A gap waveguide liquid crystal phase shifter

Abstract

The application relates to a gap waveguide liquid crystal phase shifter, which comprises, from top to bottom, an upper layer structure, a middle metal layer and a lower layer structure; the upper layer structure comprises, from top to bottom, an upper metal layer, an upper dielectric plate, an upper glass plate, a metal patch and a liquid crystal layer; the lower layer structure comprises, from top to bottom, a lower glass plate, a lower dielectric plate and a lower metal layer; the upper dielectric plate is provided with a plurality of upper metal through holes, and the lower dielectric plate is provided with a plurality of lower metal through holes; the plurality of upper metal through holes form a gap waveguide type cavity, and the middle metal layer is provided with two slit structures. When a driving voltage is applied between the metal patch and the middle metal layer, the liquid crystal molecule deflection occurs, when the liquid crystal molecule reaches the full deflection state, the transmission phase change reaches the maximum value, and finally the continuous adjustable liquid crystal phase shifter is realized, thereby solving the problems that the traditional liquid crystal phase shifter has large loss in the microwave band and needs a certain transmission line length to achieve corresponding phase shifting capacity.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of phase shifter, in particular to a gap waveguide liquid crystal phase shifter. BACKGROUND

[0002] At present, the adjustable phase shifter is a microwave device for realizing the phase control of radio frequency signals, which is widely used in the fields of antennas, radars and wireless communications. At present, the commonly used phase shifters include PIN type phase shifter, semiconductor phase shifter, ferrite phase shifter and liquid crystal phase shifter. The PIN type phase shifter can usually only work in the low frequency band of microwaves (below X band), and has small power capacity, cannot continuously phase shift, so that the application scene is greatly limited. The semiconductor phase shifter has large loss in the millimeter wave band and high cost, which greatly limits the application in large-scale phased arrays. The ferrite phase shifter cannot be widely used due to its large size, low working frequency band and difficulty in integration.

[0003] Liquid crystal is an anisotropic material, as a uniaxial crystal, its molecular long axis has a specific direction, under the action of an external electric field or magnetic field, the long axis direction of the liquid crystal molecule will be deflected, thereby causing the change of the macroscopic dielectric constant of the liquid crystal material. Compared with the above other phase shifters, the liquid crystal phase shifter has the advantages of continuous tuning, high linearity, small size, light weight and the like.

[0004] However, the existing liquid crystal phase shifter is generally based on the traditional microstrip transmission line semi-open structure, which has large loss in the microwave band, and needs a certain transmission line length to achieve the corresponding phase shift capability, which seriously limits its actual application value. SUMMARY

[0005] The purpose of the present application is to provide a gap waveguide liquid crystal phase shifter, when a driving voltage is applied between the metal patch and the intermediate metal layer, the liquid crystal molecule direction is deflected, when the liquid crystal molecule reaches the full deflection state, the transmission phase change reaches the maximum value, finally realizing the continuous adjustable liquid crystal phase shifter, solving the problem that the traditional liquid crystal phase shifter has large loss in the microwave band, and needs a certain transmission line length to achieve the corresponding phase shift capability.

[0006] To achieve the above purpose, the present application provides the following technical scheme:

[0007] A gap waveguide liquid crystal phase shifter, from top to bottom, includes an upper layer structure, an intermediate metal layer and a lower layer structure; the upper layer structure includes, from top to bottom, an upper metal layer, an upper dielectric plate, an upper glass plate, a metal patch and a liquid crystal layer; the lower layer structure includes, from top to bottom, a lower glass plate, a lower dielectric plate and a lower metal layer;

[0008] The upper dielectric plate is provided with a plurality of upper metal vias, and the lower dielectric plate is provided with a plurality of lower metal vias; the plurality of upper metal vias form a gap waveguide type cavity, the intermediate metal layer is provided with two slit structures for coupling of electromagnetic energy of upper and lower layers; and the plurality of lower metal vias form a pair of back-to-back gap waveguides.

[0009] Optionally, the plurality of upper metal vias are arranged to form a gap waveguide type cavity.

[0010] Optionally, two rows of lower metal vias are uniformly arranged on the front and back sides of the lower dielectric plate along the length direction of the lower dielectric plate; and two rows of lower metal vias are uniformly arranged at the center of the lower dielectric plate along the width direction of the lower dielectric plate, and the plurality of lower metal vias form the pair of back-to-back gap waveguides.

[0011] Optionally, the metal patch is provided with two metal patches, and the two metal patches are located directly above the two slit structures, respectively.

[0012] Optionally, the two slit structures are close to the short-circuit terminals of the two gap waveguides.

[0013] Optionally, the diameter of the upper metal via is the same as the diameter of the lower metal via.

[0014] The pitch between adjacent two upper metal vias is the same as the pitch between adjacent two lower metal vias.

[0015] The pitch between the upper metal via and the edge of the upper dielectric plate is the same as the pitch between the lower metal via and the edge of the lower dielectric plate.

[0016] Optionally, the height of the upper metal via and the lower metal via is h1=0.25λ g , λ g is the dielectric wavelength corresponding to the working center frequency.

[0017] Optionally, the dielectric parameters of the liquid crystal molecules of the liquid crystal layer are: ε r，⊥ =2.24, ε r， / / =3.22, tanδ ⊥ =0.06, tanδ / / =0.004.

[0018] Optionally, the dielectric constant of the upper glass plate and the lower glass plate is 4.7.

[0019] Compared with the prior art, the embodiments of the present application have the following beneficial effects:

[0020] 1. When the driving voltage is applied between the metal patch and the intermediate metal layer, the liquid crystal molecule orientation deflects, and when the liquid crystal molecule reaches the full deflection state, the transmission phase change reaches the maximum value, finally realizing the continuously adjustable liquid crystal phase shifter, solving the problem that the traditional liquid crystal phase shifter has large loss in the microwave band and needs a certain transmission line length to achieve the corresponding phase shifting capability;

[0021] 2. The electromagnetic wave starts to transmit from the gap waveguide on the left side of the lower structure, is coupled to the gap waveguide cavity of the upper structure via the reflection of the shorted terminal between the gap waveguide type cavity and the gap structure on the left end, is transmitted along the gap waveguide type cavity to the gap structure on the right end, and is coupled to the gap waveguide cavity of the gap waveguide type cavity structure to reach the output port again. The metal patch combined with the liquid crystal layer can play a disturbance role on the electromagnetic wave transmission. When the driving voltage is applied between the metal patch and the intermediate metal layer, the liquid crystal molecule orientation in the liquid crystal layer deflects, and with the change of the driving voltage value, the deflection angle of the liquid crystal molecule can continuously change, so that the dielectric constant of the liquid crystal material continuously changes, which makes the capacitance formed by the metal patch and the opposite intermediate metal layer continuously change, and plays a continuous disturbance role on the propagation of the electromagnetic wave. This continuous disturbance will cause the phase of the electromagnetic wave transmitted between the upper and lower layers to change, and with the continuous change of the applied driving voltage value, the phase of the transmitted electromagnetic wave will also continuously change, and when the liquid crystal molecule reaches the full deflection state, the transmission phase change reaches the maximum value, finally realizing the continuously adjustable liquid crystal phase shifter. BRIEF DESCRIPTION OF DRAWINGS

[0022] Fig. 1 is an exploded view of the gap waveguide liquid crystal phase shifter of one embodiment of the application;

[0023] Fig. 2 is a sectional view of the gap waveguide liquid crystal phase shifter of one embodiment of the application;

[0024] Fig. 3 is a schematic view of the upper dielectric plate and the upper metal via of one embodiment of the application;

[0025] Fig. 4 is a schematic view of the lower dielectric plate and the lower metal via of one embodiment of the application;

[0026] In the figure, 1 is an upper structure, 11 is an upper metal layer, 12 is an upper dielectric plate, 13 is an upper metal via, 14 is an upper glass plate, 15 is a metal patch, 16 is a liquid crystal layer, 2 is an intermediate metal layer, 21 is a gap structure, 3 is a lower structure, 31 is a lower glass plate, 32 is a lower dielectric plate, 33 is a lower metal via, and 34 is a lower metal layer. DETAILED DESCRIPTION

[0027] Embodiments of the present application are described below in detail with reference to the accompanying drawings, wherein the same or similar elements or elements having the same or similar functions are denoted by the same or similar reference signs throughout. The embodiments described below by reference to the accompanying drawings are exemplary and are only used to explain the present application and cannot be understood as a limitation of the present application.

[0028] In the description of the present application, it should be understood that the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, which are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application. In addition, the features defined as "first" and "second" can explicitly or implicitly include one or more of the features, which are used to distinguish the described features, without order or importance.

[0029] In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0030] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0031] The embodiments of the present application are described below in conjunction with Figs. 1 to 4 A gap waveguide liquid crystal phase shifter.

[0032] A gap waveguide liquid crystal phase shifter, comprising from top to bottom an upper layer structure 1, a middle metal layer 2 and a lower layer structure 3; the upper layer structure 1 comprises from top to bottom an upper metal layer 11, an upper dielectric plate 12, an upper glass plate 14, a metal patch 15 and a liquid crystal layer 16; the lower layer structure 3 comprises from top to bottom a lower glass plate 31, a lower dielectric plate 32 and a lower metal layer 34;

[0033] The upper dielectric plate 12 is provided with a plurality of upper metal vias 13, and the lower dielectric plate 32 is provided with a plurality of lower metal vias 33; a plurality of the upper metal vias 13 form a gap waveguide type cavity, the middle metal layer 2 is provided with two slit structures 21, the slit structures 21 are used for the coupling of electromagnetic energy between the upper and lower layers; a plurality of the lower metal vias 33 form a pair of back-to-back gap waveguides.

[0034] The working process of the gap waveguide liquid crystal phase shifter of the present solution is as follows: electromagnetic waves are transmitted from the gap waveguide on the left side of the lower structure 3, and the electromagnetic waves are coupled to the gap waveguide cavity of the upper structure 1 via the reflection of the gap structure 21 on the left end and the short-circuit terminal between the two gap waveguides, transmitted along the gap waveguide type cavity to the gap structure 21 on the right end, and then coupled to the gap waveguide cavity of the gap waveguide type cavity structure to reach the output port.

[0035] It is worth mentioning that the metal patch 15 in combination with the liquid crystal layer 16 can play a role in disturbing the transmission of electromagnetic waves. When a driving voltage is applied between the metal patch 15 and the intermediate metal layer 2, the orientation of the liquid crystal molecules in the liquid crystal layer 16 is deflected, and as the value of the driving voltage changes, the deflection angle of the liquid crystal molecules can continuously change, thereby causing the dielectric constant of the liquid crystal material to continuously change, which causes the capacitance formed by the metal patch 15 and the opposite intermediate metal layer 2 to continuously change, thereby continuously disturbing the propagation of electromagnetic waves.

[0036] This continuous disturbance will cause the phase of the electromagnetic waves transmitted between the upper and lower layers to change, and as the value of the applied driving voltage continuously changes, the phase of the transmitted electromagnetic waves will also continuously change. When the liquid crystal molecules reach the full deflection state, the transmission phase change reaches a maximum value, and finally a continuously adjustable liquid crystal phase shifter is realized, solving the problem of large loss of traditional liquid crystal phase shifters in the microwave band and the need for a certain transmission line length to achieve the corresponding phase shift capability.

[0037] A plurality of the upper metal vias 13 are arranged to form a gap waveguide type cavity.

[0038] The gap waveguide type cavity is arranged on the upper dielectric plate 12, so that the electromagnetic waves can be coupled to the gap waveguide type cavity under the reflection of the gap structure 21 and the short-circuit terminal, and the electromagnetic waves can be transported along the gap waveguide type cavity to another gap structure 21.

[0039] The front and back sides of the lower dielectric plate 32 are uniformly arranged with two rows of lower metal vias 33 along the length direction of the lower dielectric plate 32; the center of the lower dielectric plate 32 is uniformly arranged with two rows of lower metal vias 33 along the width direction of the lower dielectric plate 32, and a plurality of the lower metal vias 33 form the pair of back-to-back gap waveguides.

[0040] The two gap waveguides of the lower dielectric plate 32 are arranged back to back, so that a short-circuit terminal is formed in the middle of the two gap waveguides, and the electromagnetic waves can be coupled to the gap waveguide type cavity under the reflection of the circuit terminal.

[0041] The metal patch 15 is provided with two, two of the metal patch 15 is located above the gap structure 21.

[0042] The metal patch 15 is long l4, wide w4, the metal patch 15 is processed in the upper glass plate 14 lower surface, and two metal patches 15 are located above two gap structures 21 respectively. The metal patch 15 can be adjusted with the middle metal layer 2 together to regulate the liquid crystal layer 16, so that the deflection angle of liquid crystal molecules can be changed continuously.

[0043] Two of the gap structure 21 is close to the short circuit terminal of two gap waveguides.

[0044] The gap structure 21 is long l3, wide w3, and the gap structure 21 is located in the middle metal layer 2, and the gap structure 21 is close to the short circuit terminal of two gap waveguides, which can be used for the coupling of upper and lower electromagnetic energy.

[0045] The diameter of the upper metal via 13 is the same as the diameter of the lower metal via 33;

[0046] The distance between adjacent two upper metal vias 13 is the same as the distance between adjacent two lower metal vias 33;

[0047] The distance between the upper metal via 13 and the edge of the upper dielectric plate 12 is the same as the distance between the lower metal via 33 and the edge of the lower dielectric plate 32.

[0048] Preferably, all metal via diameter is 0.2mm, and the distance between vias is 0.4mm. On the one hand, it reduces the complexity of processing, on the other hand, the diameter and distance of metal via exist the optimal solution for the suppression of electromagnetic wave leakage, and the consistent upper and lower parameters can minimize electromagnetic wave leakage and improve transmission efficiency.

[0049] The height of the upper metal via 13 and the lower metal via 33 is h1=0.25λ g , λ g is the medium wavelength corresponding to the working center frequency. The dielectric parameters of the liquid crystal molecules of the liquid crystal layer 16 are: ε r，⊥ =2.24, ε r， / / =3.22, tanδ ⊥ =0.06, tanδ / / =0.004. The dielectric constant of the upper glass plate 14 and the lower glass plate 31 is 4.7.

[0050] Preferably, the specific structural parameters of the adjustable gap waveguide liquid crystal phase shifter working in the range of 25-30 GHz are h1=1.5 mm, h2=0.5 mm, h3=0.008 mm, t=0.003 mm, l1=12 mm, w1=5.2 mm, w2=0.5 mm, l2=3.8 mm, l3=2.4 mm, w3=0.15 mm, l4=0.3 mm, w4=0.4 mm, d=1.4 mm. In addition, the dielectric plate material is Rogers RO3003, the dielectric constant of the upper glass plate 14 and the lower glass plate 31 is 4.7, the loss tangent is 0.0048, and the dielectric parameters of the liquid crystal material are: ε r，⊥ =2.24, ε r， / / =3.22, tan δ ⊥ =0.06, tan δ / / =0.004.

[0051] The adjustable gap waveguide liquid crystal phase shifter prepared by using the specific structural parameters described above has a maximum adjustable phase shift greater than 70° in the working frequency band range of 25-30 GHz for both the horizontal and aligned states of the liquid crystal molecules.

[0052] Other configurations and operations of the gap waveguide liquid crystal phase shifter according to the embodiments of the present application are known to those skilled in the art, and will not be described in detail here.

[0053] In the description of the present specification, the description referring to the terms "embodiment", "example", and the like means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0054] Although the embodiments of the present application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions, and variations can be made to the embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the claims and their equivalents.

Claims

1. A gap waveguide liquid crystal phase shifter, characterized by, From top to bottom, the structure comprises an upper layer structure, a middle metal layer and a lower layer structure; the upper layer structure comprises, from top to bottom, an upper metal layer, an upper dielectric plate, an upper glass plate, a metal patch and a liquid crystal layer; the lower layer structure comprises, from top to bottom, a lower glass plate, a lower dielectric plate and a lower metal layer; The upper dielectric plate is provided with a plurality of upper metal vias, and the lower dielectric plate is provided with a plurality of lower metal vias; the plurality of upper metal vias form a gap waveguide type cavity, the middle metal layer is provided with two slit structures, and the slit structures are used for coupling of electromagnetic energy of upper and lower layers; The plurality of lower metal vias form a pair of back-to-back gap waveguides. The height of the upper metal via and the lower metal via is h1=0.25 , is the medium wavelength corresponding to the operating center frequency; The metal patch is provided with two metal patches, and the two metal patches are located directly above the slit structures.

2. A gap waveguide liquid crystal phase shifter according to claim 1, characterized in that, The plurality of upper metal vias are arranged to form a gap waveguide type cavity.

3. The gap waveguide liquid crystal phase shifter of claim 1, wherein, The front and back sides of the lower dielectric plate are uniformly arranged with two rows of lower metal vias along the length direction of the lower dielectric plate; the center of the lower dielectric plate is uniformly arranged with two rows of lower metal vias along the width direction of the lower dielectric plate, and the plurality of lower metal vias form the pair of back-to-back gap waveguides.

4. The gap waveguide liquid crystal phase shifter of claim 1, wherein, The two slit structures are close to the short-circuit terminals of the two gap waveguides.

5. The gap waveguide liquid crystal phase shifter according to claim 1, wherein, The diameter of the upper metal via is the same as that of the lower metal via; The spacing between adjacent two upper metal vias is the same as that between adjacent two lower metal vias; The spacing between the upper metal via and the edge of the upper dielectric plate is the same as that between the lower metal via and the edge of the lower dielectric plate.

6. The gap waveguide liquid crystal phase shifter according to claim 1, wherein, The liquid crystal molecules of the liquid crystal layer have a dielectric parameter of: , , , .

7. The gap waveguide liquid crystal phase shifter according to claim 1, wherein, The dielectric constant of the upper glass plate and the lower glass plate is 4.7.

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