resonant structure and the metal layer, and a small number of polystyrene microspheres are respectively disposed at both ends of the liquid crystal layer; the thickness of the liquid crystal layer is controlled by the diameter of the polystyrene microspheres; a polyimide film is spin-coated between the resonant structure, the metal layer, and the liquid crystal layer; the polyimide film is rubbed and aligned with the liquid crystal layer; the liquid crystal layer is sealed with epoxy resin; the upper dielectric substrate and the resonant structure are combined and bonded to the combination of the metal layer and the lower dielectric substrate.

[0020] The beneficial effects of this application are as follows:

[0021] This application provides a dual-band terahertz liquid crystal phase shifter structure for phased antennas. By applying voltage to the resonant structure and the metal layer, and applying an electric field to the liquid crystal layer between the resonant structure and the metal layer, the liquid crystal molecules are deflected, thereby changing the dielectric constant of the liquid crystal in this region, and thus realizing the control of the phase parameters of the two terahertz waves. Attached Figure Description

[0022] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings, wherein:

[0023] Figure 1 This is a schematic diagram of the structure of a dual-band terahertz liquid crystal phase shifter used in phased antennas.

[0024] Figure 2 This is a schematic diagram of the patch unit of a dual-band terahertz liquid crystal phase shifter used in phased antennas.

[0025] Figure 3This is a schematic diagram of the metal layer structure of a dual-band terahertz liquid crystal phase shifter used in phased antennas.

[0026] Figure 4 This is a cross-sectional view of the dual-band terahertz liquid crystal phase shifter used in phased antennas when no power is applied.

[0027] Figure 5 This is a cross-sectional view of a dual-band terahertz liquid crystal phase shifter used in a phased antenna when a full-scale bias voltage is applied.

[0028] Figure 6 The simulated phase-shifting dot plots show the initial and full-scale bias states of the liquid crystal phase shifter used in the dual-band terahertz liquid crystal phase shifter for phased antennas in the 230-290 GHz range.

[0029] Figure 7 The simulated phase-shifting dot plots show the initial and full-scale polarization states of the liquid crystal phase shifter used in the dual-band terahertz liquid crystal phase shifter for phased antennas in the 320-370 GHz range.

[0030] Figure 8 The simulated phase-shifting plots of the dual-band terahertz liquid crystal phase shifter used in phased antennas at different dielectric constants in the 230-290 GHz range are shown.

[0031] Figure 9 The simulated phase-shifting plots of the dual-band terahertz liquid crystal phase shifter used in phased antennas at different dielectric constants in the 320-370 GHz range are shown.

[0032] The markings in the above figures are all:

[0033] The diagram is marked as follows:

[0034] 1. Top dielectric substrate,

[0035] 2. Lower dielectric substrate,

[0036] 3. Liquid crystal layer

[0037] 4. Resonant structure,

[0038] 5. Metal layer, 501, metal patch,

[0039] 6. First connecting patch; 601. Upper patch; 602. Lower patch; 603. First connecting segment; 604. First long arm; 605. First short arm.

[0040] 7. Second connecting patch, 701. Left patch, 702. Right patch, 703. Second connecting segment, 704. Second long arm, 705. Second short arm. Detailed Implementation

[0041] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings, in order to help those skilled in the art to have a more complete, accurate and in-depth understanding of the inventive concept and technical solution of the present invention, and to facilitate its implementation.

[0042] Figure 1 The dual-band terahertz liquid crystal phase shifter for phased antenna shown includes an upper dielectric substrate 1 and a lower dielectric substrate 2; a liquid crystal layer 3 is disposed between the upper dielectric substrate 1 and the lower dielectric substrate 2; a resonant structure 4 is disposed between the upper dielectric substrate 1 and the liquid crystal layer 3; a metal layer 5 is disposed between the liquid crystal layer 3 and the lower dielectric substrate 2; the resonant structure 4 includes patch units; both the resonant structure 4 and the metal layer 5 are connected to a power supply; the resonant structure 4 and the metal layer 5 serve as electrodes for deflecting the liquid crystal, in addition to being resonant structures.

[0043] By applying voltage to the resonant structure 4 and the metal layer 5, an electric field is applied to the liquid crystal layer 3 between the resonant structure 4 and the metal layer 5, causing the liquid crystal molecules to deflect, thereby changing the dielectric constant of the liquid crystal in this region, and thus realizing the control of the phase parameters of the two terahertz waves; by applying different voltages to the resonant structure 4 and the metal layer 5, the phase change of the liquid crystal phase shifter can be adjusted.

[0044] like Figure 2 The patch unit shown includes a first connecting patch 6 and a second connecting patch 7; the first connecting patch 6 and the second connecting patch 7 are arranged crosswise; one end of the first connecting patch 6 is provided with an upper patch 601, and the other end of the first connecting patch 6 is provided with a lower patch 602; one end of the second connecting patch 7 is provided with a left patch 701, and the other end of the second connecting patch 7 is provided with a right patch 702.

[0045] The resonant structure 4 includes multiple patch units; the patch units can be windmill-shaped patch units 2.1; the first connecting patch 6 and the second connecting patch 7 are fixedly connected and have a cross-shaped structure; the upper patch 601 and the lower patch 602 have the same structure and are fixedly connected to the two ends of the first connecting patch 6 respectively; the left patch 701 and the right patch 702 have the same structure and are fixedly connected to the two ends of the second connecting patch 7 respectively.

[0046] Both the upper patch 601 and the lower patch 602 include a first connecting segment 603; the first connecting segment 603 is connected to the first connecting patch 6; one end of the first connecting segment 603 is provided with a first long arm 604, and the other end of the first connecting segment 603 is provided with a first short arm 605; both the left patch 701 and the right patch 702 include a second connecting segment 703; the second connecting segment 703 is connected to the second connecting patch 7; one end of the second connecting segment 703 is connected to the second long arm 704, and the other end of the second connecting segment 703 is connected to the second short arm 705.

[0047] In this embodiment, the length of the first connecting segment 603 is L1 = 180 μm and the width is W1 = 43 μm; the length of the first long arm 604 is L3 = 58 μm and the width is W3 = 95 μm; the length of the first short arm 605 is L2 = 18 μm and the width is W2 = 24 μm; the upper patch 601 and the lower patch 602 are each recessed by Y = 6 μm; the length of the second connecting segment 703 is L1r = 150 μm and the width is W1r = 58 μm; the length of the second long arm 704 is L3r = 13 μm and the width is W3r = 100 μm; the length of the second short arm 705 is L2r = 33 μm and the width is W2r = 22 μm; the length of the first connecting patch 6 is L4 = 13 μm; and the width of the second connecting patch 7 is W4 = 13 μm.

[0048] The upper patch 601 and the lower patch 602 are arranged symmetrically with respect to the intersection of the first connecting patch 6 and the second connecting patch 7; the left patch 701 and the right patch 702 are arranged symmetrically with respect to the intersection of the first connecting patch 6 and the second connecting patch 7; and multiple patch units are arranged periodically on the upper dielectric substrate 1.

[0049] The resonant structure 4 is composed of windmill-shaped patch units 2.1 arranged in a periodic manner, with a period length of P and a period number that is a positive integer greater than 1.

[0050] like Figure 3 The metal layer 5 shown includes a metal patch 501; the metal patch 501 is disposed on the lower dielectric substrate 2.

[0051] The metal patch 501 is a rectangular metal patch 501, plated on a quartz plate with a period of P = 450 μm; the metal patch 501 is recessed to the left and right by X = 6 μm, and has a width of P = 450 μm; multiple metal patches 501 are arranged at equal intervals on the lower dielectric substrate 2, similar to a grating structure, which can be used for column control of the phase shifter.

[0052] The resonant structure 4 has a polyimide film on the side near the liquid crystal layer 3; the metal layer 5 has a polyimide film on the side near the liquid crystal layer 3; and polystyrene microspheres are respectively provided at both ends of the liquid crystal layer 3.

[0053] The liquid crystal type of liquid crystal layer 3 is nematic liquid crystal, and its thickness is controlled by the diameter of a small number of polystyrene microspheres distributed at the edge of liquid crystal layer 3. In this embodiment, the diameter of the polystyrene microspheres is 40 μm, so the thickness of liquid crystal layer 3 can be controlled to be 40 μm. A polyimide film is spin-coated on the surface of resonant structure 4 and metal layer 5, and an initial horizontal orientation is provided to the liquid crystal by frictional orientation.

[0054] Both the chip unit and the metal chip 501 are copper chips; the liquid crystal layer 3 is a nematic liquid crystal; the upper dielectric substrate 1 and the lower dielectric substrate 2 are both quartz plates.

[0055] The resonant structure 4 and the metal layer 5 are both made of copper and have a thickness of 0.5 μm; the upper dielectric substrate 1 and the lower dielectric substrate 2 are both made of quartz glass and have a thickness of 315 μm; a liquid crystal layer 3 with a thickness of 40 μm is filled between the resonant structure 4 and the metal layer 5.

[0056] A method for manufacturing a dual-band terahertz liquid crystal phase shifter for a phased antenna includes the following steps:

[0057] S1: Copper is plated on the upper dielectric substrate 1, and the resonant structure 4 is fabricated by ultraviolet photolithography;

[0058] S2: Copper is plated on the lower dielectric substrate 2, and a metal layer 5 is formed by ultraviolet photolithography;

[0059] S3: Fill the space between the resonant structure 4 and the metal layer 5 with liquid crystal layer 3; connect the resonant structure 4 and the metal layer 5 to a power source.

[0060] In step S1, copper is first plated onto the upper dielectric substrate 1, and then the copper on the upper dielectric substrate 1 is processed into a resonant structure 4; in step S2, copper is first plated onto the lower dielectric substrate 2, and then the copper on the lower dielectric substrate 2 is processed into a metal layer 5; in step S3, a liquid crystal layer 3 is filled between the resonant structure 4 and the metal layer 5; the resonant structure 4 and the metal layer 5 are connected to a power source, thereby applying a voltage to the resonant structure 4 and the metal layer 5.

[0061] In S1: the first connecting patch 6 and the second connecting patch 7 are vertically arranged; the upper patch 601 and the lower patch 602 are symmetrically arranged with a 180° rotational angle based on the intersection of the first connecting patch 6 and the second connecting patch 7; the left patch 701 and the right patch 702 are symmetrically arranged with a 180° rotational angle based on the intersection of the first connecting patch 6 and the second connecting patch 7; multiple patch units are periodically arranged on the upper dielectric substrate 1, with a period length of P and a period number that is a positive integer greater than 1;

[0062] In S2, a metal patch 501 is plated onto the lower dielectric substrate 2; the metal patch 501 is recessed to the left and right by a certain interval.

[0063] In S3, a liquid crystal layer 3 is filled between the resonant structure 4 and the metal layer 5, and a small number of polystyrene microspheres are respectively placed at both ends of the liquid crystal layer 3; the thickness of the liquid crystal layer 3 is controlled by the diameter of the polystyrene microspheres; a polyimide film is spin-coated between the resonant structure 4, the metal layer 5 and the liquid crystal layer 3; the polyimide film is rubbed and aligned with the liquid crystal layer 3; the liquid crystal layer 3 is sealed with epoxy resin; the copper plated on the upper dielectric substrate 1 is processed into the resonant structure 4, and the copper plated on the lower dielectric substrate 2 is processed into the metal layer 5.

[0064] The specific workflow of this invention is as follows:

[0065] When a y-polarized electromagnetic wave is incident in the Z direction, the phase of the reflected wave changes when the deflection state of the liquid crystal molecules is altered by a voltage. Based on the metal layer 5 within this phase shifter unit, when a voltage is applied to the metal layer 5 and the resonant structure 4 above it, a vertical electric field exists in the region. This biased vertical electric field causes the long axis of the liquid crystal molecules in this region to be parallel to the direction of the electric field. When no voltage is applied to this region, the long axis of the liquid crystal molecules is perpendicular to the direction of the electric field. When the resonant structure 4 and the metal layer 5 are in an uncharged state, the dielectric constant of the liquid crystal is at its minimum. A side cross-sectional view of the dual-band liquid crystal-based terahertz phase shifter is shown below. Figure 4 As shown; when a full-scale bias voltage is applied to the resonant structure 4 and the metal layer 5, the dielectric constant of the liquid crystal is at its maximum. A side cross-sectional view of the dual-band liquid crystal-based terahertz phase shifter is shown below. Figure 5 As shown, at this time, the liquid crystal molecules become vertical due to the influence of the electric field.

[0066] In this embodiment, the phase shift curve of the phase shifter is as follows: Figure 6 As shown, it can be seen that when the dielectric constant ε = 2.47 to 3.37, the dual-band liquid crystal phase shifter exhibits a phase shift greater than 180° between 254 GHz and 269 GHz, with a maximum phase shift of 264° at 261 GHz; Figure 7 As shown, when the dielectric constant ranges from ε = 2.47 to 3.31, the dual-band liquid crystal phase shifter exhibits a phase shift greater than 180° between 337 GHz and 355 GHz, with a maximum phase shift of 241° at 346 GHz. Figure 8 Simulated phase-shifting point plots for different dielectric constants in the 230-290 GHz range;

[0067] Figure 9 The simulated phase shift plots are shown for different dielectric constants in the 320-370 GHz range.

[0068] This application achieves phase parameter modulation of terahertz waves by applying voltage to the resonant structure 4 and the metal layer 5 to control the deflection state of liquid crystal molecules in the region; different phase shifts are achieved by applying different voltages.

[0069] The present invention has been described above by way of example with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvements made using the inventive concept and technical solution; or the direct application of the inventive concept and technical solution to other situations without modification, are all within the protection scope of the present invention.

Claims

1. A dual-band terahertz liquid crystal phase shifter for phased-array antennas, characterized in that: It includes an upper dielectric substrate (1) and a lower dielectric substrate (2); a liquid crystal layer (3) is disposed between the upper dielectric substrate (1) and the lower dielectric substrate (2); a resonant structure (4) is disposed between the upper dielectric substrate (1) and the liquid crystal layer (3); a metal layer (5) is disposed between the liquid crystal layer (3) and the lower dielectric substrate (2); the resonant structure (4) includes a patch unit; both the resonant structure (4) and the metal layer (5) are connected to a power source; The patch unit includes a first connecting patch (6) and a second connecting patch (7); the first connecting patch (6) and the second connecting patch (7) are arranged crosswise; one end of the first connecting patch (6) is provided with an upper patch (601), and the other end of the first connecting patch (6) is provided with a lower patch (602); one end of the second connecting patch (7) is provided with a left patch (701), and the other end of the second connecting patch (7) is provided with a right patch (702); Both the upper patch (601) and the lower patch (602) include a first connecting segment (603); the first connecting segment (603) is connected to the first connecting patch (6); one end of the first connecting segment (603) is provided with a first long arm (604), and the other end of the first connecting segment (603) is provided with a first short arm (605); both the left patch (701) and the right patch (702) include a second connecting segment (703); the second connecting segment (703) is connected to the second connecting patch (7); one end of the second connecting segment (703) is connected to a second long arm (704), and the other end of the second connecting segment (703) is connected to a second short arm (705); The upper patch (601) and the lower patch (602) are arranged symmetrically with respect to the intersection of the first connecting patch (6) and the second connecting patch (7); the left patch (701) and the right patch (702) are arranged symmetrically with respect to the intersection of the first connecting patch (6) and the second connecting patch (7); a plurality of patch units are arranged periodically on the upper dielectric substrate (1).

2. A dual-band terahertz liquid crystal phase shifter for a phased-array antenna according to claim 1, characterized in that: The metal layer (5) includes a metal patch (501); the metal patch (501) is disposed on the lower dielectric substrate (2).

3. A dual-band terahertz liquid crystal phase shifter for a phased antenna according to claim 2, characterized in that: The resonant structure (4) has a polyimide film on the side near the liquid crystal layer (3); the metal layer (5) has a polyimide film on the side near the liquid crystal layer (3); and polystyrene microspheres are respectively provided at both ends of the liquid crystal layer (3).

4. A dual-band terahertz liquid crystal phase shifter for a phased antenna according to claim 2 or 3, characterized in that: Both the patch unit and the metal patch (501) are copper patches; the liquid crystal layer (3) is a nematic liquid crystal; the upper dielectric substrate (1) and the lower dielectric substrate (2) are both quartz plates.

5. A method for manufacturing a dual-band terahertz liquid crystal phase shifter for a phased antenna as described in any one of claims 1-4, characterized in that: Includes the following steps: S1: Copper is plated on the upper dielectric substrate (1), and the copper is etched into a resonant structure (4); S2: Copper is plated on the lower dielectric substrate (2), and the copper is etched into a metal layer (5); S3: Fill the space between the resonant structure (4) and the metal layer (5) with a liquid crystal layer (3); connect the resonant structure (4) and the metal layer (5) to a power source.

6. The manufacturing method according to claim 5, characterized in that: In S1: the first connecting patch (6) and the second connecting patch (7) are vertically arranged; the upper patch (601) and the lower patch (602) are symmetrically arranged with respect to the intersection point of the first connecting patch (6) and the second connecting patch (7) at 180°; the left patch (701) and the right patch (702) are symmetrically arranged with respect to the intersection point of the first connecting patch (6) and the second connecting patch (7) at 180°; multiple patch units are periodically arranged on the upper dielectric substrate (1), with a period length of P and a period number that is a positive integer greater than 1; in S2, a metal patch (501) is plated on the lower dielectric substrate (2); the metal patch (501) is recessed to the left and right by a certain interval.

7. The manufacturing method according to claim 6, characterized in that: In step S3, a liquid crystal layer (3) is filled between the resonant structure (4) and the metal layer (5), and a small number of polystyrene microspheres are respectively disposed at both ends of the liquid crystal layer (3); the thickness of the liquid crystal layer (3) is controlled by the diameter of the polystyrene microspheres; a polyimide film is spin-coated between the resonant structure (4), the metal layer (5) and the liquid crystal layer (3); the polyimide film is rubbed and aligned with the liquid crystal layer (3); the liquid crystal layer (3) is sealed with epoxy resin.

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