A phased array antenna cascaded with two-stage liquid crystal phase shifters

Abstract

The present invention relates to a phased array antenna with two cascaded liquid crystal phase shifters. The antenna comprises, from top to bottom, a radiating layer, a first dielectric layer, a second phase shifter layer, a second dielectric layer, and a first phase shifter layer. Liquid crystal and bias electrodes are provided on both the first and second phase shifter layers. Copper pillars connect the radiating layer and the second phase shifter layer, as well as the second and first phase shifter layers. The first phase shifter layer is responsible for beam scanning in the y-direction. After phase shifting, the signal is fed into the second phase shifter layer via the copper pillars. The second phase shifter layer is responsible for beam scanning in the x-direction. After phase shifting, the signal is fed into the radiating layer via the copper pillars for transmission. The present invention reduces the complexity of the control circuit, mitigates the impact of electromagnetic coupling on the performance of the array antenna, and further reduces the weight and cost of the antenna, thereby promoting the mass production and commercialization of liquid crystal phased array antennas.

Description

Technical Field

[0001] The present 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 advancement of communications and radar technologies, antennas, as the bridge for wireless electromagnetic wave propagation, have received widespread attention from academia and industry. Within the antenna field, phased array antennas have become a hot topic in recent years. Phased array antennas can change the shape of their radiation patterns by controlling the feed phase of the radiating elements in the array antenna, allowing for flexible control of beam pointing. Compared to parabolic antennas, which 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 materials such as diodes, varactors, MEMS, and ferrites to create phase shifters. Liquid crystal, as an electrically tunable anisotropic material, holds great potential for the fabrication of phased array phase shifters. Phase shifters fabricated with this material offer advantages such as low cost, light weight, continuous phase adjustment, and ease of integration. However, these phase shifters still suffer from immature design and processing techniques, presenting challenges in their practical application.

[0004] Passive liquid crystal phased array antennas based on delay line structures work by applying a bias voltage to the liquid crystal medium to change the dielectric constant of the delay line, thereby changing the electrical length of the liquid crystal phase shifters and the phase shift amount of each liquid crystal phase shifter, thereby achieving the purpose of phased array antenna beam deflection. However, existing phased array antennas of this type require a set of bias control circuits for each phase shifter unit. As the number of array units increases, the required bias circuits become increasingly complex and may even cause electromagnetic coupling, affecting the performance of the entire phased array antenna. 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, which solves the shortcomings of the prior art.

[0006] The objectives of the present invention are achieved through the following technical solution: a phased array antenna with two cascaded liquid crystal phase shifters, comprising, from top to bottom, a radiation layer, a first dielectric layer, a first-stage phase shifter layer, a second dielectric layer, and a second-stage phase shifter layer. Liquid crystals and bias electrodes are provided on both the first-stage phase shifter layer and the second-stage phase shifter layer. Copper pillars connect the radiation layer and the first-stage phase shifter layer, as well as the second-stage phase shifter layer and the first-stage phase shifter layer.

[0007] The second-stage phase shifter layer is responsible for achieving beam scanning in the x-direction. After phase shifting, the signal is fed into the first-stage phase shifter layer through the copper pillar. The first-stage phase shifter layer is responsible for achieving beam scanning in the y-direction. After phase shifting, the signal is fed into the radiation layer through the copper pillar 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 achieve beam scanning.

[0008] The first-stage phase shifter layer includes a feed 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, and a first bias electrode is arranged below the liquid crystal. 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. After phase shifting, the signal is fed into the second-stage phase shifter layer through the copper column.

[0009] The second-stage phase shifter layer includes four second one-to-four power dividers, 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, a second bias electrode is arranged below the liquid crystal, and a second GND insulated from the second bias electrode is arranged on the same plane as the second bias electrode. Every four second-stage phase shifters are given a bias voltage by a second bias electrode to control the phase shift, thereby 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.

[0010] A plurality of radiation patches are arranged in an array on the upper surface of the radiation layer, and a third GND is provided on the lower surface of the radiation layer.

[0011] 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.

[0012] 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 is connected to the copper column.

[0013] 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 impact of electromagnetic coupling on the performance of the array antenna, 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

[0014] Figure 1 It is a schematic diagram of the explosion structure of the present invention;

[0015] Figure 2 Schematic diagram of the structure of the upper surface of the first-stage phase shifter layer;

[0016] Figure 3 Schematic diagram of the structure of the lower surface of the first-stage phase shifter layer;

[0017] Figure 4 Schematic diagram of the structure of the upper surface of the second-stage phase shifter layer;

[0018] Figure 5 Schematic diagram of the structure of the lower surface of the second-stage phase shifter layer;

[0019] Figure 6 Schematic diagram of the structure of the upper surface of the radiation layer;

[0020] Figure 7 Schematic diagram of the structure of the lower surface of the radiation layer;

[0021] 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 patch, 17-third GND, 18-copper pillar. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions 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 generally 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 present application for which protection is claimed, 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 are within the scope of protection of the present application. The present invention is further described below in conjunction with the drawings.

[0023] The present invention specifically relates to a phased array antenna with two cascaded stages of liquid crystal phase shifters. This structure employs two cascaded stages of phase shifters, each of which controls beam deflection in two orthogonal directions. Because the bias voltage is approximately linearly related to the dielectric constant of the liquid crystal 10, a set of bias voltages on the same stage of phase shifters can control beam deflection in one orthogonal direction. By cascading the two stages of phase shifters, two-dimensional beam deflection can be achieved.

[0024] like Figure 1 As shown, the present invention comprises, from top to bottom, a radiation layer 1, a first dielectric layer 2, a first-stage phase shifter layer 4, a second dielectric layer 3, and a second-stage phase shifter layer 5. Liquid crystals 10 and bias electrodes are provided on both the first-stage phase shifter layer 4 and the second-stage phase shifter layer 5. Copper pillars 18 connect the radiation layer 1 and the first-stage phase shifter layer 4, as well as the second-stage phase shifter layer 5 and the first-stage phase shifter layer 4.

[0025] Among them, 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 first-stage phase shifter layer 4 through the copper column 18. 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 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.

[0026] 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. 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. After phase shifting, the signal is fed to the second-stage phase shifter layer 5 through the copper column 18.

[0027] 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 pillar 18 .

[0028] 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. A second GND 15 insulated from the second bias electrode 14 is arranged on the same plane as the second bias electrode 14. Every four second-stage phase shifters 13 are given a bias voltage by a second bias electrode 14 to control the phase shift, thereby 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.

[0029] 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 pillar 18 .

[0030] 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 .

[0031] 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 the 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.

[0032] The present invention can greatly reduce the number and complexity of control circuits in liquid crystal phased array antennas with delay line structures, as the number of units increases, and the complexity of control circuits increases. 2 While the structure of the present invention requires only 2×n control circuits for bias control, a conventional design of a 4×4 liquid crystal phased array antenna with a delay line structure requires 16 control circuits. However, the present invention requires only 8 control circuits. If the array is further expanded, such as a 100×100 liquid crystal phased array antenna, 10,000 control circuits are required, while the present structure requires only 200.

[0033] The foregoing description is merely 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 construed as excluding other embodiments. Rather, the present invention is capable of various other combinations, modifications, and improvements, and is capable of modifications within the scope of the concepts described herein, through the above teachings, or through techniques or knowledge in the relevant fields. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention are intended to be within the scope of the appended claims.

Claims

1. A phased array antenna with two cascaded liquid crystal phase shifters, characterized in that: It comprises, from top to bottom, a radiation layer (1), a first dielectric layer (2), a first-stage phase shifter layer (4), a second dielectric layer (3) and a second-stage phase shifter layer (5); 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 first-stage phase shifter layer (4) are connected, as are the second-stage phase shifter layer (5) and the first-stage phase shifter layer (4) via copper pillars (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 first-stage phase shifter layer (4) through the copper column (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 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, and a variable phase difference is generated between the antenna units to realize beam scanning.

2. The phased array antenna with two cascaded liquid crystal phase shifters according to claim 1, characterized in that: The first-stage phase shifter layer (4) includes 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 cascaded liquid crystal phase shifters according to claim 1, characterized in that: The second-stage phase shifter layer (5) includes four second one-to-four power dividers (12), the output end of each second one-to-four power divider (12) is connected to a second-stage phase shifter (13), each second-stage phase shifter (13) is arranged above the liquid crystal (10), 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), and each of the four second-stage phase shifters (13) is given a bias voltage by a second bias electrode (14) to control the phase shift, thereby realizing beam scanning in the x-direction, and after the signal is phase shifted, it is fed into the radiation layer (1) through the copper column (18) for signal transmission.

4. The phased array antenna with two cascaded liquid crystal phase shifters 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 cascaded liquid crystal phase shifters 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 cascaded liquid crystal phase shifters 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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