Liquid crystal phase shifter and liquid crystal phased array antenna

Abstract

The application provides a liquid crystal phase shifter and a liquid crystal phased array antenna, and the liquid crystal phase shifter comprises a microstrip line, a metal ground, liquid crystal and double-layer glass; wherein the microstrip line, the metal ground and the liquid crystal are located between the upper glass and the lower glass of the double-layer glass; the lower surface of the upper glass is in contact with the upper surface of the microstrip line; the lower surface of the microstrip line and the upper surface of the metal ground are sandwiched with the liquid crystal; the metal ground is provided with a plurality of slots; and the lower surface of the metal ground is in contact with the upper surface of the lower glass. The liquid crystal in the liquid crystal phase shifter is filled in the sandwiched layer of the microstrip line and the metal ground, the dielectric constant of the liquid crystal material can be changed to adjust the time delay of the signal transmission on the microstrip line, so that the phase modulation function is realized, and the functional requirements of the phased array antenna can be met; the structure of the microstrip line and the metal ground in the liquid crystal phase shifter is simple, the miniaturization of the liquid crystal phase shifter is facilitated, and the requirement of the limited area of the unit channel in the phased array antenna is met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of microwave phase-shifting equipment, in particular to a liquid crystal phase shifter and a liquid crystal phased array antenna. BACKGROUND

[0002] The phased array antenna has high requirements for the time-frequency response, frequency selection, phase shift control and transmission matching of the phase shifter, and the phase shifter obtained by using semiconductor technology has high power consumption and high use cost, and is difficult to form wide application. Therefore, the liquid crystal technology is fused into the phased array antenna in the prior art, mainly classified into two types of scenes: one type is to directly apply the liquid crystal holographic technology to the radiation unit of the phased array antenna, and the other type is to use the liquid crystal phase shifter.

[0003] However, in actual application, the liquid crystal phased array antenna based on the liquid crystal holographic technology has high requirements for the precision of mechanical processing, has great difficulty in industrial production, has low yield, and is difficult to control the cost; and when the holographic technology is directly applied to the microwave radiation unit, the bandwidth is too narrow, and it is difficult to obtain wide application in the communication field pursuing wideband performance.

[0004] At present, the liquid crystal phase shifter is mostly simple and similar to a planar structure of a planar capacitor, and the phase shift efficiency is low. A large planar area is required to support the phase shift requirement of 0 to 360° (or 370°) (the basic requirement of most phased array antennas). When applied to millimeter waves, the planar area of each unit is more nervous, and the above-mentioned planar capacitor type liquid crystal phase shifter cannot meet the performance and tight area requirements of the phased array antenna. SUMMARY

[0005] Therefore, the purpose of the present application is to provide a liquid crystal phase shifter and a liquid crystal phased array antenna. The liquid crystal in the liquid crystal phase shifter is filled in the middle of the microstrip line and the metal ground, the dielectric constant of the liquid crystal material can be changed to adjust the time delay of the signal transmission on the transmission line, so as to realize the phase modulation function, and the performance requirements of the phased array antenna can be met; the structure of the microstrip line and the metal ground in the liquid crystal phase shifter is simple, the miniaturization of the liquid crystal phase shifter can be realized, the harsh requirements of the signal channel of the phased array antenna unit on the area can be met; and the processing cost is low, and mass production can be realized.

[0006] In a first aspect, the present application provides a liquid crystal phase shifter, which comprises: a microstrip line, a metal ground, a liquid crystal and a double-layer glass.

[0007] The double-layer glass comprises an upper glass and a lower glass, and the microstrip line, the metal ground and the liquid crystal are filled between the upper glass and the lower glass.

[0008] The lower surface of the upper glass is in contact with the upper surface of the microstrip line; the lower surface of the microstrip line is filled with liquid crystal in the upper surface of the metal ground; the metal ground is provided with a plurality of slots; the lower surface of the metal ground is in contact with the upper surface of the lower glass.

[0009] Optionally, the slots of the metal ground are dumbbell-shaped, and the metal ground comprises a connecting portion, a first protruding portion and a second protruding portion, the first protruding portion and the second protruding portion being connected by the connecting portion; the liquid crystal is filled between the metal ground and the microstrip line, and the microstrip line traverses the connecting portion corresponding to each slot structure in spatial position.

[0010] Optionally, the microstrip line and the metal ground are both copper conductors.

[0011] Optionally, the microstrip line is a planar copper line.

[0012] Optionally, the microstrip line comprises a single main line and a plurality of stubs; the stubs are connected perpendicularly to the main line; the liquid crystal is filled between the main line, the stubs and the metal ground; the stubs are vertically arranged above the adjacent slots of the metal ground in spatial position.

[0013] Optionally, the microstrip line comprises an input matching region, an output matching region and a main region; the size of the stubs in the main region is different from the size of the stubs in the input matching region and the output matching region.

[0014] The input matching region and the output matching region are located at two ends of the microstrip line, and the main region is located between the input matching region and the output matching region.

[0015] Optionally, the stubs in the input matching region and the output matching region are in a mirror image relationship.

[0016] Optionally, the slots and the stubs are alternately arranged in spatial position.

[0017] Optionally, the sizes of the slots in the main region are different, and the sizes of the stubs in the main region are different.

[0018] In a second aspect, the application provides a liquid crystal phased array antenna, wherein the phased array antenna is provided with the liquid crystal phase shifter mentioned in the first aspect.

[0019] The application provides a liquid crystal phase shifter and a liquid crystal phased array antenna.

[0020] Additional features and advantages of the application will be set forth in the description that follows, and in part will be apparent from the description, or can be learned by practice of the application. The objectives and other advantages of the application will be realized and attained by the structure particularly pointed out in the description and claims.

[0021] In order to make the above objectives, characteristics and advantages of the application more obvious and easy to understand, the following preferred embodiments are specifically described below, and the accompanying drawings are referred to for illustration. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the specific embodiments of the application or the technical solutions in the prior art, the following will briefly introduce the drawings needed to be used in the specific embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0023] Figure 1 The structure schematic diagram of the first liquid crystal phase shifter provided by the embodiment of the application is shown in the figure;

[0024] Figure 2 The structure schematic diagram of the second liquid crystal phase shifter provided by the embodiment of the application is shown in the figure;

[0025] Figure 3 The structure schematic diagram of the third liquid crystal phase shifter provided by the embodiment of the application is shown in the figure;

[0026] Figure 4 The structure schematic diagram of the fourth liquid crystal phase shifter provided by the embodiment of the application is shown in the figure;

[0027] Figure 5A fifth liquid crystal phase shifter provided by an embodiment of the present application is shown in the structural diagram.

[0028] Icon:

[0029] 10 - microstrip line; 20 - metal ground; 30 - liquid crystal; 41 - upper glass; 42 - lower glass;

[0030] 21 - slot; 21a - connecting part; 21b - first protruding part; 21c - second protruding part;

[0031] 11 - main line; 12 - stub line;

[0032] 10a - input matching area; 10b - output matching area; 10c - main body area. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme of the present application will be described clearly and completely below in combination with embodiments. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0034] The phased array antenna has high requirements for the time-frequency response, frequency selection, phase shift control, transmission matching and other performances of the phase shifter. The phase shifter obtained by using semiconductor technology has high power consumption and high use cost, and is difficult to form wide application. Therefore, the liquid crystal technology is fused into the phased array antenna in the prior art, mainly classified into two types of scenes: one type is to directly apply liquid crystal holographic technology to the radiation unit of the phased array antenna, and the other type is to use a liquid crystal phase shifter.

[0035] Both types adopt a "sandwich" structure filled with liquid crystal between two layers of glass, and change the structure capacitance and impedance by controlling the change of the dielectric constant of the liquid crystal, to realize the time-frequency response, frequency selection, phase shift control, transmission matching and other functions based on the variable capacitance structure.

[0036] However, in actual application, the liquid crystal phased array antenna based on the liquid crystal holographic technology has high requirements for the precision of mechanical processing, has great difficulty in industrial production, has low yield, and is difficult to control the cost; and when the holographic technology is directly applied to the microwave radiation unit, the bandwidth is too narrow, and it is difficult to obtain wide application in the communication field pursuing wideband performance.

[0037] And the current liquid crystal phase shifter is mostly a simple plane structure, and the phase shifting efficiency is low, and a large plane area is needed to support the phase shifting requirement of 0 to 360 degrees (or 370 degrees) (the basic requirement of most phased array antennas). Especially in the application of millimeter wave, the plane area of each unit is more nervous, so that the liquid crystal cannot meet the phase shifting range requirement of the phased array antenna when used as a phase shifting material. Based on this, the present application provides a liquid crystal phase shifter and a liquid crystal phased array antenna, the liquid crystal in the liquid crystal phase shifter is filled between the microstrip line and the metal ground, the dielectric constant of the liquid crystal material can be changed to adjust the time delay of the signal transmission on the microstrip line, so as to realize the phase modulation function, and the functional requirements of the phased array antenna can be met; the structure of the microstrip line and the metal ground in the liquid crystal phase shifter is simple, the miniaturization of the liquid crystal phase shifter can be realized, the requirement of the unit channel limited area in the phased array antenna can be met, and the processing cost is low, so that mass production can be realized.

[0038] In order to facilitate the understanding of the present application, first, a kind of liquid crystal phase shifter disclosed in the present application is introduced in detail, as shown in Figure 1 The structure diagram of the first liquid crystal phase shifter, including: microstrip line 10, metal ground 20, liquid crystal 30 and double-layer glass;Wherein, double-layer glass includes upper glass 41 and lower glass 42, microstrip line 10, metal ground 20, liquid crystal 30 are located between upper glass 41 and lower glass 42. The lower surface of the upper glass 41 is in contact with the upper surface of the microstrip line 10;The lower surface of the microstrip line 10 and the upper surface of the metal ground 20 are filled with liquid crystal 30;Metal ground 20 is provided with a plurality of slots;The lower surface of the metal ground 20 is in contact with the upper surface of the lower glass 42. The microstrip line 10 and the metal ground 20 are filled with liquid crystal 30;The lower surface of the metal ground 20 is in contact with the upper surface of the lower glass 42.

[0039] Specifically, the overall structure of the liquid crystal phase shifter is composed of five layers, including upper and lower glass layers, intermediate liquid crystal material layer, microstrip line layer and microstrip line metal ground layer. Among them, the liquid crystal material is filled in the interlayer between the microstrip line structure and the metal ground plate, and the time delay of the signal transmission on the microstrip line can be adjusted by changing the dielectric constant of the liquid crystal material, so as to realize the phase modulation function.

[0040] As shown in Figure 2 The structure diagram of the second liquid crystal phase shifter, the metal ground 20 is provided with a plurality of slots 21, and the slots 21 and the microstrip line 10 are filled with liquid crystal 30. The slot 21 is dumbbell type, including: connecting part 21a, first protruding part 21b and second protruding part 21c, the first protruding part 21b and the second protruding part 21c are connected through the connecting part 21a;The liquid crystal 30 is filled between the connecting part 21a and the microstrip line 10, and the microstrip line 10 traverses the corresponding connecting part 21a of each slot 21 in space position.

[0041] Optionally, the microstrip line 10 and the metal ground 20 are both copper conductors.

[0042] Optionally, the microstrip line 10 is a planar copper line.

[0043] Figure 2 The microstrip line 10 in the liquid crystal phase shifter is a single planar copper line, and the microstrip line in the two glass layers is a through structure. In order to shorten the actual length of the microstrip line, a plurality of slot structures are added on the metal ground through which the microstrip line passes. These slot structures can make the current equivalent to increase the electrical length of the signal when passing through the slot. The working principle of this kind of structure is similar to that of a low-pass filter.

[0044] As shown in Figure 3 In order to further shorten the length of the entire structure and make the structure more compact, the microstrip line 10 can optionally include a single main line 11 and a plurality of stubs 12. The stubs 12 are connected perpendicularly to the main line 11. The liquid crystal 30 is filled between the main line 11, the stubs 12 and the metal ground 20. The main line 11 is spatially located at the center of the dumbbell-shaped slot 21 on each metal ground 20. The stubs 12 are spatially located between adjacent slots 21.

[0045] The stubs 12 are added on both sides of the microstrip line 10 conductor, and the stubs 12 are spatially located between every two slots 21 on the metal ground 20, forming a "loaded stub microstrip line". The liquid crystal 30 is filled between the loaded stub microstrip line and the metal ground with slot structure, thereby forming a "loaded stub microstrip line liquid crystal phase shifter".

[0046] The stub structure is designed at this specific position (the middle of the slot on the metal ground plate) because the change in the dielectric constant of the liquid crystal only occurs in the part with the metal ground plate, but not in the part with the slot on the ground plate. Its effect is equivalent to increasing the "additional" delay produced by the electromagnetic wave signal passing through, so that the "loaded stub" liquid crystal phase shifter can be arranged in a limited unit channel area.

[0047] The liquid crystal is "driven" by applying a bias voltage to the microstrip line to change its dielectric constant.

[0048] In a simple way, this method of adding stubs to the microstrip line and opening slots in the metal ground can be called the "loaded stub" method. The "loaded stub" microstrip line structure, combined with the metal ground with slots and the liquid crystal filled between them, can make the overall structure of the liquid crystal phase shifter more compact, and can produce sufficient phase shift in a limited phased array antenna unit area to realize the overall function of the phased array antenna.

[0049] In order to make the "loading stub" structure better used in application scenarios with different bandwidth requirements, the mechanical structure of the stub can be appropriately adjusted, such as optimizing its length, width, and position parameters, to meet the requirements of different bandwidths. As shown in Figure 4 Optionally, the microstrip line 10 includes an input matching region 10a, an output matching region 10b, and a main body region 10c; the size of the stubs in the main body region 10c can be different from the size of the stubs in the input matching region 10a and the output matching region 10b, and in some scenarios, they can also be the same; wherein the input matching region 10a and the output matching region 10b are located at both ends of the microstrip line 10, and the main body region 10c is located between the input matching region 10a and the output matching region 10b.

[0050] For example, when the operating frequency band of the phased array antenna corresponding to the liquid crystal phase shifter is 17.30-21.20GHz, the size and position of the first three and the last three stub structures can be adjusted. At this time, the stubs in the input matching region 10a and the output matching region 10b are mirror images of each other. The size of the slots 21 in the main body region 10c is the same, and the size of the stubs 12 in the main body region 10c is the same. Similarly, the period and size of the slots on the ground can also be changed to achieve similar bandwidth matching.

[0051] By using the periodic layout of the "loading stub" of the microstrip line combined with appropriate size adjustment, the overall size of the phase shifter can be reduced. The "loading stub" method composed of periodic units can effectively reduce the overall structure of the liquid crystal phase shifter, which is particularly suitable for the field of phased array antennas (especially millimeter wave phased array antennas) with limited space.

[0052] As shown in Figure 5 Optionally, the size of the slots 21 in the main body region 10c can be different, and the size of the stubs 12 in the main body region 10c can also be different. Although Figure 5 The structure shown in the main body region appropriately changes the non-repetitive structure and size, the complexity of the structure design increases, but it provides more freedom for design, and also provides feasibility for achieving a larger phase shift in the same periodic unit.

[0053] Therefore, the liquid crystal phase shifter in the above embodiments has the following technical effects:

[0054] 1. The liquid crystal phase shifter can be miniaturized;

[0055] 2. The liquid crystal phase shifter can be truly applied to flat panel phased array antennas, especially in millimeter wave communication applications;

[0056] 3. It can effectively meet the demand of communication equipment for different bandwidth, especially for wideband communication equipment;

[0057] 4. The processing cost is low, the processing technology used by the "loaded stub microstrip" liquid crystal phase shifter is basically the same as the processing technology of the mature liquid crystal display at present, and there is no need for additional equipment investment;

[0058] 5. It can be mass-produced like a liquid crystal display.

[0059] In summary, the liquid crystal in the liquid crystal phase shifter is filled between the microstrip line and the metal ground, the time delay of the signal transmitted on the transmission line can be adjusted by changing the dielectric constant of the liquid crystal material, so that the phase adjusting function is realized, and the performance requirements of the phased array antenna can be met; the structure of the microstrip line and the metal ground in the liquid crystal phase shifter is simple, which facilitates the miniaturization of the liquid crystal phase shifter and meets the area requirements of the phased array antenna; at the same time, the processing cost is low, and mass production can be realized.

[0060] The embodiment of the application also provides a liquid crystal phased array antenna, which is provided with the liquid crystal phase shifter mentioned in the above embodiment.

[0061] The liquid crystal phased array antenna provided by the embodiment of the application has the same implementation principle and technical effects of the liquid crystal phase shifter as the above-mentioned liquid crystal phase shifter embodiment, and for brief description, the part not mentioned in this embodiment can refer to the corresponding content in the above-mentioned liquid crystal phase shifter embodiment.

[0062] In several embodiments provided in the present application, it should be understood that the disclosed system, device and method can be implemented in other ways. The above-described device embodiments are only schematic, for example, the division of the units is only a logical function division, and actual implementation can have another division manner, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the units shown or discussed can be indirect coupling or communication connection through some communication interfaces, devices or units, and can be electrical, mechanical or other forms.

[0063] The units described as separate components can or can not be physically separated, and the components shown as units can or can not be physical units, that is, they can be located in one place, or can be distributed on a plurality of network units. According to actual needs, part or all of the units can be selected to achieve the purpose of the embodiment scheme.

[0064] In addition, each function unit in each embodiment of the present application can be integrated in one processing unit, or each unit can be physically present separately, or two or more units can be integrated in one unit.

[0065] If the functions are realized in the form of software function units and sold or used as independent products, they can be stored in a nonvolatile computer readable storage medium executable by a processor. Based on this understanding, the technical solutions of the present application or the part of the present application that essentially contributes to the prior art can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes a plurality of instructions for causing a computer device (which can be a personal computer, an electronic device, or a network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and various program code storage media.

[0066] Finally, it should be noted that the above-described embodiments are merely specific implementations of the present application, which are used to illustrate the technical solutions of the present application, but not to limit the same. The protection scope of the present application is not limited thereto. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can make modifications or easily think of changes to the technical solutions recorded in the foregoing embodiments, or make equivalent replacements to some technical features thereof, without departing from the technical scope disclosed by the present application. Such modifications, changes or replacements do not cause the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A liquid crystal phase shifter, characterized by, The liquid crystal phase shifter comprises a microstrip line, a metal ground, liquid crystal and double-layer glass. The double-layer glass comprises upper glass and lower glass, and the microstrip line, the metal ground and the liquid crystal are filled between the upper glass and the lower glass. The lower surface of the upper glass is in contact with the upper surface of the microstrip line, the lower surface of the microstrip line and the upper surface of the metal ground are filled with the liquid crystal, the metal ground is provided with a plurality of slots, and the lower surface of the metal ground is in contact with the upper surface of the lower glass. The slots of the metal ground are dumbbell-shaped, and each of the slots comprises a connecting portion, a first protruding portion and a second protruding portion, the first protruding portion and the second protruding portion are connected by the connecting portion, and the microstrip line traverses the connecting portion of each slot in the extension direction.

2. The liquid crystal phase shifter of claim 1, wherein, The microstrip line and the metal ground are both copper conductors.

3. The liquid crystal phase shifter of claim 2, wherein, The microstrip line is a planar copper line.

4. The liquid crystal phase shifter of claim 2, wherein, The microstrip line comprises a single main line and a plurality of stubs, the stubs are connected perpendicularly to the main line, the liquid crystal is filled between the main line, the stubs and the metal ground, and the stubs are arranged perpendicularly above the metal ground between adjacent slots in the extension direction of the main line.

5. The liquid crystal phase shifter of claim 4, wherein, The microstrip line comprises an input matching region, an output matching region and a main region, the size of the stubs in the main region is different from the size of the stubs in the input matching region and the output matching region. The input matching region and the output matching region are located at two ends of the microstrip line, and the main region is located between the input matching region and the output matching region.

6. The liquid crystal phase shifter of claim 5, wherein, The stubs in the input matching region and the output matching region are mirror images of each other.

7. The liquid crystal phase shifter of claim 5, wherein, The slots and the stubs in the main region are alternately arranged in the extension direction of the main line.

8. The liquid crystal phase shifter of claim 5, wherein, The sizes of the slots in the main region are different, and the sizes of the stubs in the main region are different.

9. A liquid crystal phased array antenna, characterized by, The liquid crystal phase array antenna is provided with the liquid crystal phase shifter according to any one of claims 1 to 8.

Images