Liquid crystal antenna and communication device

Abstract

The invention provides a liquid crystal antenna and a communication device, and relates to the technical field of antennas. The liquid crystal antenna comprises a feed structure, a first substrate, a liquid crystal box and a radiant panel which are sequentially stacked, the feed structure comprises a plurality of first output ends, and the feed structure is configured to feed the first substrate through the plurality of first output ends; the first substrate comprises a plurality of first substrate integrated waveguides, one first substrate integrated waveguide is arranged opposite to one first output end, and each first substrate integrated waveguide comprises a plurality of second output ends; the liquid crystal box comprises a plurality of liquid crystal phase shifters, and one liquid crystal phase shifter is arranged opposite to one second output end; the radiation plate comprises a plurality of radiation units, and the radiation units and the liquid crystal phase shifter are oppositely arranged. And the feed loss of the liquid crystal antenna is reduced.

Description

Liquid crystal antenna and communication device Technical Field

[0001] The present disclosure relates to the field of antenna technology, and in particular to a liquid crystal antenna and a communication device. Background Art

[0002] Liquid crystal phased array antennas have been widely used due to their low cost, but they suffer from high losses, which can affect antenna performance. To reduce these losses, some use substrate-integrated waveguides for feeding. However, when the array size of a liquid crystal phased array antenna is large, the losses increase significantly when using substrate-integrated waveguides for feeding.

[0003] Summary of the Invention

[0004] Embodiments of the present disclosure provide a liquid crystal antenna and a communication device, which reduce the feeding loss of the liquid crystal antenna.

[0005] To achieve the above objectives, the embodiments of the present disclosure adopt the following technical solutions:

[0006] On the one hand, a liquid crystal antenna is provided, comprising a feed structure, a first substrate, a liquid crystal box, and a radiation plate, which are stacked in sequence. The feed structure includes multiple first output ends, and the feed structure is configured to feed power to the first substrate through the multiple first output ends; the first substrate includes multiple first-substrate integrated waveguides, one of the first-substrate integrated waveguides is arranged opposite to one of the first output ends, and each of the first-substrate integrated waveguides includes multiple second output ends; the liquid crystal box includes multiple liquid crystal phase shifters, one of the liquid crystal phase shifters is arranged opposite to one of the second output ends; and the radiation plate includes multiple radiation units, and the radiation units are arranged opposite to the liquid crystal phase shifters.

[0007] In some embodiments, the first substrate includes a first conductive layer, a first dielectric layer, and a second conductive layer stacked in sequence, wherein the second conductive layer is closer to the liquid crystal box; the first conductive layer includes a first region, the second conductive layer includes a second region, the first region and the second region are opposite to each other, the first dielectric layer is provided with a plurality of first conductive pillars, one end of the first conductive pillar is electrically connected to the first region, and the other end of the first conductive pillar is electrically connected to the second region, the plurality of first conductive pillars are arranged at intervals and surround the first region and the second region; the first region, the second region, and the plurality of first conductive pillars surrounding the first region and the second region form the first substrate integrated waveguide; the first region is provided with a first gap, the first gap is opposite to the first output end, the second output end includes a second gap provided in the second region, and the second region is provided with a plurality of second gaps.

[0008] In some embodiments, the first region and the second region both include a conversion region and a power division region connected to the conversion region, the first gap is provided in the conversion region, and the second gap is provided in the power division region.

[0009] In some embodiments, the first conductive layer includes a plurality of first regions, which are disconnected from each other or connected to each other; the second conductive layer includes a plurality of second regions, which are disconnected from each other or connected to each other.

[0010] In some embodiments, the radiation plate includes a second substrate, which is connected to a side of the liquid crystal box away from the first substrate. The radiation unit includes a second substrate integrated waveguide arranged on the second substrate, and the second substrate integrated waveguide is arranged opposite to the liquid crystal phase shifter.

[0011] In some embodiments, the radiation plate further includes a radiation stack connected to a side of the second substrate away from the first substrate, and the radiation unit further includes a radiation patch arranged on the radiation stack, and the radiation patch is arranged opposite to the second substrate integrated waveguide.

[0012] In some embodiments, one or more fourth slots are provided on the side of the second substrate integrated waveguide facing the radiation patch, one fourth slot corresponds to one radiation patch, and the orthographic projection of the fourth slot on the radiation stack at least partially overlaps with the radiation patch.

[0013] In some embodiments, one or more fourth slots are provided on the side of the second substrate integrated waveguide facing the radiation patch, and one fourth slot corresponds to a plurality of the radiation patches. The radiation stack also includes a power splitter structure electrically connected to the plurality of radiation patches, and the orthographic projection of the fourth slot on the radiation stack at least partially overlaps with the power splitter structure.

[0014] In some embodiments, the radiating patch is rectangular, hexagonal, or irregular in shape.

[0015] In some embodiments, one or more fourth slits are provided on a side of the second substrate integrated waveguide away from the liquid crystal cell, and the second substrate integrated waveguide radiates electromagnetic waves into free space through the fourth slits.

[0016] In some embodiments, the radiation plate includes a radiation stack connected to a side of the liquid crystal cell away from the first substrate, and the radiation unit includes a radiation patch disposed on the radiation stack.

[0017] In some embodiments, the feeding structure is a waveguide power splitter or a suspended strip line.

[0018] In some embodiments, the waveguide power divider includes a metal block with a hollow pipe provided therein; or, the waveguide power divider includes a plastic block with a hollow pipe provided therein, and the sidewall of the hollow pipe is provided with a metal coating; the hollow pipe is tree-shaped, the root of the hollow pipe is the first input end, and the tip end of the hollow pipe is the first output end.

[0019] On the other hand, a liquid crystal antenna is provided, comprising a waveguide power divider, a first substrate, a liquid crystal box, and a second substrate stacked in sequence, wherein the waveguide power divider includes a plurality of first output ends; the first substrate includes a plurality of first substrate integrated waveguides, one of the first substrate integrated waveguides is arranged opposite to one of the first output ends, and each of the first substrate integrated waveguides includes a plurality of second output ends; the liquid crystal box is provided with a plurality of liquid crystal phase shifters, one of the liquid crystal phase shifters is arranged opposite to one of the second output ends; and the second substrate is provided with a plurality of second substrate integrated waveguides, the second substrate integrated waveguides are arranged opposite to the liquid crystal phase shifters.

[0020] On the other hand, a communication device is provided, comprising the liquid crystal antenna.

[0021] In the liquid crystal antenna provided in the embodiments of the present disclosure, the feed portion includes both a feed structure and multiple first-substrate integrated waveguides. The feed structure includes multiple first output terminals, with each first output terminal corresponding to a corresponding first-substrate integrated waveguide. The RF signal within the feed structure undergoes power distribution and is transmitted to the multiple first output terminals, which are then coupled by the multiple first output terminals into the multiple first-substrate basic waveguides. Because the first substrate includes multiple first-substrate integrated waveguides, the number of second output terminals in each first-substrate integrated waveguide is reduced, given a fixed array size of the liquid crystal antenna. This reduces transmission loss in the first-substrate integrated waveguide and prevents a sharp increase in transmission loss in the first-substrate integrated waveguide due to the larger array size of the liquid crystal antenna. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0023] FIG1 is a cross-sectional view of a liquid crystal antenna provided in an embodiment of the present disclosure;

[0024] FIG2 is a top view of a waveguide power splitter according to an embodiment of the present disclosure;

[0025] FIG3 is a schematic diagram of a waveguide power splitter according to an embodiment of the present disclosure;

[0026] FIG4 is a top view of a first substrate integrated waveguide according to an embodiment of the present disclosure;

[0027] FIG5 is a bottom view of a first substrate integrated waveguide according to an embodiment of the present disclosure;

[0028] FIG6 is a cross-sectional view of FIG4 taken along line AA;

[0029] FIG7 is a cross-sectional view of another liquid crystal antenna according to an embodiment of the present disclosure;

[0030] FIG8 is a top view of a first substrate integrated waveguide according to an embodiment of the present disclosure;

[0031] FIG9 is a top view of a second substrate integrated waveguide according to an embodiment of the present disclosure;

[0032] FIG10 is a cross-sectional view of a second substrate integrated waveguide according to an embodiment of the present disclosure;

[0033] FIG11 is a cross-sectional view of another liquid crystal antenna provided in an embodiment of the present disclosure;

[0034] FIG12 is an arrangement of radiation patches in an embodiment of the present disclosure;

[0035] FIG13 shows another arrangement of radiation patches in an embodiment of the present disclosure;

[0036] FIG14 shows another arrangement of radiation patches in an embodiment of the present disclosure;

[0037] FIG15 shows another arrangement of radiation patches in an embodiment of the present disclosure;

[0038] FIG16 shows a positional relationship between the radiation patch and the fourth slit in an embodiment of the present disclosure;

[0039] FIG17 shows another positional relationship between the radiation patch and the fourth slot in an embodiment of the present disclosure;

[0040] FIG18 is a cross-section of another liquid crystal antenna according to an embodiment of the present disclosure;

[0041] FIG. 19 is a diagram showing the positional relationship between the first substrate and the first output end in an embodiment of the present disclosure.

[0042] Figure numerals: 1-waveguide power divider; 2-first substrate; 3-liquid crystal box; 4-second substrate; 5-radiation stack; 10-radiation plate; 11-body; 12-hollow pipe; 13-first input end; 14-first output end; 20-first substrate integrated waveguide; 21-first conductive layer; 22-second conductive layer; 23-first dielectric layer; 24-first conductive column; 211-first gap; 222-second gap; 31-lower substrate; 32-upper substrate; 33-lower electrode; 34-upper electrode; 35-liquid crystal molecules; 40-second substrate integrated waveguide; 41-third conductive layer; 42-fourth conductive layer; 43-second dielectric layer; 44-second conductive column; 411-third gap; 421-fourth gap; 51-radiation patch; 52-power divider structure. Specific embodiments

[0043] The following will be combined with the accompanying drawings in the embodiments of the present disclosure to clearly and completely describe the technical solutions in the embodiments of the present disclosure. Obviously, the embodiments described are only part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present disclosure.

[0044] In the embodiments of the present disclosure, words such as "first", "second", "third", and "fourth" are used to distinguish between identical or similar items with substantially the same functions and effects. This is only for the purpose of clearly describing the technical solutions of the embodiments of the present disclosure, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features.

[0045] In the embodiments of the present disclosure, “a plurality of” means two or more, and “at least one” means one or more, unless otherwise clearly and specifically defined.

[0046] In the embodiments of the present disclosure, the orientations or positional relationships indicated by terms such as “upper” and “lower” are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present disclosure and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present disclosure.

[0047] Liquid crystal antennas typically consist of three components: a feeder, a liquid crystal phase shifter, and a radiator. The feeder receives the RF signal, the liquid crystal phase shifter adjusts the phase of the RF signal, and the radiator radiates electromagnetic waves into free space. During operation, the feeder feeds the RF signal into the liquid crystal phase shifter. The phase-adjusted RF signal is then fed into the radiator, which stimulates the radiator to radiate electromagnetic waves into free space. While antenna structures based on liquid crystal phase shifters offer advantages such as low cost, they also suffer from high losses, which can affect antenna performance.

[0048] Conventional liquid crystal antennas typically use a microstrip line as their feed. To reduce losses in liquid crystal antennas, related technologies have proposed liquid crystal antennas using a substrate integrated waveguide (SIW) as their feed. When an liquid crystal antenna includes a small number of liquid crystal phase shifters and radiating elements, the SIW also has fewer output terminals. In this case, the SIW's transmission loss is lower than that of a microstrip line, resulting in lower transmission losses for liquid crystal antennas using the SIW as their feed.

[0049] However, when the liquid crystal antenna includes a large number of radiation parts and liquid crystal phase shifters, the substrate integrated waveguide needs to be provided with more output ends, which will cause the transmission loss of the substrate integrated waveguide to increase significantly, thereby increasing the loss of the liquid crystal antenna.

[0050] In view of this, an embodiment of the present disclosure provides a liquid crystal antenna, which can be a liquid crystal phased array antenna or another type of liquid crystal antenna. For ease of description, the following explanation is given using the liquid crystal phased array antenna as an example. The feeding portion of the liquid crystal antenna includes a feeding structure and multiple substrate integrated waveguides. The feeding structure is used to feed power to the substrate integrated waveguides, and the substrate integrated waveguides are used to feed power to the liquid crystal phase shifter. Because the feeding portion includes multiple substrate integrated waveguides, the number of output terminals of each substrate integrated waveguide is small, thereby reducing the transmission loss of each substrate integrated waveguide, thereby reducing the overall transmission loss of the liquid crystal antenna.

[0051] Figure 1 is a cross-sectional view of a liquid crystal antenna provided by an embodiment of the present disclosure. As shown in Figure 1, the liquid crystal antenna comprises a feed structure, a first substrate 2, a liquid crystal cell 3, and a radiating plate 10, stacked in sequence. During operation, a radio frequency signal is fed through the feed structure, first substrate 2, and liquid crystal cell 3, and then into the radiating plate 10, thereby stimulating the radiating plate 10 to radiate electromagnetic waves into free space.

[0052] The feeding structure includes a first input terminal 13 and multiple first output terminals 14. The feeding structure can receive radio frequency signals through the first input terminal 13 and simultaneously output radio frequency signals through the multiple first output terminals 14. That is, the feeding structure can realize power distribution.

[0053] The feed structure can be a waveguide power divider 1, a suspended strip line, or a microstrip line, as long as it can achieve power distribution. For example, the transmission loss of the feed structure is less than the transmission loss of the microstrip line, thereby reducing the loss of the liquid crystal antenna and improving the performance of the liquid crystal antenna.

[0054] Since the transmission loss of the waveguide power divider 1 is smaller than the transmission loss of the microstrip line, the liquid crystal antenna provided by the embodiment of the present disclosure is described in detail below by taking the waveguide power divider 1 as an example of a feeding structure.

[0055] Figure 2 is a top view of a waveguide power splitter according to an embodiment of the present disclosure. As shown in Figures 1 and 2, the waveguide power splitter 1 includes a body 11, within which is disposed a tree-shaped hollow tube 12. Hollow tube 12 includes a root portion and multiple distal ends. The root portion is the end of the hollow tube 12 facing away from the liquid crystal cell 3, while the distal ends are the ends of the hollow tube 12 facing the liquid crystal cell 3. The root portion of the hollow tube 12 serves as a first input end 13 of the waveguide power splitter 1, while the distal ends of the hollow tube 12 serve as a first output end 14 of the waveguide power splitter 1.

[0056] For example, as shown in Figure 2, each rectangular opening is a second output terminal, and multiple second output terminals are arranged in an array. It should be noted that the shape, number, and arrangement of the second output terminals are not limited in the embodiments of the present disclosure and can be flexibly adjusted as needed in actual application.

[0057] The body 11 of the waveguide power splitter 1 can be a metal block or a non-metal block such as plastic. When the body 11 of the waveguide power splitter 1 is a metal block, a hollow tube 12 can be formed within the body 11 using metal processing techniques such as machining and casting. When the body 11 of the waveguide power splitter 1 is a non-metal block such as plastic, the hollow tube 12 can be formed within the body 11 using processing techniques such as machining and injection molding. A metal coating can then be formed on the inner wall of the hollow tube 12 using a process such as electroplating, thereby allowing electromagnetic waves to propagate within the metal coating of the hollow tube 12.

[0058] Of course, the waveguide power divider 1 can also be manufactured by other processes, and the embodiment of the present disclosure does not limit the manufacturing process of the waveguide power divider 1.

[0059] FIG3 is a schematic diagram of a waveguide power splitter 1 according to an embodiment of the present disclosure. For example, as shown in FIG3 , the waveguide power splitter 1 includes a first input terminal 13 and eight first output terminals 14 , with three one-to-two power splitting structures 52 disposed between the first input terminal 13 and the first output terminal 14 .

[0060] In actual application, the waveguide power divider 1 can also include a waveguide converter, one end of which is connected to the coaxial line, and the other end of the waveguide converter is connected to the first input end 13 to convert the guided wave in the coaxial line and transmit the converted signal in the hollow pipe 12.

[0061] Continuing with reference to FIG1 , the first substrate 2 includes a plurality of first substrate integrated waveguides 20 (structures within the dotted box in FIG1 ). One first substrate integrated waveguide 20 is disposed opposite to one first output terminal 14 , and the feeding structure couples the RF signal into the first substrate integrated waveguide 20 through the first output terminal 14 .

[0062] Exemplarily, the first substrate integrated waveguides 20 correspond one-to-one with the first output terminals 14. For example, the waveguide power splitter 1 includes eight first output terminals 14, and the first substrate 2 includes eight first substrate integrated waveguides 20. The first substrate integrated waveguides 20 correspond one-to-one with the first output terminals 14, so that the waveguide power splitter 1 simultaneously transmits radio frequency signals to the eight first substrate integrated waveguides 20 through the eight first output terminals 14.

[0063] Continuing with FIG1 , the first substrate 2 includes a first conductive layer 21, a first dielectric layer 23, and a second conductive layer 22, which are stacked in sequence. The second conductive layer 22 is closer to the liquid crystal cell 3. A plurality of first conductive pillars 24 are disposed within the first dielectric layer 23 at intervals. One end of each first conductive pillar 24 is electrically connected to the first conductive layer 21, and the other end of each first conductive pillar 24 is electrically connected to the second conductive layer 22.

[0064] Figure 4 is a top view of a first substrate integrated waveguide 20 according to an embodiment of the present disclosure, Figure 5 is a bottom view of a first substrate integrated waveguide 20 according to an embodiment of the present disclosure, and Figure 6 is a cross-sectional view taken along line AA in Figure 4. As shown in Figure 4, the first conductive layer 21 includes a first region, which is a closed region enclosed by a plurality of first conductive pillars 24 arranged at intervals. Specifically, the plurality of first conductive pillars 24 are arranged at intervals along the edge of the first region, and the plurality of first conductive pillars 24 surround the first region. As shown in Figure 5, the second conductive layer 22 includes a second region, which is a closed region enclosed by a plurality of first conductive pillars 24 arranged at intervals. Specifically, the plurality of first conductive pillars 24 are arranged at intervals along the edge of the second region, and the plurality of first conductive pillars 24 surround the second region.

[0065] It should be noted that there may not be a clear physical boundary between the first region and other regions of the first conductive layer 21. That is, the first region may be connected to other regions of the first conductive layer 21 as a whole, and the first region may be divided by virtual lines connecting the multiple first conductive pillars 24. Of course, the first region may also have a clear physical boundary between it and other regions of the first conductive layer 21, for example, the closed area enclosed by the virtual connection of the multiple first conductive pillars 24 may be hollowed out.

[0066] Similarly, there may be no obvious physical boundary between the second region and other regions of the second conductive layer 22 , or there may be an obvious physical boundary between the second region and other regions of the second conductive layer 22 .

[0067] The first region and the second region are opposite to each other. Exemplarily, the first region and the second region are directly opposite to each other, and at this time, the first conductive pillar 24 extends in a direction perpendicular to the first conductive layer 21 and the second conductive layer 22 .

[0068] The first region, the second region, and a plurality of first conductive pillars 24 surrounding the first and second regions form a first substrate integrated waveguide 20. The first region, the second region, and the plurality of first conductive pillars 24 surrounding the first and second regions, which are arranged opposite each other, collectively form a cavity. The cavity is filled with a first dielectric layer 23, allowing radio frequency signals to propagate within the cavity.

[0069] The orthographic projection of the second region on the waveguide power splitter 1 may at least partially overlap with the first output end 14 , so that the RF signal may be coupled from the first output end 14 to the first substrate integrated waveguide 20 and propagate in the cavity.

[0070] For example, as shown in Figures 5 and 6, a first slot 211 may be provided in the first region, and the orthographic projection of the first slot 211 on the waveguide power divider 1 at least partially overlaps with the first output end 14, so that the radio frequency signal is coupled into the cavity of the first substrate integrated waveguide 20 through the first output end 14 and the first slot 211.

[0071] Exemplarily, the orthographic projection of the first slot 211 on the waveguide power splitter 1 is located within the range of the first output end 14. That is, the opening area of ​​the first slot 211 is smaller than the opening area of ​​the first output end 14, which increases the overlapping area between the first slot 211 and the first output end 14 and improves the coupling efficiency of the RF signal.

[0072] In actual application, the first dielectric layer 23 may include multiple groups of first conductive columns 24, each group of first conductive columns 24 may include multiple first conductive columns 24, and multiple first conductive columns 24 in the same group of first conductive columns 24 and the first conductive layer 21 and the second conductive layer 22 form a cavity. Multiple groups of first conductive columns 24 form multiple cavities, and the multiple cavities are spaced apart.

[0073] Multiple first conductive pillars 24 in the same group of first conductive pillars 24 form a first region in the first conductive layer 21. Multiple groups of first conductive pillars 24 form multiple first regions in the first conductive layer 21. The multiple first regions can be arranged at intervals. The multiple first regions can be electrically connected or disconnected.

[0074] Multiple first conductive pillars 24 in the same group of first conductive pillars 24 form a second region in the second conductive layer 22. Multiple groups of first conductive pillars 24 form multiple second regions in the second conductive layer 22. The multiple second regions can be arranged at intervals. The multiple second regions can be electrically connected or disconnected.

[0075] Figure 1 illustrates a configuration where two adjacent first regions are disconnected, and two adjacent second regions are disconnected. Figure 7 is a cross-sectional view of another liquid crystal antenna according to an embodiment of the present disclosure. As shown in Figure 7, two adjacent first regions can also be connected to form an integral structure, and two adjacent second regions can also be connected to form an integral structure.

[0076] Continuing with Figure 1 , when two adjacent first regions are disconnected and two adjacent second regions are disconnected, the first dielectric layers 23 of two adjacent first substrate-integrated waveguides 20 can also be disconnected. In this case, each first substrate-integrated waveguide 20 is an independent component, increasing the flexibility of the first substrate-integrated waveguide 20 layout. Furthermore, the versatility of the first substrate-integrated waveguide 20 is enhanced, allowing it to be applied to liquid crystal antennas of varying array sizes.

[0077] Exemplarily, the first substrate 2 may be a printed circuit board (PCB), and the first conductive pillars 24 are metallized vias electrically connecting the first conductive layer 21 and the second conductive layer 22 .

[0078] When the feeding structure is a waveguide power splitter 1, the waveguide power splitter 1 can be bonded to the first substrate 2. For example, the waveguide power splitter 1 and the first substrate 2 can be provided with mutually cooperating alignment structures, so that after the waveguide power splitter 1 and the first substrate 2 are bonded, the first output end 14 is aligned with the first slit 211, as shown in FIG19 .

[0079] The first substrate integrated waveguide 20 may include a second input terminal and a plurality of second output terminals, so that the first substrate integrated waveguide 20 transmits radio frequency signals through the plurality of second output terminals. That is, the first substrate integrated waveguide 20 may have a power distribution function.

[0080] 4 and 6 , the second output end may be a second slot 222 disposed in the second region. A plurality of second slots 222 are disposed in the second region, so that the first substrate integrated waveguide 20 transmits a radio frequency signal to the liquid crystal phase shifter through the plurality of second slots 222 .

[0081] 4 shows the second slit 222 as an elongated strip slit, and FIG5 shows the first slit 211 as an elongated strip slit. In actual applications, the shapes of the first slit 211 and the second slit 222 are not limited thereto and can be flexibly set as needed.

[0082] 1 , the liquid crystal cell 3 includes a plurality of liquid crystal phase shifters. The liquid crystal phase shifters may include an upper electrode 34 , a lower electrode 33 , and a tunable layer located between the upper electrode 34 and the lower electrode 33 .

[0083] Exemplarily, the liquid crystal cell 3 includes an upper substrate 32 and a lower substrate 31 arranged opposite each other. An upper electrode 34 is provided on the side of the upper substrate 32 facing the lower substrate 31, and a lower electrode 33 is provided on the side of the lower substrate 31 facing the upper substrate 32. Liquid crystal molecules 35 are disposed between the upper and lower electrodes 34, 33. During operation, a bias voltage is applied between the upper and lower electrodes 34, 33, causing the liquid crystal molecules 35 to deflect under the bias voltage, thereby changing the dielectric constant of the liquid crystal phase shifter and, in turn, adjusting the phase of the radio frequency signal.

[0084] The liquid crystal phase shifter can be a linear liquid crystal phase shifter or a curved liquid crystal phase shifter. In practical applications, the liquid crystal phase shifter can further include a guide film to guide the arrangement of the liquid crystal molecules 35.

[0085] It should be noted that, in addition to the liquid crystal molecules 35 , the tunable layer may also be made of other materials, as long as the tunable layer can change its own dielectric constant under the action of a bias voltage.

[0086] A liquid crystal phase shifter is disposed opposite a second output terminal, so that the first substrate integrated waveguide 20 couples the radio frequency signal into the liquid crystal phase shifter through the second output terminal. When the second output terminal includes a second slit 222 disposed in the second region, the liquid crystal phase shifter is disposed opposite the second slit 222.

[0087] Exemplarily, the liquid crystal phase shifters correspond to the second output terminals one-to-one, that is, the number of the liquid crystal phase shifters is the same as the number of the second output terminals in the first substrate 2 .

[0088] The liquid crystal phase shifter can transmit radio frequency signals through the upper electrode 34 , can also transmit radio frequency signals through the lower electrode 33 , or can simultaneously transmit radio frequency signals through the upper electrode 34 and the lower electrode 33 .

[0089] Exemplarily, the liquid crystal phase shifter transmits radio frequency signals through the lower electrode 33 , and the orthographic projection of the lower electrode 33 on the first substrate 2 at least partially overlaps with the second slit 222 , so that the radio frequency signal is coupled into the lower electrode 33 through the second slit 222 .

[0090] The radiating plate 10 includes multiple radiating elements, which are positioned opposite the liquid crystal phase shifter. These radiating elements radiate electromagnetic waves into free space when excited by the RF signal modulated by the liquid crystal phase shifter. The radiating elements can be single-layer or multi-layer structures. The present disclosure does not limit the structure of the radiating elements, as long as they can radiate electromagnetic waves into free space.

[0091] Exemplarily, the radiation units correspond to the liquid crystal phase shifters on a one-to-one basis, that is, the number of the radiation units is equal to the number of the liquid crystal phase shifters.

[0092] The radiation units of the radiation panel 10 may be arranged in an array to form a radiation unit array. The radiation unit array may be a triangular array, a rectangular array, a circular array, etc. The arrangement of the radiation unit array in the embodiment of the present disclosure is not limited.

[0093] In the liquid crystal antenna provided in the embodiments of the present disclosure, the feed portion includes both a feed structure and multiple first substrate integrated waveguides 20. The feed structure includes multiple first output terminals 14, with each first output terminal 14 corresponding to a first substrate integrated waveguide 20. The RF signal within the feed structure undergoes power distribution and is transmitted to the multiple first output terminals 14, where it is then coupled to the multiple first substrate basic waveguides by the multiple first output terminals 14. Because the first substrate 2 includes multiple first substrate integrated waveguides 20, the number of second output terminals in each first substrate integrated waveguide 20 is reduced, given a fixed array size of the liquid crystal antenna. This reduces transmission loss in the first substrate integrated waveguide 20 and prevents a sharp increase in transmission loss in the first substrate integrated waveguide 20 due to the larger array size of the liquid crystal antenna.

[0094] For example, the radiation units in the liquid crystal antenna are arranged in a 4*4 array. When the first substrate 2 includes only one first substrate integrated waveguide 20, the first substrate integrated waveguide 20 includes eight second output ends. At this time, the transmission loss of the first substrate integrated waveguide 20 is relatively large. When the first substrate 2 includes four first substrate integrated waveguides 20, each first substrate integrated waveguide 20 includes four second output ends. Compared with the case where each first substrate integrated waveguide 20 includes eight second output ends, the transmission loss is significantly reduced, thereby reducing the overall loss of the liquid crystal antenna and improving the performance of the liquid crystal antenna.

[0095] Figure 8 is a top view of a first substrate-integrated waveguide 20 according to an embodiment of the present disclosure. As shown in Figure 8 , the second region may include a conversion region s and a power splitting region d connected to the conversion region s. The second slot 222 is provided in the power splitting region d. For example, as shown in Figure 8 , with the dashed line as the dividing line, the area to the left of the dashed line is the conversion region s, and the area to the right of the dashed line is the power splitting region d.

[0096] Correspondingly, the first region may also include a conversion region s and a power division region d, and the first slit 211 is provided in the conversion region s. The conversion region s of the first region is opposite to the conversion region s of the second region, and the power division region d of the first region is opposite to the power division region d of the second region.

[0097] The RF signal is coupled into the space between the two conversion regions s through the first output terminal 14 and the first gap 211, so that the RF signal is converted from propagating in a direction perpendicular to the first substrate 2 to propagating in a direction parallel to the first substrate 2, and power distribution is achieved in the space between the two power division regions d.

[0098] For example, the power division area d is divided into four parts, and the power division area d of the second region is provided with four second gaps 222. Of course, the power division area d can also be divided into two parts, three parts, etc., which is not limited in the embodiment of the present disclosure.

[0099] Continuing to refer to Figures 1 and 7, the radiation plate 10 may include a second substrate 4, which is connected to a side of the liquid crystal box 3 away from the first substrate 2, and the radiation unit includes a second substrate integrated waveguide 40 arranged on the second substrate 4, and the second substrate integrated waveguide 40 is arranged opposite to the liquid crystal phase shifter.

[0100] Figure 9 is a top view of a second substrate integrated waveguide 40 according to an embodiment of the present disclosure, and Figure 10 is a cross-sectional view of a second substrate integrated waveguide 40 according to an embodiment of the present disclosure. As shown in Figures 9 and 10, the second substrate 4 may include a third conductive layer 41, a second dielectric layer 43, and a fourth conductive layer 42, which are stacked in sequence. The third conductive layer 41 is closer to the liquid crystal cell 3. A plurality of second conductive pillars 44 are arranged in a spaced-apart pattern within the second dielectric layer 43. One end of each second conductive pillar 44 is electrically connected to the third conductive layer 41, and the other end of each second conductive pillar 44 is electrically connected to the fourth conductive layer 42.

[0101] The third conductive layer 41 includes a third region, which is a closed area enclosed by a plurality of second conductive pillars 44 arranged at intervals. Specifically, the plurality of second conductive pillars 44 are arranged at intervals along the edge of the third region, and the plurality of second conductive pillars 44 surround the third region. The fourth conductive layer 42 includes a fourth region, which is a closed area enclosed by a plurality of second conductive pillars 44 arranged at intervals. Specifically, the plurality of second conductive pillars 44 are arranged at intervals along the edge of the fourth region, and the plurality of second conductive pillars 44 surround the fourth region.

[0102] It should be noted that there may not be a clear physical boundary between the third region and other regions of the third conductive layer 41. That is, the third region may be connected to other regions of the third conductive layer 41 as a whole, and the third region may be divided by virtual lines connecting the multiple second conductive pillars 44. Of course, the third region may also have a clear physical boundary between it and other regions of the third conductive layer 41, for example, the closed area enclosed by the virtual connection of the multiple second conductive pillars 44 may be hollowed out.

[0103] Similarly, there may be no obvious physical boundary between the fourth region and other regions of the fourth conductive layer 42 , or there may be an obvious physical boundary between them.

[0104] The third region and the fourth region are opposite to each other. Exemplarily, the third region and the fourth region are directly opposite to each other, and in this case, the second conductive pillar 44 extends in a direction perpendicular to the third conductive layer 41 and the fourth conductive layer 42 .

[0105] The third region, the fourth region, and the plurality of second conductive pillars 44 surrounding the third and fourth regions form a second substrate integrated waveguide 40. The third region, the fourth region, and the plurality of second conductive pillars 44 surrounding the third and fourth regions, which are arranged opposite to each other, collectively form a cavity. The cavity is filled with a second dielectric layer 43, allowing radio frequency signals to propagate within the cavity.

[0106] The orthographic projection of the third region on the liquid crystal cell 3 may at least partially overlap with the liquid crystal phase shifter, so that the radio frequency signal may be coupled to the second substrate integrated waveguide 40 by the liquid crystal phase shifter and propagate in the cavity.

[0107] Exemplarily, the second substrate 4 may be a printed circuit board, and the first conductive pillars 24 in the second substrate 4 are metallized vias in the printed circuit board.

[0108] For example, with continued reference to FIG9 , the third conductive layer 41 is provided with a third slit 411, which is disposed opposite the liquid crystal phase shifter. The fourth conductive layer 42 is provided with a fourth slit 421, which is disposed opposite the radiation unit. The third conductive layer 41 is located below the fourth conductive layer 42, and the third slit 411 is disposed in the third conductive layer 41. Therefore, the third slit 411 is indicated by a dotted line in FIG9 .

[0109] The structure of the second substrate integrated waveguide 40 is not limited thereto, and the structure of the second substrate integrated waveguide 40 may be the same as that of the first substrate integrated waveguide 20 or may be different from that of the first substrate integrated waveguide 20 .

[0110] Exemplarily, each second substrate integrated waveguide 40 includes a third slit 411, the third conductive layer 41 is provided with multiple third slits 411, and the number of third slits 411 is equal to the number of liquid crystal phase shifters (that is, the number of second substrate integrated waveguides 40 is equal to the number of liquid crystal phase shifters), and the number of liquid crystal phase shifters is the same as the number of second slits 222.

[0111] Exemplarily, each second substrate integrated waveguide 40 includes one fourth slot 421; alternatively, each second substrate integrated waveguide 40 includes multiple fourth slots 421, so that the second substrate integrated waveguide 40 has a power splitting function. For example, each second substrate integrated waveguide 40 includes four fourth slots 421, so that the second substrate integrated waveguide 40 can be equivalent to a one-to-four power splitter.

[0112] The second substrate-integrated waveguide 40 can directly radiate electromagnetic waves into free space. Figure 11 is a cross-sectional view of another liquid crystal antenna provided by an embodiment of the present disclosure. As shown in Figure 11, the radiation plate 10 can include only the second substrate 4, and radiate electromagnetic waves into free space through the second substrate-integrated waveguide 40 in the second substrate 4.

[0113] The second substrate-integrated waveguide 40 radiates electromagnetic waves into free space through the fourth slot 421. Linear polarization, 45-degree polarization, and the like can be achieved by changing the slot pattern of the fourth slot 421. For example, the fourth slot 421 can extend horizontally as shown in FIG9 , vertically as shown in FIG9 , or obliquely as shown in FIG9 .

[0114] The transmission loss of the second substrate integrated waveguide 40 is relatively small. Electromagnetic waves are radiated through the second substrate integrated waveguide 40 , thereby reducing the transmission loss of the liquid crystal antenna.

[0115] Continuing with reference to Figures 1 and 7 , the radiation plate 10 may further include a radiation stack 5 connected to a side of the second substrate 4 away from the first substrate 2. The radiation unit may further include a radiation patch 51 disposed on the radiation stack 5. The radiation patch 51 is disposed opposite the second substrate integrated waveguide 40. An RF signal within the second substrate integrated waveguide 40 may be coupled into the radiation patch 51, thereby exciting the radiation patch 51 to radiate electromagnetic waves into free space.

[0116] The radiation patch 51 may be a single-layer structure or a multi-layer structure. For ease of description, the present disclosure only uses the radiation patch 51 as an example for description.

[0117] Figure 12 illustrates an arrangement of radiating patches 51 in one embodiment of the present disclosure, Figure 13 illustrates another arrangement of radiating patches 51 in another embodiment of the present disclosure, and Figure 14 illustrates yet another arrangement of radiating patches 51 in another embodiment of the present disclosure. As shown in Figures 12 to 14 , the radiating stack 5 may include multiple radiating patches 51, which may be arranged in an array. For example, Figures 12 to 14 illustrate multiple radiating patches 51 arranged in a rectangular array. Figure 15 illustrates yet another arrangement of radiating patches 51 in another embodiment of the present disclosure. As shown in Figure 15 , multiple radiating patches 51 may also be arranged in a triangular array.

[0118] The shape of the radiation patch 51 can be rectangular, as shown in Figure 12. The shape of the radiation patch 51 can also be hexagonal, as shown in Figure 13. The shape of the radiation patch 51 can also be irregular, as shown in Figure 14.

[0119] There may be various corresponding relationships between the radiation patches 51 and the fourth slots 421 . The fourth slots 421 may correspond to each radiation patch 51 one to one, or a plurality of radiation patches 51 may correspond to one fourth slot 421 .

[0120] FIG16 illustrates a positional relationship between the radiating patch 51 and the fourth slot 421 in an embodiment of the present disclosure. As shown in FIG16 , when the fourth slot 421 corresponds one-to-one with the radiating patch 51, the orthographic projection of the fourth slot 421 on the radiating stack 5 at least partially overlaps with the radiating patch 51, allowing the RF signal within the second substrate integrated waveguide 40 to be coupled into the radiating patch 51 through the fourth slot 421.

[0121] Figure 17 illustrates another positional relationship between the radiating patch 51 and the fourth slot 421 in an embodiment of the present disclosure. As shown in Figure 17 , when multiple radiating patches 51 are provided corresponding to one fourth slot 421, the radiating stack 5 further includes a power splitter structure 52 electrically connected to the multiple radiating patches 51, and the orthographic projection of the fourth slot 421 on the radiating stack 5 at least partially overlaps with the power splitter structure 52.

[0122] Exemplarily, the power splitting structure 52 and the radiation patch 51 are arranged on the same layer.

[0123] The radiation unit includes both the second substrate integrated waveguide 40 and the radiation patch 51 , so that the second substrate integrated waveguide 40 can adjust the waveform of the liquid crystal antenna.

[0124] Figure 18 is a cross-section of another liquid crystal antenna according to an embodiment of the present disclosure. As shown in Figure 18 , the radiating plate 10 may comprise only a radiating stack 5, which is connected to the side of the liquid crystal cell 3 away from the first substrate 2. The radiating element comprises a radiating patch 51 disposed on the radiating stack 5. The RF signal, after phase modulation by the liquid crystal phase shifter, is coupled into the radiating patch 51, thereby stimulating the radiating patch 51 to radiate electromagnetic waves into free space. In this case, the liquid crystal antenna has a simple structure and a small cross-section, making it easier to miniaturize.

[0125] The shape and arrangement of the radiation patch 51 can be referred to FIG. 12 to FIG. 15 , and will not be described in detail here.

[0126] An embodiment of the present disclosure further provides a communication device, which includes the above-mentioned liquid crystal antenna and transmits or receives electromagnetic waves through the liquid crystal antenna. The communication device can be applied to a variety of communication systems, such as satellite communication systems, Internet of Things (IoT), narrowband Internet of Things (NB-IoT) systems, global system for mobile communications (GSM), enhanced data rate for GSM evolution (EDGE), wideband code division multiple access (WCDMA), code division multiple access 2000 (CDMA2000), time division-synchronization code division multiple access (TD-SCDMA), long term evolution (LTE), fifth generation (5G) communication systems such as 5G new radio (NR), and three major application scenarios of 5G mobile communication systems: enhanced mobile broadband (eMBB), ultra reliable low latency communications (uRLLC), and massive machine type communications (MTC). communications, mMTC), device-to-device (D2D) communication system, machine-to-machine (M2M) communication system, Internet of Vehicles communication system, or other or future communication systems, which are not specifically limited in the embodiments of the present disclosure.

[0127] In the communication device provided in the embodiments of the present disclosure, the feed portion includes both a feed structure and multiple first substrate integrated waveguides 20. The feed structure includes multiple first output terminals 14, with each first output terminal 14 corresponding to a first substrate integrated waveguide 20. The RF signal within the feed structure undergoes power distribution and is transmitted to the multiple first output terminals 14, where it is then coupled to the multiple first substrate basic waveguides by the multiple first output terminals 14. Because the first substrate 2 includes multiple first substrate integrated waveguides 20, the number of second output terminals in each first substrate integrated waveguide 20 is reduced when the array size of the liquid crystal antenna is constant, thereby reducing the transmission loss of the first substrate integrated waveguide 20 and preventing a sharp increase in the transmission loss of the first substrate integrated waveguide 20 due to the large array size of the liquid crystal antenna.

[0128] The above description is merely a specific embodiment of the present disclosure, but the scope of protection of the present disclosure is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this disclosure should be included in the scope of protection of the present disclosure. Therefore, the scope of protection of the present disclosure should be based on the scope of protection of the claims.

Claims

1. A liquid crystal antenna, characterized in that: It includes a feeding structure, a first substrate, a liquid crystal box and a radiation plate which are stacked in sequence. The feeding structure comprises a plurality of first output ends, and the feeding structure is configured to feed power to the first substrate through the plurality of first output ends; The first substrate includes a plurality of first substrate integrated waveguides, one of the first substrate integrated waveguides is arranged opposite to one of the first output ends, and each of the first substrate integrated waveguides includes a plurality of second output ends; The liquid crystal box comprises a plurality of liquid crystal phase shifters, and one of the liquid crystal phase shifters is arranged opposite to one of the second output ends; The radiation plate includes a plurality of radiation units, and the radiation units are arranged opposite to the liquid crystal phase shifter.

2. The liquid crystal antenna according to claim 1, wherein: The first substrate comprises a first conductive layer, a first dielectric layer and a second conductive layer which are stacked in sequence, wherein the second conductive layer is closer to the liquid crystal box; the first conductive layer comprises a first region, the second conductive layer comprises a second region, the first region and the second region are opposite, the first dielectric layer is provided with a plurality of first conductive pillars, one end of the first conductive pillar is electrically connected to the first region, the other end of the first conductive pillar is electrically connected to the second region, the plurality of first conductive pillars are arranged at intervals and surround the first region and the second region; the first region, the second region and the plurality of first conductive pillars surrounding the first region and the second region form the first substrate integrated waveguide; The first region is provided with a first slit, the first slit is opposite to the first output end, the second output end includes a second slit arranged in the second region, and the second region is provided with a plurality of the second slits.

3. The liquid crystal antenna according to claim 2, wherein: The first region and the second region both include a conversion region and a power division region connected to the conversion region, the first gap is arranged in the conversion region, and the second gap is arranged in the power division region.

4. The liquid crystal antenna according to claim 2, wherein: The first conductive layer includes a plurality of the first regions, which are disconnected from each other or connected to each other; the second conductive layer includes a plurality of the second regions, which are disconnected from each other or connected to each other.

5. The liquid crystal antenna according to any one of claims 1 to 4, wherein: The radiation plate includes a second substrate connected to a side of the liquid crystal box away from the first substrate. The radiation unit includes a second substrate integrated waveguide arranged on the second substrate. The second substrate integrated waveguide is arranged opposite to the liquid crystal phase shifter.

6. The liquid crystal antenna according to claim 5, wherein: The radiation plate further includes a radiation stack connected to a side of the second substrate away from the first substrate. The radiation unit further includes a radiation patch arranged on the radiation stack, and the radiation patch is arranged opposite to the second substrate integrated waveguide.

7. The liquid crystal antenna according to claim 6, wherein: One or more fourth slots are provided on a side of the second substrate integrated waveguide facing the radiation patch, one radiation patch is corresponding to one of the fourth slots, and the orthographic projection of the fourth slot on the radiation stack at least partially overlaps with the radiation patch.

8. The liquid crystal antenna according to claim 6, wherein: One or more fourth slots are provided on the side of the second substrate integrated waveguide facing the radiation patch, and one fourth slot corresponds to a plurality of the radiation patches. The radiation stack also includes a power division structure electrically connected to the plurality of radiation patches, and the orthographic projection of the fourth slot on the radiation stack at least partially overlaps with the power division structure.

9. The liquid crystal antenna according to claim 7 or 8, wherein: The radiation patch is rectangular, hexagonal or irregular in shape.

10. The liquid crystal antenna according to claim 5, wherein: One or more fourth slits are provided on a side of the second substrate integrated waveguide away from the liquid crystal box, and the second substrate integrated waveguide radiates electromagnetic waves to free space through the fourth slits.

11. The liquid crystal antenna according to claim 1, wherein: The radiation plate includes a radiation stack connected to a side of the liquid crystal box away from the first substrate, and the radiation unit includes a radiation patch arranged on the radiation stack.

12. The liquid crystal antenna according to any one of claims 1 to 4, wherein: The feeding structure is a waveguide power divider or a suspended strip line.

13. The liquid crystal antenna according to claim 13, wherein: The waveguide power divider comprises a metal block, in which a hollow pipe is provided; or, the waveguide power divider comprises a plastic block, in which a hollow pipe is provided, and a side wall of the hollow pipe is provided with a metal coating; The hollow pipe is in a tree shape, the root of the hollow pipe is the first input end, and the tip end of the hollow pipe is the first output end.

14. A liquid crystal antenna, characterized in that: It includes a waveguide power divider, a first substrate, a liquid crystal box and a second substrate which are stacked in sequence. The waveguide power divider includes a plurality of first output ends; The first substrate includes a plurality of first substrate integrated waveguides, one of the first substrate integrated waveguides is arranged opposite to one of the first output ends, and each of the first substrate integrated waveguides includes a plurality of second output ends; The liquid crystal box is provided with a plurality of liquid crystal phase shifters, and one of the liquid crystal phase shifters is arranged opposite to one of the second output ends; The second substrate is provided with a plurality of second substrate integrated waveguides, and the second substrate integrated waveguides are arranged opposite to the liquid crystal phase shifter.

15. A communication device, characterized in that: The invention comprises the liquid crystal antenna according to any one of claims 1 to 14.

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