A PCB liquid crystal phased array antenna

Abstract

The invention discloses a PCB liquid crystal phased array antenna, comprising: an antenna cover layer and a spacing layer, wherein the antenna cover layer and the spacing layer are spaced apart, and an air dielectric layer is formed between the antenna cover layer and the spacing layer; a first transmission line layer is arranged on the spacing layer and is located in the air dielectric layer; the air dielectric layer is provided with an active device, and the active device is connected to the first transmission line layer; a phase shifter layer is connected to the spacing layer, and the phase shifter layer is electrically connected to the active device through a first metallized via hole; a third dielectric layer is connected to the phase shifter layer; a second transmission line layer is connected to the third dielectric layer, and the second transmission line layer is electrically connected to the phase shifter layer through a second metallized via hole; the invention solves the problem that a liquid crystal phase shifter as an independent device is difficult to be centrally packaged in the same chip with a power device like a traditional phase shifter, so that the loss of the phase shifter is difficult to be compensated by the power device.

Description

Technical Field

[0001] The present invention relates to the field of wireless communications, and in particular to the technical field of phased array antennas. Background Art

[0002] The demand for low-cost phased array antennas is becoming increasingly prominent in new infrastructure fields such as satellite communications and 5G. The advancement of high-performance electromagnetic liquid crystal material technology has provided an effective solution for the design of low-cost and low-power phased array antennas. As a revolutionary technological innovation, liquid crystal phased array antenna technology has become the focus of research and development for many manufacturers.

[0003] Liquid crystal molecules can deflect according to the change of electric field strength, thereby achieving the purpose of adjustable relative dielectric constant. The basic principle of realizing liquid crystal phase shifter is to adjust and control the relative dielectric constant of liquid crystal. However, on the one hand, the liquid crystal phase shifter is sealed separately in a glass box, and the glass metallization via process is still difficult; on the other hand, as an independent device, it is difficult to package the liquid crystal phase shifter with the power device in the same chip as the traditional phase shifter, which makes it difficult to compensate for the loss of the phase shifter with the power device.

[0004] In the existing technology, researchers have achieved hole-free signal transmission through non-contact coupling technology, as shown in Figure 8; by opening a coupling gap on the metal floor and selecting top and bottom layer transmission lines of special length and width to be placed at the coupling gap, the transition transmission of the signal from the top layer input port to the bottom layer output port can be achieved. On the other hand, as shown in Figure 9; the high-power output power amplifier has a high power amplifier efficiency and can achieve low input and high output functions. Connecting a high-power power amplifier to the total port of the phased array antenna can improve the system efficiency, ensure that the phased array antenna transmits the equivalent maximum radiated power, and effectively avoid the problem of low system efficiency introduced by the loss of the liquid crystal phase shifter. However, these solutions themselves have the following defects.

[0005] Whether it is a hole-free solution based on non-contact coupling technology or a technology based on high-power devices to compensate for the inherent losses brought by the liquid crystal phase shifter, it is impossible to fundamentally solve the problem of inherent losses in existing liquid crystal phase shifters.

[0006] On the one hand, the coupling technology will introduce the loss problem caused by the coupling hole. On the other hand, the coupling hole itself has low-power radiation, which is superimposed on the antenna radiation and affects the radiation of the phased array antenna.

[0007] The introduction of high-power power amplifiers can improve the efficiency of power amplifiers, but their size is generally large, and the heat dissipation structure is more massive and heavy. At the same time, they are also unable to introduce the array gain introduced by distributed low-power power amplifiers, and the improvement on the equivalent maximum radiated power of the transmission is limited. In addition, for the receiving array, the noise problem introduced by the liquid crystal phase shifter cannot be compensated by the power amplifier. Summary of the invention

[0008] (I) Purpose of the invention

[0009] The purpose of the present invention is to provide a PCB liquid crystal phased array antenna, which solves the problem that the liquid crystal phase shifter is sealed separately in a glass box and the glass metallization through-hole process is still difficult; on the other hand, it solves the problem that the liquid crystal phase shifter as an independent device is difficult to be packaged together with the power device in the same chip like a traditional phase shifter, making it difficult to compensate for the loss of the phase shifter by the power device.

[0010] (II) Technical solution

[0011] To solve the above problems, the present invention provides a PCB liquid crystal phased array antenna, comprising: an antenna cover layer and a spacing layer, wherein the antenna cover layer is spaced from the spacing layer, and an air dielectric layer is formed between the antenna cover layer and the spacing layer; the spacing layer forms a plurality of chambers, and liquid crystal is arranged in each of the chambers; a first transmission line layer is arranged on the spacing layer and located in the air dielectric layer; the air dielectric layer is provided with an active device, and the active device is arranged on the surface of the spacing layer, and the active device is connected to the first transmission line layer; a phase shifter layer is connected to the spacing layer and located on the opposite side of the first transmission line layer, and the phase shifter layer is electrically connected to the active device through a first metallized via hole, and the first metallized via hole penetrates the spacing layer; a third dielectric layer is connected to the phase shifter layer and located on the opposite side of the spacing layer; a second transmission line layer is connected to the third dielectric layer and located on the opposite side of the phase shifter layer, and the second transmission line layer is electrically connected to the phase shifter layer through a second metallized via hole.

[0012] Preferably, the antenna cover layer includes a radiation sheet layer and a radiation sheet dielectric layer; the radiation sheet layer is arranged on the radiation sheet dielectric layer and is located in the air dielectric layer; the radiation sheet layer is composed of a plurality of radiation sheets, and the plurality of radiation sheets are arranged in a rectangular array.

[0013] Preferably, the spacing layer includes: a first metal floor layer, a first dielectric layer forming the air dielectric layer between the antenna cover layer, the first metal floor layer is connected to the first dielectric layer and is located on the opposite side of the first transmission line layer; a first PP layer is connected to the first metal floor layer and is located on the opposite side of the first dielectric layer; a second dielectric layer is connected to the first PP layer and is located on the opposite side of the first metal floor layer; a second metal floor layer is connected to the second dielectric layer and is located on the opposite side of the first PP layer; a second PP layer is connected to the second metal floor layer and is located on the opposite side of the second dielectric layer; and a plurality of the chambers are formed on the second PP layer or the second dielectric layer.

[0014] Preferably, a plurality of the chambers are arranged in a rectangular array, and two adjacent chambers are connected to each other via a connecting groove; the chamber is a chamber with openings at the top and bottom.

[0015] Preferably, the first metallized via hole passes through the first dielectric layer, the avoidance hole on the first metal floor layer, the first PP layer, the second dielectric layer, the avoidance hole on the second metal floor layer and the second PP layer, and is electrically connected to the transmission line arranged in the chamber; the diameter of the avoidance hole is larger than the diameter of the first metallized via hole.

[0016] Preferably, one end of the second metallized via is electrically connected to the phase shifter layer, and the other end passes through the third dielectric layer and is electrically connected to the second transmission line layer.

[0017] Preferably, the first metal floor layer is electrically connected to the second metal floor layer through a third metallized via; the third metallized via runs through the first dielectric layer, the first metal floor layer, the first PP layer, the second dielectric layer, the second metal floor layer, the second PP layer, the phase shifter layer and the third dielectric layer.

[0018] Preferably, it also includes a non-metallized via located between the first metallized via and the second metallized via; the non-metallized via passes through the first dielectric layer, the first metal floor layer, the first PP layer, the second dielectric layer, the second metal floor layer and the second PP layer, and the hole of the non-metallized via is connected to the chamber; two non-metallized vias are provided, and the two non-metallized vias are arranged at intervals.

[0019] Preferably, the active device is a power amplifier or a low noise amplifier; the phase shifter layer is composed of a plurality of phase shifters, the plurality of phase shifters are arranged in a rectangular array, and the phase shifters correspond to the chambers one by one.

[0020] Preferably, the first transmission line layer includes a first transmission line, one end of which is open, and the other end is electrically connected to the active device; the second transmission line layer includes a second transmission line and a power splitter / and-circuit network; the power splitter / and-circuit network is electrically connected to the second metallized via through the second transmission line; and a DC blocking capacitor is placed on each path of the power splitter / and-circuit network.

[0021] (III) Beneficial effects

[0022] The above technical solution of the present invention has the following beneficial technical effects:

[0023] The present invention is provided with a radiation sheet dielectric layer, a first transmission line layer, a first dielectric layer, a first metal floor layer, a first PP layer, a second dielectric layer, a second metal floor layer, a second PP layer, a phase shifter layer, a third dielectric layer, a second transmission line layer and a radiation sheet layer, so that the present invention forms a multi-layer PCB structure, and further enables the present invention to solve the problem that the liquid crystal phase shifter is sealed separately in a glass box, and the glass metallization via process is still difficult, and at the same time, it is convenient to place metallized and non-metallized vias, effectively realize multi-layer interconnection, realize signal transmission and shielding, improve system performance, and avoid external interference. The present invention adopts a PCB box making scheme, which can realize the surface high temperature welding requirements and solve the technical problem that the glass box making cannot pass the reflow soldering.

[0024] The active device of the present invention is connected to the first transmission line layer and is located in the air dielectric layer. It is also connected to the phase shifter layer through a first metallized via hole, and the phase shifter layer is also connected to the second transmission line layer through a second metallized via hole. The present invention solves the problem that the liquid crystal phase shifter as an independent device is difficult to be packaged together with the power device in the same chip as a traditional phase shifter, making it difficult to compensate for the loss of the phase shifter by the power device. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural schematic diagram of the present invention;

[0026] Figure 2 It is a schematic diagram of the structure of the dielectric layer of the radiation sheet of the present invention;

[0027] Figure 3 is a schematic diagram of the structure of the first transmission line layer of the present invention;

[0028] Figure 4 It is a schematic diagram of the structure of the first metal floor layer of the present invention;

[0029] Figure 5 is a schematic diagram of the phase shifter layer structure of the present invention;

[0030] Figure 6 is a schematic diagram of the structure of the second transmission line layer of the present invention;

[0031] Figure 7 It is a structural schematic diagram of the first embodiment of the present invention;

[0032] Figure 8 It is a schematic diagram of the structure of a phased array antenna in the prior art;

[0033] Fig. 9 It is a schematic diagram of the phased array antenna structure in the prior art.

[0034] Reference numerals:

[0035] Radiating sheet dielectric layer 1, first transmission line layer 2, first dielectric layer 3, first metal floor layer 4, first PP layer 5, second dielectric layer 6, second metal floor layer 7, second PP layer 8, phase shifter layer 9, third dielectric layer 10, second transmission line layer 11, first metallized via 12, second metallized via 13, non-metallized via 14, radiating sheet layer 15, third metallized via 16, active device 17, air dielectric layer 18, chamber 19, connecting groove 20, first transmission line 21, avoidance hole 22, second transmission line 23, liquid crystal 24, phase shifter 25, gap 26, power division / summing network connection 27, DC blocking capacitor 28. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings. It should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention.

[0037] In the description of the present invention, it should be noted that the terms “first”, “second” and “third” are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0038] like Figures 1 to 9 As shown, in an embodiment of the present invention, the present invention provides a PCB liquid crystal phased array antenna, characterized in that it includes an antenna cover layer and a spacer layer, wherein the antenna cover layer and the spacer layer are spaced apart, and an air dielectric layer 18 is formed between the antenna cover layer and the spacer layer; a plurality of chambers 19 are formed on the spacer layer, and liquid crystal is arranged in each chamber 19.

[0039] In an embodiment of the present invention, the present invention further comprises a first transmission line layer 2, a phase shifter layer 9, a third dielectric layer 10 and a second transmission line layer 11. The first transmission line layer 2 is arranged on the spacing layer and is located in the air dielectric layer 18; the air dielectric layer 18 is provided with an active device 17, the active device 17 is arranged on the surface of the spacing layer, and the active device 17 is connected to the first transmission line layer 2. The phase shifter layer 9 is connected to the spacing layer and is located on the opposite side of the first transmission line layer 2. The phase shifter layer 9 is electrically connected to the active device 17 through the first metallized via 12, and the first metallized via 12 penetrates the spacing layer. The third dielectric layer 10 is connected to the phase shifter layer 9 and is located on the opposite side of the spacing layer. The second transmission line layer 11 is connected to the third dielectric layer 10 and is located on the opposite side of the phase shifter layer 9. The second transmission line layer 11 is electrically connected to the phase shifter layer 9 through the second metallized via 13.

[0040] The present invention is provided with an antenna cover layer, a spacer layer, a first transmission line layer 2, a phase shifter layer 9, a third dielectric layer 10 and a second transmission line layer 11, so that the present invention forms a multi-layer PCB structure, and further enables the present invention to solve the problem that the liquid crystal phase shifter is sealed separately in a glass box, and the glass metallization via process is still difficult. At the same time, it is also convenient for the placement of metallized and non-metallized vias, effectively realizing multi-layer interconnection, realizing signal transmission and shielding, improving system performance, and avoiding external interference. The present invention adopts a PCB box making scheme, which can realize the surface high-temperature welding requirements and solve the technical problem that the glass box making cannot pass the reflow soldering.

[0041] The active device 17 of the present invention is connected to the first transmission line layer 2 and is located in the air dielectric layer 18. It is also connected to the phase shifter layer 9 through the first metallized via 12, and the phase shifter layer 9 is also connected to the second transmission line layer 11 through the second metallized via 13. The present invention solves the problem that the liquid crystal phase shifter as an independent device is difficult to be packaged together with the power device in the same chip as the traditional phase shifter, making it difficult to compensate for the loss of the phase shifter by the power device.

[0042] like Figure 1 As shown, in an embodiment of the present invention, the spacer layer includes a first metal floor layer 4, a first dielectric layer 3 forming an air dielectric layer 18 with the antenna cover layer, a first PP layer 5, a second dielectric layer 6, a second metal floor layer 7, and a second PP layer 8, wherein the first metal floor layer 4 is connected to the first dielectric layer 3 and is located on the opposite side of the first transmission line layer 2; the first PP layer 5 is connected to the first metal floor layer 4 and is located on the opposite side of the first dielectric layer 3. The second dielectric layer 6 is connected to the first PP layer 5 and is located on the opposite side of the first metal floor layer 4; the second metal floor layer 7 is connected to the second dielectric layer 6 and is located on the opposite side of the first PP layer 5; the second PP layer 8 is connected to the second metal floor layer 7 and is located on the opposite side of the second dielectric layer 6. In this embodiment, a plurality of cavities are formed on the second PP layer 8; in other embodiments, a plurality of cavities are formed on the second dielectric layer 6.

[0043] In some embodiments of the present invention, a power supply layer of the active device 17, a control layer of the phase shifter, etc. may be added between the second dielectric layer 6 and the first PP layer 5. In other embodiments, the first PP layer 5 is replaced with another adhesive layer that can bond the first metal floor layer 4 and the second dielectric layer 6. In the PCB manufacturing process, each dielectric layer has a front and back metal layer. When multiple metal layers are required, multiple dielectric layers need to be pressed together. A PP layer needs to be placed between the dielectric layers to press the two dielectric layers together.

[0044] like Figure 5As shown, in an embodiment of the present invention, a plurality of chambers 19 are arranged in a rectangular array, and two adjacent chambers 19 are connected to each other through a connecting groove 20, so that the present invention can provide more support areas to ensure the uniformity and accuracy of the liquid crystal thickness, and can also achieve mutual connectivity to reduce the complexity of the process of infusing liquid crystal. The size requirement of the support arm of the chamber 19 is smaller than the size requirement of the glass box sealing glue, which can reduce the process difficulty of array antenna layout. In this embodiment, the chamber 19 is a chamber with openings at the top and bottom, that is, the chamber 19 is formed by the hollowed-out second PP layer 8 or the second dielectric layer 6.

[0045] like Figure 2 As shown, in an embodiment of the present invention, the antenna cover layer includes a radiation sheet layer 15 and a radiation sheet dielectric layer 1; wherein the radiation sheet layer 15 is arranged on the radiation sheet dielectric layer 1 and is located in the air dielectric layer 18; the radiation sheet layer 15 is composed of a plurality of radiation sheets, and the plurality of radiation sheets are arranged in a rectangular array, and the radiation sheet is the antenna of the present invention, which is used to receive or send signals.

[0046] like Figure 3 As shown, in an embodiment of the present invention, the first transmission line layer 2 of the present invention includes a first transmission line 21, which receives the signal sent by the radiation sheet, wherein one end of the first transmission line 21 is open, and the other end is electrically connected to the active device 17 to amplify the radio frequency signal. In this embodiment, the active device 17 is a power amplifier, and in other embodiments, the active device 17 can also be a low noise amplifier.

[0047] like Figure 1 and Figure 4 As shown, in the embodiment of the present invention, the first metallized via 12 penetrates the first dielectric layer 3, the avoidance hole 22 on the first metal floor layer 4, the first PP layer 5, the second dielectric layer 6, the avoidance hole 22 on the second metal floor layer 7, and the second PP layer 8, and is electrically connected to the transmission line provided in the chamber 19; the first metallized via 12 of the present invention is directly connected to the first transmission line layer 2 and the transmission line inside the chamber 19, so as to realize direct signal connection, and at the same time reduce the loss and radiation introduced by the coupling transition, and improve the system performance. In this embodiment, in order to avoid the first metallized via 12 and the first metal floor layer 4 and the second metal floor layer 7 from being connected, the diameter of the avoidance hole 22 of the present invention is greater than the diameter of the first metallized via 12. In this embodiment, one end of the second metallized via 13 of the present invention is connected to the phase shifter layer 9, and the other end penetrates the third dielectric layer 10, and is electrically connected to the second transmission line layer 11, so that the present invention reduces the loss and radiation introduced by the coupling transition, and improves the system performance.

[0048] like Figure 1As shown, in the embodiment of the present invention, the present invention further includes a non-metallized via 14 for realizing a vacuum state in the cavity, and the non-metallized via 14 is located between the first metallized via 12 and the second metallized via 13. The non-metallized via 14 penetrates the first dielectric layer 3, the first metal floor layer 4, the first PP layer 5, the second dielectric layer 6, the second metal floor layer 7, and the second PP layer 8, and at the same time connects the hole of the non-metallized via 14 to the cavity 19, so that the present invention provides for the injection of liquid crystal into the cavity. In this embodiment, two non-metallized vias 14 are provided, and the two non-metallized vias 14 are arranged at intervals.

[0049] like Figure 4 As shown, in the embodiment of the present invention, the first metal floor layer 4 and the second metal floor layer 7 are both metal floor layers with gaps 26. A plurality of avoidance holes 22 are also formed on the first metal floor layer 4 and the second metal floor layer 7, and the avoidance holes 22 and the gaps 26 are arranged crosswise with each other. In this embodiment, the gaps 26 are I-shaped gaps. The first metal floor layer 4 is electrically connected to the second metal floor layer 7 through the third metalized via 16, and the third metalized via 16 runs through the first dielectric layer 3, the first metal floor layer 4, the first PP layer 5, the second dielectric layer 6, the second metal floor layer 7, the second PP layer 8, the phase shifter layer 9 and the third dielectric layer 10, so that the present invention realizes signal shielding and the interconnection of each metal floor.

[0050] like Figure 5 As shown, in an embodiment of the present invention, the phase shifter layer 9 is composed of a plurality of phase shifters 25, and the plurality of phase shifters 25 are arranged in a rectangular array, and the phase shifters 25 correspond to the chambers 19 one by one. In this embodiment, each phase shifter 25 has a first metallized via 12 and a second metallized via 13 corresponding thereto and electrically connected thereto. In this embodiment, the phase shifter 25 is electrically connected to the active device 17 through the first metallized via 12, so that the active device 17 is connected in series between the first transmission line 21 of the present invention and the phase shifter 25, which can effectively avoid the problem of low system efficiency caused by the loss of the liquid crystal phase shifter, and improve the overall performance of the liquid crystal phased array antenna.

[0051] like Figure 6 As shown, in an embodiment of the present invention, the second transmission line layer 11 includes a second transmission line 23 and a power splitter / summing network 27. The power splitter / summing network 27 is connected to the second metallized via 13 through the second transmission line 23 to achieve signal aggregation and ultimately achieve the phased array antenna function. In this embodiment, a DC blocking capacitor 28 is placed on each path of the power splitter / summing network 27 of the present invention, so that the present invention avoids voltage crosstalk on each phase shifter 25.

[0052] like Figure 7 As shown, the present invention will take a receiving antenna as an example to explain the principle and implementation method of a PCB liquid crystal phased array.

[0053] The receiving antenna unit is composed of a radiation plate dielectric layer 1, a radiation plate, an air dielectric layer 18, a first transmission line 2, a first dielectric layer 3, and a first metal floor layer with a gap 4. The antenna unit receives electromagnetic wave signals in space as electrical signals and transmits them to the right end of the first transmission line.

[0054] PCB liquid crystal phased array principle: The right end of the first transmission line 21 is cascaded with the active device 17. The active device 17 converts and amplifies the electrical signal of the first transmission line 21 and guides it to the phase shifter layer 9 through the first metal hole 12. The cavity hollowed out between the phase shifter layer 9 and the second metal floor layer 7 is filled with liquid crystal. By applying voltage to the liquid crystal layer and the second metal floor layer 7, the deflection of the liquid crystal molecules can be achieved, and the dielectric constant of the liquid crystal in the vertical direction can be changed, thereby achieving phase adjustment. The phase-adjusted electrical signal is guided to the power division / combination network 27 through the second metal hole 13. A DC blocking capacitor 28 is placed on each path of the combining network to avoid crosstalk caused by the voltage applied to each phase shifter. The electrical signal guided through the second metal hole 13 is combined with other phase-adjusted electrical signals in the phased array antenna to jointly realize the phased array antenna system.

[0055] The present invention is a multi-layer PCB liquid crystal phased array antenna, which can realize metal and non-metallized hole technology, improve transmission efficiency, reduce signal leakage, realize device welding, reduce the size of the support area, increase the support density, and improve system performance and stability, etc. This is a technical difficulty that cannot be achieved by the existing glass box liquid crystal phased array antenna.

[0056] The present invention places the active device between the antenna unit and the liquid crystal phase shifter. Compared with the technology of burying the active device inside the PCB board, the structure is simpler, the cost is lower, and it is more convenient to debug and test.

[0057] The present invention places active devices between the antenna unit and the liquid crystal phase shifter. Compared with loading the active devices on the main port, the antenna array gain is improved, the system noise introduced by the phase shifter is reduced, and the EIRP of the transmitting antenna and the G / T value of the receiving antenna are effectively improved.

[0058] In the traditional technical solution, the order from top to bottom is antenna cover layer → air dielectric layer → metal floor layer with gaps → dielectric layer → open transmission line → phase shifter; in this structure, since the phase shifter must be encapsulated inside the support, active devices cannot be placed between the transmission line and the phase shifter. However, the present invention reverses the order of opening the first transmission line and opening the metal floor layer, that is, the first transmission line is located below the air dielectric layer, so that the purpose of placing active devices in the air dielectric layer can be achieved. In addition, a structure in which active devices are placed between the first transmission line and the phase shifter is realized, and finally the purpose of compensating for the loss of the phase shifter is achieved.

[0059] One end of the first transmission line is open circuited, which together with the upper gap of the metal floor layer, the thickness of the PCB dielectric board, the air height and the size of the radiation plate determines the radiation efficiency and resonant frequency of the antenna unit. The other end of the first transmission line is cascaded with active devices including a power amplifier or a low noise amplifier to amplify the RF signal. The amplified signal is connected to the phase shifter in the chamber through the transmission line and metallized vias to achieve the phase shifting function. Placing active devices between the antenna unit and the phase shifter can effectively reduce the system function degradation caused by the phase shifter loss.

[0060] It should be understood that the above specific embodiments of the present invention are only used to illustrate or explain the principles of the present invention, and do not constitute a limitation of the present invention. Therefore, any modifications, equivalent substitutions, improvements, etc. made without departing from the spirit and scope of the present invention should be included in the protection scope of the present invention. In addition, the appended claims of the present invention are intended to cover all changes and modifications that fall within the scope and boundaries of the appended claims, or the equivalent forms of such scope and boundaries.

Claims

1. A PCB liquid crystal phased array antenna, characterized in that: include: Radome and spacer layers, The antenna cover layer and the spacing layer are spaced apart, and an air dielectric layer is formed between the antenna cover layer and the spacing layer; The spacer layer forms a plurality of chambers, and each of the chambers is provided with liquid crystal; A first transmission line layer is disposed on the spacer layer and is located in the air dielectric layer; The air dielectric layer is provided with an active device, the active device is arranged on the surface of the spacer layer, and the active device is connected to the first transmission line layer; a phase shifter layer connected to the spacer layer and located on an opposite side of the first transmission line layer, the phase shifter layer being electrically connected to the active device through a first metallized via hole, the first metallized via hole penetrating the spacer layer; a third dielectric layer connected to the phase shifter layer and located on an opposite side of the spacer layer; a second transmission line layer connected to the third dielectric layer and located at an opposite side of the phase shifter layer, wherein the second transmission line layer is electrically connected to the phase shifter layer through a second metallized via; The antenna cover layer includes a radiation sheet layer and a radiation sheet dielectric layer; The radiation sheet layer is arranged on the radiation sheet dielectric layer and is located in the air dielectric layer; The radiation sheet layer is composed of a plurality of radiation sheets, and the plurality of radiation sheets are arranged in a rectangular array; The spacer layer comprises: A first metal floor layer and a first dielectric layer between the antenna cover layer and the air dielectric layer. The first metal floor layer is connected to the first dielectric layer and is located on the opposite side of the first transmission line layer; a first PP layer connected to the first metal floor layer and located on an opposite side of the first dielectric layer; a second dielectric layer connected to the first PP layer and located on an opposite side of the first metal floor layer; a second metal floor layer connected to the second dielectric layer and located on an opposite side of the first PP layer; a second PP layer connected to the second metal floor layer and located on an opposite side of the second dielectric layer; A plurality of the cavities are formed on the second PP layer or the second dielectric layer.

2. The PCB liquid crystal phased array antenna according to claim 1, characterized in that: A plurality of the chambers are arranged in a rectangular array, and two adjacent chambers are connected to each other through a connecting groove; The chamber is a chamber with openings at the top and the bottom.

3. The PCB liquid crystal phased array antenna according to claim 2, characterized in that: The first metallized via penetrates the first dielectric layer, the avoidance hole on the first metal floor layer, the first PP layer, the second dielectric layer, the avoidance hole on the second metal floor layer and the second PP layer, and is electrically connected to the transmission line disposed in the chamber; The diameter of the avoidance hole is greater than the diameter of the first metallized via hole.

4. The PCB liquid crystal phased array antenna according to claim 1, characterized in that: One end of the second metallized via is electrically connected to the phase shifter layer, and the other end thereof passes through the third dielectric layer and is electrically connected to the second transmission line layer.

5. The PCB liquid crystal phased array antenna according to claim 1, characterized in that: The first metal floor layer is electrically connected to the second metal floor layer through a third metallized via; The third metallized via hole penetrates the first dielectric layer, the first metal floor layer, the first PP layer, the second dielectric layer, the second metal floor layer, the second PP layer, the phase shifter layer and the third dielectric layer.

6. The PCB liquid crystal phased array antenna according to claim 1, characterized in that: Also included is a non-metallized via located between the first metallized via and the second metallized via; The non-metallized via hole penetrates the first dielectric layer, the first metal floor layer, the first PP layer, the second dielectric layer, the second metal floor layer and the second PP layer, and the cavity of the non-metallized via hole is connected to the chamber; There are two non-metallized via holes, and the two non-metallized via holes are arranged at intervals.

7. The PCB liquid crystal phased array antenna according to claim 1, characterized in that: The active device is a power amplifier or a low noise amplifier; The phase shifter layer is composed of a plurality of phase shifters arranged in a rectangular array, and the phase shifters correspond to the chambers one by one.

8. The PCB liquid crystal phased array antenna according to claim 1, characterized in that: The first transmission line layer includes a first transmission line, one end of the first transmission line is open, and the other end is electrically connected to the active device; The second transmission line layer includes a second transmission line and a power splitter / and-path network; The power splitter / combiner network is electrically connected to the second metallized via through the second transmission line; Each path of the power dividing / adding network is provided with a DC blocking capacitor.

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