Liquid crystal array antenna structure

Abstract

A liquid crystal array antenna structure includes a first substrate layer, a second substrate layer, a third substrate layer, at least four liquid crystal cells, a first surface cell, a second surface cell, a third surface cell, and a fourth surface cell. The four liquid crystal cells are arranged in parallel between the second substrate layer and the third substrate layer. The fourth surface cell can feed signals using a dual-feed power distribution structure design, and phase modulation is achieved by applying a bias voltage to the liquid crystal cells to achieve beam scanning.

Description

Technical Field

[0001] This invention relates to a liquid crystal array antenna structure, particularly a liquid crystal array antenna structure applicable to the Ku band, which utilizes different voltages applied to the liquid crystal cells to achieve beam scanning functionality. Prior Technology

[0002] A liquid crystal array antenna is an antenna system constructed using liquid crystal materials. Antenna performance is adjusted by controlling the arrangement of liquid crystal molecules. This antenna structure typically consists of a planar array of liquid crystal materials arranged on a conductive substrate. Each antenna element can control the electric field state of the liquid crystal material, thereby altering the phase and amplitude of the radio frequency signal.

[0003] The key characteristics of liquid crystal array antennas lie in their adjustability and flexibility. By adjusting the arrangement of liquid crystal molecules in each antenna element, beam pointing and beamforming can be achieved, allowing the antenna to adjust the signal direction and coverage area according to different communication requirements. This flexibility makes liquid crystal array antennas widely used in wireless communication systems, enabling them to adapt to different environments and communication conditions.

[0004] However, in order to meet the needs of current practical applications (such as low-Earth orbit satellite communications), the 6x6 liquid crystal array antenna structure proposed in this case utilizes 2x2 liquid crystal unit cells to apply different bias voltages to control the array antenna to achieve beam scanning. It has better performance in both gain and beam scanning efficiency. Furthermore, this case uses the design of increasing the number of array patches to achieve the effect of suppressing side effects, which has better performance than known technologies. Therefore, this case should be the best solution. Summary of the Invention

[0005] A liquid crystal array antenna structure includes: 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; a first liquid crystal cell located between the second substrate layer and the third substrate layer, the first liquid crystal cell being positioned at a first position; a second liquid crystal cell located between the second substrate layer and the third substrate layer, the second liquid crystal cell being arranged parallel to the first liquid crystal cell, the second liquid crystal cell being positioned at a second position; and a third liquid crystal cell located between the second substrate layer and the third substrate layer, the third liquid crystal cell being arranged side-by-side with the first liquid crystal cell. The third liquid crystal unit is positioned at a third position; a fourth liquid crystal unit is located between the second substrate layer and the third substrate layer, arranged side-by-side with the second liquid crystal unit and parallel to the third liquid crystal unit, and positioned at a fourth position; a first surface unit is formed on the first lower surface, and the first surface unit has four bias metal lines wound around its first surface, wherein the positions of the four bias metal lines are respectively corresponding to the first position, the second position, the third position, and the fourth position; a second surface unit is formed on the second upper surface, and the second surface unit has four second surface region patch groups, which... The second surface area patch group includes three cross-shaped patches, which are connected through an inner metal wire on the second surface. The positions of the three cross-shaped patches in the four second surface area patch groups correspond to the first position, the second position, the third position, and the fourth position, respectively. A third surface unit is formed on the third upper surface. The third surface unit has four third surface area patch groups, each of which corresponds to one of the second surface area patch groups. Each third surface area patch group includes three slits, and the slit positions of different third surface area patch groups correspond to ten of the positions of different second surface area patch groups. The text describes a patch assembly with a fourth surface unit formed on the third lower surface. The fourth surface unit has two sets of fourth surface distribution lines. Each fourth surface distribution line is formed by two first metal lines extending from the edge of the third lower surface towards the center of the third lower surface from a fourth surface metal line. Each first metal line further extends a second metal line and a third metal line towards the center of the third lower surface. The third metal line further extends a fourth metal line and a fifth metal line. The endpoints of the second, fourth, and fifth metal lines correspond to the positions of the three slits in the patch assembly on the third surface region. The two sets of fourth surface distribution lines are located on different sides of the third lower surface.The first two metal lines on the same side are parallel to each other, the second and third metal lines on the same side are parallel to each other, and the fourth and fifth metal lines on the same side are parallel to each other. The beam scanning angle of the liquid crystal array antenna structure, controlled by applying a liquid crystal bias voltage to the liquid crystal unit, has a frequency range of 14~15 GHz and can achieve a beam scanning range of ±23~±25 degrees.

[0006] More specifically, the liquid crystal cell changes its dielectric properties due to the change in electric field, thereby altering the characteristics of the antenna beam.

[0007] More specifically, the biased metal wire system inside each of the first surfaces is connected to the edge of the first lower surface.

[0008] More specifically, one of the cross-shaped patches in the second surface area patch group is connected to the edge of the second upper surface through a metal wire on the outer side of the second surface.

[0009] More specifically, the cross-shaped patch system of the four second surface region patch groups can be arranged into a binomial array, which is an antenna array design based on the binomial coefficient distribution.

[0010] More specifically, the third surface unit is a metal ground plane, which is fed in through the slit and then fed in through the fourth surface unit on both sides.

[0011] More specifically, the slit system is H-shaped.

[0012] More specifically, a T-connector is used at the bifurcation points of the two first metal wires, the bifurcation points of the second and third metal wires, and the bifurcation points of the fourth and fifth metal wires.

[0013] More specifically, the corners of the first metal wire, the second metal wire, the third metal wire, the fourth metal wire, and the fifth metal wire are tangential structures, which are used to improve the capacitance effect.

[0014] More specifically, the first surface unit, the second surface unit, the third surface unit, and the fourth surface unit are formed of metal. Simple Explanation of the Diagram

[0015] Figure 1A is a schematic diagram of the multi-layer structure of the liquid crystal array antenna structure of the present invention. [Figure 1B] is a schematic diagram of the multi-layer structure combination of the liquid crystal array antenna structure of the present invention. [Figure 2A] is a schematic diagram of the single-cell design of the first surface unit of the liquid crystal array antenna structure of the present invention. [Figure 2B] is a schematic diagram of the structure of the four liquid crystal units of the liquid crystal array antenna structure of the present invention. [Figure 2C] is a schematic diagram of the unit cell design of the second surface unit of the liquid crystal array antenna structure of the present invention. [Figure 2D] is a schematic diagram of the unit cell design of the second surface unit of the liquid crystal array antenna structure of the present invention. [Figure 2E] is a schematic diagram of the unit cell design of the third surface unit of the liquid crystal array antenna structure of the present invention. [Figure 2F] is a schematic diagram of the unit cell design of the third surface unit of the liquid crystal array antenna structure of the present invention. [Figure 2G] is a schematic diagram of the unit cell design of the fourth surface unit of the liquid crystal array antenna structure of the present invention. [Figure 2H] is a schematic diagram of the unit cell design of the fourth surface unit of the liquid crystal array antenna structure of the present invention. [Figure 3A] is a schematic diagram of the S11 characteristics of the first embodiment of the liquid crystal array antenna structure of the present invention. [Figure 3B] is a beam scanning gain diagram of the first embodiment of the liquid crystal array antenna structure of the present invention. [Figure 4A] is a schematic diagram of the S11 characteristics of the second embodiment of the liquid crystal array antenna structure of the present invention. [Figure 4B] is a beam scanning gain diagram of the second embodiment of the liquid crystal array antenna structure of the present invention. [Figure 5A] is a schematic diagram of the S11 characteristics of the third embodiment of the liquid crystal array antenna structure of the present invention. [Figure 5B] is a beam scanning gain diagram of the third embodiment of the liquid crystal array antenna structure of the present invention. Implementation

[0016] Other technical contents, features and effects of the present invention will be clearly presented in the following detailed description of the preferred embodiments with reference to the accompanying drawings.

[0017] Please refer to Figures 1A and 1B, which are schematic diagrams of the multilayer structure of the liquid crystal array antenna. As shown in the figures, the design of the liquid crystal array antenna structure is mainly a three-layer, four-sided circuit board. 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 a first liquid crystal unit 81, a second liquid crystal unit 82, a third liquid crystal unit 83, and a fourth liquid crystal unit 84 (LC1, LC2, LC3, LC4).

[0018] The first substrate layer 1 has a first upper surface 11 and a first lower surface 12.

[0019] The second substrate layer 2 has a second upper surface 21 and a second lower surface 22.

[0020] The third substrate layer 3 has a third upper surface 31 and a third lower surface 32.

[0021] The first substrate layer 1, the second substrate layer 2 and the third substrate layer 3 are double-sided circuit boards (for example, the dielectric constant is 3~4 (preferably 3.45), the dielectric loss is 0.002~0.003 (preferably 0.0025), and the thickness is 0.5~0.51 mm (preferably 0.508 mm)), but this invention is not limited to this type of circuit board.

[0022] The first surface unit 4, the second surface unit 5, the third surface unit 6, and the fourth surface unit 7 are formed of a metallic material (e.g., copper foil).

[0023] The four liquid crystal cells (LC1, LC2, LC3, LC4) are arranged in parallel between the second substrate layer 2 and the third substrate layer 3.

[0024] The first liquid crystal unit 81 is located between the second substrate layer 2 and the third substrate layer 3, and the arrangement position of the first liquid crystal unit 81 is a first position.

[0025] The second liquid crystal unit 82 is located between the second substrate layer 2 and the third substrate layer 3. The second liquid crystal unit 82 is arranged in parallel with the first liquid crystal unit 81. The arrangement position of the second liquid crystal unit 82 is a second position.

[0026] The third liquid crystal unit 83 is located between the second substrate layer 2 and the third substrate layer 3. The third liquid crystal unit 83 is arranged side by side with the first liquid crystal unit 81. The arrangement position of the third liquid crystal unit 83 is a third position.

[0027] The fourth liquid crystal unit 84 is located between the second substrate layer 2 and the third substrate layer 3. The fourth liquid crystal unit 84 is arranged side by side with the second liquid crystal unit 82 and parallel to the third liquid crystal unit 83. The fourth liquid crystal unit 84 is positioned at a fourth position.

[0028] The characteristics of the first liquid crystal unit 81, the second liquid crystal unit 82, the third liquid crystal unit 83, and the fourth liquid crystal unit 84, when the liquid crystal material is ZOC-A018XX, are as follows: (1) The dielectric constant is 2.55~3.76, the dielectric loss is 0.004~0.007, and the thickness is 0.1mm. (2) In the optimal implementation, when the liquid crystal molecules are horizontal, the dielectric constant is 3.76 and the dielectric loss is 0.004 (before the first liquid crystal layer is biased); while when the liquid crystal molecules are vertical, the dielectric constant is 2.55 and the dielectric loss is 0.007 (after the first liquid crystal layer is biased), but this invention is not limited to this type of liquid crystal material.

[0029] The first liquid crystal unit 81, the second liquid crystal unit 82, the third liquid crystal unit 83, and the fourth liquid crystal unit 84, when the liquid crystal material is E7, have the following characteristics: (1) The dielectric constant is 2.72~3.17, the dielectric loss is 0.033~0.05, and the thickness is 0.1mm. (2) In the optimal implementation, when the liquid crystal molecules are horizontal, the dielectric constant is 3.17 and the dielectric loss is 0.033 (before the first liquid crystal layer is biased); while when the liquid crystal molecules are vertical, the dielectric constant is 2.72 and the dielectric loss is 0.05 (after the first liquid crystal layer is biased), but this invention is not limited to this type of liquid crystal material.

[0030] The first liquid crystal unit 81, the second liquid crystal unit 82, the third liquid crystal unit 83, and the fourth liquid crystal unit 84, when the liquid crystal material is GT7, have the following characteristics: (1) The dielectric constant is 2.72~3.17, the dielectric loss is 0.033~0.05, and the thickness is 0.1mm. (2) In the optimal implementation, when the liquid crystal molecules are horizontal, the dielectric constant is 3.53 and the dielectric loss is 0.0064 (before the first liquid crystal layer is biased); while when the liquid crystal molecules are vertical, the dielectric constant is 2.46 and the dielectric loss is 0.0116 (after the first liquid crystal layer is biased), but this invention is not limited to this type of liquid crystal material.

[0031] The first liquid crystal unit 81, the second liquid crystal unit 82, the third liquid crystal unit 83, and the fourth liquid crystal unit 84 change their dielectric properties due to the change of electric field, thereby changing the characteristics of the antenna beam. The principle is that before the liquid crystal material is biased, the liquid crystal molecules are arranged parallel to the metal patch and the metal ground plane; after the bias is applied, the liquid crystal molecules will change to be arranged perpendicular to the metal patch and the metal ground plane, thereby achieving the effect of shifting the center frequency.

[0032] As shown in Figure 2A, the first surface unit 4 is formed on the first lower surface 12. The first lower surface 12 is formed by etching a metal layer (e.g., copper foil with a thickness of 0.035 mm) to form multiple first surface units 4 arranged in an array (only a single one is shown in this case).

[0033] The dimensions of the first lower surface 12 are as follows: A is 67~68 mm (preferably 67.6 mm) and B is 70~71 mm (preferably 70.1 mm).

[0034] The first surface unit 4 has four bias metal lines 41, 42, 43, 44 wound around the first surface, wherein the bias metal lines 41, 42, 43, 44 wound around the first surface correspond to different liquid crystal units 81, 82, 83, 84 as shown in Figure 2B.

[0035] The biased metal wires 41, 42, 43, and 44 inside the first surface are connected to the edge of the first lower surface 12.

[0036] The design of the bias metal lines 41, 42, 43, and 44 within the first surface is primarily based on the fact that the loop-shaped bias lines guide the electric field along a specific path, thereby altering the electric field and refractive index distribution of the liquid crystal material. This specific path of electric field may induce a non-uniform refractive index distribution, affecting the phase delay mode, and consequently influencing beam formation and scanning direction.

[0037] The bias metal lines 41, 42, 43, and 44 on the first surface correspond to the center of different liquid crystal units 81, 82, 83, and 84, respectively, and different voltages are applied to the first liquid crystal unit 81, the second liquid crystal unit 82, the third liquid crystal unit 83, and the fourth liquid crystal unit 84 to achieve the beam scanning effect.

[0038] The unit cell design specifications of the first surface unit 4 are as follows: C<=1mm (optimal is 0.9mm) and C1 is 4~5mm (optimal is 4.55mm), where C1 is the distance from the inner edge of the outer ring to the outer edge of the inner ring.

[0039] The horizontal spacing between the bias metal lines 41 and 43 on the first surface is 10~12mm (11.06mm is optimal).

[0040] The horizontal spacing between the bias metal lines 42 and 44 on the first surface is 10~12mm (11.06mm is optimal).

[0041] The vertical spacing between the bias metal lines 41 and 42 on the first surface is 6-7 mm (6.7 mm is optimal).

[0042] The vertical spacing between the bias metal lines 43 and 44 on the first surface is 6-7 mm (6.7 mm is optimal).

[0043] As shown in Figure 2B, the dimensions of the first liquid crystal unit 81, the second liquid crystal unit 82, the third liquid crystal unit 83, and the fourth liquid crystal unit 84 (LC1, LC2, LC3, LC4) are as follows: M is 28~29mm (optimal is 28.6mm) and N is 28~29mm (optimal is 28.6mm).

[0044] The vertical spacing between the liquid crystal cells 81 and 83 is 1~2mm (1.4mm is optimal).

[0045] The vertical spacing between the liquid crystal cells 82 and 84 is 1~2mm (1.4mm is optimal).

[0046] The horizontal spacing between the liquid crystal cells 81 and 82 is 6~7mm (6.25mm is optimal).

[0047] As shown in Figure 2C, the second surface unit 5 is formed on the second upper surface 21. The second upper surface 21 is formed by etching a metal layer (e.g., copper foil with a thickness of 0.035 mm) to form multiple second surface units 5 arranged in an array (only a single one is shown in this case).

[0048] The dimensions of the second upper surface 21 are as follows: D is 125~126mm (preferably 125.2mm) and E is 66~67mm (preferably 66.1mm).

[0049] The second surface unit 5 has four second surface area patch groups 51, 52, 53, 54, each of which includes three cross-shaped patches 511, 512, 513, 521, 522, 523, 531, 532, 533, and 541, 542, 543. The three cross-shaped patches 511, 512, 513, 521, 522, 523, 531, 532, 533, and 541, 542, 543 are connected through a metal wiring 55, 56, 57 on the inner side of the second surface. Each second surface area patch group 51, 52, 53, 54 corresponds to a different liquid crystal unit 81, 82, 83, 84.

[0050] The positions of the three cross-shaped patches 511, 512, 513, 521, 522, 523, 531, 532, 533, 541, 542, 543 in the second surface area patch group 51, 52, 53, 544 are respectively corresponding to the first position, the second position, the third position, and the fourth position.

[0051] The second surface region patch group 51, 52, 53, 54 causes the liquid crystal molecules to rotate when a voltage is applied by means of bias metal lines 43, 44 wound around the first surface.

[0052] As shown in Figures 2C and 2D, the unit cell design specifications of the second surface unit 5 (taking the cross-shaped patch 511 as an example) are as follows: F is 3~4mm (optimal is 3.35mm), G is 5~6mm (optimal is 5.19mm), H<=1mm (optimal is 0.57mm), I is 5~6mm (optimal is 5.19mm), J is 6~7mm (optimal is 6.7mm), Y1 is 1~2mm (optimal is 1.19mm), Y2 is 17~18mm (optimal is 17.48mm), Y3 is 1~2mm (optimal is 1.72mm), Y4 is 3~4mm (optimal is 3.3mm), and Y5 is 3~4mm (optimal is 3.3mm).

[0053] The second surface area patch group 51, 52 is 50~60mm (ideally 55mm).

[0054] The distance between the patch groups 51 and 53 on the second surface area is 3~4mm (3.3mm is optimal).

[0055] The second surface area patch group 53, 54 is 50~60mm (ideally 55mm).

[0056] The cross-shaped patch 511 has a length of 5~6mm (5.19mm is optimal) and a width of 3~4mm (3.35mm is optimal).

[0057] The cross-shaped patches 511, 521, 531, and 541 of the patch group 51, 52, 53, and 54 of the second surface area are connected to the edge of the second upper surface 21 through a metal wire 57 on the outer side of the second surface; wherein the line width connecting each patch is 0.5~0.6mm (preferably 0.57mm).

[0058] The second surface unit 5 is a 6x6 metal patch composed of 12 groups of 1x3 patches. The antenna patches are arranged in a binomial array, which is an antenna array design based on the binomial coefficient distribution. An antenna array is composed of multiple individual antenna elements arranged in a certain geometric shape to control the radiation pattern of the antenna, thereby achieving better signal transmission or reception performance.

[0059] The primary goal of a binomial array is to optimize the antenna's radiation pattern, particularly by reducing sidelobe levels. Sidelobes are secondary radiation regions outside the main beam of the antenna, and their presence can cause interference and errors. By weighting the excitation currents of each antenna element according to binomial coefficients, a radiation pattern with ideal sidelobe suppression can be formed.

[0060] As shown in Figure 2E, the third surface unit 6 is formed on the third upper surface 31. A metal layer (e.g., copper foil with a thickness of 0.035 mm) is etched on the third upper surface 31 to form multiple third surface units 6 arranged in an array (only a single one is shown in this case).

[0061] The dimensions of the third upper surface 31 are as follows: K is 133~134mm (preferably 133.2mm) and L is 66~67mm (preferably 66.1mm).

[0062] The third surface unit 6 has four third surface region patch groups 61, 62, 63, 64, wherein each third surface region patch group 61, 62, 63, 64 contains three slits 611, 612, 613, 621, 622, 623, 631, 632, 633, 641, 642, 643; and each third surface region patch group corresponds to a different liquid crystal unit, and the horizontal spacing between each pair of slits is 50~60mm (ideally 55mm) and the vertical spacing is 10mm.

[0063] Each third surface region patch group 61, 62, 63, 64 corresponds to one of the second surface region patch groups 51, 52, 53, 54. The positions of the slits 611, 612, 613, 621, 622, 623, 631, 632, 633, 641, 642, 643 of the different third surface region patch groups 61, 62, 63, 644 correspond to the outermost patch position of the cross-shaped patch of the different second surface region patch groups 51, 52, 53, 54.

[0064] As shown in Figure 2F, the unit cell design specifications of the third surface unit 6 (taking slit 611 as an example) are as follows: W1 is 3mm, W2<=1mm, L2<=1mm, with W2=0.5mm and L2=0.5mm being optimal, and the two sides of the H-shaped slit are of equal length.

[0065] As shown in Figure 2G, the fourth surface unit 7 is formed on the third lower surface 32. A metal layer (e.g., copper foil with a thickness of 0.035 mm) is etched on the third lower surface 32 to form multiple fourth surface units 7 arranged in an array (only a single one is shown in this case).

[0066] The dimensions of the third lower surface 32 are as follows: K is 133~134mm (preferably 133.2mm) and L is 66~67mm (preferably 66.1mm).

[0067] The fourth surface unit 7 has two sets of fourth surface distribution lines 71, 72. Each fourth surface distribution line 71, 72 is formed by a fourth surface metal line 711, 721 extending from the edge of the third lower surface 32 toward the center of the third lower surface 32.

[0068] Among them, the two sets of fourth surface distribution lines 71 and 72 are located on different sides of the third lower surface 32.

[0069] The fourth surface metal line 711 extends into two first metal lines 7111 and 7112. Each of the first metal lines 7111 and 7112 extends into the center of the third lower surface into a second metal line 71111 and 71121 and a third metal line 71112 and 71122. The third metal lines 71112 and 71122 further extend into a fourth metal line 71113 and 71123 and a fifth metal line 71114 and 71124. The endpoints of the second metal lines 71111 and 71121, the fourth metal lines 71113 and 71123, and the fifth metal lines 71114 and 71124 correspond to the positions of the three slits 611, 612, 613, 631, 632, and 633 of the patch group 61 and 63 in the third surface area, respectively.

[0070] The fourth surface metal line 721 extends into two first metal lines 7211 and 7212. Each of the first metal lines 7211 and 7212 extends into the center of the third lower surface into a second metal line 72111 and 72121 and a third metal line 72112 and 72122. The third metal lines 72112 and 72122 further extend into a fourth metal line 72113 and 72123 and a fifth metal line 72114 and 72124. The endpoints of the second metal lines 72111 and 72121, the fourth metal lines 72113 and 72123, and the fifth metal lines 72114 and 72124 correspond to the positions of the three slits 621, 622, 623, 641, 642, and 643 of the patch group 62 and 64 in the third surface area, respectively.

[0071] Among them, the two first metal lines 7211 and 7212 on the same side are parallel to each other, the second metal lines 72111 and 72121 and the third metal lines 72112 and 72122 on the same side are parallel to each other, and the fourth metal lines 72113 and 72123 and the fifth metal lines 72114 and 72124 on the same side are parallel to each other.

[0072] In this case, the second metal wires 71111, 71121, 72111, 72121 and the third metal wires 71112, 71122, 72112, 72122 are symmetrical and parallel. The third metal wires 71112, 71122, 72112, 72122 each extend two branches (the fourth metal wire and the fifth metal wire), making a total of six branches (two second metal wires, two fourth metal wires and two fifth metal wires). The distance between the six branches is 10mm, and the endpoints of the six branches correspond to the center positions of the six slits.

[0073] A T-connector is used at the bifurcation points of the two first metal wires 7111, 7112, 7211, 7212, the bifurcation points of the second metal wires 71111, 71121, 72111, 72121 and the third metal wires 71112, 71122, 72112, 72122, and the bifurcation points of the fourth metal wires 71113, 71123, 72113, 72123 and the fifth metal wires 71114, 71124, 72114, 72124.

[0074] The corners of the first metal lines 7111, 7112, 7211, 7212, the second metal lines 71111, 71121, 72111, 72121, the third metal lines 71112, 71122, 72112, 72122, the fourth metal lines 71113, 71123, 72113, 72123, and the fifth metal lines 71114, 71124, 72114, 72124 are tangential structures, which are used to improve the capacitance effect.

[0075] As shown in Figure 2H, the unit cell design specifications of the fourth surface unit 7 (taking the fourth surface distribution line 71 as an example) are as follows: O is 1~2mm (optimal 1.13mm, impedance 50Ω), P is 1~2mm (optimal 1.32mm, impedance 50Ω), Q is 15~16mm (optimal 15.1mm, impedance 50Ω), R is 5mm (impedance 35.3Ω), S is 2~3mm (optimal 2.28mm, impedance 35.3Ω), and T is 2~3mm (optimal 2.44mm). The line widths are as follows: U = 3~4mm (optimal 3.68mm, impedance 50Ω), V = 4~5mm (optimal 4.43mm, impedance 50Ω), W = 13~14mm (optimal 13.01mm, impedance 50Ω), and X = 10~11mm (optimal 10.09mm, impedance 50Ω). The line width for 50Ω impedance is 1~1.5mm (optimal 1.13mm), and the line width for 35.3Ω impedance is 1~1.5mm (optimal 1.32mm).

[0076] The third surface unit 6 has a metal ground plane. Since it uses slit-coupled feed, it uses an H-shaped slit. The number of ports is reduced by the two 1-to-6 power dividers of the fourth surface unit 7 to reduce the difficulty of implementation. It also uses bilateral feed to improve the gain effect.

[0077] The fourth surface distribution lines 71 and 72 of the fourth surface unit 7 are a one-to-six power divider. The advantage of this method is that a single signal input can allow each antenna to radiate simultaneously, reducing the number of ports and the trouble of too many soldering.

[0078] This design utilizes a slit-coupled feeding method to feed signals to the surface mount. Furthermore, the signal and bias voltage are separated, thus preventing the external bias voltage applied to the LCD from mixing with the signal, which could cause network analyzer malfunctions. It also eliminates the need to install a bias tee.

[0079] This case uses three liquid crystal materials (E7, GT7-29001, and ZOC-A018XX) for simulation implementation, and examines their characteristics through S-parameter (S11 parameter) diagrams, where the information in the diagrams is as follows: (1) In the figure, Off means that the liquid crystal cell is not powered on. (2) In the figure, On means that the liquid crystal cell has been powered on.

[0080] When the liquid crystal material is E7, as shown in Figure 3A, the following simulation data are available, explained below: (1) Before the bias voltage is applied, its center frequency is 14~15 GHz (14.1 GHz is optimal), and its bandwidth is 0.4 GHz with -10dB as the reference point. (1) When LC1 and LC2 are biased, and LC3 and LC4 are not biased, the center frequency is 14~15 GHz (14 GHz is optimal) and the bandwidth is 0.35 GHz. (2) When LC3 and LC4 are biased, and LC1 and LC2 are not biased, the center frequency is 14~15 GHz (14 GHz is optimal) and the bandwidth is 0.35 GHz. (3) When LC1, LC2, LC3 and LC4 are all biased, their center frequency is 13~14 GHz (optimal is 13.95 GHz) and their bandwidth is 0.2 GHz.

[0081] As shown in Figure 3B, applying different bias voltages to the four liquid crystal cells can change the dielectric constant and dielectric loss of the liquid crystal molecules. Observing the maximum scannable angle in the gain graph, the beam scanning results are as follows: (1) When LC1 and LC2 are not subjected to voltage, and LC3 and LC4 are subjected to voltage, the beam scanning angle is 23° and the gain is 9.05dBi. (2) When voltage is applied to LC1 and LC2, and no voltage is applied to LC3 and LC4, the beam scanning angle is -23° and the gain is 9.17dBi. (3) Therefore, in this embodiment, the beam scanning angle can be performed within ±23°. (4) The difference between the side lobe and the main lobe, expressed as SLL, is -4 dB at 23° and -3.07 dB at -23°, while the side lobe is 5.05 dBi at 23° and 6.1 dBi at -23°.

[0082] The SLL mentioned above refers to information about the size of the side lobes in the antenna radiation pattern. They are usually compared with the difference between them and the maximum peak value of the main beam, and the difference is expressed in dB.

[0083] When the liquid crystal material is GT7-29001, as shown in Figure 4A, the following simulation data are available, explained below: (1) Before the bias voltage is applied, its center frequency is 14~15 GHz (14.2 GHz is optimal), and its bandwidth is 0.27 GHz with -10dB as the reference point. (2) When LC1 and LC2 are biased, and LC3 and LC4 are not biased, the center frequency is 14~15 GHz (optimal is 14.25 GHz) and the bandwidth is 0.2 GHz. (3) When LC3 and LC4 are biased, and LC1 and LC2 are not biased, the center frequency is 14~15 GHz (optimal is 14.23 GHz) and the bandwidth is 0.2 GHz. (4) When LC1, LC2, LC3 and LC4 are all biased, their center frequency is 13~14 GHz (13.95 GHz is optimal) and their bandwidth is 0.1 GHz.

[0084] As shown in Figure 4B, applying different bias voltages to the four liquid crystal cells can change the dielectric constant and dielectric loss of the liquid crystal molecules. Observing the maximum scannable angle in the gain graph, the beam scanning results are as follows: (1) When LC1 and LC2 are not subjected to voltage, and LC3 and LC4 are subjected to voltage, the beam scanning angle is 24° and the gain is 11.05dBi. (2) When voltage is applied to LC1 and LC2, and no voltage is applied to LC3 and LC4, the beam scanning angle is -24° and the gain is 10.14dBi. (3) Therefore, in this embodiment, the beam scanning angle can be performed within ±24°. (4) The difference between the side lobe and the main lobe, expressed as SLL, is -5.4 dB at 24° and -5.02 dB at -24°, while the side lobe is 5.65 dBi at 24° and 5.02 dBi at -24°.

[0085] When the liquid crystal material is ZOC-A018XX, as shown in Figure 5A, the following simulation data is available, explained below: (1) Before the bias voltage is applied, its center frequency is 14~15 GHz (14.12 GHz is optimal), its bandwidth is 0.32 GHz with -10dB as the reference point, and its frequency range is 14~14.32 GHz. (2) When LC1 and LC2 are biased, and LC3 and LC4 are not biased, the center frequency is 14~15 GHz (14.2 GHz is optimal), the bandwidth is 0.2 GHz, and the frequency range is 14.1~14.3 GHz. (3) When LC3 and LC4 are biased, and LC1 and LC2 are not biased, the center frequency is 14~15 GHz (14.2 GHz is optimal), the bandwidth is 0.2 GHz, and the frequency range is 14.1~14.3 GHz. (4) When LC1, LC2, LC3 and LC4 are all biased, their center frequency is 13~14 GHz (13.95 GHz is optimal), their bandwidth is 0.2 GHz, and their frequency range is 14.1~14.3 GHz.

[0086] As shown in Figure 5B, applying different bias voltages to the four liquid crystal cells can change the dielectric constant and dielectric loss of the liquid crystal molecules. Observing the maximum scannable angle in the gain graph, the beam scanning results are as follows: (1) When LC1 and LC2 are not subjected to voltage, and LC3 and LC4 are subjected to voltage, the beam scanning angle is 25° and the gain is 12.76dBi. (2) When voltage is applied to LC1 and LC2, and no voltage is applied to LC3 and LC4, the beam scanning angle is -25° and the gain is 12.15dBi. (3) Therefore, in this embodiment, the beam scanning angle can be performed within ±25°. (4) The difference between the side lobe and the main lobe, expressed as SLL, is -6.52 dB at 25° and -6.08 dB at -25°, while the side lobe is 6.34 dBi at 25° and 6.27 dBi at -25°.

[0087] Table 1 below shows the characteristics of antennas using different liquid crystal materials. The data is as follows: Table 1. Antenna Characteristics of Different Liquid Crystal Materials liquid crystal material Liquid crystal thickness (mm) Center frequency (GHz) Number of arrays Beam scanning scope Gain (dBi) SLL (dB) E7 0.1 14.1 6x6 -23°~23° -23°: 9.17dBi -23°: -3.07dB 23°: 9.05dBi 23°: -4dB GT7 0.1 14.2 6x6 -24°~24° -24°: 10.04dBi -24°: -5.02dB 24°: 11.05dBi 24°: -5.4dB ZOC-A018XX 0.1 14.12 6x6 -25°~25° -25°: 12.35dBi -25°: -6.08dB 25°: 12.86dBi 25°: -6.52dB

[0088] The liquid crystal array antenna structure provided by this invention has the following advantages compared with other conventional technologies: (1) The 6x6 liquid crystal array antenna structure proposed in this case uses 2x2 liquid crystal unit cells to apply different bias voltages to control the array antenna to achieve the purpose of beam scanning. It has better performance in both gain and beam scanning performance. Furthermore, this case uses the design of increasing the number of array patches to achieve the effect of suppressing side effects, which has better performance than known technologies. (2) Regardless of whether the liquid crystal material used in this case is a display type liquid crystal material such as MERCK E7 or a microwave application liquid crystal material such as MERCK GT7-29001 or ZOC-A018XX, a beam scanning range of approximately ±23~±25 degrees can be achieved, and it has good gain and directivity. In addition, the large number of arrays can also effectively suppress side lobes. (3) The liquid crystal array antenna structure design proposed in this case adopts a multi-layer structure design with three substrates, one liquid crystal layer, and one ground layer. The design of the first substrate mainly involves depositing four metal curves on its underside. The design of the second substrate mainly consists of metal patches deposited on the substrate and an H-shaped slit ground plane designed below. There is a liquid crystal layer between the first and second substrates. This liquid crystal layer is composed of four liquid crystal units. Each liquid crystal unit mainly uses a cavity to fill the liquid crystal, and a bias voltage is applied through the metal patches and the tortuous metal lines to deflect the orientation of the molecules in the middle liquid crystal layer. The third substrate mainly uses the design of two dual-feed (1:6) power dividers at the bottom to feed the signal.

[0089] The present invention has been disclosed above through the embodiments described above, but it is not intended to limit the present invention. Any person skilled in the art can make some modifications and refinements after understanding the foregoing technical features and embodiments of the present invention, without departing from the spirit and scope of the present invention. Therefore, the scope of patent protection of the present invention shall be determined by the claims attached to this specification.

[0090] 1: First substrate layer 11: First upper surface 12: First lower surface 2: Second substrate layer 21: Second upper surface 22: Second lower surface 3: Third substrate layer 31: Third upper surface 32: Third lower surface 4: First surface unit 41: Biased metal wire wound on the first surface 42: Biased metal wire wound on the first surface 43: Biased metal wire wound on the first surface 44: Biased metal wire wound on the first surface 5: Second surface unit 51: Second surface area patch group 511: Cross-shaped patch 512: Cross-shaped patch 513: Cross-shaped patch 52: Second surface area patch group 521: Cross-shaped patch 522: Cross-shaped patch 523: Cross-shaped patch 53: Second surface area patch group 531: Cross-shaped patch 532: Cross-shaped patch 533: Cross-shaped patch 54: Second surface area patch group 541: Cross-shaped patch 542: Cross-shaped patch 543: Cross-shaped patch 55: Metal wiring on the inner side of the second surface 56: Metal wiring on the inner side of the second surface 57: Metal wiring on the inner side of the second surface 6: Third surface unit 61: Third surface area patch group 611: Slit 612: Slit 613: Slit 62: Third surface area patch group 621: Slit 622: Slit 623: Slit 63: Third surface area patch group 631: Slit 632: Slit 633: Slit 64: Third surface area patch group 641: Slit 642: Slit 643: Slit 7: Fourth surface unit 71: Fourth surface distribution line 711: Fourth surface metal line 7111: First Metal Wire 71111: Second metal wire 71112: Third metal wire 71113: Fourth Metal Wire 71114: Fifth Metal Wire 7112: First Metal Wire 71121: Second metal wire 71122: Third metal wire 71123: Fourth Metal Wire 71124: Fifth Metal Wire 72: Fourth surface distribution line 721: Fourth surface metal line 7211: First Metal Wire 72111: Second metal wire 72112: Third metal wire 72113: Fourth Metal Wire 72114: Fifth Metal Wire 7212: First Metal Wire 72121: Second metal wire 72122: Third metal wire 72123: Fourth Metal Wire 72124: Fifth Metal Wire 81: Liquid Crystal Unit 82: Liquid Crystal Unit 83: Liquid Crystal Unit 84: Liquid Crystal Unit

Claims

1. A liquid crystal array antenna structure, comprising: A first substrate layer has a first upper surface and a first lower surface; A second substrate layer has a second upper surface and a second lower surface; a third substrate layer has a third upper surface and a third lower surface; a first liquid crystal cell is located between the second substrate layer and the third substrate layer, and the first liquid crystal cell is positioned at a first position; a second liquid crystal cell is located between the second substrate layer and the third substrate layer, and the second liquid crystal cell is arranged parallel to the first liquid crystal cell, and the second liquid crystal cell is positioned at a second position; a third liquid crystal cell is located between the second substrate layer and the third substrate layer, and the third liquid crystal cell is arranged side by side with the first liquid crystal cell, and the third liquid crystal cell is positioned at a third position; a fourth liquid crystal cell is located between the second substrate layer and the third substrate layer, and the fourth liquid crystal cell is arranged side by side with the second liquid crystal cell and parallel to the third liquid crystal cell, and the fourth liquid crystal cell is positioned at a fourth position. A first surface unit is formed on the first lower surface, and the first surface unit has four bias metal wires wound around the first surface, wherein the positions of the four bias metal wires wound around the first surface correspond to the first position, the second position, the third position and the fourth position respectively; A second surface unit is formed on the second upper surface, and the second surface unit has four second surface area patch groups, wherein each second surface area patch group includes three cross-shaped patches, wherein the three cross-shaped patches are connected through a second surface inner metal wire, and the positions of the three cross-shaped patches of the four second surface area patch groups correspond to the first position, the second position, the third position and the fourth position respectively; A third surface unit is formed on the third upper surface. The third surface unit has four third surface region patch groups, each of which corresponds to one of the second surface region patch groups. Each third surface region patch group includes three slits, and the slit positions of different third surface region patch groups correspond to the cross-shaped patch positions of different second surface region patch groups. A fourth surface unit is formed on the third lower surface. The fourth surface unit has two sets of fourth surface distribution lines. Each fourth surface distribution line is formed by two first metal lines extending from the edge of the third lower surface to the center of the third lower surface from a fourth surface metal line. Each first metal line further extends a second metal line and a third metal line towards the center of the third lower surface. The third metal line further extends a fourth metal line and a fifth metal line. The endpoints of the second, fourth, and fifth metal lines correspond to the positions of the three slits of the third surface region patch group. The two sets of fourth surface distribution lines are located on different sides of the third lower surface.The first two metal lines on the same side are parallel to each other, the second and third metal lines on the same side are parallel to each other, and the fourth and fifth metal lines on the same side are parallel to each other. The beam scanning angle of the liquid crystal array antenna structure is controlled by applying a liquid crystal bias voltage to the liquid crystal unit, with a frequency range of 14~15 GHz and a beam scanning range of ±23~±25 degrees.

2. The liquid crystal array antenna structure as described in claim 1, wherein the liquid crystal cell changes its dielectric properties due to a change in the electric field, thereby achieving a change in the characteristics of the antenna beam.

3. The liquid crystal array antenna structure as described in claim 1, wherein a bias metal wire system is wound around each of the first surfaces and connected to the edge of the first lower surface.

4. The liquid crystal array antenna structure as described in claim 1, wherein one of the cross-shaped patches of the second surface region patch group is connected to the edge of the second upper surface through a metal wiring on the outer side of the second surface.

5. The liquid crystal array antenna structure as described in claim 1, wherein the cross-shaped patch system of the four second surface region patch groups can be arranged into a binomial array, which is an antenna array design based on a binomial coefficient distribution.

6. The liquid crystal array antenna structure as described in claim 1, wherein the third surface unit is a metal ground plane, the metal ground plane is coupled in through the slit and then fed in through the fourth surface unit on both sides.

7. The liquid crystal array antenna structure as described in claim 1, wherein the slit is H-shaped.

8. The liquid crystal array antenna structure as described in claim 1, wherein a T-connector is used at the bifurcation of the two first metal lines, the bifurcation of the second metal line and the third metal line, and the bifurcation of the fourth metal line and the fifth metal line.

9. The liquid crystal array antenna structure as described in claim 1, wherein the corners of the first metal line, the second metal line, the third metal line, the fourth metal line and the fifth metal line are tangential structures, which are used to improve the capacitance effect.

10. The liquid crystal array antenna structure as described in claim 1, wherein the first surface unit, the second surface unit, the third surface unit and the fourth surface unit are formed of metal.

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