Phased array antenna with two stages of cascaded liquid crystal phase shifters

Abstract

The invention relates to a two-stage liquid crystal phase shifter cascaded phased array antenna which sequentially comprises a radiation layer, a first dielectric layer, a second-stage phase shifter layer, a second dielectric layer and a first-stage phase shifter layer from top to bottom, and liquid crystals and bias electrodes are arranged on the first-stage phase shifter layer and the second-stage phase shifter layer. The radiation layer and the second-stage phase shifter layer are connected through a copper column, and the second-stage phase shifter layer and the first-stage phase shifter layer are connected through a copper column. The first-stage phase shifter layer is responsible for achieving wave beam scanning in the y direction, signals are fed into the second-stage phase shifter layer through the copper columns after being subjected to phase shifting, the second-stage phase shifter layer is responsible for achieving wave beam scanning in the x direction, and the signals are fed into the radiation layer through the copper columns after being subjected to phase shifting for signal emission. According to the invention, the complexity of a control circuit is reduced, the influence of electromagnetic coupling on the performance of the array antenna is reduced, the weight of the antenna is further reduced, the cost is reduced, and the mass production and commercialization of the liquid crystal phased array antenna can be promoted.

Description

Technical Field

[0001] The invention relates to the field of communications, and in particular to a phased array antenna with two-stage liquid crystal phase shifters cascaded. Background Art

[0002] With the continuous development of communication and radar technology, antennas, as the bridge for wireless propagation of electromagnetic waves, have received widespread attention from academia and industry. In the field of antennas, phased array antennas have become a hot topic in antenna research in recent years. Phased array antennas can change the shape of the radiation pattern by controlling the feeding phase of the radiating unit in the array antenna, and can flexibly control the beam direction. Compared with parabolic antennas that rely on mechanical devices to achieve beam scanning, phased array antennas improve response speed, overcome mechanical wear, and reduce costs.

[0003] Currently, most mature phased array antennas use diodes, varactor diodes, MEMS, ferrites and other materials to make phase shifters. Liquid crystal, as an electrically tunable anisotropic material, has great potential in the preparation of phased array phase shifters. Phase shifters made of this material have the advantages of low cost, light weight, continuous phase adjustment, and easy commonality. However, this type of phase shifter still has shortcomings such as immature design technology and processing technology, and its practical application has been challenged from various aspects.

[0004] The principle of the passive liquid crystal phased array antenna based on the delay line structure is to change the dielectric constant of the liquid crystal medium on the delay line by applying a bias voltage to the liquid crystal medium, thereby changing the electrical length of the liquid crystal phase shifter to change the phase shift amount of each liquid crystal phase shifter, so as to achieve the purpose of phased array antenna beam deflection. However, in the existing phased array antennas of this type, each phase shifter unit corresponds to a set of bias control circuits. As the number of array units increases, the required bias circuit will become more and more complex, and even electromagnetic coupling will occur, affecting the performance of the entire phased array antenna, and the weight and cost of the phased array antenna will also increase exponentially. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a phased array antenna with two-stage liquid crystal phase shifters cascaded, thereby solving the shortcomings of the prior art.

[0006] The object of the present invention is achieved by the following technical scheme: a phased array antenna with two-stage liquid crystal phase shifters cascaded, which comprises, from top to bottom, a radiation layer, a first dielectric layer, a second-stage phase shifter layer, a second dielectric layer and a first-stage phase shifter layer, the first-stage phase shifter layer and the second-stage phase shifter layer are both provided with liquid crystals and bias electrodes, the radiation layer and the second-stage phase shifter layer and the second-stage phase shifter layer and the first-stage phase shifter layer are connected by copper columns; The first-stage phase shifter layer is responsible for realizing beam scanning in the y direction. After phase shifting, the signal is fed into the second-stage phase shifter layer through the copper column. The second-stage phase shifter layer is responsible for realizing beam scanning in the x direction. After phase shifting, the signal is fed into the radiation layer through the copper column for signal transmission. By applying a bias voltage to the liquid crystal to change the dielectric constant of the transmission line, thereby changing the electrical length of the transmission line, a variable phase difference is generated between the antenna units to realize beam scanning.

[0007] The first-stage phase shifter layer includes a feeding port, one end of which is connected to a signal input, and the other end is connected to a first one-to-four power divider, each port of the first one-to-four power divider is connected to a first-stage phase shifter, each first-stage phase shifter is arranged above the liquid crystal, a first bias electrode is arranged below the liquid crystal, and a first GND insulated from the first bias electrode is arranged on the same plane as the first bias electrode. The four first-stage phase shifters are given a bias voltage by the four first bias electrodes to control the phase shift, thereby realizing beam scanning in the y direction, and the signal is fed to the second-stage phase shifter layer through the copper column after phase shifting.

[0008] The second-stage phase shifter layer includes four second one-to-four power dividers, and the output end of each second one-to-four power divider is connected to a second-stage phase shifter, each second-stage phase shifter is arranged above the liquid crystal, and a second bias electrode is arranged below the liquid crystal. A second GND insulated from the second bias electrode is arranged on the same plane as the second bias electrode. A bias voltage is given to each of the four second-stage phase shifters by a second bias electrode to control the phase shift, thereby realizing beam scanning in the x direction. After the signal is phase shifted, it is fed into the radiation layer through the copper column to transmit the signal.

[0009] A plurality of radiation patches are arranged in an array on the upper surface of the radiation layer, and a third GND is disposed on the lower surface of the radiation layer.

[0010] The first-stage phase shifter is composed of a serpentine delay line, one end of which is connected to the output end of the first one-to-four power divider, and the other end is connected to the copper column.

[0011] The second-stage phase shifter is composed of a spiral delay line, one end of which is connected to the output end of the second one-to-four power divider, and the other end of which is connected to the copper column.

[0012] The present invention has the following advantages: a phased array antenna with two-stage cascaded liquid crystal phase shifters reduces the complexity of the control circuit, reduces the influence of electromagnetic coupling on the performance of the array antenna, and further reduces the weight of the antenna, reduces the cost, and can promote the mass production and commercialization of liquid crystal phased array antennas. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the explosion structure of the present invention; Figure 2 is a schematic diagram of the structure of the upper surface of the first-stage phase shifter layer; Figure 3 is a schematic structural diagram of the lower surface of the first-stage phase shifter layer; Figure 4 is a schematic structural diagram of the upper surface of the second-stage phase shifter layer; Figure 5 is a schematic structural diagram of the lower surface of the second-stage phase shifter layer; Figure 6 is a schematic diagram of the structure of the upper surface of the radiation layer; Figure 7 It is a schematic diagram of the structure of the lower surface of the radiation layer; In the figure: 1-radiation layer, 2-first dielectric layer, 3-second dielectric layer, 4-first-stage phase shifter layer, 5-second-stage phase shifter layer, 6-feeding port, 7-first one-to-four power divider, 8-first-stage phase shifter, 9-first bias electrode, 10-liquid crystal, 11-first GND, 12-second one-to-four power divider, 13-second-stage phase shifter, 14-second bias electrode, 15-second GND, 16-radiation plate, 17-third GND, 18-copper column. DETAILED DESCRIPTION

[0014] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the detailed description of the embodiments of the present application provided below in conjunction with the drawings is not intended to limit the scope of protection of the application claimed for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application. The present invention is further described below in conjunction with the drawings.

[0015] The present invention specifically relates to a phased array antenna with two-stage liquid crystal phase shifters cascaded, which adopts a two-stage phase shifter cascade structure, and the two-stage phase shifters respectively control the beam deflection in two orthogonal directions. Since the magnitude of the bias voltage is approximately linearly related to the dielectric constant of the liquid crystal 10, the magnitude of a group of bias voltages on the same stage of phase shifters can control the beam deflection in an orthogonal direction, and then the two-stage phase shifters are cascaded to achieve two-dimensional beam deflection.

[0016] like Figure 1As shown, the present invention comprises, from top to bottom, a radiation layer 1, a first dielectric layer 2, a second-stage phase shifter layer 5, a second dielectric layer 3 and a first-stage phase shifter layer 4, liquid crystals 10 and bias electrodes are disposed on the first-stage phase shifter layer 4 and the second-stage phase shifter layer 5, and the radiation layer 1 and the second-stage phase shifter layer 5 and the first-stage phase shifter layer 4 are connected via copper pillars 18; Among them, the first-stage phase shifter layer 4 is responsible for realizing beam scanning in the y direction. After phase shifting, the signal is fed into the second-stage phase shifter layer 5 through the copper column 18. The second-stage phase shifter layer 5 is responsible for realizing beam scanning in the x direction. After phase shifting, the signal is fed into the radiation layer 1 through the copper column 18 for signal transmission. By applying a bias voltage to the liquid crystal to change the dielectric constant of the transmission line, thereby changing the electrical length of the transmission line, a variable phase difference is generated between the antenna units to realize beam scanning.

[0017] like Figure 2 and Figure 3 As shown, the first-stage phase shifter layer 4 includes a feeding port 6, one end of the feeding port 6 is connected to the signal input, and the other end is connected to the first one-to-four power divider 7, each port of the first one-to-four power divider 7 is connected to a first-stage phase shifter 8, each first-stage phase shifter 8 is arranged above the liquid crystal 10, and a first bias electrode 9 is arranged below the liquid crystal, and a first GND 11 insulated from the first bias electrode 9 is arranged on the same plane as the first bias electrode 9. The four first-stage phase shifters 8 are given a bias voltage by the four first bias electrodes 9 to control the phase shift, thereby realizing the beam scanning in the y direction, and the signal is fed to the second-stage phase shifter layer 5 through the copper column 18 after phase shifting.

[0018] Furthermore, the first-stage phase shifter 8 is composed of a serpentine delay line, one end of which is connected to the output end of the first one-to-four power divider 7 , and the other end of which is connected to the copper column 18 .

[0019] like Figure 4 and Figure 5 As shown, the second-stage phase shifter layer 5 includes four second one-to-four power dividers 12, and the output end of each second one-to-four power divider 12 is respectively connected to a second-stage phase shifter 13, each second-stage phase shifter 13 is arranged above the liquid crystal 10, and a second bias electrode 14 is arranged below the liquid crystal, and a second GND 15 insulated from the second bias electrode 14 is arranged on the same plane as the second bias electrode 14. A bias voltage is given to each of the four second-stage phase shifters 13 by a second bias electrode 14 to control the phase shift, thereby realizing beam scanning in the x direction, and after the phase shift, the signal is fed into the radiation layer 1 through the copper column 18 to transmit the signal.

[0020] Furthermore, the second-stage phase shifter 13 is composed of a spiral delay line, one end of which is connected to the output end of the second one-to-four power divider 12 , and the other end of which is connected to the copper column 18 .

[0021] like Figure 6 and Figure 7 As shown, a plurality of radiation patches 16 are arranged in an array on the upper surface of the radiation layer 1 , and a third GND 17 is provided on the lower surface of the radiation layer 1 .

[0022] The working principle of the present invention is: applying a bias voltage to the liquid crystal to change the dielectric constant of the transmission line, thereby changing the electrical length of the transmission line, and then generating a variable phase difference between the antenna units, thereby realizing the beam scanning of the liquid crystal phased array antenna of the present invention; wherein, the transmission line refers to a liquid crystal phase shifter structure, which is a microstrip transmission line structure composed of a liquid crystal medium and a phase shifter. Applying a bias voltage to the liquid crystal 10 changes the dielectric constant of the liquid crystal 10, which is also the dielectric constant of the transmission line and the dielectric constant of the phase shifter.

[0023] The present invention can greatly reduce the number and complexity of control circuits in the case that the more units a liquid crystal phased array antenna with a delay line structure has, the more complex the control circuit becomes. 2 In the present invention, only 2×n control circuits are needed to control the bias voltage. For example, the number of control circuits required for designing a 4×4 delay line structure liquid crystal phased array antenna by the traditional method is 16, while in the present invention, the number of control circuits is only 8. If the array continues to grow, such as designing a 100×100 liquid crystal phased array antenna, the number of control circuits required is 10,000, while the number of control circuits required for the present structure is only 200.

[0024] The above is only a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used for various other combinations, modifications and improvements, and can be modified within the scope of the concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art do not deviate from the spirit and scope of the present invention, and should be within the scope of protection of the claims attached to the present invention.

Claims

1. A phased array antenna with two-stage liquid crystal phase shifters cascaded, characterized in that: It comprises, from top to bottom, a radiation layer (1), a first dielectric layer (2), a second-stage phase shifter layer (5), a second dielectric layer (3) and a first-stage phase shifter layer (4); liquid crystals (10) and bias electrodes are provided on the first-stage phase shifter layer (4) and the second-stage phase shifter layer (5); the radiation layer (1) and the second-stage phase shifter layer (5) and the second-stage phase shifter layer (5) and the first-stage phase shifter layer (4) are connected via copper pillars (18); The first-stage phase shifter layer (4) is responsible for realizing beam scanning in the y direction. After the signal is phase shifted, it is fed into the second-stage phase shifter layer (5) through the copper column (18). The second-stage phase shifter layer (5) is responsible for realizing beam scanning in the x direction. After the signal is phase shifted, it is fed into the radiation layer (1) through the copper column (18) for signal transmission. By applying a bias voltage to the liquid crystal to change the dielectric constant of the transmission line, the electrical length of the transmission line is changed, so that a variable phase difference is generated between the antenna units to realize beam scanning.

2. The phased array antenna with two-stage liquid crystal phase shifters cascaded according to claim 1, characterized in that: The first-stage phase shifter layer (4) comprises a feed port (6), one end of the feed port (6) is connected to a signal input, and the other end is connected to a first one-to-four power divider (7), each port of the first one-to-four power divider (7) is connected to a first-stage phase shifter (8), each first-stage phase shifter (8) is arranged above the liquid crystal (10), a first bias electrode (9) is arranged below the liquid crystal, and a first GND (11) insulated from the first bias electrode (9) is arranged on the same plane as the first bias electrode (9), the four first-stage phase shifters (8) are given a bias voltage by the four first bias electrodes (9) to control the phase shift, thereby realizing beam scanning in the y direction, and the signal is fed into the second-stage phase shifter layer (5) through the copper column (18) after phase shifting.

3. The phased array antenna with two-stage liquid crystal phase shifters cascaded according to claim 1, characterized in that: The second-stage phase shifter layer (5) comprises four second one-to-four power dividers (12), the output end of each second one-to-four power divider (12) being connected to a second-stage phase shifter (13), each second-stage phase shifter (13) being arranged above the liquid crystal (10), a second bias electrode (14) being arranged below the liquid crystal, and a second GND (15) insulated from the second bias electrode (14) being arranged on the same plane as the second bias electrode (14), each of the four second-stage phase shifters (13) being provided with a bias voltage by a second bias electrode (14) to control phase shifting, thereby achieving beam scanning in the x-direction, and the signal being phase shifted and fed into the radiation layer (1) through a copper column (18) to transmit the signal.

4. The phased array antenna with two-stage liquid crystal phase shifters cascaded according to claim 1, characterized in that: A plurality of radiation patches (16) are arranged in an array on the upper surface of the radiation layer (1), and a third GND (17) is provided on the lower surface of the radiation layer (1).

5. The phased array antenna with two-stage liquid crystal phase shifters cascaded according to claim 2, characterized in that: The first-stage phase shifter (8) is composed of a serpentine delay line, one end of which is connected to the output end of the first one-to-four power divider (7), and the other end of which is connected to the copper column (18).

6. The phased array antenna with two-stage liquid crystal phase shifters cascaded according to claim 3, characterized in that: The second-stage phase shifter (13) is composed of a spiral delay line, one end of which is connected to the output end of the second one-to-four power divider (12), and the other end of which is connected to the copper column (18).

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