Liquid crystal antenna and communication device

Abstract

This invention discloses a liquid crystal antenna and a communication device. The first dipole radiating electrode directly couples the received microwave signal to the first and second electrodes vertically below. Since the first and second electrodes form a differential line pair structure, the signals transmitted on the first and second electrodes above and below the liquid crystal layer have the same amplitude and a phase difference of 180°, realizing the feeding of differential-mode signals of equal amplitude on the first and second electrodes. That is, the liquid crystal antenna of this invention can directly receive microwave signals from the first dipole radiating electrode to form differential-mode signals for feeding, without the need for the balun structure used in the prior art to generate differential-mode signals, thus avoiding the loss and bandwidth loss caused by the balun structure and reducing the energy loss of the entire structure.

Description

Technical Field

[0001] This invention relates to the field of microwave communication technology, and more particularly to liquid crystal antennas and communication equipment. Background Technology

[0002] Liquid crystal antennas are a new type of arrayed antenna based on liquid crystal phase shifters, and are widely used in satellite receiving antennas, vehicle radar, base station antennas, and other fields. The liquid crystal phase shifter is the core component of the liquid crystal antenna; it controls the deflection of liquid crystal molecules to adjust the phase of electromagnetic waves. Summary of the Invention

[0003] The present invention provides a liquid crystal antenna and a communication device. The liquid crystal antenna can directly receive microwave signals from the first dipole radiating electrode to form a differential mode signal feed-in, without the need for a balun to generate a differential mode structure, thus avoiding the loss and bandwidth loss caused by the balun structure and reducing the energy loss of the entire structure.

[0004] This invention provides a liquid crystal antenna, including multiple liquid crystal antenna units. Each liquid crystal antenna unit includes a liquid crystal phase shifter and a first radiating structure. The first radiating structure includes a first dipole radiating electrode and a first ground electrode, which are located on opposite sides of the liquid crystal phase shifter.

[0005] The liquid crystal phase shifter includes a first substrate and a second substrate disposed opposite to each other, and a liquid crystal layer located between the first substrate and the second substrate. The first substrate includes a first base and a first electrode located on the side of the first base near the liquid crystal layer. The second substrate includes a second base and a second electrode located on the side of the second base near the liquid crystal layer.

[0006] The first electrode and the second electrode form a differential line pair structure, and the first dipole radiating electrode and the first electrode have an overlapping region, and the first dipole radiating electrode and the second electrode have an overlapping region.

[0007] Optionally, in the liquid crystal antenna provided in the embodiments of the present invention, the first electrode includes a first transmission section and a first branch structure electrically connected to one end of the first transmission section, the second electrode includes a second transmission section and a second branch structure electrically connected to one end of the second transmission section, the first transmission section and the second transmission section overlap each other, the first branch structure and the second branch structure are located at the same end of the overlapping region, and the first branch structure and the second branch structure are located on both sides of the overlapping region.

[0008] Optionally, in the liquid crystal antenna provided in the embodiments of the present invention, the first dipole radiating electrode overlaps with the first branch structure, the first dipole radiating electrode overlaps with the second branch structure, and the first ground electrode covers the second substrate.

[0009] Optionally, in the liquid crystal antenna provided in the embodiments of the present invention, the first transmission section and the second transmission section completely overlap, and the first branch structure and the second branch structure have the same shape and size.

[0010] Optionally, the liquid crystal antenna provided in the embodiments of the present invention further includes a second ground electrode located on the side of the first substrate away from the liquid crystal layer, and the second ground electrode has an overlapping area with the liquid crystal phase shifter.

[0011] Optionally, in the liquid crystal antenna provided in the embodiments of the present invention, the second ground electrode and the first dipole radiating electrode are on the same layer and are independently disposed from each other.

[0012] Optionally, in the liquid crystal antenna provided in the embodiments of the present invention, the first electrode further includes a third branch structure electrically connected to the other end of the first transmission section, wherein the first branch structure and the third branch structure are respectively located on both sides of the first transmission section;

[0013] The second electrode also includes a fourth branch structure electrically connected to the other end of the second transmission section, and the second branch structure and the fourth branch structure are located on both sides of the second transmission section, respectively.

[0014] Optionally, in the liquid crystal antenna provided in the embodiments of the present invention, the liquid crystal antenna further includes a second radiating structure, the second radiating structure including a second dipole radiating electrode and a third ground electrode, the first dipole radiating electrode and the third ground electrode being disposed in the same layer, and the second dipole radiating electrode and the first ground electrode being disposed in the same layer.

[0015] The second dipole radiating electrode overlaps with the third branch structure, the second dipole radiating electrode overlaps with the fourth branch structure, and the third ground electrode covers the first substrate.

[0016] Optionally, in the liquid crystal antenna provided in the embodiments of the present invention, the first transmission section and the second transmission section completely overlap, the first branch structure and the second branch structure have the same shape and size, and the third branch structure and the fourth branch structure have the same shape and size.

[0017] Accordingly, embodiments of the present invention also provide a communication device, including the liquid crystal antenna provided in the embodiments of the present invention.

[0018] The liquid crystal antenna and communication device provided in this embodiment of the invention, wherein the first dipole radiating electrode adopts a dipole structure, and the first dipole radiating electrode directly couples the received microwave signal to the first electrode and the second electrode vertically below. Since the first electrode and the second electrode form a differential line pair structure, that is, the signal transmitted on the first electrode and the second electrode above and below the liquid crystal layer has the same amplitude and a phase difference of 180°, the differential mode signal of equal amplitude is fed into the first electrode and the second electrode. That is, the liquid crystal antenna of this embodiment of the invention can directly receive microwave signals from the first dipole radiating electrode to form a differential mode signal feed-in, without the need for the balun generating differential mode structure in the prior art, avoiding the loss and bandwidth loss caused by the balun structure, and reducing the energy loss of the entire structure. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 A cross-sectional schematic diagram of a liquid crystal antenna provided in an embodiment of the present invention;

[0021] Figure 2 A cross-sectional schematic diagram of another liquid crystal antenna provided in an embodiment of the present invention;

[0022] Figure 3 This is a top view of a liquid crystal antenna;

[0023] Figure 4 for Figure 3 A schematic diagram of the cross-section along the CC' direction;

[0024] Figure 5 A top view schematic diagram of the first electrode;

[0025] Figure 6 A top view schematic diagram of the second electrode;

[0026] Figure 7 A top view schematic diagram of the first dipole radiating electrode;

[0027] Figure 8 This is a top view of the first ground electrode;

[0028] Figure 9 This is another schematic cross-sectional view of a liquid crystal antenna;

[0029] Figure 10 This is another top view schematic diagram of the first electrode;

[0030] Figure 11 This is another top view schematic diagram of the second electrode;

[0031] Figure 12 This is a top view of the first dipole radiating electrode and the third ground electrode;

[0032] Figure 13 This is a top view of the second dipole radiating electrode and the first ground electrode. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Furthermore, the embodiments and features in the embodiments of the present invention can be combined with each other without conflict. Based on the described embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect.

[0035] It should be noted that the dimensions and shapes of the figures in the accompanying drawings do not reflect actual proportions and are intended only to illustrate the content of the invention. Furthermore, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout.

[0036] This invention provides a liquid crystal antenna, including multiple liquid crystal antenna elements, such as... Figure 1 and Figure 2 As shown, Figure 1 and Figure 2 This diagram illustrates only a cross-sectional view of a single liquid crystal antenna unit 100, in which... Figure 1 Main view, Figure 2As shown in the side view, each liquid crystal antenna unit 100 includes a liquid crystal phase shifter 1 and a first radiating structure 2. The first radiating structure 2 includes a first dipole radiating electrode 21 and a first ground electrode 22, which are located on opposite sides of the liquid crystal phase shifter 1.

[0037] The liquid crystal phase shifter 1 includes a first substrate 11 and a second substrate 12 disposed opposite to each other, and a liquid crystal layer 13 located between the first substrate 11 and the second substrate 12. The first substrate 11 includes a first base 111 and a first electrode 112 located on the side of the first base 111 near the liquid crystal layer 13. The second substrate 12 includes a second base 121 and a second electrode 122 located on the side of the second base 121 near the liquid crystal layer 13.

[0038] The first electrode 112 and the second electrode 122 form a differential line pair structure. The first dipole radiating electrode 21 and the first electrode 112 have overlapping regions, and the first dipole radiating electrode 21 and the second electrode 122 have overlapping regions.

[0039] The liquid crystal antenna provided in this embodiment of the invention uses a dipole structure for the first dipole radiating electrode. The first dipole radiating electrode directly couples the received microwave signal to the first electrode and the second electrode vertically below. Since the first electrode and the second electrode form a differential line pair structure, the signals transmitted on the first electrode and the second electrode above and below the liquid crystal layer have the same amplitude and a phase difference of 180°, realizing the feeding of differential mode signals of equal amplitude on the first electrode and the second electrode. That is, the liquid crystal antenna structure of this embodiment of the invention can directly receive microwave signals from the first dipole radiating electrode to form differential mode signals for feeding, without the need for the balun structure used in the prior art to generate differential mode, avoiding the loss and bandwidth loss caused by the balun structure, and reducing the energy loss of the entire structure.

[0040] Furthermore, since the signals transmitted on the first and second electrodes have the same amplitude but a 180° phase difference, this effectively forms an equivalent virtual ground plane at the center of the liquid crystal layer. By applying different voltages to the liquid crystal layer, the deflection state of the liquid crystal molecules is changed, thereby altering the dielectric constant of the liquid crystal layer and thus changing the phase of the microwave signal transmitted to it. Since the adjustable capacitance of the liquid crystal layer is inversely proportional to the distance between the first electrode and ground, and inversely proportional to the distance between the second electrode and ground, the structure of the liquid crystal phase shifter of this invention increases the proportion of adjustable capacitance in the liquid crystal layer, thus increasing the maximum phase shift amount for the same size and improving the phase shift efficiency. If the phase shift amount is the same, the transmission loss of the liquid crystal antenna provided in this embodiment of the invention is relatively small.

[0041] like Figure 3 As shown, Figure 3 This is a top view schematic diagram of a liquid crystal antenna, which includes multiple liquid crystal antenna elements 100 arranged in an array. Figure 1and Figure 2 for Figure 3 A cross-sectional schematic diagram of a liquid crystal antenna unit 100, as shown below. Figure 4 As shown, Figure 4 for Figure 3 A schematic diagram of the cross-section along the CC' direction, and Figure 4 The liquid crystal phase shifter 1 shown in the diagram represents the equivalent circuit structure. Figure 3 and Figure 4 The feed source 200 is used to feed microwave signals to the first dipole radiating electrode 21. The first dipole radiating electrode 21 directly couples the received microwave signals to the first electrode 112 and the second electrode 122 vertically below, achieving equal-amplitude differential-mode signal feeding on the first and second electrodes. Utilizing the deflection characteristics of the liquid crystal molecules in the liquid crystal layer 13, a planar reconfigurable liquid crystal antenna with adjustable dielectric constant is realized. A liquid crystal phase shifter 1 is added after each first dipole radiating electrode 21 to independently control the output phase assignment of each liquid crystal antenna element 100, superimposing interference in space to ultimately achieve beam-enhanced signal reception in a specified direction.

[0042] In specific implementation, in the liquid crystal antenna provided in the embodiments of the present invention, such as Figure 5 and Figure 6 As shown, Figure 5 This is a top view of the first electrode 112. Figure 6 This is a top view of the second electrode 122. The first electrode 112 includes a first transmission section 10 and a first branch structure 20 electrically connected to one end of the first transmission section 10. The second electrode 122 includes a second transmission section 30 and a second branch structure 40 electrically connected to one end of the second transmission section 30. The first transmission section 10 and the second transmission section 30 overlap each other. The first branch structure 20 and the second branch structure 40 are located at the same end of the overlapping area, and the first branch structure 20 and the second branch structure 40 are located on opposite sides of the overlapping area. The first dipole radiating electrode 21 couples the received microwave signal to the vertically downward first branch structure 20 and the second branch structure 40. The signal amplitudes on the first branch structure 20 and the second branch structure 40 are the same, and the phase difference is 180°. Then, the signals are transmitted through the corresponding first transmission section 10 and the second transmission section 30, respectively. In a specific implementation, in the liquid crystal antenna provided in the embodiment of the present invention, as shown... Figure 7 and Figure 8 As shown, Figure 7 This is a top view schematic diagram of the first dipole radiating electrode 21. Figure 8 This is a top view of the first ground electrode 22. The first dipole radiating electrode 21 overlaps with the first branch structure 20, and the first dipole radiating electrode 21 overlaps with the second branch structure 40. The first ground electrode 22 covers the second substrate 12. Specifically, firstly... Figure 7The right-side first dipole radiating electrode 21 receives microwave signals in space, and the received microwave signals are used as high-frequency currents in... Figure 5 and Figure 6 Transport on the middle electrode, Figure 5 and Figure 6 The electrode structure in it is a differential line pair structure. Figure 5 and Figure 6 The electrodes are structurally located on the upper and lower sides of the liquid crystal layer. Figure 5 and Figure 6 The area within the orthogonal region of the electrodes is the effective adjustable liquid crystal region. During microwave signal transmission, a virtual ground plane is formed within the liquid crystal layer. The microwave signal is transmitted first along the direction of arrow A1 and then along the direction of arrow A2. The end of the differential line pair structure (on the side of the first dipole radiating electrode 21) is set as an open circuit. The microwave signal is totally reflected at the end, and the signal is radiated again from the first dipole radiating electrode 21, thus realizing the reflective liquid crystal antenna design. The reflective liquid crystal antenna provided in this embodiment can achieve a transmission line of the same physical length (e.g., the length of the first transmission section 10), and the microwave signal can achieve twice the phase shift effect, making it easier to meet the requirements of miniaturized antennas. In addition, the first ground electrode 22 is set across the entire surface, effectively reducing the microwave signal energy radiation on the opposite side. By controlling... Figure 5 and Figure 6 The voltage difference between the two electrodes causes a change in the phase of the transmitted signal, and the information carried by the radiated microwave signal changes accordingly.

[0043] In specific implementation, in the liquid crystal antenna provided in the embodiments of the present invention, such as Figure 5 and Figure 6 As shown, the first transmission section 10 and the second transmission section 30 completely overlap, and the first branch structure 20 and the second branch structure 40 have the same shape and size. This ensures that the signal amplitude transmitted on the first electrode 112 and the second electrode 122 is the same and the phase difference is 180°.

[0044] In specific implementation, in the liquid crystal antenna provided in the embodiments of the present invention, such as Figure 1 and Figure 7 As shown, it also includes a second ground electrode 3 located on the side of the first substrate 11 opposite to the liquid crystal layer, and the second ground electrode 3 has an overlapping area with the liquid crystal phase shifter 1. The second ground electrode 3 can shield the signals radiated outward from the first electrode 112 and the second electrode 122, reducing signal loss.

[0045] In specific implementation, in the liquid crystal antenna provided in the embodiments of the present invention, such as Figure 1 and Figure 7As shown, the second ground electrode 3 and the first dipole radiating electrode 21 are on the same layer and independently arranged. In this way, only the original pattern needs to be changed when forming the first dipole radiating electrode 21, and the patterns of the second ground electrode 3 and the first dipole radiating electrode 21 can be formed in one patterning process. There is no need to add a separate process for preparing the second ground electrode 3, which can simplify the preparation process, save production costs, and improve production efficiency.

[0046] In specific implementation, in the liquid crystal antenna provided in the embodiments of the present invention, such as Figures 9-11 As shown, Figure 9 This is another cross-sectional schematic diagram of a liquid crystal antenna. Figure 10 This is another top view schematic diagram of the first electrode 112. Figure 11 This is another top view of the second electrode 122. The first electrode 112 also includes a third branch structure 50 electrically connected to the other end of the first transmission section 10. The first branch structure 20 and the third branch structure 50 are located on both sides of the first transmission section 10, respectively.

[0047] The second electrode 122 also includes a fourth branch structure 60 electrically connected to the other end of the second transmission section 30, and the second branch structure 40 and the fourth branch structure 60 are located on both sides of the second transmission section 30, respectively.

[0048] The liquid crystal antenna also includes a second radiating structure 4, which includes a second dipole radiating electrode 41 and a third ground electrode 42. The first dipole radiating electrode 21 and the third ground electrode 42 are arranged in the same layer, and the second dipole radiating electrode 41 and the first ground electrode 22 are arranged in the same layer.

[0049] like Figure 12 and Figure 13 As shown, Figure 12 This is a top view schematic diagram of the first dipole radiating electrode 21 and the third ground electrode 42. Figure 13 This is a top view of the second dipole radiating electrode 41 and the first ground electrode 22. The second dipole radiating electrode 41 overlaps with the third branch structure 50 and the second dipole radiating electrode 41 overlaps with the fourth branch structure 60. The third ground electrode 42 covers the first substrate 11.

[0050] Specifically, firstly Figure 12 The right-side first dipole radiating electrode 21 receives microwave signals in space, and the received microwave signals are used as high-frequency currents in... Figure 10 and Figure 11 Transport on the middle electrode, Figure 10 and Figure 11 The electrode structure in it is a differential line pair structure. Figure 10 and Figure 11 The electrodes are structurally located on the upper and lower sides of the liquid crystal layer. Figure 10 and Figure 11 The area within the orthogonal region of the electrodes constitutes the effective adjustable liquid crystal region. During microwave signal transmission, a virtual ground plane is formed within the liquid crystal layer. The microwave signal propagates along the direction of arrow A1, approximately in an asymmetric stripline structure, and is then radiated from the second dipole radiating electrode 41, thus realizing the design of a transmissive liquid crystal antenna. By controlling the voltage difference between the first electrode 112 and the second electrode 122, the phase of the transmitted signal is changed, and the information carried by the radiated signal changes accordingly. Based on the design principle of this transmissive liquid crystal antenna unit, the differential mode trace length can be adjusted according to the required maximum phase shift to realize the design of the array structure and complete the transmissive reconfigurable antenna.

[0051] In specific implementation, in the liquid crystal antenna provided in the embodiments of the present invention, such as Figure 10 and Figure 11 As shown, the first transmission section 10 and the second transmission section 30 completely overlap, the first branch structure 20 and the second branch structure 40 have the same shape and size, and the third branch structure 50 and the fourth branch structure 60 have the same shape and size. This ensures that the signal amplitude transmitted on the first electrode 112 and the second electrode 122 is the same and the phase difference is 180°.

[0052] In practical implementation, the lengths of the first branch structure 20, the second branch structure 40, the third branch structure 50, and the fourth branch structure 60 are 1 / 4 of the microwave wavelength (i.e., 4 / λ), respectively, to achieve impedance matching.

[0053] It should be noted that, in the embodiments of the present invention, both the first substrate and the second substrate can be transparent substrates, specifically substrates made of light-guiding and non-metallic materials with a certain degree of rigidity, such as glass, quartz, and transparent resin.

[0054] Furthermore, the liquid crystal antenna provided in this embodiment of the invention can reduce the transmission loss of the entire system and enhance the signal coverage. Because an equivalent ground plane is formed within the cathode layer, one metal structure layer can be reduced, increasing design flexibility. In LCD-based designs, this can be achieved through a double-sided glass-metal structure, avoiding the use of PCBs (flexible printed circuit boards) and realizing lightweight and low-cost structures.

[0055] In summary, the liquid crystal antenna provided in the embodiments of the present invention has the following advantages:

[0056] (1) Using dipole radiation electrodes to receive microwave signals, the received microwave signals directly form differential mode signals, eliminating the need for a balun to generate a differential mode structure, thus avoiding the loss and bandwidth loss caused by the balun structure and reducing the energy loss of the entire structure.

[0057] (2) The differential mode signals received by the first electrode and the second electrode form an equivalent ground plane at the middle position of the liquid crystal layer. Based on the same structure, the denominator d of the adjustable capacitance C of the liquid crystal layer becomes d / 2. Under the same size, the adjustable range of the dielectric constant of the liquid crystal layer of the liquid crystal phase shifter becomes larger, and the phase shifting efficiency is improved.

[0058] (3) The liquid crystal layer has no whole-plane ground plane structure on the top and bottom sides, has a low metal ratio, and has high design flexibility. Especially in large-scale array design, more space is reserved for the routing area of ​​control lines, which is beneficial to large-scale array design.

[0059] (4) The reflective liquid crystal antenna unit structure allows the microwave signal to be totally reflected after reaching the open port. After twice the trace length, the size of the liquid crystal phase shifter can be reduced by half, which is beneficial for miniaturization design.

[0060] (5) The first and second bases are made of glass substrates. Based on the design of all-glass materials, they have high light transmittance and can be used as aesthetic antennas.

[0061] Based on the same inventive concept, embodiments of the present invention also provide a communication device, including the liquid crystal antenna provided in the embodiments of the present invention.

[0062] The communication device provided in this embodiment of the invention can be, for example, any product or component with communication functions, such as a mobile phone. Other essential components of this communication device are understood by those skilled in the art and will not be described in detail here, nor should they be construed as limiting the invention. Implementation of this communication device can refer to the above-described embodiment of the liquid crystal antenna; repeated details will not be elaborated upon.

[0063] The liquid crystal antenna and communication device provided in this embodiment of the invention, wherein the first dipole radiating electrode adopts a dipole structure, and the first dipole radiating electrode directly couples the received microwave signal to the first electrode and the second electrode vertically below. Since the first electrode and the second electrode form a differential line pair structure, that is, the signal transmitted on the first electrode and the second electrode above and below the liquid crystal layer has the same amplitude and a phase difference of 180°, the differential mode signal of equal amplitude is fed into the first electrode and the second electrode. That is, the liquid crystal antenna of this embodiment of the invention can directly receive microwave signals from the first dipole radiating electrode to form a differential mode signal feed-in, without the need for the balun generating differential mode structure in the prior art, avoiding the loss and bandwidth loss caused by the balun structure, and reducing the energy loss of the entire structure.

[0064] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A liquid crystal antenna, characterized in that, It includes multiple liquid crystal antenna units, each of which includes a liquid crystal phase shifter and a first radiating structure. The first radiating structure includes a first dipole radiating electrode and a first ground electrode, which are located on opposite sides of the liquid crystal phase shifter. The liquid crystal phase shifter includes a first substrate and a second substrate disposed opposite to each other, and a liquid crystal layer located between the first substrate and the second substrate. The first substrate includes a first base and a first electrode located on the side of the first base near the liquid crystal layer. The second substrate includes a second base and a second electrode located on the side of the second base near the liquid crystal layer. The first electrode and the second electrode form a differential line pair structure, configured to transmit differential-mode signals with the same amplitude and a phase difference of 180°, so as to form an equivalent virtual ground plane in the liquid crystal layer; the first dipole radiating electrode has an overlapping region with the first electrode, and the first dipole radiating electrode has an overlapping region with the second electrode, for coupling the received microwave signal to the first electrode and the second electrode to form the differential-mode signal.

2. The liquid crystal antenna according to claim 1, characterized in that, The first electrode includes a first transmission section and a first branch structure electrically connected to one end of the first transmission section. The second electrode includes a second transmission section and a second branch structure electrically connected to one end of the second transmission section. The first transmission section and the second transmission section overlap each other. The first branch structure and the second branch structure are located at the same end of the overlapping area, and the first branch structure and the second branch structure are located on both sides of the overlapping area.

3. The liquid crystal antenna according to claim 2, characterized in that, The first dipole radiating electrode overlaps with the first branch structure, the first dipole radiating electrode overlaps with the second branch structure, and the first ground electrode covers the second substrate.

4. The liquid crystal antenna according to claim 3, characterized in that, The first transmission unit and the second transmission unit completely overlap, and the first branch structure and the second branch structure have the same shape and size.

5. The liquid crystal antenna according to claim 4, characterized in that, It also includes a second ground electrode located on the side of the first substrate away from the liquid crystal layer, the second ground electrode having an overlapping area with the liquid crystal phase shifter.

6. The liquid crystal antenna according to claim 5, characterized in that, The second ground electrode and the first dipole radiation electrode are on the same layer and are set independently of each other.

7. The liquid crystal antenna according to claim 3, characterized in that, The first electrode further includes a third branch structure electrically connected to the other end of the first transmission section, wherein the first branch structure and the third branch structure are located on both sides of the first transmission section; The second electrode also includes a fourth branch structure electrically connected to the other end of the second transmission section, and the second branch structure and the fourth branch structure are located on both sides of the second transmission section, respectively.

8. The liquid crystal antenna according to claim 7, characterized in that, The liquid crystal antenna further includes a second radiating structure, which includes a second dipole radiating electrode and a third ground electrode. The first dipole radiating electrode and the third ground electrode are disposed in the same layer, and the second dipole radiating electrode and the first ground electrode are disposed in the same layer. The second dipole radiating electrode overlaps with the third branch structure, the second dipole radiating electrode overlaps with the fourth branch structure, and the third ground electrode covers the first substrate.

9. The liquid crystal antenna according to claim 8, characterized in that, The first transmission unit and the second transmission unit completely overlap, the first branch structure and the second branch structure have the same shape and size, and the third branch structure and the fourth branch structure have the same shape and size.

10. A communication device, characterized in that, Includes the liquid crystal antenna according to any one of claims 1 to 9.

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