Liquid crystal phased array based on bidirectional switch

Abstract

The utility model discloses a liquid crystal phased array based on a bidirectional switch. Comprising an upper quartz glass substrate, a lower quartz glass substrate, a liquid crystal medium arranged between the upper quartz glass substrate and the lower quartz glass substrate, polyimide films arranged above and below the liquid crystal medium, a Z-direction direct current bias network arranged on the upper surface of the lower quartz glass substrate, and a one-to-many power divider, the Y-direction direct current bias network is arranged on the lower surface of the lower quartz glass substrate, the metal ground is arranged on the lower surface of the upper quartz glass substrate, and the antenna units are coupled with the one-to-multiple power divider. Wherein the Z-direction direct-current bias network is controlled to apply a longitudinal electric field to the liquid crystal molecules, and the Y-direction direct-current bias network is controlled to apply a transverse electric field to the liquid crystal molecules. The utility model provides a liquid crystal phased array with quick response, which can obviously improve the performance index of a reconfigurable millimeter wave phased array system and is very beneficial to the integration and development of the reconfigurable millimeter wave system.

Description

Technical Field

[0001] The utility model relates to the field of wireless communications, in particular to a liquid crystal phased array based on a bidirectional switch. Background Art

[0002] To meet the diverse needs of mobile terminals operating in the L, C, Ku, Ka, or W bands for services such as wireless internet, multimedia, communications, and broadcasting, electronically reconfigurable millimeter-wave systems, with their advantages of small size, multifunctionality, high spectral efficiency, and flexibility, have become a research hotspot. They are being used in military and industrial ground station applications, including mobile terminals mounted on aircraft, ships, or vehicles. Commonly used technologies for phased array beam scanning include radio frequency microelectromechanical systems (RF MEMS), semiconductor solutions, and ferroelectrics such as barium strontium titanate (BST). Another approach is the use of liquid crystal materials, which offer low loss at high frequencies. Among these approaches, liquid crystals offer advantages over MEMS in terms of lifetime, continuity, and packaging, and over BST in terms of frequency range and bias voltage, making them ideal materials for beam-scanning phased arrays. Benefiting from the mature manufacturing process of LCD panels, liquid crystal phased arrays also offer a unique advantage in manufacturing costs. Cost-competitive and high-performance liquid crystal-based phased array modules, capable of supporting beamforming and beam steering, are key technologies for emerging small cell base stations and client devices in third-generation partnerships and new radio bands. Therefore, research on liquid crystal phased arrays suitable for various mobile terminals is of great significance for wireless communication systems.

[0003] Liquid crystal phased arrays (LCPAs) are compact, lightweight, and low-power, meeting the requirements for thinness and low power consumption of modern communications equipment. Furthermore, the electrically adjustable nature of liquid crystals enables continuous directional pattern scanning. However, due to the limitations of the inverted microstrip structure, LCPAs used in millimeter-wave frequency bands typically require a relatively thick liquid crystal layer, requiring tens or even hundreds of microns to achieve the electromagnetic wave transmission and phase modulation required by the inverted microstrip LC phase shifter. However, this thick LC layer requires high voltage regulation and results in a long response time for the phased array, typically on the order of seconds. The high bias voltage and slow response speed significantly limit the application of LCPAs in wireless communications.

[0004] It should be noted that the information disclosed in the above background technology section is only used to understand the background of this application, and therefore may include information that does not constitute prior art known to ordinary technicians in this field. Utility Model Content

[0005] The main purpose of the present invention is to overcome the defects of the above-mentioned background technology and provide a liquid crystal phased array based on bidirectional switches.

[0006] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0007] A liquid crystal phased array based on bidirectional switches comprises an upper quartz glass substrate, a lower quartz glass substrate, a liquid crystal medium disposed between the upper and lower quartz glass substrates, polyimide films disposed above and below the liquid crystal medium, a Z-direction DC bias network and a one-to-many power divider arranged on the upper surface of the lower quartz glass substrate, a Y-direction DC bias network arranged on the lower surface of the lower quartz glass substrate, a metal ground arranged on the lower surface of the upper quartz glass substrate, and a plurality of antenna units coupled to the one-to-many power divider. The Z-direction DC bias network is controlled to apply a longitudinal electric field to the liquid crystal molecules, and the Y-direction DC bias network is controlled to apply a transverse electric field to the liquid crystal molecules.

[0008] Furthermore, the Y-direction DC bias network includes a first side metal and a second side metal respectively disposed on both sides of the lower quartz glass substrate, the first side metal being connected to a row of positive electrode fingers, the second side metal being connected to a row of negative electrode fingers, and the positive electrode fingers and the negative electrode fingers being alternately arranged in a cross-isolated finger structure.

[0009] Furthermore, the multiple antenna units include a plurality of slot-coupled patch antenna units arranged on the upper surface of the upper quartz glass substrate, a plurality of coupling slots corresponding one-to-one to each slot-coupled patch antenna unit are opened on the metal ground, and the one-to-many power divider is coupled with each slot-coupled patch antenna unit through the coupling slots.

[0010] Furthermore, the slot-coupled patch antenna unit is rectangular, and its length direction is perpendicular to the extension direction of the one-to-many power divider.

[0011] Furthermore, the multiple slot-coupled patch antenna units are arranged into a rectangular antenna array.

[0012] Furthermore, the one-to-many power distributor is a one-to-four power distributor.

[0013] Furthermore, the upper quartz glass substrate and the lower quartz glass substrate are quartz glass substrates.

[0014] Furthermore, the polyimide film is a polyimide film.

[0015] The utility model has the following beneficial effects:

[0016] This utility model proposes a liquid crystal phased array based on bidirectional switches. While a Z-direction DC bias network is arranged on the upper surface of the lower quartz glass substrate, a Y-direction DC bias network is also arranged on the lower surface of the lower quartz glass substrate, providing a Y-direction bias electric field for the liquid crystal molecules, thereby increasing the control dimension of the liquid crystal molecules. This utility model constructs a design in which the Z-direction DC bias network and the Y-direction DC bias network work together, achieving multi-dimensional control of the liquid crystal molecules. This can significantly reduce the response time of the liquid crystal phased array control and significantly improve the response speed of the phased array control.

[0017] Specifically, by combining the Z-direction DC bias network and the Y-direction DC bias network, both a longitudinal electric field and a transverse electric field can be applied to the liquid crystal. Simultaneously applying transverse and longitudinal electric fields can improve the response speed of the liquid crystal phased array when it is turned on; after the liquid crystal molecules are modulated by the longitudinal electric field of the Z-direction DC bias to achieve anisotropic response, the transverse electric field of the Y-direction DC bias can continue to be applied, so that the liquid crystal molecules can be quickly reset, which is much faster than the natural reset speed of the liquid crystal molecules; in addition, applying a transverse electric field alone can significantly improve the response speed of the liquid crystal phased array when it is turned off. Therefore, the utility model provides a fast-response bidirectional switch liquid crystal phased array, which can significantly improve the performance indicators of the reconfigurable millimeter-wave phased array system, and is very beneficial to the integration and development of reconfigurable millimeter-wave systems.

[0018] Other beneficial effects of the embodiments of the present invention will be further described below. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A three-dimensional diagram of a liquid crystal phased array based on a bidirectional switch according to an embodiment of the present invention;

[0020] Figure 2 Schematic diagram of the lower and upper surfaces of the lower quartz glass substrate of the liquid crystal phased array based on bidirectional switches according to an embodiment of the present invention;

[0021] Figure 3 Schematic diagram of the lower and upper surfaces of the upper quartz glass substrate of the liquid crystal phased array based on bidirectional switches according to an embodiment of the present invention;

[0022] Figure 4 This is a schematic diagram of dual electric control of a liquid crystal phased array based on a bidirectional switch according to an embodiment of the present invention;

[0023] Figure 5 Schematic diagram of the Y-direction DC bias network of the liquid crystal phased array based on bidirectional switches according to an embodiment of the present invention.

[0024] Figure 6 Schematic diagram of liquid crystal phased array scanning control according to an embodiment of the utility model DETAILED DESCRIPTION

[0025] The following is a detailed description of the embodiments of the present invention. It should be emphasized that the following description is merely illustrative and is not intended to limit the scope and application of the present invention.

[0026] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element. In addition, connection can be used for both fixing and coupling or communication.

[0027] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0028] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of such features. In the description of the embodiments of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0029] See Figures 1 to 6 The present invention provides a bidirectional switch-based liquid crystal phased array, comprising an upper quartz glass substrate 102, a lower quartz glass substrate 108, a liquid crystal medium 105 disposed between the upper and lower quartz glass substrates, polyimide films 104 and 106 disposed above and below the liquid crystal medium 105, a Z-direction DC bias network 110 and a one-to-many power divider 107 disposed on the upper surface of the lower quartz glass substrate, a Y-direction DC bias network 109 disposed on the lower surface of the lower quartz glass substrate, a metal ground 103 disposed on the lower surface of the upper quartz glass substrate, and a plurality of antenna units coupled to the one-to-many power divider 107. The Z-direction DC bias network 110 is controlled to apply a longitudinal electric field to the liquid crystal molecules, and the Y-direction DC bias network 109 is controlled to apply a transverse electric field to the liquid crystal molecules.

[0030] By utilizing the collaboration of the Z-direction DC bias network 110 and the Y-direction DC bias network 109, which are respectively arranged on the upper and lower surfaces of the lower quartz glass substrate, the embodiment of the present invention realizes multi-dimensional electric field control of the liquid crystal molecules, effectively solving the problems of high voltage requirements and slow response time caused by the thick liquid crystal layer of the traditional liquid crystal phased array. By applying a longitudinal electric field through the Z-direction DC bias network and a transverse electric field through the Y-direction DC bias network, the present invention can not only improve the response speed of the phased array when it is turned on, but also use the transverse electric field of the Y-direction DC bias network to achieve rapid reset of the liquid crystal molecules in a manner far exceeding the natural reset speed. In addition, applying a transverse electric field alone can also significantly improve the response speed of the phased array when it is turned off. As a result, the present invention realizes a fast-response bidirectional switch liquid crystal phased array, which can significantly improve the performance indicators of the reconfigurable millimeter-wave phased array system.

[0031] like Figure 2 and Figure 4 As shown, in a preferred embodiment, the Y-direction DC bias network 109 includes a first side metal and a second side metal, respectively disposed adjacent to the lower quartz glass substrate. The first side metal is connected to a row of positive fingers, and the second side metal is connected to a row of negative fingers. The positive and negative fingers are arranged alternately in a cross-isolated structure. A preferred embodiment designs a cross-isolated Y-direction DC bias network to provide a Y-direction bias electric field for the liquid crystal molecules, thereby increasing the controllable dimension of the liquid crystal molecules. This cross-isolated Y-direction DC bias network design facilitates precise control of the liquid crystal molecule orientation and improves the overall performance of the liquid crystal phased array.

[0032] like Figure 1 and Figure 3 As shown, in a preferred embodiment, the multiple antenna units include multiple slot-coupled patch antenna units 101 arranged on the upper surface of the upper quartz glass substrate, the metal ground 103 is provided with multiple coupling slots corresponding to each slot-coupled patch antenna unit 101, and the one-to-many power divider 107 is coupled to each slot-coupled patch antenna unit 101 via the coupling slots. Figure 6 In the preferred embodiment, the patch antenna unit is designed with slot coupling feeding, and the phased array can achieve an efficient feeding method. This slot coupling can provide a good electromagnetic field distribution, which helps to improve the radiation efficiency and bandwidth of the antenna unit. It can perform two-dimensional scanning based on liquid crystal electrical control and achieve high radiation gain and wide impedance bandwidth, which can well meet the control requirements of two-dimensional scanning of liquid crystal phased array.

[0033] like Figure 1 and Figure 3 As shown, in a preferred embodiment, the slot-coupled patch antenna unit 101 is rectangular, and its length direction is perpendicular to the extension direction of the one-to-many power divider 107.

[0034] like Figure 1 and Figure 3 As shown, in a preferred embodiment, the multiple slot-coupled patch antenna units 101 are arranged into a rectangular antenna array.

[0035] like Figure 2 As shown, in some embodiments, the one-to-many power distributor 107 is a one-to-four power distributor.

[0036] See Figure 6 The Z-direction DC bias network 110 and the Y-direction DC bias network 109 can be controlled to perform one or more of the following operations: when the liquid crystal phased array is turned on, the Z-direction DC bias network 110 and the Y-direction DC bias network 109 are controlled to simultaneously apply longitudinal and transverse electric fields to improve the response speed of the liquid crystal phased array when it is turned on; after the liquid crystal molecules are longitudinally electric-field modulated by the Z-direction DC bias network 110 to achieve anisotropic response, the Y-direction DC bias network 109 continues to apply a transverse electric field to quickly reset the liquid crystal molecules; when the liquid crystal phased array is turned off, the Y-direction DC bias network 109 is independently controlled to apply a transverse electric field to improve the response speed of the liquid crystal phased array when it is turned off.

[0037] See Figures 1 to 6 In some embodiments, a liquid crystal phased array based on a bidirectional switch includes a one-to-four power divider, a Y-direction DC bias network, a Z-direction DC bias network, a slot-coupled patch antenna unit, a coupling slot, a metal ground, a liquid crystal medium, and upper and lower quartz glass substrates. The device also includes polyimide films disposed above and below the liquid crystal medium as alignment layers for the liquid crystal medium molecules. The Y-direction DC bias network is located on the lower surface of the lower quartz glass substrate, while the Z-direction DC bias network and the one-to-four power divider are located on the upper surface of the lower quartz glass substrate. The coupling slot and metal ground are located on the lower surface of the upper quartz glass substrate, and the slot-coupled patch antenna array is located on the upper surface of the upper quartz glass substrate. The Z-direction and Y-direction DC bias networks can apply both longitudinal and transverse electric fields to the liquid crystal; applying both transverse and longitudinal electric fields simultaneously significantly improves the response speed of the liquid crystal phased array when it is turned on; applying the transverse electric field alone significantly improves the response speed of the liquid crystal phased array when it is turned off; after the liquid crystal molecules are modulated by the longitudinal electric field of the Z-direction DC bias to achieve anisotropic response, the transverse electric field of the Y-direction DC bias can continue to be applied, causing the liquid crystal molecules to quickly reset at a speed much faster than the natural reset of the liquid crystal molecules.

[0038] The following further describes specific embodiments of the present invention.

[0039] like Figure 1-Figure 3As shown, a liquid crystal phased array based on bidirectional switches includes a one-to-many power divider 107, a Y-direction DC bias network 109, a Z-direction DC bias network 110, a slot-coupled patch antenna unit 101, a coupling slot 111, a metal ground 103, a liquid crystal medium 105, and upper and lower quartz glass substrates 102 and 108. It also includes polyimide films 104 and 106 arranged above and below the liquid crystal medium 105 as alignment layers for the liquid crystal medium molecules.

[0040] The Y-direction DC bias network 109 is located on the lower surface of the lower quartz glass substrate 108, while the Z-direction DC bias network 110 and the one-to-multiple power divider 107 are located on the upper surface of the lower quartz glass substrate 108. The coupling slot 111 and the metal ground 103 are located on the lower surface of the upper quartz glass substrate 102, and the slot-coupled patch antenna unit 101 is located on the upper surface of the upper quartz glass substrate 102.

[0041] The liquid crystal medium 105 is oriented by polyimide films 104 and 106 , fixed between the upper quartz glass substrate 102 and the lower quartz glass substrate 108 , and evenly distributed on the one-to-multiple power distributor 107 .

[0042] The gain of the slot-coupled patch antenna unit 101 increases with patch size. Depending on the desired radiation pattern, the coupling slot can be placed directly below or to the side of the slot-coupled patch antenna unit. In one embodiment, the coupling slot is designed as an H-shaped slot. In another embodiment, a linear slot can also be used. Optimizing the slot geometry can achieve better coupling efficiency.

[0043] like Figure 4 Figure 1 shows a schematic diagram of liquid crystal control using a bidirectional switch for a liquid crystal phased array, according to an embodiment of the present invention. Conventional liquid crystal electronic control (left) can only control the orientation of liquid crystal molecules by applying a longitudinal electric field. The bidirectional switch structure proposed in the present invention (right) can control the orientation of liquid crystal molecules by applying both longitudinal and transverse electric fields. In particular, applying both transverse and longitudinal electric fields simultaneously can improve the response speed of the liquid crystal phased array when it is turned on; applying only a transverse electric field can improve the response speed of the liquid crystal phased array when it is turned off.

[0044] like Figure 5Figure 2 shows the Y-axis DC bias network structure for a liquid crystal phased array based on bidirectional switches, according to one embodiment of the present invention. The positive and negative poles of the DC voltage are arranged alternately in a cross-isolated interdigital structure, with the positive interdigitals connected to the first metal side and the negative interdigitals connected to the second metal side. The interdigitals in the figure, from left to right, alternate between positive and negative interdigitals. By applying a DC voltage to the positive and negative metal ends of the cross-isolated Y-axis DC bias network, a transverse electric field is generated, thereby controlling the lateral rotation of the liquid crystal molecules.

[0045] In summary, the present invention provides a liquid crystal phased array based on a bidirectional switch, which can apply both a longitudinal electric field and a transverse electric field to the liquid crystal by combining a Z-direction DC bias network and a Y-direction DC bias network. Simultaneously applying transverse and longitudinal electric fields can improve the response speed of the liquid crystal phased array when it is turned on; when the liquid crystal molecules are modulated by the longitudinal electric field of the Z-direction DC bias to achieve anisotropic response, the transverse electric field of the Y-direction DC bias can continue to be applied, so that the liquid crystal molecules can be quickly reset, which is much faster than the natural reset speed of the liquid crystal molecules; in addition, applying a transverse electric field alone can significantly improve the response speed of the liquid crystal phased array when it is turned off. These three control modes correspond to different operating states of the liquid crystal phased array, including fast opening, fast reset, and fast closing, to meet the response speed requirements in different application scenarios. The solution of the present invention overcomes the defects of high voltage requirements and slow response time of traditional liquid crystal phased arrays due to the thick liquid crystal layer, can significantly improve the performance indicators of the reconfigurable millimeter wave phased array system, and is very beneficial to the integration and development of reconfigurable millimeter wave systems.

[0046] The above content is a further detailed description of the present invention in conjunction with specific / preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, without departing from the concept of the present invention, they can also make several substitutions or modifications to these described embodiments, and these substitutions or modifications should be considered to belong to the scope of protection of the present invention. In the description of this specification, the reference terms "one embodiment", "some embodiments", "preferred embodiments", "examples", "specific examples", or "some examples" and the like mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in an appropriate manner in any one or more embodiments or examples. Without mutual contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples. Although the embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions, and alterations can be made herein without departing from the scope of protection of the patent application.

Claims

1. A liquid crystal phased array based on bidirectional switches, characterized in that: The invention comprises an upper quartz glass substrate, a lower quartz glass substrate, a liquid crystal medium arranged between the upper quartz glass substrate and the lower quartz glass substrate, a polyimide film arranged above and below the liquid crystal medium, a Z-direction DC bias network and a one-to-many power distributor arranged on the upper surface of the lower quartz glass substrate, a Y-direction DC bias network arranged on the lower surface of the lower quartz glass substrate, a metal ground arranged on the lower surface of the upper quartz glass substrate, and a plurality of antenna units coupled to the one-to-many power distributor; wherein the Z-direction DC bias network is controlled to apply a longitudinal electric field to the liquid crystal molecules, and the Y-direction DC bias network is controlled to apply a transverse electric field to the liquid crystal molecules.

2. The liquid crystal phased array based on bidirectional switches according to claim 1, characterized in that: The Y-direction DC bias network includes a first side metal and a second side metal respectively arranged on both sides of the lower quartz glass substrate, the first side metal is connected to a row of positive electrode fingers, the second side metal is connected to a row of negative electrode fingers, and the positive electrode fingers and the negative electrode fingers are alternately arranged in a cross-isolated finger structure.

3. The liquid crystal phased array based on bidirectional switches according to claim 1 or 2, characterized in that: The multiple antenna units include multiple slot-coupled patch antenna units arranged on the upper surface of the upper quartz glass substrate, a plurality of coupling slots corresponding to each slot-coupled patch antenna unit are opened on the metal ground, and the one-to-many power divider is coupled with each slot-coupled patch antenna unit through the coupling slots.

4. The liquid crystal phased array based on bidirectional switches according to claim 3, characterized in that: The slot-coupled patch antenna unit is rectangular, and its length direction is perpendicular to the extension direction of the one-to-many power divider.

5. The liquid crystal phased array based on bidirectional switches according to claim 3, characterized in that: The plurality of slot-coupled patch antenna units are arranged into a rectangular antenna array.

6. The liquid crystal phased array based on bidirectional switches according to claim 1 or 2, characterized in that: The one-to-many power distributor is a one-to-four power distributor.

Images