Antenna

Abstract

The invention provides an antenna, belongs to the technical field of communication, and can solve the problems that an existing holographic antenna is low in array surface utilization rate and low in radiation efficiency. The antenna of the present disclosure comprises: a waveguide structure; a first electrode having a plurality of slit openings; the plurality of first radiation electrodes are arranged on one side, deviating from the waveguide structure, of the first electrode; the plurality of second radiation electrodes are arranged on one side, deviating from the waveguide structure, of the first radiation electrode; orthographic projections of one slit opening, one first radiation electrode and one second radiation electrode on the layer where the first electrode is located are overlapped, and a radiation unit is formed; the radiation unit further comprises two switch units which are located between the layer where the first radiation electrode is located and the first electrode and arranged on the two sides of the first straight line respectively, and the two switch units are symmetrically arranged with the first straight line as the symmetry axis. The switch unit comprises at least one switch which is configured to control on or off of the first radiation electrode and the first electrode.

Description

Technical Field

[0001] This disclosure belongs to the field of communication technology, and specifically relates to an antenna. Background Technology

[0002] Reconfigurable antennas are antennas that can dynamically change the radiation direction, amplitude, phase, and other radiation properties of the radiated signal. They offer advantages such as increased network capacity, enhanced coverage, and integrated communication and sensing. Phased array antennas, as traditional reconfigurable antennas, typically use solid-state transceiver modules and employ complex feeding methods and beamforming structures. This results in drawbacks such as high complexity, high cost, and large size, which to some extent limits their widespread application.

[0003] A holographic antenna consists of a source antenna and a holographic structure. The electromagnetic wave radiated by the source antenna serves as a reference wave. The holographic structure, analogous to holographic film in optical holography, records the interference field formed by the source and target antennas. The source antenna generates the reference wave, and the target antenna generates the desired target wave. The interference field refers to the hologram formed by the interference of the reference and target waves. The holographic antenna operates by using the reference wave emitted by the source antenna to illuminate the hologram on the holographic structure. The holographic structure modulates the wavefront of the reference wave, thereby reproducing the target wave and ensuring the electromagnetic wave radiates in the desired direction. As a current research frontier, reconfigurable holographic smart surface antennas represent the future development direction of holographic antennas. They consist of multiple antenna elements, each of which is an adjustable unit controllable by circuitry or functional materials. By controlling the on / off / intermediate states of each element, different holograms can be generated, thus achieving the reconstruction of phase, amplitude, and direction.

[0004] However, reconfigurable holographic antennas in related technologies suffer from problems such as large size, complex structure and layout, and insufficient gain. Summary of the Invention

[0005] This invention aims to at least solve one of the technical problems existing in the prior art. In one aspect, it provides an antenna comprising: a waveguide structure; a first electrode disposed on the waveguide structure; the first electrode having a plurality of slit openings extending along its thickness direction; a plurality of first radiating electrodes disposed on a side of the first electrode opposite to the waveguide structure; a plurality of second radiating electrodes disposed on the side of the first radiating electrodes opposite to the waveguide structure; the orthographic projections of one of the slit openings, one of the first radiating electrodes, and one of the second radiating electrodes on the layer containing the first electrode overlap and constitute a radiating unit; the radiating unit further comprises two switching units located between the layer containing the first radiating electrode and the first electrode, respectively disposed on both sides of a first straight line, and the two switching units are symmetrically arranged about the first straight line as an axis of symmetry; the first straight line is a straight line extending through the center of the slit opening and along the extension direction of the slit opening; each switching unit includes at least one switch, the switch being configured to control the first radiating electrode and the first electrode to be turned on or off.

[0006] In some optional embodiments, the antenna further includes: a first dielectric layer disposed on the side of the first electrode facing away from the waveguide structure; a second dielectric layer disposed between the first dielectric layer and the first radiating electrode; a switching unit located between the first dielectric layer and the second dielectric layer; the radiating unit further includes a transmission link corresponding to the switching unit; the transmission link includes a combiner and multiple branches connected to the combiner; one switch is configured on each branch; the combiner is connected to the first radiating electrode through a first connection via penetrating the second dielectric layer; each branch is connected to the first electrode through a second connection via penetrating the first dielectric layer.

[0007] In some optional embodiments, when the switching unit includes multiple switches, the shortest distance between the orthographic projection of each second connection via on the layer where the first electrode is located and the center of the slit opening is different for each of the second connection vias corresponding to each switch.

[0008] In some optional embodiments, the antenna further includes: a first dielectric layer disposed on the side of the first electrode facing away from the waveguide structure; a second dielectric layer disposed between the first dielectric layer and the first radiating electrode; a switching unit located between the first dielectric layer and the second dielectric layer; the radiating unit further includes a transmission link corresponding to the switching unit; the transmission link includes multiple sub-links, each sub-link being configured with one switch; the sub-link is connected to the first radiating electrode through a third connection via penetrating the second dielectric layer, and connected to the first electrode through a fourth connection via penetrating the first dielectric layer.

[0009] In some optional embodiments, when the switching unit includes multiple switches, the shortest distance between the orthographic projection of each of the fourth connecting vias corresponding to each of the switches and the center of the slit opening is different; and / or, the shortest distance between the orthographic projection of each of the third connecting vias corresponding to each of the switches and the center of the slit opening is different.

[0010] In some alternative embodiments, the waveguide structure includes opposing bottom and top walls, and a third dielectric layer filling the space between the bottom and top walls; the third dielectric layer includes a slow-wave dielectric.

[0011] In some alternative embodiments, in the direction from the bottom wall to the top wall, the third dielectric layer includes a first sub-dielectric layer, a second sub-dielectric layer, and a first dielectric substrate stacked sequentially; the first sub-dielectric layer includes polytetrafluoroethylene; the second sub-dielectric layer includes a plastic foam board; and the first dielectric substrate includes one or more of glass, ceramic, and plastic.

[0012] In some optional embodiments, the antenna further includes: a second dielectric substrate disposed between the first dielectric substrate and the first dielectric layer; the second dielectric substrate includes one or more of glass, ceramic, and plastic.

[0013] In some optional embodiments, the centers of the slit opening, the first radiation electrode, and the second radiation electrode in the radiation unit coincide, and both the first radiation electrode and the second radiation electrode are symmetrical about the first line.

[0014] In some optional embodiments, the antenna further includes: a fourth dielectric layer disposed on the side of the layer containing the first radiating electrode away from the waveguide structure; the second radiating electrode being located on the side of the fourth dielectric layer away from the waveguide structure; the fourth dielectric layer comprising an insulating material. Attached Figure Description

[0015] Figure 1 This is a top view schematic diagram of a liquid crystal holographic antenna in related technologies.

[0016] Figure 2 for Figure 1 The diagram shows a cross-sectional view of the liquid crystal radiating element along the thickness direction in the liquid crystal holographic antenna shown.

[0017] Figure 3 This is a top view of the antenna structure provided in this disclosure.

[0018] Figure 4 This is a three-dimensional structural diagram of the radiating element in the antenna provided in this disclosure.

[0019] Figure 5 for Figure 4 The top perspective view of the radiating element shown.

[0020] Figure 6 for Figure 4 A magnified view of a localized radiating element.

[0021] Figure 7 for Figure 5 The diagram shows a cross-sectional view of the radiating element along AB.

[0022] Figure 8 This is a top view of the switching unit and transmission link in the first connection method.

[0023] Figure 9 This is the equivalent circuit diagram of the transmission link in the first connection method.

[0024] Figure 10 This is a top perspective view of the switching unit and transmission link in the second connection method.

[0025] Figure 11 for Figure 10 The diagram shows a cross-sectional view of the structure along CD.

[0026] Figure 12 This is the equivalent circuit diagram of the transmission link in the second connection method.

[0027] Figure 13 This is a schematic diagram of a cross-section of the waveguide structure along its thickness direction.

[0028] Figure 14 This is a schematic diagram of the cross-sectional structure of the antenna along the thickness direction.

[0029] Figure 15 The curves show the performance of the first and second type antennas as a function of frequency.

[0030] Figure 16 The simulation curves of the antenna provided in this disclosure at different frequencies are shown.

[0031] Figure 17 The curves show the antenna performance as a function of operating frequency in the second and third states.

[0032] Figure 18 The curve showing the antenna performance as a function of operating frequency in the fourth state.

[0033] Figure 19 The simulation results show the radiation pattern of a traditional liquid crystal holographic antenna.

[0034] Figure 20 The simulation results of the radiation pattern of the antenna provided in this disclosure.

[0035] The attached figures are labeled as follows:

[0036] 100, Liquid crystal radiating unit; 101, Lower metal ground plane; 102, Air dielectric layer; 103, Lower glass substrate; 104, Upper metal ground plane; 105, Liquid crystal layer; 106, Radiation patch; 107, Upper glass substrate; 10, Radiation unit; 208, First radiation electrode; 209, Second radiation electrode; 207, Switch; 204, First dielectric layer; 205, Second dielectric layer; 206, Fourth dielectric layer; 201, Bottom wall; 202, Third dielectric layer; 203, Top wall; 2021, First sub-dielectric layer; 2022, Second sub-dielectric layer; 2023, First dielectric substrate; 210, Second dielectric substrate. Detailed Implementation

[0037] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0038] Unless otherwise defined, the technical or scientific terms used in this disclosure shall 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, the terms “an,” “a,” or “the,” and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms “including,” “comprising,” or “containing,” and similar terms 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. The terms “connected,” “linked,” or similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The terms “upper,” “lower,” “left,” and “right,” etc., are used only to indicate relative positional relationships, and these relative positional relationships may change accordingly when the absolute position of the described objects changes.

[0039] 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°.

[0040] 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.

[0041] In this article, "electrical connection" includes the situation where constituent elements are connected together by a component that has a certain electrical function. There are no particular restrictions on the "component that has a certain electrical function" as long as it enables the transmission and reception of electrical signals between the connected constituent elements. Examples of "components that have a certain electrical function" include not only electrodes and wiring, but also switching elements such as transistors, resistors, inductors, capacitors, and other components with various functions.

[0042] This document describes exemplary embodiments with reference to sectional views and / or plan views, which are idealized exemplary drawings. In the drawings, the thickness of layers and regions is enlarged for clarity. Therefore, variations in shape relative to the drawings are contemplated due to, for example, manufacturing techniques and / or tolerances. Therefore, exemplary embodiments should not be construed as limited to the shapes of the regions shown herein, but rather include shape deviations due to, for example, manufacturing processes. Thus, the regions shown in the drawings are schematic in nature, and their shapes are not intended to show the actual shapes of the regions of the device, nor are they intended to limit the scope of the exemplary embodiments.

[0043] As a necessary technical groundwork, before introducing the specific technical solutions of this disclosure, the working principle of holographic antennas, as well as the structure of liquid crystal holographic antennas and the technical problems they present, will be explained.

[0044] In the field of optics, interference refers to the phenomenon where two or more light waves meet and superimpose under specific conditions, causing a redistribution of light intensity in space, resulting in alternating bright and dark or colored fringes. When two light waves interfere, they can be referred to as the reference wave and the object wave, respectively, and the interference fringes they generate are called the interference field.

[0045] When interference theory from the field of optics is introduced into the field of antennas, the two interfering electromagnetic waves can be referred to as reference waves. and target wave The interference field between the two is In simple terms, a holographic antenna consists of a source antenna and a holographic structure. The electromagnetic wave radiated by the source antenna is the reference wave. The holographic structure is equivalent to the holographic film in optical holography, used to record the interference field formed by the source and target antennas. The target antenna generates the desired target wave. The working process of a holographic antenna is as follows: First, through electromagnetic simulation, the interference process between the reference wave and the target wave is simulated to obtain the interference pattern and thus the holographic structure is obtained. Then, the source antenna emits a reference wave that illuminates the holographic structure, causing the holographic structure to modulate the wavefront of the reference wave, thereby reproducing the target wave and causing the electromagnetic wave to radiate in the desired direction.

[0046] Currently, holographic antennas based on reconfigurable smart surfaces are gradually becoming a research hotspot in the industry due to their advantages such as intelligent reconfigurability, electromagnetic tunability, high gain, low cost, and flexible deployment. The structure of a holographic antenna based on reconfigurable smart surfaces typically consists of a large number of tunable antenna elements arranged in a specific space, forming an antenna array. These tunable antenna elements can be, for example, metasurface elements or other electromagnetic control devices. The antenna works by obtaining the interference pattern of a reference wave and a target wave through electromagnetic simulation. This interference pattern can be considered as the working state of each antenna element in the antenna array. The reference wave is then radiated onto the interference pattern, and each antenna element modulates the reference wave to generate the desired target wave. Compared to traditional phased array antennas, this type of antenna has advantages such as low profile, easy conformal design, reconfigurability, and high gain.

[0047] Figure 1 This is a top view schematic diagram of a liquid crystal holographic antenna in related technologies; Figure 2 for Figure 1 The diagram shows a cross-sectional view of the liquid crystal radiating element along the thickness direction in the liquid crystal holographic antenna shown. Figure 1 and Figure 2 As shown, the liquid crystal holographic antenna includes multiple liquid crystal radiating units 100 arranged in an array. Each liquid crystal radiating unit 100 includes a lower metal ground plane 101, an air dielectric layer 102, a lower glass substrate 103, an upper metal ground plane 104, a liquid crystal layer 105, a radiating patch 106, and an upper glass substrate 107. Specifically, the upper metal ground plane 104, the air dielectric layer 102, and the lower metal ground plane 101 constitute a parallel plate waveguide. The upper metal ground plane 104 serves as both the upper metal ground plane of the parallel plate waveguide and the lower electrode for applying a bias voltage to the liquid crystal layer 105. A coupling gap is formed on the upper metal ground plane 104. The liquid crystal layer 105 is encapsulated between the upper glass substrate 107 and the lower glass substrate 103. The radiating patch 106 serves as both a radiating electrode and the upper electrode for applying a bias voltage to the liquid crystal layer 105. The voltage between the upper and lower electrodes is the voltage applied to the liquid crystal molecules.

[0048] According to holographic control theory, by setting the state of each liquid crystal radiating element 100 in the antenna, multiple radiating elements can simulate the state of an interference pattern. This allows the desired target wave to be reproduced using a reference wave and the interference pattern. In other words, by controlling the phase information or radiated energy of each radiating element 100, the phase or amplitude of the radiated wave can be controlled.

[0049] Before using the liquid crystal holographic antenna, the performance of each radiating element 100 needs to be calibrated. This involves acquiring the phase-voltage and amplitude-voltage curves of each radiating element 100 to ensure that each element has the required amplitude / phase parameters. Specifically, the calibration process for each radiating element 100 is roughly as follows: 1. In an anechoic chamber, a horn antenna is used as the source antenna to excite the radiating element 100, while other radiating elements 100 are in an impedance-matched state. 2. Different bias voltages are applied to the working radiating element 100. A vector network analyzer is used to measure the S-parameters (including S21 and S11) between the radiating element 100 and the source antenna under each bias voltage, and the amplitude and phase information of the radiating element 100 under each bias voltage is recorded. 3. After repeating the above steps for each radiating element 100, a phase-voltage lookup table and an amplitude-voltage lookup table for each radiating element 100 are generated. During the operation of the liquid crystal holographic antenna, the phase / amplitude state of each radiating element 100 can be obtained according to the interference pattern of electromagnetic simulation. Then, the bias voltage of each radiating element 100 can be controlled by looking up a table, so that multiple radiating elements can simulate interference patterns, thereby achieving precise beam control.

[0050] However, the inventors discovered the following problems when calibrating each of the radiating units 100 individually: 1. Due to the large number of radiating units 100, calibration is time-consuming; 2. Before calibration, the center of the speaker needs to be aligned with the center of the radiating unit to be calibrated, which is difficult to achieve; 3. ... Figure 1 As shown, the extension directions of the coupling slots in each radiating element 100 are not the same. The extension direction of the coupling slot determines the polarization direction of the radiated or received electromagnetic waves. However, the horn antenna used in the calibration process is fixed-polarized. Therefore, in order to match the polarization of the horn antenna with that of each radiating element 100, the polarization direction of the horn antenna needs to be adjusted each time the calibration is performed, i.e., the horn antenna needs to be manually rotated. This makes the calibration process time-consuming, labor-intensive, and inaccurate. Therefore, the above-mentioned liquid crystal holographic antenna has the problems of requiring a lot of time and manpower for calibration and having poor control accuracy.

[0051] In addition, such as Figure 1As shown, the liquid crystal holographic antenna can be divided into four quadrants arranged clockwise. There is a blank area between adjacent quadrants, where no radiating elements 100 are placed; instead, liquid crystal encapsulating material is used. Therefore, the liquid crystal holographic antenna also suffers from low array utilization.

[0052] In order to solve at least one of the above-mentioned technical problems, in one respect, this disclosure provides an antenna.

[0053] Figure 3 This is a top view of the antenna provided in this disclosure. Figure 3 As shown, the antenna provided in this disclosure is an antenna array, which includes a waveguide structure (described in detail below). Figure 3 (Not shown) and multiple radiating elements 10 disposed on the waveguide structure. The multiple radiating elements 10 can be divided into multiple rings of radiating elements QR arranged nested from the inside out, with each ring of radiating elements QR sharing a common center, which serves as the antenna center. Each ring of radiating elements QR includes multiple radiating elements 10 arranged in a clockwise direction. It is understood that the antenna also includes a feed source, such as a coaxial probe, located at the center and extending into the waveguide structure. The feed source emits electromagnetic waves into the waveguide structure, which propagate through the waveguide structure to each radiating element 10.

[0054] The general working process of the above antenna is as follows: First, based on holographic theory, electromagnetic simulation software is used to calculate the interference pattern between the reference wave emitted by the feed and the desired target wave. The calculation process of the interference pattern is roughly as follows.

[0055] According to holographic theory, the reference wave can be described by the following formula:

[0056]

[0057] in, Let be the propagation coefficient of electromagnetic waves within the waveguide structure. The distance from the radiating element 10 to the feed source.

[0058] The target wave can be described by the following formula:

[0059]

[0060] in, Let be the propagation coefficient of electromagnetic waves in free space. and They jointly characterize the desired direction of the target wave. The angle between the desired direction and the positive z-axis. Let be the angle between the orthogonal projection of the desired direction onto the plane containing the antenna array and the positive x-axis. It should be noted that the plane containing the antenna is the xy-plane, and the z-axis is the normal direction of the antenna.

[0061] The interference pattern of the reference wave and the target wave can be described by the following formula:

[0062] .

[0063] Next, based on the interference pattern, the state of the radiating elements at each location (e.g., on or off, corresponding to strong or weak radiation) is calculated, and the radiating elements are controlled to be in the corresponding states, thereby forming a similar "hologram" on the antenna array surface, achieving the modulation of the phase or amplitude of the radiated wave. Taking amplitude modulation as an example, based on the above... The excitation amplitude of the radiating element can be obtained as follows: .

[0064] Figure 4 A three-dimensional structural diagram of the radiating element in the antenna provided in this disclosure; Figure 5 for Figure 4 Top perspective view of the radiating element shown; Figure 6 for Figure 4 A magnified view of a localized radiating element is shown. (Refer to...) Figures 3-6 The antenna provided in this disclosure includes a waveguide structure G1, a first electrode E1, a plurality of first radiating electrodes 208, and a plurality of second radiating electrodes 209. The first electrode E1 is disposed on the waveguide structure G1 and has a plurality of slit openings S1 extending through it along its thickness direction; the plurality of first radiating electrodes 208 are disposed on the side of the first electrode E1 facing away from the waveguide structure G1; and the plurality of second radiating electrodes 209 are disposed on the side of the first radiating electrodes 208 facing away from the waveguide structure G1.

[0065] like Figure 5 As shown, at least two of the following—a slit opening S1, a first radiating electrode 208, and a second radiating electrode 209—have overlapping orthographic projections on the layer where the first electrode E1 is located, and constitute a radiating unit 10. Figures 4-6 As shown, the radiation unit 10 also includes two switching units located between the layer containing the first radiation electrode 208 and the first electrode E1, respectively disposed on both sides of the first straight line L1. These are the first switching unit SW1 and the second switching unit SW2, and the first switching unit SW1 and the second switching unit SW2 are symmetrically arranged about the first straight line L1 as an axis of symmetry. The first straight line L1 refers to a straight line that passes through the center O1 of the slit opening S1 and extends along the direction of the slit opening S1. The switching unit includes at least one switch 207, which is configured to control the conduction or deactivation of the first radiation electrode 208 and the first electrode E1.

[0066] The antenna provided in this disclosure can change the current transmission path of electromagnetic waves in the corresponding radiating element by changing the on / off state of the switch, thereby changing the amount of energy leaked from the slit opening S1 in the radiating element 10, and thus achieving modulation of the radiated wave amplitude. The number of switches in the switching element determines the number of states of the radiating element. For example, when the switching element includes only one switch, the radiating element has two states (e.g., 0 / 1), i.e., 2 bits. When the switching element includes N switches (N is an integer greater than 1), the radiating element has 2 states. species, that is Therefore, the antenna provided in this disclosure can achieve fine-tuning of the radiating element state by designing the number of switches in the switching unit, thereby achieving precise modulation of the antenna beam. Furthermore, traditional reconfigurable antennas typically place the switching unit on the first electrode layer, i.e., on the same layer as the slit opening. Each switch requires a control line connected to the control circuitry surrounding the antenna array to control the on / off state of each switch. When the switching unit is placed on the same layer as the first electrode layer, the switches and their wiring increase the area occupied by the first electrode layer, which is detrimental to the miniaturization of the antenna array. In contrast, this disclosure places the switching unit and control line between the first electrode layer and the first radiating electrode. Compared to traditional antennas, this significantly reduces the area occupied by the switching unit and wiring on the antenna array plane, thus facilitating the miniaturization of the antenna array.

[0067] Continue to refer to Figures 4-6 In a specific embodiment, both the first switching unit SW1 and the second switching unit SW2 include three switches 207. The three switches in the first switching unit SW1 are designated as first switch 207a, second switch 207b, and third switch 207c; correspondingly, the three switches in the second switching unit SW2 are designated as fourth switch 207a', fifth switch 207b', and sixth switch 207c'. For ease of description, the symmetrically arranged first switch 207a and fourth switch 207a' are referred to as the first switch group, the symmetrically arranged second switch 207b and fifth switch 207b' as the second switch group, and the symmetrically arranged third switch 207c and sixth switch 207c' as the third switch group. Two switches in the same switch group can be simultaneously turned on or simultaneously turned off. Furthermore, the performance of the three switch groups is different. That is, even in two states where the number of switches on and off is the same (e.g., state 1 where two switches in the first switch group are on, and state 2 where two switches in the second switch group are on), the amplitude of the radiation unit's excitation differs in different states due to the different performance of the different switch groups. Therefore, by controlling the on / off combinations of the three switch groups, the radiation unit 10 can generate 8 types of ( (Types) of different working states, that is, the antenna provided in the embodiments of this disclosure is an 8-bit holographic antenna.

[0068] Table 1 below summarizes the eight different excitation amplitudes generated by the on / off combinations of the three switch groups in the radiation unit 10.

[0069] Table 1

[0070]

[0071] In practical implementation, the number of switches in the switching unit can be flexibly adjusted according to the antenna's performance requirements and cost requirements. This disclosure only takes the switching unit including 3 switches 207 as an example to introduce the specific structure of the antenna, which does not constitute a limitation on the technical solution of this disclosure.

[0072] Continue to refer to Figure 4 Specifically, the antenna also includes a first dielectric layer 204, a second dielectric layer 205, and a first conductive layer C1 located between the first dielectric layer 204 and the second dielectric layer 205. The first dielectric layer 204 is disposed on the side of the first electrode E1 facing away from the waveguide structure G1, and the second dielectric layer 205 is disposed between the first dielectric layer 204 and the first radiating electrode 208. The first conductive layer C1 includes switching units and control lines CL1 corresponding to each switch in the switching units (see...). Figure 8 ).

[0073] The following describes two ways to connect the switch 207 to the first radiation electrode 208 and the first electrode E1.

[0074] First connection method

[0075] Figure 7 for Figure 5 A schematic diagram of the cross-section of the radiating element along AB; Figure 8 This is a top view of the switching unit and transmission link in the first connection method; Figure 9 This is the equivalent circuit diagram of the transmission link in the first connection method. The first connection method is as follows: Figures 5-8 As shown. (Refer to...) Figures 5-9 The radiation unit 10 also includes a transmission link corresponding to the switch unit. Each transmission link includes a combiner and multiple branches connected to the combiner. A switch 207 is configured on each branch. The combiner is connected to the first radiation electrode 208 through a first connection via EL1 penetrating the second dielectric layer 205. Each branch is connected to the first electrode E1 through a second connection via EL2 penetrating the first dielectric layer 204.

[0076] It should be noted that the connection vias mentioned in this disclosure refer to vias used to achieve electrical connections between different circuit layers. Taking the first connection via EL1 as an example, its key fabrication steps include:

[0077] S1. Using processes such as laser drilling, mechanical drilling, or plasma etching, a through hole is formed that penetrates the second dielectric layer 205.

[0078] S2. A conductive layer covering the hole wall is formed in the via using chemical deposition and electroplating thickening processes. For example, chemical deposition refers to depositing a thin copper layer less than 1 micrometer thick as a seed layer on the hole wall; electroplating thickening refers to using an electroplating solution to react with the seed layer to generate a thickened copper layer tens of micrometers thick. This step ensures the conductivity and mechanical strength of the first connecting via EL1.

[0079] S3. Based on step S2, fill the through hole with conductive material to form the first connection via EL1. For example, the conductive material can be conductive silver paste, copper paste, or conductive epoxy resin, which can ensure the conductivity and heat dissipation performance of the first connection via EL1.

[0080] Continuing with the example above, the switching unit includes three switches 207. See [reference needed]. Figure 7 The transmission link corresponding to the switch unit includes a combiner and three branches. The combiner is connected to the first radiation electrode 208 through the first connection via EL1 penetrating the second dielectric layer 205. Each of the three branches is equipped with a switch 207. Correspondingly, the three branches are connected to the first electrode E1 through the second connection via EL2 penetrating the first dielectric layer 204.

[0081] It should be noted that since the two switching units are symmetrically arranged about the first straight line, this article only describes one switching unit, and the other switching unit will not be described in detail. Additionally, it can be understood that the radiation unit 10 also includes control lines (such as...) connected to each switch 207. Figure 8 The control line CL1 needs to be connected to the control circuit located on the periphery of the antenna array to control the on / off state of switch 207. In this disclosure, the control line CL1 connected to switch 207 is arranged on the same layer as switch 207, located between the layer where the first electrode E1 and the first radiating electrode 208 are located.

[0082] Traditional liquid crystal holographic antennas require calibration of the radiation performance curves of each radiating element before use. After liquid crystal encapsulation, they cannot be tested and calibrated again. However, the antenna provided in this disclosure only requires a multimeter to measure the connection vias on both sides of the switch to determine the switch's status if the switch performance needs to be tested. Therefore, the antenna provided in this disclosure has the advantage of flexible testing.

[0083] Furthermore, to ensure that the electromagnetic waves in the radiation unit 10 have different current paths when different switches are on and off, it is necessary to set that the shortest distance between the orthographic projection of each second connection via EL2 connected to each switch 207 on the layer where the first electrode E1 is located and the center O1 of the slit opening S1 is different. Specifically, as shown in the figure... Figure 8 As shown, the shortest distances between the orthographic projection of the first switch 207a, the second switch 207b, and the third switch 207c corresponding to the second connection vias EL2 on the layer where the first electrode E1 is located and the center O1 of the slit opening S1 are D1, D2, and D3, respectively. In order to ensure that the radiation unit has different current paths when different switches are on and off, D1, D2, and D3 need to be different.

[0084] The second connection method

[0085] Figure 10 This is a top perspective view of the switching unit and transmission link in the second connection method; Figure 11 for Figure 10 A schematic diagram of the cross-section of the structure shown along CD; Figure 12 This is the equivalent circuit diagram of the transmission link in the second connection method. For example... Figures 10-12 As shown, in the second connection method, the radiation unit 10 further includes a transmission link corresponding to the switch unit. This transmission link includes multiple sub-links, and each sub-link is configured with a switch 207. Furthermore, for the corresponding sub-links and switches 207, the sub-links are connected to the first radiation electrode 208 through a third connection via EL3 penetrating the second dielectric layer 205, and to the first electrode E1 through a fourth connection via EL4 penetrating the first dielectric layer 204.

[0086] Continuing with the example of the above-mentioned switch unit including three switches 207, the transmission link now includes three sub-links. Each sub-link is configured with one switch 207. For any sub-link, it is connected to the first radiating electrode 208 through the third connection via EL3 penetrating the second dielectric layer 205, and connected to the first electrode E1 through the fourth connection via EL4 penetrating the first dielectric layer 204.

[0087] In simple terms, the first connection method has one combiner and three branches in parallel, with each branch equipped with a switch. The second connection method has three sub-links in parallel, each with a switch. Compared to the second method, the first method simplifies the fabrication process and the structure of the radiating elements in the antenna.

[0088] Similarly, to ensure that the electromagnetic waves in the radiation unit 10 have different current paths when different switches are on and off, it is necessary to ensure that the shortest distance between the orthographic projection of each third connection via EL3 connected to each switch 207 on the layer where the first electrode E1 is located and the center O1 of the slit opening S1 is different; and / or, the shortest distance between the orthographic projection of each fourth connection via EL4 connected to each switch and the center O1 of the slit opening S1 is different. Specifically, as shown... Figure 10 As shown, the shortest distances between the orthographic projection of the first switch 207a, the second switch 207b, and the third switch 207c corresponding to the fourth connection via EL4 on the layer where the first electrode E1 is located and the center O1 of the slit opening S1 are Da, Db, and Dc, respectively. In order to ensure that the radiation unit has different current paths when different switches are on and off, Da, Db, and Dc need to be different.

[0089] The above describes two connection methods between switch 207 and the first radiating electrode 208 and the first electrode E1. The following section will elaborate on the hierarchical structure of the antenna.

[0090] Figure 13 This is a schematic cross-sectional view of the waveguide structure along its thickness direction. For example... Figure 4 and Figure 13 As shown, the waveguide structure G1 includes a bottom wall 201, a top wall 203, and a third dielectric layer 202 filled between the bottom wall 201 and the top wall 203. The bottom wall 201 serves as a reference electrode layer, employing a metal reflector made of materials such as copper or aluminum, with a thickness between 0.5 mm and 2 mm. The top wall 203 serves as the first electrode E1, also made of materials such as copper or aluminum, with a thickness of up to 0.002 mm. The third dielectric layer 202 uses a slow-wave dielectric. Figure 13 This is a schematic diagram of the structure of the third dielectric layer, as shown below. Figure 13 As shown, specifically, in the direction from the bottom wall 201 to the top wall 203, the third dielectric layer 202 includes a first sub-dielectric layer 2021, a second sub-dielectric layer 2022, and a first dielectric substrate 2023 stacked sequentially. For example, the first sub-dielectric layer 2021 is made of polytetrafluoroethylene (PTFE) with a thickness of 2.5 mm; the second sub-dielectric layer 2022 is a plastic foam board with a thickness of 1.2 mm. Different slow-wave materials can be combined to form the required dielectric constant. Of course, in other examples, the third dielectric layer 202 can be a single-layer structure instead of a composite structure. The first dielectric substrate 2023 is made of an insulating material, including but not limited to glass, ceramics, and plastics.

[0091] Figure 14 This is a schematic diagram of the cross-sectional structure of the antenna along its thickness direction. (Example:) Figure 14As shown, the antenna provided in this disclosure includes a waveguide structure G1, a second dielectric substrate 210, a first dielectric layer 204, a first conductive layer C1, a second dielectric layer 205, a second conductive layer C2, a fourth dielectric layer 206, and a third conductive layer C3, which are sequentially disposed on the waveguide structure G1 in a direction from the bottom wall 201 to the top wall 203. The first conductive layer C1 includes each switching unit and a control line CL1, the second conductive layer C2 includes each first radiating electrode, and the third conductive layer C3 includes each second radiating electrode.

[0092] For example, the second dielectric substrate 210 is an insulating material, including but not limited to glass, ceramics, etc.; the first dielectric layer 204 is made of plastic foam board with a dielectric constant of 1 or other insulating materials. It is understood that in some examples, the first dielectric layer 204 and the second dielectric substrate 210 use different insulating materials. In this case, the connection via between the switch 207 and the first electrode E1 needs to penetrate both the first dielectric layer 204 and the second dielectric substrate 210. In other examples, the first dielectric layer 204 and the second dielectric substrate 210 use the same material. In this case, their stack can be considered a single-layer structure, and the connection via between the switch 207 and the first electrode E1 only needs to penetrate this single-layer structure. For example, the second dielectric layer 205 and the fourth dielectric layer 206 can be made of plastic foam board with a dielectric constant of 1 or other insulating materials. For example, the first conductive layer C1, the second conductive layer C2, and the third conductive layer C3 can all be made of metal materials such as copper or silver, and all three have a thickness of 0.002 mm.

[0093] In other examples, the first conductive layer C1 only includes the control line CL1, and the switching unit can be located on the same layer as the first electrode E1, that is, on the same layer as the slit opening S1. Since the switching ratio of the antenna has a significant impact on the antenna performance, placing the switch on the same layer as the slit opening S1 can effectively reduce the operating amplitude of the slit opening S1 when the switch is off, thereby reducing the switching ratio. However, this will result in occupying a larger planar layout space and increasing the difficulty of the manufacturing process.

[0094] In some preferred embodiments, the centers of the slit opening S1, the first radiation electrode 208, and the second radiation electrode 209 in the same radiation unit 10 coincide, and both the first radiation electrode 208 and the second radiation electrode 209 are symmetrical about a first straight line L1. For example, refer to... Figure 4The first radiating electrode 208 and the second radiating electrode 209 can be elongated rectangles (preferably rounded rectangles), whose extending direction intersects the extending direction of the slit opening S1. The orthographic projections of the first radiating electrode 208 and the second radiating electrode 209 on the layer containing the first electrode E1 can completely overlap, or the orthographic projection of one of them on the layer containing the first electrode E1 may lie within the orthographic projection of the other on the layer containing the first electrode E1. For example, the dimensions of the first radiating electrode 208 and / or the second radiating electrode 209 can be... .

[0095] In other words, the antenna provided in this disclosure adopts a double-layer radiating patch structure. It can be understood that the radiating patch here refers to either the first radiating electrode or the second radiating electrode. To visually demonstrate the effect of the double-layer radiating patch, the inventors simulated the performance of antennas without a radiating patch and those with a double-layer radiating patch. First, the inventors simulated a first-type antenna with a slit opening S1 length of 7.1 mm and no radiating patch, and a second-type antenna with a slit opening S1 length of 6.1 mm and no radiating patch. Figure 15 The performance curves of the first and second type antennas as a function of frequency are shown below. Figure 15 As can be seen, the first type of antenna operates at a frequency of 12 GHz, while the second type operates at a frequency of 13.7 GHz. The latter has very low operating capability in the 12 GHz band and is not suitable as a holographic antenna array. Therefore, if a non-radiating patch structure is adopted, the length of the antenna slit opening S1 needs to be set to be relatively large, which is not conducive to the miniaturization of the antenna array and the high density of the radiating elements.

[0096] Therefore, the antenna provided in this disclosure adopts a double-layer radiating patch structure. Figure 16 The simulation curves of the antenna performance provided in this disclosure at different frequencies are shown. The antenna slit opening S1 used in the simulation has a length of 6.1 mm and includes a double-layer radiating patch. Figure 16 It is evident that the antenna operates at a frequency of 12 GHz, meeting the requirements of a holographic antenna array. This demonstrates that by employing a double-layer radiating patch structure, the size of the slit opening S1 can be reduced while ensuring antenna performance, which is beneficial for the high integration and density of the radiating elements.

[0097] In addition, to visually demonstrate the corresponding changes in the state of the radiating element 10 when the antenna of this disclosure changes its on / off state under different switch groups, the inventors have made the following modifications. Figures 5-9 The provided embodiments simulate the antenna radiation performance under different switching states. Figures 5-9In the provided embodiment, the switching unit includes three switches 207, and the antenna is an 8-bit antenna with eight different radiation states (refer to Table 1 above). For ease of description, the state in which all switch groups are turned off is referred to as the first state; the state in which only the first switch group is turned on and the other two switch groups are turned off is referred to as the second state; the state in which only the second switch group is turned on and the other two switch groups are turned off is referred to as the third state; and the state in which all switch groups are turned on is referred to as the fourth state. Figure 17 The curves show the antenna performance as a function of operating frequency in the second and third states. Figure 18 This is the antenna performance versus operating frequency curve in the fourth state. Figure 17 and Figure 18 While it cannot reflect the excitation amplitude of the radiating element, it can reflect the radiation capability. Clearly, the radiation capability of the radiating element 10 differs depending on the switch state. This demonstrates that the antenna provided in this disclosure can achieve precise control of the radiation capability of the radiating element by controlling the switch state.

[0098] In addition, in order to intuitively demonstrate the effect of the antenna provided in this disclosure compared with the traditional liquid crystal holographic antenna, the inventors simulated the radiation patterns of the traditional liquid crystal holographic antenna and the antenna provided in this disclosure respectively. Figure 19 The simulation results show the radiation pattern of a traditional liquid crystal holographic antenna. Figure 20 The simulation results of the radiation pattern of the antenna provided in this disclosure; wherein, Figure 19 (a) and Figure 20 In the middle (a), the curves of the antenna radiation intensity versus the elevation angle on a vertical cross-section of 12 GHz and 0° azimuth angle are respectively for the liquid crystal holographic antenna and the antenna provided in this disclosure. Figure 19 (b) and Figure 20 (b) shows the radiation intensity curves of the liquid crystal holographic antenna and the antenna provided in this disclosure on a vertical cross-section at 12 GHz and an azimuth angle of 90°, respectively, as a function of the elevation angle. By comparison... Figure 19 and Figure 20 As can be seen, the antenna provided in this disclosure has a gain of about 3dB compared to the traditional liquid crystal holographic antenna, and therefore has higher radiation efficiency.

[0099] In addition, compared with traditional liquid crystal antennas, the antenna provided in this disclosure does not require encapsulation of the liquid crystal layer, therefore no space needs to be reserved in the array. Figure 1 The “blank” areas shown are used to fill the encapsulating adhesive, which theoretically can improve the array utilization and increase the number of radiating elements.

[0100] It is understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, and the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. An antenna, characterized in that, include: Waveguide structure; The first electrode is disposed on the waveguide structure; The first electrode has a plurality of slit openings extending through its thickness direction; Multiple first radiating electrodes are disposed on the side of the first electrode that is away from the waveguide structure; Multiple second radiating electrodes are disposed on the side of the first radiating electrode that is away from the waveguide structure; The orthographic projections of the slit opening, the first radiating electrode, and the second radiating electrode onto the layer where the first electrode is located overlap and constitute a radiating unit. The radiation unit further includes two switching units located between the layer containing the first radiation electrode and the first electrode, respectively disposed on both sides of the first straight line, and the two switching units are symmetrically arranged with the first straight line as the axis of symmetry; the first straight line is a straight line that passes through the center of the slit opening and extends along the direction of the slit opening; the switching unit includes at least one switch, which is configured to control the first radiation electrode and the first electrode to be turned on or off.

2. The antenna according to claim 1, characterized in that, Also includes: A first dielectric layer is disposed on the side of the first electrode away from the waveguide structure; A second dielectric layer is disposed between the first dielectric layer and the first radiating electrode; The switching unit is located between the first dielectric layer and the second dielectric layer; The radiation unit further includes a transmission link corresponding to the switch unit; the transmission link includes a combiner and multiple branches connected to the combiner; one switch is configured on each branch; The combined path is connected to the first radiating electrode through a first connection via penetrating the second dielectric layer; each of the branch paths is connected to the first electrode through a second connection via penetrating the first dielectric layer.

3. The antenna according to claim 2, characterized in that, When the switching unit includes multiple switches, the shortest distance between the orthographic projection of each second connection via on the layer where the first electrode is located and the center of the slit opening is different for each of the second connection vias connected to each of the switches.

4. The antenna according to claim 1, characterized in that, Also includes: A first dielectric layer is disposed on the side of the first electrode away from the waveguide structure; A second dielectric layer is disposed between the first dielectric layer and the first radiating electrode; The switching unit is located between the first dielectric layer and the second dielectric layer; The radiation unit also includes a transmission link corresponding to the switch unit; the transmission link includes multiple sub-links, and each sub-link is configured with one switch; The sub-link is connected to the first radiating electrode through a third connection via penetrating the second dielectric layer, and is also connected to the first electrode through a fourth connection via penetrating the first dielectric layer.

5. The antenna according to claim 4, characterized in that, When the switching unit includes multiple switches, the shortest distance between the orthographic projection of each fourth connection via on the layer where the first electrode is located and the center of the slit opening is different for each of the fourth connection vias connected to each of the switches. And / or, in each of the third connection vias corresponding to each of the switches, the shortest distance between the orthographic projection of each third connection via on the layer where the first electrode is located and the center of the slit opening is different.

6. The antenna according to any one of claims 1-5, characterized in that, The waveguide structure includes an opposing bottom wall and a top wall, and a third dielectric layer filling the space between the bottom wall and the top wall; the third dielectric layer includes a slow-wave dielectric.

7. The antenna according to claim 6, characterized in that, In the direction from the bottom wall to the top wall, the third dielectric layer includes a first sub-dielectric layer, a second sub-dielectric layer, and a first dielectric substrate stacked sequentially. The first sub-dielectric layer comprises polytetrafluoroethylene; the second sub-dielectric layer comprises a plastic foam board; and the first dielectric substrate comprises one or more of glass, ceramic, and plastic.

8. The antenna according to claim 7, characterized in that, Also includes: The second dielectric substrate is disposed between the first dielectric substrate and the first dielectric layer; The second dielectric substrate includes one or more of glass, ceramic, and plastic.

9. The antenna according to any one of claims 1-5, characterized in that, In the radiation unit, the centers of the slit opening, the first radiation electrode, and the second radiation electrode coincide, and both the first radiation electrode and the second radiation electrode are symmetrical about the first line.

10. The antenna according to any one of claims 1-5, characterized in that, Also includes: The fourth dielectric layer is disposed on the side of the layer containing the first radiating electrode that is away from the waveguide structure; the second radiating electrode is located on the side of the fourth dielectric layer that is away from the waveguide structure. The fourth dielectric layer includes an insulating material.

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