Liquid crystal phase shifter and antenna

Abstract

A liquid crystal phase shifter and an antenna. The liquid crystal phase shifter, comprising: a first substrate (1), a second substrate (2), a liquid crystal layer (3), a microstrip line layer (5), and a reference electrode layer (4). The microstrip line layer (5) comprises a first electrode (51) and a second electrode (52) spaced apart from each other in a first direction; the first electrode (51) comprises a first main body portion (511) and a plurality of first branch portions (512) located on the side of the first main body portion (511) away from the second electrode (52) and arranged at intervals in a second direction; and the second electrode (52) comprises a second main body portion (521) and a plurality of second branch portions (522) located on the side of the second main body portion (521) away from the first electrode (51) and arranged at intervals in the second direction. The first direction intersects the second direction. The orthographic projections of the first electrode (51) and the second electrode (52) on the first substrate (1) overlap the orthographic projection of the reference electrode layer (4) on the first substrate (1); the reference electrode layer (4) is provided with openings (30), and the orthographic projections of the first branch portions (512) and the second branch portions (522) on the first substrate (1) do not overlap the orthographic projections of the openings (30) on the first substrate (1).

Description

Liquid crystal phase shifter and antenna TECHNICAL FIELD

[0001] The present disclosure relates to the field of communication technology, and in particular to a liquid crystal phase shifter and an antenna. BACKGROUND

[0002] With the gradual development of communication technology, liquid crystal phase shifters have been more and more widely used. The liquid crystal phase shifter is a device used to change the phase of an electromagnetic wave signal. For example, in the case of a liquid crystal phase shifter, the liquid crystal in the liquid crystal cell rotates under the action of the electric field formed between the microstrip line and the ground electrode, the dielectric constant of the liquid crystal changes, and thus the radio frequency signal transmitted in the liquid crystal phase shifter is phase shifted. Liquid crystal phase shifters can be widely used in satellite communication, communication base stations and other scenarios.

[0003] SUMMARY

[0004] The present disclosure aims to at least solve one of the technical problems existing in the prior art, and proposes a liquid crystal phase shifter and an antenna.

[0005] In order to achieve the above-mentioned purpose, the present disclosure provides a liquid crystal phase shifter, comprising:

[0006] a first substrate and a second substrate arranged opposite to each other;

[0007] a liquid crystal layer located between the first substrate and the second substrate;

[0008] a microstrip line layer located on one side of the first substrate facing the liquid crystal layer;

[0009] a reference electrode layer located on one side of the second substrate facing the liquid crystal layer;

[0010] wherein the microstrip line layer comprises a first electrode and a second electrode arranged at intervals along a first direction; the first electrode comprises a first main body portion extending along a second direction and a plurality of first branch portions electrically connected to the first main body portion, the plurality of first branch portions being located on a side of the first main body portion away from the second electrode and arranged at intervals along the second direction; the second electrode comprises a second main body portion extending along the second direction and a plurality of second branch portions electrically connected to the second main body portion, the plurality of second branch portions being located on a side of the second main body portion away from the first electrode and arranged at intervals along the second direction; and the first direction intersects the second direction.

[0011] The first electrode and the second electrode have a projection on the first substrate that overlaps with a projection of the reference electrode layer on the first substrate; the reference electrode layer has an opening, and the first branch and the second branch have a projection on the first substrate that does not overlap with a projection of the opening on the first substrate.

[0012] In some embodiments, the reference electrode layer includes a third electrode and a fourth electrode arranged along the first direction, and a plurality of extension electrodes between the third electrode and the fourth electrode, the plurality of extension electrodes being arranged at intervals along the second direction, and the opening includes a first sub-gap between two adjacent extension electrodes;

[0013] The third electrode has a projection on the first substrate that overlaps with the first branch, and the fourth electrode has a projection on the first substrate that overlaps with the second branch; and the extension electrodes have a projection on the first substrate that overlaps with the first branch and the second branch.

[0014] In some embodiments, the extension electrodes include a first extension and a second extension arranged at intervals along the first direction, the first extension being electrically connected to the third electrode, and the second extension being electrically connected to the fourth electrode;

[0015] The opening further includes a second sub-gap between the first extension and the second extension, and the first sub-gap is connected to the second sub-gap;

[0016] The first main body and the second main body have a third gap therebetween, and the second sub-gap has a projection on the first substrate that overlaps with a projection of the third gap on the first substrate.

[0017] In some embodiments, the third electrode and the fourth electrode are electrically connected through the extension electrodes, and two adjacent first sub-gaps are independent of each other.

[0018] In some embodiments, the reference electrode layer further includes a connection electrode extending along the second direction;

[0019] The connection electrode is electrically connected to the extension electrodes, and the connection electrode separates the first sub-gap into a first gap part adjacent to the third electrode and a second gap part adjacent to the fourth electrode.

[0020] In some embodiments, the reference electrode layer comprises a middle region and edge regions located on opposite sides of the middle region in the second direction, and a plurality of the first sub-gaps extending in the first direction are arranged in both the middle region and the edge regions; in the edge regions, the length of the plurality of the first sub-gaps gradually increases in a direction close to the middle region.

[0021] In some embodiments, there is a first gap between two adjacent first branch parts, and a second gap between two adjacent second branch parts.

[0022] The first gap and the second gap each correspond to one of the first sub-gaps.

[0023] The lengths of two first branch parts adjacent to the ith first gap in the first direction are Ci and Ci+1 respectively, the lengths of two second branch parts adjacent to the ith second gap in the first direction are Li and Li+1 respectively, the width of the first main part in the first direction is H1, the width of the second main part in the first direction is H2, the width of the third gap in the first direction is S, and the length of the ith first sub-gap in the first direction is Ki, where Ki = max[Ci, Ci+1] + max[Li, Li+1] + H1 + H2 + S, max[] represents a maximum function, i = 1, 2, 3, …, n-1; n is the total number of the first branch parts or the second branch parts.

[0024] In some embodiments, the opening comprises a plurality of third sub-gaps arranged at intervals in the second direction.

[0025] The orthogonal projection of any one of the first gap, the second gap, the first main part and the second main part on the first substrate overlaps with the orthogonal projection of the third sub-gap on the first substrate.

[0026] The plurality of third sub-gaps are symmetrical about a first symmetry axis, wherein the first symmetry axis extends in the first direction.

[0027] In some embodiments, the third sub-gap comprises a first slit, a second slit and a third slit.

[0028] The first slit and the second slit are arranged at intervals in the first direction, and both the first slit and the second slit extend in the second direction.

[0029] The third slit extends in the first direction and is located between and communicates the first slit and the second slit.

[0030] In some embodiments, the width of the third slit is constant from both ends to the center of the third slit; or,

[0031] The width of at least part of the third slit gradually decreases from both ends to the center of the third slit.

[0032] In some embodiments, the third slit has a first edge and a second edge oppositely arranged in the second direction; the distance between the first edge and the second edge gradually decreases from both ends to the center of the third slit;

[0033] The first edge and the second edge are both part of an ellipse, wherein the length of the major axis of the ellipse is a, the length of the minor axis of the ellipse is b; the minimum distance between the first edge and the second edge is d; the center frequency point of the liquid crystal phase shifter corresponds to a wavelength λ;

[0034] Wherein, λ≥a>b≥λ / 100; λ / 2≥d≥λ / 100.

[0035] In some embodiments, the third sub-interstitial space includes a fourth slit extending in the first direction and a plurality of fifth slits arranged on both sides of the fourth slit in the second direction and spaced apart; the fifth slit communicates with the fourth slit.

[0036] In some embodiments, the third sub-interstitial space is an axisymmetric pattern symmetrical about a second axis of symmetry, and the second axis of symmetry extends in the first direction; and / or, the third sub-interstitial space is a center-symmetric pattern symmetrical about the center of the third sub-interstitial space.

[0037] In some embodiments, the sum of the areas of a plurality of the third sub-interstitial spaces does not exceed 1 / 2 of the area of the reference electrode layer;

[0038] And / or, the length of the third sub-interstitial space in the first direction does not exceed 1 / 4 of the length of the reference electrode layer in the second direction.

[0039] In some embodiments, the thickness of the liquid crystal layer is H, the distance between the first main body part and the second main body part is S, the length of the first main body part in the first direction is H1; the length of the second main body part in the first direction is H2;

[0040] Wherein, S / H≥0.005, H1 / H≤5, H2 / H≤5.

[0041] In some embodiments, a distance between the first body part and the second body part is S, a length of the first body part in the first direction is H1; a length of the second body part in the first direction is H2; a length of the first body part in the second direction is H3; a length of the second body part in the second direction is H4; and a wavelength corresponding to a center frequency point of the liquid crystal phase shifter is λ.

[0042] wherein S≤λ / 100; H1≤λ / 100; H2≤λ / 100; H3≥λ / 2; and H4≥λ / 2.

[0043] In some embodiments, a length of the first branch part in the second direction is Y, a length of the first branch part in the first direction is L, a length of the second branch part in the second direction is T, a length of the second branch part in the first direction is C; and a wavelength corresponding to a center frequency point of the liquid crystal phase shifter is λ.

[0044] wherein Y≤λ / 10, L≤λ / 10, T≤λ / 10, and C≤λ / 10.

[0045] The present disclosure provides an antenna comprising the liquid crystal phase shifter according to any one of the above. BRIEF DESCRIPTION OF DRAWINGS

[0046] The accompanying drawings are included to provide a further understanding of the present disclosure and constitute a part of the specification, illustrate embodiments of the present disclosure and together with the specific description given below serve the purpose of explaining the present disclosure. In the drawings:

[0047] FIG. 1 is an exploded view of a structure of a liquid crystal phase shifter in some embodiments of the present disclosure;

[0048] FIG. 2 is a schematic view of a structure of a microstrip line layer and a reference electrode layer in some embodiments of the present disclosure;

[0049] FIG. 3 is a schematic view of a structure of a microstrip line layer and a reference electrode layer in some other embodiments of the present disclosure;

[0050] FIG. 4 is a schematic view of a structure of a microstrip line layer and a reference electrode layer in some other embodiments of the present disclosure;

[0051] FIG. 5 is a schematic view of a structure of a microstrip line layer and a reference electrode layer in some other embodiments of the present disclosure;

[0052] FIG. 6 is a schematic view of a structure of a microstrip line layer and a reference electrode layer in some other embodiments of the present disclosure;

[0053] FIG. 7 is a schematic view of a structure of a microstrip line layer and a reference electrode layer in some other embodiments of the present disclosure;

[0054] FIG. 8 is a simulation effect diagram in some embodiments of the present disclosure. Detailed Implementation

[0055] The specific embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit this disclosure.

[0056] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the described embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0057] Unless otherwise defined, the technical or scientific terms used in the embodiments of this disclosure should have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms "first," "second," and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0058] As used herein, “parallel” and “perpendicular” include the described situation and situations that are similar to the described situation, within an acceptable range of deviation, which is determined by those skilled in the art taking into account the measurement under discussion and the error associated with the measurement of a particular quantity (i.e., the limitations of the measurement system). For example, “parallel” includes absolute parallelism and approximate parallelism, where an acceptable range of deviation for approximate parallelism may be, for example, within 5°; “perpendicular” includes absolute perpendicularity and approximate perpendicularity, where an acceptable range of deviation for approximate perpendicularity may also be, for example, within 5°.

[0059] It should be understood that when a layer or element is referred to as being on another layer or substrate, it can mean that the layer or element is directly on the other layer or substrate, or that there is an intermediate layer between the layer or element and the other layer or substrate.

[0060] Exemplary embodiments are described herein with reference to cross-sectional and / or plan view illustrations that are schematic and for purposes of illustration only. Variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and / or tolerances, are to be expected. Thus, exemplary embodiments should not be construed as limited to the particular shapes of the regions illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. The regions illustrated in the figures are schematic in nature and their shapes are not intended to illustrate the actual shape of a region of a device and are not intended to limit the scope of exemplary embodiments.

[0061] In the related art, the transmission characteristics of the liquid crystal phase shifter based on the microstrip line structure are all periodic loading structures with low-pass characteristics, and the phase shift effect is achieved by adjusting some parameters. However, the phase shift degree in the unit loss is low, so the loss is large when a large angle of phase shift is achieved, thereby reducing the overall performance of the liquid crystal phase shifter. Therefore, improving the phase shift degree is a key point in the research of the liquid crystal phase shifter. The liquid crystal phase shifter as a core device of the feed network basically determines the level of antenna performance. Common liquid crystal phase shifters based on the microstrip line structure include liquid crystal phase shifters based on the CPW (coplanar waveguide) structure and liquid crystal phase shifters based on MEMS switches. Among them, the liquid crystal phase shifter based on the CPW has the disadvantage of large loss. Although the liquid crystal phase shifter based on the MEMS switch can make a low-loss liquid crystal phase shifter and reduce the insertion loss of the liquid crystal phase shifter, long-term use will cause mechanical fatigue and short service life of the switch, thereby further challenging the wide application of the liquid crystal phase shifter based on the MEMS switch.

[0062] Meanwhile, the liquid crystal phase shifter based on the microstrip line structure also has the problems of relatively low phase shift amount, which cannot meet the development needs of high-performance liquid crystal phase shifters.

[0063] To at least alleviate or solve one of the above-mentioned technical problems, the present disclosure provides a liquid crystal phase shifter and an antenna.

[0064] The present disclosure provides a liquid crystal phase shifter. FIG. 1 is an exploded view of the structure of the liquid crystal phase shifter in some embodiments of the present disclosure.

[0065] In some embodiments, as shown in FIG. 1, the liquid crystal phase shifter in the embodiments of the present disclosure includes a first substrate 1, a second substrate 2, a liquid crystal layer 3, a microstrip line layer 5, and a reference electrode layer 4. Wherein, the first substrate 1 and the second substrate 2 are oppositely arranged, the liquid crystal layer 3 is located between the first substrate 1 and the second substrate 2, the microstrip line layer 5 is located on the side of the first substrate 1 facing the liquid crystal layer 3, and the reference electrode layer 4 is located on the side of the second substrate 2 facing the liquid crystal layer 3.

[0066] Optionally, the material of the first substrate 1 can be a common PCB insulating board material such as a polytetrafluoroethylene glass fiber pressboard, a phenolic paper laminate, a phenolic glass cloth laminate, etc., or a hard material such as quartz or glass with low microwave loss.

[0067] Optionally, the material of the second substrate 2 can be an insulating board material such as a polytetrafluoroethylene glass fiber pressboard, a phenolic paper laminate, a phenolic glass cloth laminate, etc., or a hard material such as quartz or glass with low microwave loss.

[0068] Optionally, the material of the microstrip line layer 5 can be a low-resistance and low-loss metal such as copper, gold, or silver.

[0069] Optionally, the material of the reference electrode layer 4 can be a low-resistance and low-loss metal such as copper, gold, or silver.

[0070] Optionally, the microstrip line layer 5 and the reference electrode layer 4 can be prepared by using a plurality of methods such as Sputter, thermal evaporation, electroplating, etc., or a combination of the methods, for example, a first layer of metal can be prepared by using Sputter, and then another layer of metal can be prepared on the basis of the first layer of metal by using electroplating.

[0071] FIG. 2 is a structural schematic diagram of a microstrip line layer and a reference electrode layer in some embodiments of the present disclosure. FIG. 3 is a structural schematic diagram of a microstrip line layer and a reference electrode layer in some other embodiments of the present disclosure. FIG. 4 is a structural schematic diagram of a microstrip line layer and a reference electrode layer in some other embodiments of the present disclosure. FIG. 5 is a structural schematic diagram of a microstrip line layer and a reference electrode layer in some other embodiments of the present disclosure. FIG. 6 is a structural schematic diagram of a microstrip line layer and a reference electrode layer in some other embodiments of the present disclosure. FIG. 7 is a structural schematic diagram of a microstrip line layer and a reference electrode layer in some other embodiments of the present disclosure.

[0072] In some embodiments, as shown in FIGS. 2 to 7, the microstrip line layer 5 includes first electrodes 51 and second electrodes 52 arranged at intervals along a first direction; the first electrode 51 includes a first main body part 511 extending along a second direction and a plurality of first branch parts 512 electrically connected to the first main body part 511. The plurality of first branch parts 512 are located on a side of the first main body part 511 away from the second electrode 52 and arranged at intervals along the second direction. The second electrode 52 includes a second main body part 521 extending along the second direction and a plurality of second branch parts 522 electrically connected to the second main body part 521. The plurality of second branch parts 522 are located on a side of the second main body part 521 away from the first electrode 51 and arranged at intervals along the second direction. The first direction intersects the second direction. Optionally, the first direction is perpendicular to the second direction.

[0073] The orthographic projection of the first electrode 51 on the first substrate 1 and the orthographic projection of the reference electrode layer 4 on the first substrate 1 both exist overlapping, the orthographic projection of the second electrode 52 on the first substrate 1 and the orthographic projection of the reference electrode layer 4 on the first substrate 1 exist overlapping, and the reference electrode layer 4 is provided with the opening 30. Moreover, the orthographic projection of the first branch part 512 and the second branch part 522 on the first substrate 1 both do not overlap with the orthographic projection of the opening 30 on the first substrate 1.

[0074] The microstrip line layer 5 and the reference electrode layer 4 are designed in the liquid crystal phase shifter, the opening is arranged on the reference electrode layer to form a defect ground structure, and the parallel variable plate capacitance is introduced by designing the position of the microstrip line layer 5 and the opening, and the effective dielectric constant εr of the liquid crystal layer 3 between the microstrip line layer 5 and the reference electrode layer 4 is further changed, so that the capacitance value of the variable capacitance is changed, so as to realize the phase shift.

[0075] Further, the positions and shapes of the first main body part 511, the first branch part 512, the second main body part 521 and the second branch part 522 are designed, and a plurality of variable capacitances can be formed between the first main body part 511, the first branch part 512, the second main body part 521 and the second branch part 522 and the reference electrode layer 4, so as to realize the change of the phase and achieve the purpose of the phase shift.

[0076] Further, the opening 30 on the reference electrode layer 4 can be periodically distributed or non-periodically distributed. Due to the existence of the defect ground structure, the distributed capacitance and the distributed inductance of the liquid crystal phase shifter are changed, so that the liquid crystal phase shifter has specific slow wave and band gap characteristics.

[0077] Therefore, the liquid crystal phase shifter based on the defect ground structure in the embodiment of the present disclosure has the advantages of small loss, wider SW (short wave) frequency range and higher quality factor, and simultaneously has higher power handling capacity and reduces manufacturing tolerance.

[0078] Optionally, as shown in FIGS. 2 to 7, the length H3 of the first main body part 511 in the second direction is equal to the length H4 of the second main body part 521 in the second direction, and the width H1 of the first main body part 511 in the first direction is equal to the width H2 of the second main body part 521 in the first direction.

[0079] Optionally, as shown in FIGS. 2 to 7, the first branch part 511 corresponds to the second branch part 512 one by one, the length L of the first branch part 512 in the first direction is equal to the length C of the corresponding second branch part 522 in the first direction, and the width Y of the first branch part 512 in the second direction is equal to the width T of the corresponding second branch part 522 in the second direction.

[0080] Optionally, as shown in FIGS. 2-7, the lengths L of the different first branch parts 512 in the first direction can be the same or different. The lengths Y of the different first branch parts 512 in the second direction can be the same or different. The lengths C of the different second branch parts 522 in the first direction can be the same or different. The lengths T of the different second branch parts 522 in the second direction can be the same or different.

[0081] In the embodiments of the present disclosure, the position and size of each first branch part 512 and the position and size of each second branch part 522 are adjustable, which can adapt to different impedance matching requirements and meet different migration requirements. Alternatively, after the first main part 511 and the second main part 521 are determined, the position and size of the first branch part 512 and the second branch part 522 can be simulated and optimized so that the phase shift function of the liquid crystal phase shifter meets the requirements.

[0082] In some embodiments, as shown in FIGS. 2-7, the thickness of the liquid crystal layer 3 is H, the distance between the first main part 511 and the second main part 521 is S, the length of the first main part 511 in the first direction is H1, and the length of the second main part 521 in the first direction is H2; wherein S / H≥0.005, H1 / H≤5, and H2 / H≤5. For example, S / H=0.005, 0.0052, 0.0054, 0.0056, 0.0058, 0.006, 0.007, 0.008, or 0.009. H1 / H=5, 4.8, 4.6, 4.4, 4.2, or 4. H2 / H=5, 4.8, 4.6, 4.4, 4.2, or 4.

[0083] In the embodiments of the present disclosure, by controlling the relationship between the size of the first main part 511 and the second main part 521 in the microstrip line layer 5 and the thickness of the liquid crystal layer 3, the coupling strength of the microstrip line layer 5 can be improved.

[0084] Optionally, the material of the liquid crystal layer 3 includes a liquid crystal material.

[0085] Optionally, the material of the liquid crystal layer 3 includes a liquid crystal material and other dielectric constant adjustable medium, such as graphene.

[0086] Optionally, the thickness of the liquid crystal layer 3 has a certain influence on the coupling strength, and the thickness of the liquid crystal layer should not be too large. In the embodiments of the present disclosure, the thickness of the liquid crystal layer 3 is 30-35 um, for example, it can be 30 um, 31 um, 32 um, 33 um, 34 um, or 35 um.

[0087] The embodiments of the present disclosure can realize continuous adjustment of the phase by adjusting the dielectric constant of the liquid crystal material through an external voltage. The embodiments of the present disclosure can not only improve the phase adjustment accuracy of the liquid crystal phase shifter, but also greatly reduce the size and power consumption of the liquid crystal phase shifter.

[0088] In some embodiments, as shown in FIGS. 2 to 7, the distance between the first body part 511 and the second body part 521 is S, the length of the first body part 511 in the first direction is H1; the length of the second body part 521 in the first direction is H2; the length of the first body part 511 in the second direction is H3; the length of the second body part 521 in the second direction is H4; and the wavelength corresponding to the center frequency point of the liquid crystal phase shifter is λ.

[0089] S≤λ / 100; H1≤λ / 100; H2≤λ / 100; H3≥λ / 2; and H4≥λ / 2.

[0090] For example, S = 0.01λ, 0.009λ, 0.008λ, 0.007λ, 0.006λ, or 0.005λ, etc. H1 = 0.01λ, 0.009λ, 0.008λ, 0.007λ, 0.006λ, or 0.005λ, etc. H2 = 0.01λ, 0.009λ, 0.008λ, 0.007λ, 0.006λ, or 0.005λ, etc. H3 = 0.5λ, 0.52λ, 0.54λ, 0.56λ, 0.58λ, 0.6λ, 0.7λ, or 0.8λ, etc. H4≥0.5λ, 0.52λ, 0.54λ, 0.56λ, 0.58λ, 0.6λ, 0.7λ, or 0.8λ.

[0091] The embodiments of the present disclosure can control the center frequency point of the liquid crystal phase shifter by setting the size of the first body part 511 and the second body part 521, so that the liquid crystal phase shifter can meet different requirements.

[0092] In some embodiments, as shown in FIGS. 2, 4 to 7, the length of the first branch part 512 in the second direction is Y, the length of the first branch part 512 in the first direction is L, the length of the second branch part 522 in the second direction is C, and the length of the second branch part 522 in the first direction is T; wherein L≤λ / 10, C≤λ / 10, Y≤λ / 10, and T≤λ / 10.

[0093] For example, L = 0.1λ, 0.09λ, 0.095λ, 0.085λ, 0.08λ, 0.075λ, 0.07λ, 0.065λ, 0.06λ, 0.055λ, or 0.5λ. T = 0.1λ, 0.09λ, 0.095λ, 0.085λ, 0.08λ, 0.075λ, 0.07λ, 0.065λ, 0.06λ, 0.055λ, or 0.5λ. C = 0.1λ, 0.09λ, 0.095λ, 0.085λ, 0.08λ, 0.075λ, 0.07λ, 0.065λ, 0.06λ, 0.055λ, or 0.5λ. Y = 0.1λ, 0.09λ, 0.095λ, 0.085λ, 0.08λ, 0.075λ, 0.07λ, 0.065λ, 0.06λ, 0.055λ, or 0.5λ.

[0094] The embodiment of the present disclosure can control the center frequency point of the liquid crystal phase shifter by setting the size of the first branch part 512 and the second branch part 522. Further, the embodiment of the present disclosure can accurately control the center frequency point of the liquid crystal phase shifter by setting the size of the first main body part 511, the second main body part 521, the first branch part 512, and the second branch part 522 to meet the design requirements.

[0095] In some embodiments, as shown in FIGS. 2 to 4, the reference electrode layer 4 includes third electrodes 41 and fourth electrodes 42 arranged along a first direction, and a plurality of extension electrodes 43 located between the third electrodes 41 and the fourth electrodes 42. The plurality of extension electrodes 43 are arranged at intervals along a second direction. The opening 30 includes a first sub-gap 301 between two adjacent extension electrodes 43.

[0096] The third electrodes 41 and the first branch part 512 have overlapping orthographic projections on the first substrate 1. The fourth electrodes 42 and the second branch part 522 have overlapping orthographic projections on the first substrate 1. The extension electrodes 43 and the first branch part 512 and the second branch part 522 have overlapping orthographic projections on the first substrate 1.

[0097] The embodiment of the present disclosure designs a defective ground structure corresponding to the microstrip line layer 5 on the reference electrode layer 4, specifically, the extension electrodes 43 and the first branch part 512 and the second branch part 522 have overlapping orthographic projections on the first substrate 1, and the opening 30 includes a first sub-gap 301 between two adjacent extension electrodes 43, which can achieve impedance matching between the reference electrode layer 4 and the microstrip line layer 5.

[0098] In some embodiments, as shown in FIG. 2, the extension electrode 43 includes a first extension part 431 and a second extension part 432 arranged at intervals in the first direction, the first extension part 431 is electrically connected with the third electrode 41, and the second extension part 432 is electrically connected with the fourth electrode 42. The opening 30 further includes a second sub-gap 302 between the first extension part 431 and the second extension part 432, and the first sub-gap 301 is communicated through the second sub-gap 302. The first main body part 511 and the second main body part 521 have a third gap 40 therebetween, and the second sub-gap 302 overlaps with the normal projection of the third gap 40 on the first substrate 1.

[0099] The embodiments of the present disclosure can reduce the loss while achieving impedance matching by matching the third gap 40 between the first main body part 511 and the second main body part 521 with the second sub-gap 302 between the first extension part 431 and the second extension part 432, and communicating the adjacent two first sub-gaps 301 through the second sub-gap 302.

[0100] Optionally, as shown in FIG. 2, the second sub-gap 302 overlaps with the normal projection of the third gap 40 on the first substrate 1. The width X3 of the second sub-gap 302 is the same as the width S of the third gap 40.

[0101] Optionally, as shown in FIG. 2, the length X1 of the first extension part 431 in the first direction is equal to the length X2 of the second extension part 432 in the first direction.

[0102] Optionally, as shown in FIG. 2, the length X1 of the first extension part 431 in the first direction is less than or equal to the length L of the first branch part 512 in the first direction, and the length X2 of the second extension part 432 in the first direction is less than or equal to the length C of the second branch part 522 in the first direction.

[0103] In the embodiments of the present disclosure, a plurality of capacitors are formed between the plurality of first extension parts 431 and the first main body part 511, and a plurality of independent capacitors are formed between the plurality of second extension parts 432 and the second main body part 521, which can further regulate the phase change on the basis of achieving impedance matching through the third gap 40 and the second sub-gap 302, so as to realize phase shift, which is beneficial to improve the performance of the liquid crystal phase shifter.

[0104] In some embodiments, as shown in FIG. 3, the third electrode 41 and the fourth electrode 42 are electrically connected through the extension electrode 43, and the adjacent two first sub-gaps 301 are independent of each other.

[0105] Optionally, the first sub-gap 301 overlaps with the normal projection of the third gap 40 on the first substrate 1.

[0106] Optionally, as shown in FIG. 3, there is a first gap 10 between two adjacent first branch parts 512, and there is a second gap 20 between two adjacent second branch parts 522. The first gap 10 and the second gap 20 correspond to the first sub-gaps 301 one by one. Since the orthographic projection of the first sub-gaps 301 on the first substrate 1 does not overlap with the orthographic projection of the first branch parts 512 on the first substrate 1, and the orthographic projection of the first sub-gaps 301 on the first substrate 1 does not overlap with the orthographic projection of the second branch parts 522 on the first substrate 1, it should be clear to those skilled in the art that the width of the first sub-gaps 301 in the second direction is less than or equal to the width of the first gap 10 in the second direction, and the width of the first sub-gaps 301 in the second direction is less than or equal to the width of the second gap 20 in the second direction.

[0107] In the embodiments of the present disclosure, when the first sub-gaps 301 are independent of each other, the extension electrode 43 forms an independent capacitor with the first branch part 512 and the part of the second main body part 511 adjacent to the first branch part 512, and at the same time, the extension electrode 43 forms an independent capacitor with the second branch part 522 and the part of the second main body part 511 adjacent to the second branch part 522, which can enable the defective structure to achieve impedance matching with the microstrip line layer 5 in different cases, achieve different phase shift effects, and further reduce loss.

[0108] In some embodiments, as shown in FIG. 4, the reference electrode layer 4 further includes a connection electrode 44 extending in the second direction; the connection electrode 44 is electrically connected with the extension electrode 43; and the connection electrode 44 separates the first sub-gaps 301 into a first gap part 31 adjacent to the third electrode 41 and a second gap part 32 adjacent to the fourth electrode 42.

[0109] In the embodiments of the present disclosure, by designing the connection electrode 44 extending in the second direction, the slow wave effect of the liquid crystal phase shifter can be made to be the weakest, thus the influence on the liquid crystal phase shifter is the smallest.

[0110] Optionally, the width V1 of the connection electrode 44 in the first direction is equal to the width S of the third gap 40.

[0111] Optionally, the width V3 of the first gap part 31 in the first direction is equal to the width H1 of the first main body part 511. The width V2 of the second gap part 32 in the first direction is equal to the width H2 of the second main body part 521.

[0112] The defective structure of the embodiments of the present disclosure is simple in pattern and easy to process and manufacture, and can reduce costs. In the embodiments of the present disclosure, the reference electrode layer only needs one mask to complete production, so that the design and processing costs are the lowest.

[0113] In some embodiments, as shown in FIG. 3, the reference electrode layer 4 includes a first middle region A1 and first edge regions B1 located on opposite sides of the first middle region A1 in the second direction, wherein a plurality of first sub-gaps 301 extending in the first direction are arranged in both the first middle region A1 and the first edge regions B1. In the first edge regions B1, the length of the plurality of first sub-gaps 301 gradually increases in the direction close to the first middle region A1. For example, in the first edge regions B1, the second first sub-gap 301 is closer to the first middle region A1 than the first first sub-gap 301, and thus the length K2 of the second first sub-gap 301 is greater than the length K1 of the first first sub-gap 301. For another example, in the second edge regions B2, the n-2th first sub-gap 301 is closer to the second middle region A2 than the n-1th first sub-gap 301, and thus the length Kn-2 of the n-2th first sub-gap 301 is greater than the length Kn-1 of the n-1th first sub-gap 301.

[0114] Optionally, in one example, in the first middle region A1, the length of the first sub-gaps 301 can be constant. In another example, in the first middle region A1, the length of the first sub-gaps 301 can gradually increase in the direction away from the first edge regions B1, and all the first sub-gaps 301 are symmetric about a straight line extending in the first direction.

[0115] In the embodiments of the present disclosure, the non-continuous rectangular first sub-gaps 301 arranged on the reference electrode layer 4 form a non-continuous defective ground structure, and a gradient structure is formed in the first edge regions B1. The gap of such a gradient structure is conducive to further achieving effective impedance matching between the microstrip line layer 5 and the reference electrode layer 4, optimizing the impedance characteristics of the circuit, thereby reducing the insertion loss of the liquid crystal phase shifter and improving the overall performance of the liquid crystal phase shifter.

[0116] By adopting the defective ground structure and the gradient structure design, the embodiments of the present disclosure can make the liquid crystal phase shifter have higher frequency selectivity in a narrow frequency band, and can better meet the application requirements in high frequency bands, and are suitable for various complex environments in wireless communication systems.

[0117] Meanwhile, in the embodiments of the present disclosure, the plurality of first sub-gaps 301 form a non-continuous defective ground structure. Such a non-continuous defective ground structure has a stronger slow wave effect, and thus has the following two most important advantages:

[0118] 1) Greater phase delay: The enhancement of the slow wave effect means that the electromagnetic wave can achieve greater phase delay on the same physical length. This is very advantageous for the liquid crystal phase shifter, because one of the main functions of the liquid crystal phase shifter is to achieve different phase shifts under different voltages.

[0119] 2) Improved control accuracy: stronger slow wave effect can make liquid crystal phase shifter achieve the required phase change in a shorter length, thereby improving the compactness and control accuracy of the device.

[0120] In some embodiments, as shown in FIG. 3, there is a first gap 10 between two adjacent first branch parts 512, and the first gap 10 corresponds to a first sub-gap 301 one by one. There is a second gap 20 between two adjacent second branch parts 522, and the second gap 20 corresponds to a first sub-gap 301 one by one.

[0121] The lengths of the two first branch parts 512 adjacent to the ith first gap 10 in the first direction are Ci and Ci+1, respectively, and the lengths of the two second branch parts 522 adjacent to the ith second gap 20 in the first direction are Li and Li+1, respectively. Wherein, "the two first branch parts 512 adjacent to the ith first gap 10" refers to the two first branch parts 512 located on the opposite sides of the ith first gap 10 along the second direction; "the two second branch parts 522 adjacent to the ith second gap 20" refers to the two second branch parts 522 located on the opposite sides of the ith second gap 20 along the second direction. The width of the first main body part 511 in the first direction is H1, the width of the second main body part 521 in the first direction is H2, the width of the third gap 40 in the first direction is S, and the length of the ith first sub-gap 10 in the first direction is Ki, wherein Ki = max[Ci, Ci+1] + max[Li, Li+1] + H1 + H2 + S, max[] represents the maximum function, i = 1, 2, 3, …, n-1. n is the total number of first branch parts 511 or second branch parts 521.

[0122] Optionally, as shown in FIG. 3, the microstrip line layer 5 includes a second middle area A2 and a second edge area B2 located on the opposite sides of the second middle area A2 in the second direction, wherein a plurality of first branch parts 512 extending in the first direction and a plurality of second branch parts 522 extending in the first direction are arranged in the second middle area A2 and the second edge area B2. And in the second edge area B2, in the direction close to the second middle area A2, the length Li of the first branch part 512 in the first direction gradually increases, and the length Ci of the second branch part 522 in the first direction gradually increases. For example, in the second edge area B2, the 2nd first branch part 512 is closer to the second middle area A2 than the 1st first branch part 512, so the length L2 of the 2nd first branch part 512 is greater than the length L1 of the 1st first branch part 512. For another example, in the second edge area B2, the n-1th second branch part 522 is closer to the second middle area A2 than the nth second branch part 522, so the length Cn-1 of the n-1th second branch part 522 is greater than the length Cn of the nth second branch part 522.

[0123] Optionally, in one example, in the second middle area A2, the lengths of the first branch parts 512 and the second branch parts 522 can be constant. In another example, in the second middle area A2, the lengths of the first branch parts 512 and the second branch parts 522 can gradually increase in the direction away from the first edge area B1, and all the first branch parts 512 are symmetrical about a straight line extending in the first direction, and all the second branch parts 522 are symmetrical about a straight line extending in the first direction.

[0124] The embodiments of the present disclosure can further improve the impedance matching of the microstrip line layer 5 and the reference electrode layer 4 by making the length of the first sub-gap 301 satisfy Ki = max[Ci, Ci+1] + max[Li, Li+1] + H1 + H2 + S, and such a setting can further enhance the slow wave effect of the liquid crystal phase shifter.

[0125] In some embodiments, as shown in FIGS. 5 to 7, the opening 30 includes a plurality of third sub-gaps 303 arranged in the second direction and symmetrical about the first axis of symmetry a, wherein the first axis of symmetry a extends in the first direction. The third sub-gap 303 overlaps the orthographic projection of the first gap 10 on the first substrate 1; the third sub-gap 303 overlaps the orthographic projection of the second gap 20 on the first substrate 1; the third sub-gap 303 overlaps the orthographic projection of the first main body part 511 on the first substrate 1; and the third sub-gap 303 overlaps the orthographic projection of the second main body part 521 on the first substrate 1.

[0126] The embodiments of the present disclosure can make the liquid crystal phase shifter have good bandgap characteristics by setting the plurality of third sub-gaps 303 symmetrical about the first axis of symmetry a in the reference electrode layer 5. Moreover, the embodiments of the present disclosure can simplify the manufacturing process and reduce the processing cost by forming the plurality of third sub-gaps 303 in the reference electrode layer 4.

[0127] In some embodiments, as shown in FIGS. 5 and 6, the third sub-gap 303 includes a first slit 310, a second slit 320, and a third slit 330; the first slit 310 and the second slit 320 are arranged in the first direction and extend in the second direction; and the third slit 330 extends in the first direction and is located between and communicates the first slit 310 and the second slit 320.

[0128] In the embodiments of the present disclosure, the first slit 310, the second slit 320 and the third slit 330 form a third sub-interstice 303 in the shape of an I-beam or a dumbbell, and a plurality of third sub-interstices 303 are arranged periodically. Moreover, the plurality of third sub-interstices 303 are symmetrically arranged directly below the microstrip line layer 5. The embodiments of the present disclosure can effectively realize the miniaturization of the overall structure of the liquid crystal phase shifter while maintaining the balanced artificial surface plasmon mode, thereby improving the integration and practicability of the liquid crystal phase shifter and making the liquid crystal phase shifter have good bandgap characteristics.

[0129] In some embodiments, as shown in FIG. 5, the width of the third slit 330 is constant from both ends to the center of the third slit 330.

[0130] The opening 30 in the embodiments of the present disclosure is composed of a plurality of periodically arranged dumbbell-shaped third sub-interstices 303, and the dumbbell-shaped third sub-interstices 303 are symmetrically arranged directly below the microstrip line layer 5. This design effectively realizes the miniaturization of the overall structure while maintaining the balanced artificial surface plasmon mode, thereby improving the integration and practicability of the liquid crystal phase shifter. Moreover, the design has good bandgap characteristics and is easy to integrate and has low processing cost. Moreover, since the microstrip line layer can also serve as a reflux path through the defect structure, the continuous dumbbell-shaped third sub-interstices 303 on the defect structure do not affect the common mode signal, and the design complexity of the liquid crystal phase shifter is also reduced. Moreover, the dumbbell-shaped third sub-interstices 303 have obvious low-pass filtering characteristics, can suppress high-frequency harmonics and unwanted high-frequency signals, thereby improving the signal transmission quality and the purity and transmission quality of the signal.

[0131] In other embodiments, as shown in FIG. 6, the width W2 of at least part of the third slit 330 gradually decreases from both ends to the center of the third slit 330.

[0132] Compared with the embodiment shown in FIG. 5, the coupling effect of the defect structure in the embodiment shown in FIG. 6 is weaker, but the bandwidth is narrower, and it is more suitable for liquid crystal phase shifters of the narrowband type.

[0133] In some embodiments, as shown in FIG. 6, the third slit 330 has a first edge 331 and a second edge 332 arranged opposite to each other in the second direction; the distance W2 between the first edge 331 and the second edge 332 gradually decreases from both ends to the center of the third slit 330, and both the first edge 331 and the second edge 332 are part of an ellipse, wherein the length of the major axis of the ellipse is a, and the length of the minor axis of the ellipse is b; the minimum distance between the first edge 331 and the second edge 332 is d; the center frequency point of the liquid crystal phase shifter corresponds to a wavelength λ; wherein λ≥a>b≥λ / 100; λ / 2≥d≥λ / 100.

[0134] At this time, the third sub-interstice 303 can be understood as an elliptical structure one-dimensional slit. The third sub-interstice 303 of the embodiment of the present disclosure is easier to design and simpler to manufacture, but the coupling effect is weaker and the bandwidth is narrower compared with the dumbbell-shaped third sub-interstice 303, and thus is more suitable for narrow-band microwave devices. In addition, the elliptical structure one-dimensional slit can enable the liquid crystal phase shifter to provide stable phase response in a specific frequency band, is suitable for precise phase control, and can meet the needs of high-precision applications.

[0135] In some embodiments, as shown in FIG. 7, the third sub-interstice 303 includes a fourth slit 340 extending along the first direction and a plurality of fifth slits 350 arranged at intervals on opposite sides of the fourth slit 340 in the second direction; the fifth slits 350 are in communication with the fourth slit 340.

[0136] Optionally, the specific shape of the fifth slit 350 can be a quarter circle or a rounded quadrilateral, for example, a square with at least one rounded corner.

[0137] The embodiment of the present disclosure can reduce the dispersion of the liquid crystal phase shifter by arranging a plurality of fifth slits 350 on opposite sides of the fourth slit 340 in the second direction, so that the performance of the liquid crystal phase shifter is more balanced.

[0138] In some embodiments, as shown in FIGS. 5 to 7, the third sub-interstice 303 is an axisymmetric figure symmetrical about the second symmetry axis b, and the first symmetry axis b extends along the second direction.

[0139] In some embodiments, as shown in FIGS. 5 to 7, the third sub-interstice 303 is a center-symmetric figure symmetrical about the center of the third sub-interstice 303.

[0140] In some embodiments, as shown in FIGS. 5 to 7, the third sub-interstice 303 is an axisymmetric figure symmetrical about the second symmetry axis b, and the third sub-interstice 303 is a center-symmetric figure symmetrical about the center of the third sub-interstice 303.

[0141] In some embodiments, as shown in FIG. 7, the third sub-interstice 303 is a center-symmetric figure symmetrical about the center of the fourth slit 340.

[0142] In the embodiments of the present disclosure, by making the third sub-gap 303 a symmetric pattern, the defect ground structure can have self-similarity. In particular, the embodiment shown in FIG. 7 can make the self-similarity of the defect ground structure the strongest. The defect ground structure having self-similarity can make the liquid crystal phase shifter produce significant electromagnetic property changes in multiple frequency bands, i.e., multi-band properties. The multi-band properties enable the liquid crystal phase shifter to achieve stable phase control in multiple frequency bands, adapt to the communication needs of different frequency bands, and at the same time improve the bandwidth properties. The high-bandwidth properties enable the liquid crystal phase shifter to maintain good performance within a wide frequency band, increasing the flexibility and scope of application of the liquid crystal phase shifter.

[0143] In some embodiments, the sum of the areas of the plurality of third sub-gaps 303 is no more than 1 / 2 of the area of the reference electrode layer 5. For example, the ratio of the sum of the areas of the plurality of third sub-gaps 303 to the area of the reference electrode layer 5 can be 0.5, 0.49, 0.48, 0.47, 0.46, 0.45, 0.44, 0.43, 0.42, 0.41, 0.4, 0.39, 0.38, 0.37, 0.36, or 0.35, etc.

[0144] In some embodiments, the area of the opening 30 is no more than 1 / 2 of the area of the reference electrode layer 5.

[0145] The embodiments of the present disclosure can effectively ensure the bandgap properties of the reference electrode layer 5 by controlling the area of the opening 30 or the total area of the plurality of third sub-gaps 303, thereby improving the phase shift performance of the liquid crystal phase shifter.

[0146] In some embodiments, the length of the opening 30 in the first direction is less than or equal to max[Ci, i = 1, 2, …, n] + max[Li, i = 1, 2, …, n] + H1 + H2 + S.

[0147] In the embodiments of the present disclosure, the length of the opening 30 in the first direction is set to be less than or equal to max[Ci, i = 1, 2, …, n] + max[Li, i = 1, 2, …, n] + H1 + H2 + S.

[0148] In some embodiments, as shown in FIGS. 5 to 7, the length D of the third sub-gap 303 in the first direction is no more than 1 / 4 of the length W1 of the reference electrode layer 5 in the second direction.

[0149] The defect ground structure formed in the embodiments of the present disclosure can significantly improve the impedance properties of the circuit, enhance the coupling effect, and thus achieve more efficient phase shift function.

[0150] In some embodiments, the opening 3 can adopt a periodic structure design. For example, the first sub-gap 301 in FIG. 3 is regularly arranged in a periodic manner in the second direction, or the third sub-gap 302 in FIG. 5 is arranged in a periodic manner. The periodic structure design in the embodiments of the present disclosure, in combination with the strong slow wave effect, enables the liquid crystal phase shifter to achieve 180° phase adjustment in a smaller physical size. Such a structure design can effectively shorten the length of the liquid crystal phase shifter and improve the flexibility and efficiency of phase adjustment.

[0151] FIG. 8 is a simulation effect diagram in some embodiments of the present disclosure. Specifically, in the embodiment shown in FIG. 2, the microstrip line layer 5 and the reference electrode layer 4 are simulated and analyzed: when the thickness H of the liquid crystal layer is 2 μm, the thickness h_copper of the microstrip line layer 5 is 0.2 μm (H, h_copper < λ / 1000), the effective dielectric constant εr of the liquid crystal layer is 2.461-3.571, and the phase shifter has a phase shift of more than 180° at the design center frequency f0. In FIG. 8, the curve S11 represents the return loss curve, and the curve S21 represents the transmission loss curve. The horizontal axis is frequency (Frequency) in GHz, and the vertical axis is loss (Loss) in dB. As shown in FIG. 8, the insertion loss of the coupling microstrip line liquid crystal phase shifter based on the defect ground structure in the embodiments of the present disclosure is significantly reduced, and the maximum transmission loss during phase shift is only -1.1 dB.

[0152] In summary, the liquid crystal phase shifter in the embodiments of the present disclosure has the following advantages: simpler structure, smaller insertion loss of the liquid crystal phase shifter itself; due to the presence of the defect ground structure, the structure of the microstrip line layer is easier to design and optimize; the overlapping electric field region formed between the defect ground structure and the microstrip line layer can excite the liquid crystal molecules to deflect to generate phase shift; in theory, the dispersion characteristics of the liquid crystal phase shifter can be changed by changing the specific shape and size of the defect ground structure to improve the phase shifting ability of the liquid crystal phase shifter, thereby reducing the number of liquid crystal phase shifters used and reducing the overall insertion loss of the liquid crystal phase shifter transmission line; at the same frequency, the coupling microstrip line liquid crystal phase shifter based on the defect ground structure has a smaller size and is easier to integrate and miniaturize.

[0153] The defect ground structure in the embodiments of the present disclosure can be used as the core of the phase shifter design. Therefore, the embodiments of the present disclosure can introduce periodic or non-periodic defects (openings) by etching or adding specific patterns on the reference electrode layer, thereby changing the propagation characteristics of electromagnetic waves on the ground plane. Further, by controlling the size, shape and position of the openings, the phase of the electromagnetic wave can be accurately controlled.

[0154] The defect ground structure in the embodiments of the present disclosure can effectively change the dispersion characteristics of the liquid crystal phase shifter. The dispersion characteristics refer to the phenomenon that different frequency components have different phase velocities and group velocities when electromagnetic waves propagate in a medium. Further, by adjusting the structural shape of the opening, the liquid crystal phase shifter can have a stronger dispersion effect in a specific frequency range, thereby improving the phase shifting capability of a single shift unit in the liquid crystal phase shifter, and ultimately achieving the miniaturization of the phase shifter and the improvement of the quality factor.

[0155] It can be understood that the above embodiments are only exemplary embodiments adopted for illustrating the principles of the present disclosure, and the present disclosure is not limited thereto. Various modifications and improvements can be made by those of ordinary skill in the art without departing from the spirit and essence of the present disclosure, and these modifications and improvements are also considered within the protection scope of the present disclosure.

Claims

1. A liquid crystal phase shifter, wherein, Comprising: a first substrate and a second substrate oppositely arranged; a liquid crystal layer between the first substrate and the second substrate; a microstrip line layer on a side of the first substrate facing the liquid crystal layer; a reference electrode layer on a side of the second substrate facing the liquid crystal layer; wherein the microstrip line layer comprises a first electrode and a second electrode arranged at intervals along a first direction; the first electrode comprises a first main body portion extending along a second direction and a plurality of first branch portions electrically connected to the first main body portion, the plurality of first branch portions being arranged at intervals along the second direction on a side of the first main body portion away from the second electrode; the second electrode comprises a second main body portion extending along the second direction and a plurality of second branch portions electrically connected to the second main body portion, the plurality of second branch portions being arranged at intervals along the second direction on a side of the second main body portion away from the first electrode; the first direction intersects the second direction; orthographic projections of the first electrode and the second electrode on the first substrate all overlap orthographic projections of the reference electrode layer on the first substrate; the reference electrode layer has an opening, and orthographic projections of the first branch portions and the second branch portions on the first substrate all do not overlap orthographic projections of the opening on the first substrate.

2. The liquid crystal phase shifter of claim 1, wherein, the reference electrode layer comprises a third electrode and a fourth electrode arranged along the first direction, and a plurality of extension electrodes between the third electrode and the fourth electrode, the plurality of extension electrodes being arranged at intervals along the second direction, and the opening comprises a first sub-gap between adjacent two of the extension electrodes; orthographic projections of the third electrode and the first branch portions on the first substrate overlap; orthographic projections of the fourth electrode and the second branch portions on the first substrate overlap; and orthographic projections of the extension electrodes on the first substrate all overlap orthographic projections of the first branch portions and the second branch portions on the first substrate. the extension electrodes comprise a first extension portion and a second extension portion arranged at intervals along the first direction, the first extension portion being electrically connected to the third electrode, and the second extension portion being electrically connected to the fourth electrode; 3. The liquid crystal phase shifter of claim 2, wherein, the opening further comprises a second sub-gap between the first extension portion and the second extension portion, and the first sub-gap is communicated through the second sub-gap; the first main body portion and the second main body portion have a third gap therebetween, and orthographic projections of the second sub-gap and the third gap on the first substrate overlap. the third electrode and the fourth electrode are electrically connected through the extension electrodes, and adjacent two of the first sub-gaps are independent of each other.

4. The liquid crystal phase shifter of claim 2, wherein, the reference electrode layer further comprises a connection electrode extending along the second direction; 5. The liquid crystal phase shifter of claim 4, wherein, the connection electrode is electrically connected to the extension electrodes, and the connection electrode separates the first sub-gap into a first gap portion adjacent to the third electrode and a second gap portion adjacent to the fourth electrode.

6. The liquid crystal phase shifter according to claim 2, wherein, ​ The reference electrode layer comprises a middle region and edge regions located on opposite sides of the middle region in the second direction, and a plurality of first sub-gaps extending in the first direction are arranged in the middle region and the edge regions; in the edge regions, the length of the plurality of first sub-gaps gradually increases in the direction close to the middle region.

7. The liquid crystal phase shifter of any one of claims 1 to 6, wherein, The first gap is between two adjacent first branch parts, and the second gap is between two adjacent second branch parts; The first gap and the second gap each correspond to one of the first sub-gaps; The length of the two first branch parts adjacent to the ith first gap in the first direction is Ci and Ci+1 respectively, the length of the two second branch parts adjacent to the ith second gap in the first direction is Li and Li+1 respectively, the width of the first main part in the first direction is H1, the width of the second main part in the first direction is H2, the width of the third gap in the first direction is S, and the length of the ith first sub-gap in the first direction is Ki, wherein Ki = max[Ci, Ci+1] + max[Li, Li+1] + H1 + H2 + S, max[] represents the maximum function, i = 1, 2, 3, …, n-1; n is the total number of the first branch parts or the second branch parts.

8. The liquid crystal phase shifter of claim 1, wherein, The opening comprises a plurality of third sub-gaps arranged at intervals in the second direction; The orthogonal projection of any one of the first gap, the second gap, the first main part and the second main part on the first substrate overlaps with the orthogonal projection of the third sub-gap on the first substrate; The plurality of third sub-gaps are symmetrical about a first symmetry axis, wherein the first symmetry axis extends in the first direction.

9. The liquid crystal phase shifter of claim 8, wherein, The third sub-gap comprises a first slit, a second slit and a third slit; The first slit and the second slit are arranged at intervals in the first direction, and both the first slit and the second slit extend in the second direction; The third slit extends in the first direction and is located between and communicates the first slit and the second slit.

10. The liquid crystal phase shifter of claim 9, wherein, The width of the third slit is constant from both ends to the center of the third slit; Or, The width of at least part of the third slit gradually decreases from both ends to the center of the third slit.

11. The liquid crystal phase shifter of claim 10, wherein, The third slit has a first edge and a second edge oppositely arranged in the second direction; the distance between the first edge and the second edge gradually decreases from both ends to the center of the third slit; The first edge and the second edge are both parts of an ellipse, wherein the major axis length of the ellipse is a, the minor axis length of the ellipse is b; the minimum distance between the first edge and the second edge is d; the center frequency point of the liquid crystal phase shifter corresponds to a wavelength λ; Wherein, λ≥a>b≥λ / 100; λ / 2≥d≥λ / 100.

12. The liquid crystal phase shifter of claim 8, wherein, The third sub-interstice includes a fourth slit extending along the first direction and a plurality of fifth slits arranged at intervals on opposite sides of the fourth slit in the second direction; the fifth slits are in communication with the fourth slit.

13. The liquid crystal phase shifter of any one of claims 8-12, wherein, The third sub-interstice is an axially symmetric pattern about a second axis of symmetry extending along the first direction; and / or, the third sub-interstice is a centrally symmetric pattern about the center of the third sub-interstice.

14. The liquid crystal phase shifter of any one of claims 8-13, wherein, The sum of the areas of a plurality of the third sub-interstices does not exceed 1 / 2 of the area of the reference electrode layer. And / or, the length of the third sub-interstice in the first direction does not exceed 1 / 4 of the length of the reference electrode layer in the second direction. The thickness of the liquid crystal layer is H, the distance between the first main part and the second main part is S, the length of the first main part in the first direction is H1; the length of the second main part in the first direction is H2; 15. The liquid crystal phase shifter of any one of claims 1 to 14, wherein, Wherein, S / H≥0.005, H1 / H≤5, H2 / H≤5. The distance between the first main part and the second main part is S, the length of the first main part in the first direction is H1; 16. The liquid crystal phase shifter of any one of claims 1 to 15, wherein, The length of the second main part in the first direction is H2; The length of the first main part in the second direction is H3; the length of the second main part in the second direction is H4; the wavelength corresponding to the center frequency point of the liquid crystal phase shifter is λ; Wherein, S≤λ / 100; H1≤λ / 100; H2≤λ / 100; H3≥λ / 2; H4≥λ / 2. The length of the first branch part in the second direction is Y, the length of the first branch part in the first direction is L, the length of the second branch part in the second direction is T, and the length of the second branch part in the first direction is C; the wavelength corresponding to the center frequency point of the liquid crystal phase shifter is λ; 17. The liquid crystal phase shifter of any one of claims 1 to 16, wherein, Wherein, Y≤λ / 10, L≤λ / 10, T≤λ / 10, C≤λ / 10. The liquid crystal phase shifter as claimed in any one of claims 1 to 17.

18. An antenna, wherein, The liquid crystal phase shifter as claimed in any one of claims 1 to 17.

Images