Liquid crystal array antenna structure

Abstract

This invention provides a liquid crystal array antenna structure that can meet the demands of low Earth orbit satellite communications by achieving a central operating frequency and beam scanning range, and effectively suppressing sidelobe levels. [Solution] A liquid crystal array antenna structure having a special structural design is provided. The liquid crystal array antenna structure includes a first substrate layer, a second substrate layer, a third substrate layer, four liquid crystal cells, a first surface unit, a second surface unit, a third surface unit, and a fourth surface unit. The four liquid crystal cells are arranged between the first substrate layer and the second substrate layer. When a bias is applied to the liquid crystal cells, the central operating frequency and beam scanning range of the liquid crystal array antenna structure are in a first frequency band and a first range, respectively.

Description

TECHNICAL FIELD

[0001] The present invention relates to an antenna array structure, and particularly to a liquid crystal array antenna structure.

BACKGROUND ART

[0002] The liquid crystal array antenna structure is an antenna system constructed using liquid crystal materials, and its performance is related to the alignment of liquid crystal molecules. Specifically, the important characteristics of the liquid crystal array antenna structure lie in its adjustability and flexibility. By adjusting the alignment of the liquid crystal molecules (that is, applying a voltage to the liquid crystal cells), beam steering and beam forming are realized, enabling the liquid crystal array antenna structure to meet different communication requirements.

SUMMARY OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0003] In view of this, the present invention provides a liquid crystal array antenna structure capable of performing beam scanning via different voltages applied to the liquid crystal cells.

MEANS FOR SOLVING THE PROBLEMS

[0004] An embodiment of the present invention provides a liquid crystal array antenna structure including a first substrate layer, a second substrate layer, a third substrate layer, four liquid crystal cells, a first surface unit, a second surface unit, a third surface unit, and a fourth surface unit. The first substrate layer has a first upper surface and a first lower surface. The second substrate layer has a second upper surface and a second lower surface. The third substrate layer has a third upper surface and a third lower surface. The four liquid crystal cells are arranged between the first substrate layer and the second substrate layer. The first surface unit is arranged on the first lower surface. The second surface unit is arranged on the second upper surface. The third surface unit is arranged on the third upper surface. The fourth surface unit is arranged on the third lower surface. When a bias is applied to the liquid crystal cells, the central operating frequency and the beam scanning range of the liquid crystal array antenna structure are in the first frequency band and the first range, respectively.

[0005] In embodiments of the present invention, the first surface unit includes four first surface inward-wound bias metal wires. Each of the four first surface inward-wound bias metal wires corresponds to one of four liquid crystal cells.

[0006] In embodiments of the present invention, each first surface inward-wound bias metal wire is connected to the edge of the first lower surface. The four second surface region patch groups each correspond to four liquid crystal cells.

[0007] In embodiments of the present invention, each first surface inward-winding bias metal wire is an equally spaced square spiral metal wire.

[0008] In embodiments of the present invention, the number of turns of the equally spaced square spiral metal wire is at least 2.

[0009] In embodiments of the present invention, the second surface unit includes four groups of second surface region patches.

[0010] In embodiments of the present invention, the four second surface region patch groups are arranged as a binary array.

[0011] In embodiments of the present invention, each second surface region patch group includes three surface cross-shaped patches, and the central points of the three surface cross-shaped patches are interconnected via an inner surface metal wire.

[0012] In an embodiment of the present invention, one of the three surface cross-shaped patches is connected to the edge of the second upper surface via an outer surface metal wire.

[0013] In embodiments of the present invention, each surface cross-shaped patch includes a surface left patch, a surface center patch, a surface right patch, and a surface connecting patch. The surface left patch, the surface center patch, and the surface right patch are connected via the surface connecting patch. The length and width of the surface left patch are the same as those of the surface right patch. The length of the surface center patch is longer than the lengths of the surface left patch and the surface right patch. The widths of the surface left patch, the surface center patch, and the surface right patch are the same.

[0014] In embodiments of the present invention, the third surface unit is a metal grounding layer.

[0015] In embodiments of the present invention, the third surface unit includes four groups of surface slits. Each of the four groups of surface slits corresponds to one of four liquid crystal cells.

[0016] In embodiments of the present invention, each group of surface slits includes three third surface slits.

[0017] In embodiments of the present invention, the third surface slit is an H-shaped slit.

[0018] In embodiments of the present invention, the fourth surface unit includes two 3-stage 1-to-6 wiring configurations.

[0019] In an embodiment of the present invention, the power supply ends of two 3-stage 1:6 distribution lines are connected to the edge of the third lower surface.

[0020] In embodiments of the present invention, the output terminals of the two three-stage 1-to-6 wirings each correspond to a plurality of third surface slits of the third surface unit.

[0021] In embodiments of the present invention, the first surface unit, the second surface unit, the third surface unit, and the fourth surface unit are all made of a metal material.

[0022] In embodiments of the present invention, the first frequency band is 14 GHz to 15 GHz.

[0023] In an embodiment of the present invention, the first range is ±23 to ±25 degrees. [Effects of the Invention]

[0024] As described above, the liquid crystal array antenna structure of the present invention, through its special structural design, can provide a central operating frequency and a beam scanning range that can meet the demands of low-orbit satellite communications. [Brief Description of the Drawings]

[0025] [Figure 1A] This shows a schematic diagram of the multi-layer structure of a liquid crystal array antenna structure according to one embodiment of the present invention. [Figure 1B] This shows a cross-sectional view of a liquid crystal array antenna structure according to one embodiment of the present invention. [Figure 2A] This shows a schematic diagram of the single cell design of the first surface unit according to one embodiment of the present invention. [Figure 2B] This shows a schematic diagram of the single cell design of the liquid crystal cell according to one embodiment of the present invention. [Figure 2C] This shows a schematic diagram of the single cell design of the second surface unit according to one embodiment of the present invention. [Figure 2D] This shows a schematic diagram of the surface cross-shaped patch in the second surface unit according to one embodiment of the present invention. [Figure 2E] This shows a schematic diagram of the single cell design of the third surface unit according to one embodiment of the present invention. [Figure 2F] This shows a schematic diagram of the third surface slit in the third surface unit according to one embodiment of the present invention. [Figure 2G] This shows a schematic diagram of the single cell design of the fourth surface unit according to one embodiment of the present invention. [Figure 2H] This shows a schematic diagram of the three-stage 1-to-6 distribution wiring in the fourth surface unit according to one embodiment of the present invention. [Figure 3A]This diagram shows a schematic representation of the S11 parameter of the liquid crystal array antenna structure according to the first embodiment of the present invention. [Figure 3B] This diagram shows the beam scanning gain of a liquid crystal array antenna structure according to the first embodiment of the present invention. [Figure 4A] This diagram shows a schematic representation of the S11 parameter of the liquid crystal array antenna structure according to the second embodiment of the present invention. [Figure 4B] This figure shows the beam scanning gain diagram of a liquid crystal array antenna structure according to a second embodiment of the present invention. [Figure 5A] This diagram shows a schematic representation of the S11 parameter of the liquid crystal array antenna structure according to the third embodiment of the present invention. [Figure 5B] This diagram shows the beam scanning gain of a liquid crystal array antenna structure according to a third embodiment of the present invention. [Modes for carrying out the invention]

[0026] Here, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Wherever possible, the same reference numerals are used in the drawings and description to indicate the same or similar parts.

[0027] Figure 1A shows a schematic diagram of the multilayer structure of a liquid crystal array antenna structure according to one embodiment of the present invention, and Figure 1B shows a cross-sectional view of the liquid crystal array antenna structure according to one embodiment of the present invention. Referring to Figures 1A and 1B, the design of the liquid crystal array antenna structure is mainly a 3-layer, 4-face circuit board, and the liquid crystal array antenna structure includes a first substrate layer 1, a second substrate layer 2, a third substrate layer 3, a first surface unit 4, a second surface unit 5, a third surface unit 6, a fourth surface unit 7, and at least four liquid crystal cells 81, 82, 83, 84. The first substrate layer 1 has a first upper surface 11 and a first lower surface 12. The second substrate layer 2 has a second upper surface 21 and a second lower surface 22. The third substrate layer 3 has a third upper surface 31 and a third lower surface 32.

[0028] Liquid crystal cells 81, 82, 83, and 84 are arranged between the first substrate layer 1 and the second substrate layer 2. The first surface unit 4 is arranged on the first lower surface 12. The second surface unit 5 is arranged on the second upper surface 21. The third surface unit 6 is arranged on the third upper surface 31. The fourth surface unit 7 is arranged on the third lower surface 32.

[0029] The first substrate layer 1, the second substrate layer 2, and the third substrate layer 3 are, for example, high-frequency printed circuit boards. The board material used for the first substrate layer 1, the second substrate layer 2, and the third substrate layer 3 is, for example, Rogers RO4533. In one embodiment, the dielectric constant of the first substrate layer 1, the second substrate layer 2, and the third substrate layer 3 is, for example, 3.0 to 4.0 (optimal dielectric constant is 3.45), the loss tangent is, for example, 0.002 to 0.003 (optimal loss tangent is 0.0025), and the thickness is, for example, 0.50 to 0.51 mm (optimal thickness is 0.508 mm).

[0030] The first surface unit 4, the second surface unit 5, the third surface unit 6, and the fourth surface unit 7 are formed from, for example, a metallic material (e.g., a metallic conductor such as copper foil or gold foil, or another metal oxide conductor such as indium tin oxide). The copper foil thickness of the first surface unit 4, the second surface unit 5, the third surface unit 6, and the fourth surface unit 7 is, for example, 0.035 mm. The third surface unit 6 is a single metallic ground layer.

[0031] The liquid crystal material used in liquid crystal cells 81-84 is, for example, JNC ZOC-A018XX, MERCK E7, or MERCK GT7-29001, with a thickness of 0.1 mm. Liquid crystal cells 81-84 have adjustable dielectric properties, and when an external voltage is applied to them, the rotation of their liquid crystal molecules changes, thereby changing their dielectric constant and loss tangent.

[0032] Taking JNC ZOC-A018XX as an example, the dielectric constant and loss tangent of liquid crystal cells 81-84 are 2.55-3.76 and 0.004-0.007, respectively. When no bias is applied to liquid crystal cells 81-84, the liquid crystal orientation direction of liquid crystal cells 81-84 is parallel to the electric field direction, and the dielectric constant of liquid crystal cells 81-84 is 3.76, and the loss tangent is 0.004. On the other hand, after a bias is applied to liquid crystal cells 81-84, the liquid crystal orientation direction of liquid crystal cells 81-84 becomes perpendicular to the electric field, the dielectric constant changes to 2.55, and the loss tangent changes to 0.007.

[0033] Taking the MERCK E7 as an example, the dielectric constant and loss tangent of liquid crystal cells 81-84 are 2.72-3.17 and 0.033-0.05, respectively. When no bias is applied to liquid crystal cells 81-84, the liquid crystal orientation direction of cells 81-84 is parallel to the electric field direction, and the dielectric constant of cells 81-84 is 3.17, with a loss tangent of 0.033. On the other hand, after a bias is applied to liquid crystal cells 81-84, the liquid crystal orientation direction of cells 81-84 becomes perpendicular to the electric field, the dielectric constant changes to 2.72, and the loss tangent changes to 0.05.

[0034] Taking the MERCK GT7-29001 as an example, the dielectric constant and loss tangent of liquid crystal cells 81-84 are 2.46-3.53 and 0.0064-0.0116, respectively. When no bias is applied to liquid crystal cells 81-84, the liquid crystal orientation direction of cells 81-84 is parallel to the electric field direction, and the dielectric constant of cells 81-84 is 3.53, with a loss tangent of 0.0064. On the other hand, after a bias is applied to liquid crystal cells 81-84, the liquid crystal orientation direction of cells 81-84 becomes perpendicular to the electric field, the dielectric constant changes to 2.46, and the loss tangent changes to 0.0116.

[0035] The dielectric properties of liquid crystal cells 81-84 change with the electric field, which in turn alters the beam characteristics of the liquid crystal array antenna structure. More specifically, when no bias is applied to liquid crystal cells 81-84, the alignment direction of the liquid crystal molecules within them is parallel to the metal patch and the metal ground plane. When a bias is applied to liquid crystal cells 81-84, the alignment direction of the liquid crystal molecules becomes perpendicular to the metal patch and the metal ground plane, thereby causing a shift in the central operating frequency of the liquid crystal array antenna structure.

[0036] The types of the first substrate layer 1, the second substrate layer 2, the third substrate layer 3, and the liquid crystal cells 81-84 are not limited in this invention, as they can be designed according to actual requirements.

[0037] Figure 2A shows a schematic diagram of a single-cell design of a first surface unit according to one embodiment of the present invention, and Figure 2B shows a schematic diagram of a single-cell design of a liquid crystal cell according to one embodiment of the present invention. Referring to Figures 2A and 2B, the first surface unit 4 is located on the first lower surface 12. The first surface unit 4 is formed by etching the original metal layer of the first lower surface 12 (for example, a copper foil with a thickness of 0.035 mm).

[0038] The first surface unit 4 includes four first surface inward-wound bias metal wires 41-44. Here, the first surface inward-wound bias metal wires 41-44 are equally spaced square spiral metal wires. The first surface inward-wound bias metal wires 41-44 correspond to liquid crystal cells 81-84, respectively. The first surface inward-wound bias metal wires 41-44 are also connected to the edge of the first lower surface 12.

[0039] It should be explained that the bias wires in the shape of a circuit (helix) formed by the first surface-wound bias metal wires 41-44 induce the electric field to be distributed along a specific path, thereby changing the electric field distribution and refractive index distribution of the liquid crystal cells 81-84. Furthermore, the electric field along a specific path causes, for example, a non-uniform refractive index distribution, which affects the phase delay scheme, and thereby changes the beam and scanning direction of the liquid crystal array antenna structure. The number of turns of the first surface-wound bias metal wires 41-44 is at least 2. That is, the number of circuits (helices) formed by the first surface-wound bias metal wires 41-44 is at least 2.

[0040] The width and length of the first lower surface 12 are A and B shown in Figure 2A, respectively. The width of the first surface in-winding bias metal wires 41-44 is C shown in Figure 2A. The circuit (helical) spacing of the first surface in-winding bias metal wires 41-44 is C1 shown in Figure 2A. The width and length of the liquid crystal cells 81-84 are M and N shown in Figure 2B, respectively.

[0041] In one embodiment, the width and length of the first lower surface 12 (A and B shown in Figure 2A) are, for example, 67-68 mm (optimal width is 67.6 mm) and 70-71 mm (optimal length is 70.1 mm), respectively; the width of the first surface in-winding bias metal wires 41-44 (C shown in Figure 2A) is, for example, less than 1 mm (optimal width is 0.9 mm); the circuit (helical) spacing of the first surface in-winding bias metal wires 41-44 (C1 shown in Figure 2A) is, for example, 4-5 mm (optimal circuit spacing is 4.55 mm); and the width and length of the liquid crystal cells 81-84 (M and N shown in Figure 2B) are, for example, 28-29 mm (optimal width and length are 28.6 mm).

[0042] Figure 2C shows a schematic diagram of a single-cell design of a second surface unit in one embodiment of the present invention, and Figure 2D shows a schematic diagram of a surface cross-shaped patch in the second surface unit in one embodiment of the present invention. Referring to Figures 2C and 2D, the second surface unit 5 is located on the second upper surface 21. The second surface unit 5 is formed by etching the original metal layer of the second upper surface 21 (e.g., a copper foil with a thickness of 0.035 mm).

[0043] The second surface unit 5 includes four second surface area patch groups 51 to 54. Each of the second surface area patch groups 51 to 54 corresponds to a liquid crystal cell 81 to 84. Each of the second surface area patch groups 51 to 54 includes three surface cross-shaped patches 511 to 513, 521 to 523, 531 to 533, and 541 to 543. Specifically, the central points of the three surface cross-shaped patches are connected to each other via inner surface metal wires, and one of the surface cross-shaped patches is connected to the edge of the second upper surface 21 via an outer surface metal wire. Taking the second surface area patch group 53 as an example, the three surface cross-shaped patches 531 to 533 included in the second surface area patch group 53 are connected via inner surface metals 55 and 56, and surface cross-shaped patch 531 is connected to the edge of the second upper surface 21 via an outer surface metal wire 57. The second surface region patch groups 51, 52, and 54 can be inferred from the explanation of the second surface region patch group 53 described above, so their explanation is omitted here.

[0044] The width and length of the second lower surface 21 are D and E, respectively, as shown in Figure 2C.

[0045] Furthermore, regarding the specifications for the second surface unit 5, the specifications for surface cross-shaped patches 511-513, 521-523, 531-533, and 541-543 are all the same. Taking surface cross-shaped patch 511 as an example, surface cross-shaped patch 511 consists of surface left patch 5111, surface center patch 5112, surface right patch 5113, and surface connection patch 5114. Surface left patch 5111, surface center patch 5112, and surface right patch 5113 are connected via surface connection patch 5114. The length (F shown in Figure 2D) and width (G shown in Figure 2D) of surface left patch 5111 are the same as the length and width of surface right patch 5113. The length (J shown in Figure 2D) of surface center patch 5112 is longer than the length of surface left patch 5111 and surface right patch 5113. The widths of the left-side patch 5111, the right-side patch 5113, and the center patch 5112 (I shown in Figure 2D) are the same. The length of the surface connection patch 5114 is H shown in Figure 2D.

[0046] In one embodiment, the width and length of the second lower surface 21 (D and E shown in Figure 2C) are, for example, 125–126 mm (optimal width is 125.2 mm) and 66–67 mm (optimal length is 66.1 mm), respectively.

[0047] Furthermore, the lengths of Y1, Y2, Y3, Y4, and Y5 shown in Figure 2C are, for example, 1-2 mm (optimal length is 1.19 mm), 17-18 mm (optimal length is 17.48 mm), 1-2 mm (optimal length is 1.72 mm), 3-4 mm (optimal length is 3.30 mm), and 3-4 mm (optimal length is 3.30 mm), respectively, and the lengths of F, G, H, I, and J shown in Figure 2D are, for example, 3-4 mm (optimal length is 3.35 mm), 5-6 mm (optimal length is 5.19 mm), less than 1 mm (optimal length is 0.57 mm), 5-6 mm (optimal length is 5.19 mm), and 6-7 mm (optimal length is 6.70 mm), respectively.

[0048] It should be explained that, as shown in Figure 2C, the second surface unit 5 includes a set of 6x6 metal patches composed of 12 sets of 1x3 metal patches (i.e., surface cross-shaped patches 511-513, 521-523, 531-533, 541-543). In other words, the second surface region patch group 51-54 is arranged in a binomial array. Specifically, a binomial array is an antenna array designed based on a binomial coefficient distribution, where multiple single-type antenna components are arranged based on a specific geometric shape, and by lowering the sidelobe level, a radiation pattern diagram with ideal sidelobe suppression is realized. Furthermore, sidelobes are secondary radiation portions other than the antenna's main beam, and since they cause transmission interference and errors, superior transmission performance can be achieved by suppressing the sidelobe level.

[0049] Figure 2E shows a schematic diagram of a single-cell design of a third surface unit according to one embodiment of the present invention, and Figure 2F shows a schematic diagram of a third surface slit in a third surface unit according to one embodiment of the present invention. Referring to Figures 2E and 2F, the third surface unit 6 is located on the third upper surface 31. The third surface unit 6 is formed by etching the original metal layer of the third upper surface 31 (for example, a copper foil with a thickness of 0.035 mm). Here, the third surface unit 6 is a metal grounding layer.

[0050] The third surface unit 6 includes four surface slit groups 61 to 64. Each of the surface slit groups 61 to 64 corresponds to a liquid crystal cell 81 to 84. Each of the surface slit groups 61 to 64 includes three third surface slits 611 to 613, 621 to 623, 631 to 633, and 641 to 643. The third surface slits 611 to 613, 621 to 623, 631 to 633, and 641 to 643 are, for example, H-shaped slits.

[0051] The width and length of the third upper surface 31 are K and L, respectively, as shown in Figure 2E.

[0052] In one embodiment, the width and length of the third upper surface 31 (K and L shown in Figure 2E) are, for example, 133–134 mm (optimal width is 133.2 mm) and 66–67 mm (optimal length is 66.1 mm), respectively.

[0053] Furthermore, regarding the specifications for the third surface unit 6, the specifications for the third surface slits 611-613, 621-623, 631-633, and 641-643 are all the same. Taking the third surface slit 611 as an example, the lengths of L1, L2, W1, and W2 shown in Figure 2F are, for example, 3 mm, less than 1 mm (optimal length is 0.5 mm), 3 mm, and less than 1 mm (optimal length is 0.5 mm), respectively. As shown in Figure 2F, the H-shaped slit (i.e., the third surface slit 611) has equal lengths on both sides.

[0054] Figure 2G shows a schematic diagram of a single-cell design of the fourth surface unit in one embodiment of the present invention, and Figure 2H shows a schematic diagram of a three-stage 1:6 distribution line in the fourth surface unit in one embodiment of the present invention. Referring to Figures 2G and 2H, the fourth surface unit 7 is located on the third lower surface 32. The fourth surface unit 7 is formed by etching the original metal layer of the third lower surface 32 (e.g., a copper foil with a thickness of 0.035 mm).

[0055] The fourth surface unit 7 includes two 3-stage 1-to-6 splitter wirings 71 and 72. Specifically, the 3-stage 1-to-6 splitter wirings 71 and 72 are, for example, 3-stage 1-to-6 power dividers having one feed terminal and six output terminals, and are used to split the fed signal into output signals that are equal to or unequal to the 6-way energy. The feed terminals of the 3-stage 1-to-6 splitter wirings 71 and 72 (see metal wires 711 and 721 in Figure 2G) are connected to the edges of the third lower surface 32, and the output terminals of the 3-stage 1-to-6 splitter wiring 71 correspond to the third surface slits 611-613 and 621-623 of the third surface unit 6, respectively, and the output terminals of the 3-stage 1-to-6 splitter wiring 72 correspond to the third surface slits 631-633 and 641-643 of the third surface unit 6, respectively, thereby realizing a high-gain, high-efficiency double-sided slit-fed antenna structure.

[0056] Notably, the liquid crystal array antenna structure of the present invention employs a three-stage 1-to-6 wiring system 71, 72 to effectively reduce the number of feed terminals and further reduce hardware costs.

[0057] The branching points of the 3-stage 1-to-6 wiring 71, specifically the branching points of branches 7111 and 7112, 71111 and 71112, 71113 and 71114, 71121 and 71122, and 71123 and 71124, are T-shaped connections, and the capacity effect is improved by adopting a tangential structure at the corners.

[0058] Similarly, the branching points of the 3-stage 1-to-6 wiring 72, specifically the branching points of branches 7211 and 7212, 72111 and 72112, 72113 and 72114, 72121 and 72122, and 72123 and 72124, are T-shaped connections, and the capacitive effect is improved by adopting a tangential structure at the corners.

[0059] The width and length of the third lower surface 32 are K and L, respectively, as shown in Figure 2G.

[0060] In one embodiment, the width and length of the third lower surface 32 (K and L shown in Figure 2G) are equal to the width and length of the third upper surface 31 (K and L shown in Figure 2E). The width and length of the third lower surface 32 are, for example, 133–134 mm (optimal width is 133.2 mm) and 66–67 mm (optimal length is 66.1 mm), respectively.

[0061] Furthermore, regarding the specifications for the fourth surface unit 7, the specifications for the 3-stage 1-to-6 wiring 71 and 72 are all the same. Taking the 3-stage 1-to-6 wiring 71 as an example, the length of O shown in Figure 2H is 1-2 mm (optimal length is 1.13 mm), the length of P is 1-2 mm (optimal length is 1.32 mm), the length of Q is 15-16 mm (optimal length is 15.1 mm), the length of R is 5 mm, the length of S is 2-3 mm (optimal length is 2.28 mm), the length of T is 2-3 mm (optimal length is 2.44 mm), the length of U is 3-4 mm (optimal length is 3.68 mm), the length of V is 4-5 mm (optimal length is 4.43 mm), the length of W is 13-14 mm (optimal length is 13.01 mm), and the length of X is 10-11 mm (optimal length is 10.09 mm).

[0062] Furthermore, the three-stage 1-to-6 distribution wiring 71 and 72 have two different wire diameters (see O and P shown in Figure 2H), and each has a different impedance for a different wire diameter. Specifically, the impedance of the distribution wire corresponding to length O is 50 ohms, and the impedance of the distribution wire corresponding to length P is 35 ohms.

[0063] It should be explained that the liquid crystal array antenna structure of the present invention realizes a double-sided slit-fed antenna structure using a third surface unit 6 and a fourth surface unit 7, and receives an external voltage (bias) using liquid crystal voltages 81-84. The design of the liquid crystal array antenna structure of the present invention allows for the independent design of components for receiving signals and components for receiving bias, thereby effectively avoiding noise generation and saving on hardware costs (for example, there is no need to install an additional three-way biaser).

[0064] Figure 3A shows a schematic diagram of the S11 parameter of the liquid crystal array antenna structure according to the first embodiment of the present invention, and Figure 3B shows a beam scanning gain diagram of the liquid crystal array antenna structure according to the first embodiment of the present invention. Here, the S11 parameter is also called the input reflection coefficient and is used to indicate the return loss at the signal transmission end.

[0065] Referring to Figures 3A and 3B, in this embodiment, the liquid crystal material used in liquid crystal cells 81-84 is MERCK E7.

[0066] In Figure 3A, "Off" is used to indicate that no voltage is applied to liquid crystal cells 81-84, and "On" is used to indicate that voltage is applied to liquid crystal cells 81-84. In Figure 3A, LC1-LC4 represent liquid crystal cells 81-84, respectively.

[0067] As shown in Figure 3A, when no voltage is applied to liquid crystal cells 81-84, the center operating frequency of the liquid crystal array antenna structure is between 14 and 15 GHz (optimally 14.10 GHz), and the bandwidth is 0.40 GHz, with -10 dB as the reference point.

[0068] As shown in Figure 3A, when voltage is applied to liquid crystal cells 81 and 82, and no voltage is applied to liquid crystal cells 83 and 84, the central operating frequency of the liquid crystal array antenna structure is between 14 and 15 GHz (optimally 14 GHz), and the bandwidth is 0.35 GHz, with -10 dB as the reference point.

[0069] As shown in Figure 3A, when voltage is applied to liquid crystal cells 83 and 84, and no voltage is applied to liquid crystal cells 81 and 82, the central operating frequency of the liquid crystal array antenna structure is between 14 and 15 GHz (optimally 14 GHz), and the bandwidth is 0.35 GHz, with -10 dB as the reference point.

[0070] As shown in Figure 3A, when voltage is applied to liquid crystal cells 81-84, the center operating frequency of the liquid crystal array antenna structure is between 13 and 15 GHz (optimal is 13.95 GHz), and the bandwidth is 0.20 GHz, with -10 dB as the reference point.

[0071] On the other hand, the dielectric constant and loss tangent of liquid crystal molecules 81-84 are related to the bias voltage applied to liquid crystal molecules 81-84.

[0072] As shown in Figure 3B, when observing the maximum scannable angle, when voltage is applied to liquid crystal cells 81 and 82, but not to liquid crystal cells 83 and 84, the beam scanning angle of the liquid crystal array antenna structure is -23 degrees and the gain is 9.17 dBi. Furthermore, when no voltage is applied to liquid crystal cells 81 and 82, but voltage is applied to liquid crystal cells 83 and 84, the beam scanning angle of the liquid crystal array antenna structure is 23 degrees and the gain is 9.05 dBi.

[0073] Based on this, the beam scanning range of the liquid crystal array antenna structure is ±23 degrees.

[0074] Figure 4A shows a schematic diagram of the S11 parameters of the liquid crystal array antenna structure according to the second embodiment of the present invention, and Figure 4B shows a beam scanning gain diagram of the liquid crystal array antenna structure according to the second embodiment of the present invention. Referring to Figures 4A and 4B, in this embodiment, the liquid crystal material used for liquid crystal cells 81 to 84 is MERCK GT7-29001.

[0075] As shown in Figure 4A, when no voltage is applied to liquid crystal cells 81-84, the center operating frequency of the liquid crystal array antenna structure is between 14 and 15 GHz (optimally 14.20 GHz), and the bandwidth is 0.27 GHz, with -10 dB as the reference point.

[0076] As shown in Figure 4A, when voltage is applied to liquid crystal cells 81 and 82, and no voltage is applied to liquid crystal cells 83 and 84, the center operating frequency of the liquid crystal array antenna structure is between 14 and 15 GHz (optimally 14.25 GHz), and the bandwidth is 0.20 GHz, with -10 dB as the reference point.

[0077] As shown in Figure 4A, when voltage is applied to liquid crystal cells 83 and 84, and no voltage is applied to liquid crystal cells 81 and 82, the center operating frequency of the liquid crystal array antenna structure is between 14 and 15 GHz (optimally 14.23 GHz), and the bandwidth is 0.20 GHz, with -10 dB as the reference point.

[0078] As shown in Figure 4A, when voltage is applied to liquid crystal cells 81-84, the center operating frequency of the liquid crystal array antenna structure is between 13 and 14 GHz (optimal is 13.95 GHz), and the bandwidth is 0.10 GHz, with -10 dB as the reference point.

[0079] As shown in Figure 4B, when observing the maximum scannable angle, when voltage is applied to liquid crystal cells 81 and 82, but not to liquid crystal cells 83 and 84, the beam scanning angle of the liquid crystal array antenna structure is -24 degrees and the gain is 10.14 dBi. Furthermore, when no voltage is applied to liquid crystal cells 81 and 82, but voltage is applied to liquid crystal cells 83 and 84, the beam scanning angle of the liquid crystal array antenna structure is 24 degrees and the gain is 11.05 dBi.

[0080] Based on this, the beam scanning range of the liquid crystal array antenna structure is ±24 degrees.

[0081] Figure 5A shows a schematic diagram of the S11 parameters of the liquid crystal array antenna structure according to the third embodiment of the present invention, and Figure 5B shows a beam scanning gain diagram of the liquid crystal array antenna structure according to the third embodiment of the present invention. Referring to Figures 5A and 5B, in this embodiment, the liquid crystal material used for liquid crystal cells 81 to 84 is JNC ZOC-A018XX.

[0082] As shown in Figure 5A, when no voltage is applied to liquid crystal cells 81-84, the center operating frequency of the liquid crystal array antenna structure is between 14 and 15 GHz (optimally 14.12 GHz), and the bandwidth is 0.32 GHz, with -10 dB as the reference point.

[0083] As shown in Figure 5A, when voltage is applied to liquid crystal cells 81 and 82, and no voltage is applied to liquid crystal cells 83 and 84, the center operating frequency of the liquid crystal array antenna structure is between 14 and 15 GHz (optimally 14.20 GHz), and the bandwidth is 0.20 GHz, with -10 dB as the reference point.

[0084] As shown in Figure 5A, when voltage is applied to liquid crystal cells 83 and 84, and no voltage is applied to liquid crystal cells 81 and 82, the center operating frequency of the liquid crystal array antenna structure is between 14 and 15 GHz (optimally 14.20 GHz), and the bandwidth is 0.20 GHz, with -10 dB as the reference point.

[0085] As shown in Figure 5A, when voltage is applied to liquid crystal cells 81-84, the center operating frequency of the liquid crystal array antenna structure is between 13 and 14 GHz (optimal is 13.95 GHz), and the bandwidth is 0.20 GHz, with -10 dB as the reference point.

[0086] As shown in Figure 5B, when observing the maximum scannable angle, when voltage is applied to liquid crystal cells 81 and 82, but not to liquid crystal cells 83 and 84, the beam scanning angle of the liquid crystal array antenna structure is -25 degrees and the gain is 12.15 dBi. Furthermore, when no voltage is applied to liquid crystal cells 81 and 82, but voltage is applied to liquid crystal cells 83 and 84, the beam scanning angle of the liquid crystal array antenna structure is 25 degrees and the gain is 12.76 dBi.

[0087] Based on this, the beam scanning range of the liquid crystal array antenna structure is ±25 degrees.

[0088] As can be seen from Figures 3A to 5B above, when bias is applied to the four liquid crystal cells 81 to 84, the central operating frequency and beam scanning range of the liquid crystal array antenna structure of the present invention are between 14 GHz and 15 GHz (Ku frequency band) (also referred to as the first frequency band) and ±23 to ±25 degrees (also referred to as the first range), respectively. On the other hand, as can be seen from Figures 3B, 4B, and 5B above, the side lobes were effectively suppressed.

[0089] As described above, the liquid crystal array antenna structure provided by the embodiment of the present invention, through its special structural design, achieves a central operating frequency and beam scanning range that can meet the demands of low Earth orbit satellite communications, and can effectively suppress sidelobe levels, thereby realizing excellent transmission performance.

[0090] Finally, it should be noted that the embodiments described above are merely for illustrating the technical solutions of the present invention and do not limit the invention. Although the present invention has been described in detail with reference to the embodiments described above, a person ordinary in the art should understand that it is still possible to modify the technical solutions described in the embodiments described above, or to replace some or all of the technical features therein with equivalent ones. Furthermore, these modifications or replacements should not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of each embodiment of the present invention. [Industrial applicability]

[0091] The present invention provides a liquid crystal array antenna structure that can effectively suppress side lobe levels and achieve excellent transmission performance. [Explanation of Symbols]

[0092] 1. First substrate layer 11 1st top surface 12 1st lower surface 2. Second substrate layer 21 2nd top surface 22 Second lower surface 3. Third substrate layer 31 Third upper surface 32 Third lower surface 4. First surface unit 41, 42, 43, 44 First surface inward-wound bias metal wire 5. Second surface unit 51, 52, 53, 54 Second surface region patch group 511, 512, 513, 521, 522, 523, 531, 532, 533, 541, 542, 543 Surface cross-shaped patch 55, 56 Surface inner metal wire 57 Surface outer metal wire 6. Third Surface Unit 61, 62, 63, 64 Surface slit group 611, 612, 613, 621, 622, 623, 631, 632, 633, 641, 642, 643 Third surface slit 7. Fourth surface unit 71, 72 3-stage 1-to-6 wiring 711, 721 Metal wire 7111, 7112, 71111, 71112, 71113, 71114, 71121, 71122, 71123, 71124, 7211, 7212, 72111, 72112, 72113, 72114, 72121, 72122, 72123, 72124 branch 81, 82, 83, 84 LCD cells

Claims

1. A first substrate layer having a first upper surface and a first lower surface, A second substrate layer having a second upper surface and a second lower surface, A third substrate layer having a third upper surface and a third lower surface, Four liquid crystal cells arranged between the first substrate layer and the second substrate layer, The first surface units arranged on the first lower surface, The second surface units arranged on the second upper surface, The third surface unit arranged on the third upper surface, A fourth surface unit arranged on the third lower surface, A liquid crystal array antenna structure comprising the above, wherein when a bias is applied to the liquid crystal cell, the central operating frequency and beam scanning range of the liquid crystal array antenna structure are in a first frequency band and a first range, respectively.

2. The first surface unit includes four first surface inward-wound bias metal wires, The liquid crystal array antenna structure according to claim 1, wherein each of the four first surface-wound bias metal wires corresponds to one of the four liquid crystal cells.

3. The second surface unit includes four groups of second surface region patches, The liquid crystal array antenna structure according to claim 2, wherein each of the four second surface region patch groups corresponds to one of the four liquid crystal cells.

4. The liquid crystal array antenna structure according to claim 3, wherein the third surface unit is a metal grounding layer.

5. The liquid crystal array antenna structure according to claim 4, wherein the fourth surface unit includes two three-stage 1-to-6 wiring.

6. The liquid crystal array antenna structure according to any one of claims 2 to 5, wherein each of the first surface inward-winding bias metal wires is an equally spaced square spiral metal wire.

7. The liquid crystal array antenna structure according to claim 6, wherein the number of turns of the equally spaced square spiral metal wire is at least 2.

8. The liquid crystal array antenna structure according to claim 2, wherein each of the first surface inward-wound bias metal wires is connected to the edge of the first lower surface.

9. The liquid crystal array antenna structure according to claim 3, wherein the four second surface region patch groups are arranged in a binary array.

10. The liquid crystal array antenna structure according to claim 3, wherein each of the second surface region patch groups includes three surface cross-shaped patches, and the central points of the three surface cross-shaped patches are interconnected via an inner surface metal wire.

11. The liquid crystal array antenna structure according to claim 10, wherein one of the three surface cross-shaped patches is connected to the edge of the second upper surface via an outer surface metal wire.

12. Each of the surface cross-shaped patches includes a surface left patch, a surface center patch, a surface right patch, and a surface connecting patch. The left surface patch, the center surface patch, and the right surface patch are connected via the surface connection patch. The length and width of the left-side patch on the surface are the same as the length and width of the right-side patch on the surface. The length of the surface center patch is longer than the length of the surface left patch and the length of the surface right patch. The liquid crystal array antenna structure according to claim 10, wherein the width of the left surface patch, the width of the center surface patch, and the width of the right surface patch are the same.

13. The aforementioned third surface unit includes four groups of surface slits, The liquid crystal array antenna structure according to claim 4, wherein each of the four surface slit groups corresponds to one of the four liquid crystal cells.

14. The liquid crystal array antenna structure according to claim 13, wherein each group of surface slits includes three third surface slits.

15. The liquid crystal array antenna structure according to claim 14, wherein the third surface slit is an H-shaped slit.

16. The liquid crystal array antenna structure according to claim 5, wherein the feed ends of the two three-stage 1:6 distribution lines are connected to the edge of the third lower surface.

17. The liquid crystal array antenna structure according to claim 5, wherein the output terminals of the two three-stage 1-to-6 wirings each correspond to a plurality of third surface slits of the third surface unit.

18. The second surface unit includes four groups of second surface region patches, The liquid crystal array antenna structure according to claim 1, wherein each of the four second surface region patch groups corresponds to one of the four liquid crystal cells.

19. The four groups of second surface region patches are arranged in a binary array. Each of the second surface region patch groups includes three surface cross-shaped patches, and the central points of the three surface cross-shaped patches are interconnected by an inner surface metal wire. The liquid crystal array antenna structure according to claim 18, wherein one of the three surface cross-shaped patches is connected to the edge of the second upper surface via an outer surface metal wire.

20. Each of the surface cross-shaped patches includes a surface left patch, a surface center patch, a surface right patch, and a surface connecting patch. The left surface patch, the center surface patch, and the right surface patch are connected via the surface connection patch. The length and width of the left-side patch on the surface are the same as the length and width of the right-side patch on the surface. The length of the surface center patch is longer than the length of the surface left patch and the length of the surface right patch. The liquid crystal array antenna structure according to claim 19, wherein the width of the left surface patch, the width of the center surface patch, and the width of the right surface patch are the same.

21. The liquid crystal array antenna structure according to claim 1, wherein the third surface unit is a metal grounding layer.

22. The aforementioned third surface unit includes four groups of surface slits, The liquid crystal array antenna structure according to claim 21, wherein each of the four surface slit groups corresponds to one of the four liquid crystal cells.

23. The liquid crystal array antenna structure according to claim 22, wherein each group of surface slits includes three third surface slits.

24. The liquid crystal array antenna structure according to claim 23, wherein the third surface slit is an H-shaped slit.

25. The liquid crystal array antenna structure according to claim 1, wherein the fourth surface unit includes two three-stage 1-to-6 wiring.

26. The liquid crystal array antenna structure according to claim 25, wherein the feed ends of the two three-stage 1:6 distribution lines are connected to the edge of the third lower surface.

27. The liquid crystal array antenna structure according to claim 25, wherein the output terminals of the two three-stage 1-to-6 wirings each correspond to a plurality of third surface slits of the third surface unit.

28. The liquid crystal array antenna structure according to any one of claims 2 to 5 and 18 to 27, wherein the first surface unit, the second surface unit, the third surface unit, and the fourth surface unit are all made of a metal material.

29. The liquid crystal array antenna structure according to any one of claims 2 to 5 and 18 to 27, wherein the first frequency band is 14 GHz to 15 GHz.

30. The liquid crystal array antenna structure according to any one of claims 2 to 5 and 18 to 27, wherein the first range is ±23 to ±25 degrees.

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