Antenna structure and communication device

Abstract

Embodiments of the present application relate to the technical field of antennas, and provide an antenna structure and a communication device. The antenna structure comprises a feed structure, and a ground layer group, a partially reflective layer group, and a frequency selection layer which are sequentially stacked. The ground layer group is used for reflecting signals, and the partially reflective layer group is used for enabling some of the signals to pass therethrough and reflecting the remaining signals. The frequency selection layer comprises a hollowed-out portion and a reflective portion, wherein the hollowed-out portion is used for allowing the signals to pass through, and the reflective portion is used for reflecting the signals. The signals radiated outward by means of the hollowed-out portion and the signals that are reflected by the reflective portion and then radiated outward can undergo phase delay, and the signals can be reflected multiple times among the ground layer group, the partially reflective layer group, and the frequency selection layer and can undergo phase delay multiple times, amplifying the overall phase change of the signals, achieving a wider range of phase tuning, thereby enabling the antenna structure to achieve a wider range of beam scanning.

Description

Antenna structure and communication device

[0001] The application claims priority to the Chinese patent application filed with the China Patent Office on June 27, 2023, with application number 202310772422.X and application name “An antenna structure and communication device”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of antenna technology, and in particular to an antenna structure and a communication device. Background Art

[0003] Antennas are devices that perform energy conversion and directionally radiate or receive electromagnetic waves in wireless communications. They are widely used in engineering systems such as radio communications, broadcasting, radar, navigation, and remote sensing. For example, mobile phones, laptops, tablets, netbooks, wearable devices, and other electronic devices all have antennas, which enable signal transmission. Reconfigurable leaky-wave antennas, among others, can achieve fixed-frequency beam scanning, effectively increasing the antenna's radiation range and enjoying widespread application in antenna technology.

[0004] In related technologies, reconfigurable leaky-wave antennas typically include staggered high-dielectric-constant layers and low-dielectric-constant liquid crystal layers. A control circuit is provided on the liquid crystal layer. The control circuit can apply a bias voltage to the liquid crystal layer to change the relative dielectric constant of the liquid crystal layer, thereby changing the electromagnetic parameters of the antenna, such as the phase and radiation pattern, thereby realizing the reconfigurable characteristics of the leaky-wave antenna, enabling the antenna to achieve fixed-frequency beam scanning, and reducing the antenna scanning's dependence on a wider frequency band.

[0005] However, in the above antenna, the fixed-frequency beam scanning of the antenna is achieved by using liquid crystal materials, and its scanning range is often small, which reduces the reconfigurability of the antenna.

[0006] Summary of the Invention

[0007] The present application provides an antenna structure and a communication device, which can effectively increase the fixed-frequency beam scanning range of the antenna structure and enhance the reconfigurable characteristics of the antenna.

[0008] A first aspect of the present application provides an antenna structure, comprising a feed structure, and a stacked ground layer group, a partially reflective layer group, and a frequency selective layer;

[0009] The feeding structure is electrically connected to the ground layer group, and the partial reflection layer group is located between the ground layer group and the frequency selective layer;

[0010] The ground layer group is used to reflect signals, and the partial reflective layer group is used to allow part of the signal to pass through and reflect the rest of the signal;

[0011] The frequency selection layer includes a hollow portion and a reflection portion, the hollow portion is used for allowing the signal to pass through, and the reflection portion is used for reflecting the signal.

[0012] In the present application, a frequency selective layer is set up, and a phase delay can occur between the signal radiated outward through the hollow part of the frequency selective layer and the signal reflected by the reflective part and the partial reflective layer group and then radiated outward through the hollow part. The signal can be reflected multiple times between the ground layer group, the partial reflective layer group and the frequency selective layer, and multiple phase delays can occur. In this way, the phase change of the entire signal can be amplified, and a wider range of phase tuning can be obtained, so that the antenna structure can achieve a wider range of beam scanning, thereby improving the reconfigurable characteristics of the antenna structure.

[0013] In one possible implementation, the partially reflective layer group includes a first dielectric layer, a tuning layer, and a second dielectric layer stacked in sequence, with the frequency selective layer located on the first dielectric layer. The relative dielectric constants of the first and second dielectric layers are both greater than the relative dielectric constant of the tuning layer under a bias voltage. The tuning layer is configured to change its relative dielectric constant under the application of a bias voltage. The stacked first, tuning, and second dielectric layers can form a distributed Bragg reflector. When a signal passes through the partially reflective layer group, it can radiate a stronger signal wave, thereby helping to increase signal strength.

[0014] In one possible implementation, the frequency selective layer includes a plurality of metal patches arranged in an array, with gaps between adjacent metal patches. The metal patches form the reflective portion, and the gaps form the hollow portion. When a signal propagates from the partially reflective layer group to the frequency selective layer, a portion of the signal can radiate outward through the gaps between the metal patches, while another portion of the signal can be reflected by the metal patches onto the partially reflective layer group, and then reflected again by the partially reflective layer group into the gaps, radiating outward through the gaps, thereby amplifying the phase change of the signal radiation.

[0015] In one possible implementation, the frequency selective layer includes a metal layer having a plurality of through-holes arranged in an array. The through-holes form the hollow portion, and the metal layer outside the through-holes forms the reflective portion. When a signal propagates from the partially reflective layer group to the frequency selective layer, a portion of the signal can be radiated outward through the through-holes in the metal layer, while another portion of the signal can be reflected by the metal layer outside the through-holes onto the partially reflective layer group, and then reflected again by the partially reflective layer group into the through-holes to be radiated outward through the through-holes, thereby amplifying the phase change of the signal radiation.

[0016] In one possible implementation, the ground layer group includes a metal floor and a third dielectric layer disposed on the metal floor; the feed structure is electrically connected to the metal floor, and the partially reflective layer group is disposed on the third dielectric layer. The metal floor can reflect signals, thereby completely reflecting the signals fed by the feed structure into the partially reflective layer group. This effectively reduces or prevents signals from being projected toward the exterior of the metal floor (i.e., the side of the metal floor facing away from the partially reflective layer group), thereby causing signal loss and helping to improve the signal radiation efficiency of the antenna structure.

[0017] In one possible implementation, the partially reflective layer group includes multiple tuning layers and multiple second dielectric layers, which are interlaced between the first dielectric layer and the ground layer group. Increasing the number of tuning layers and second dielectric layers effectively improves the tuning layer's ability to control the beam scanning range, enabling the antenna structure to achieve phase control over a wider range, thereby enabling the antenna structure to achieve a wider range of beam scanning, effectively extending the antenna structure's beam scanning range.

[0018] In one possible implementation, the tuning layer is a liquid crystal layer, a vanadium dioxide layer, a ferrite layer, a graphene layer, or a diode layer. These materials and devices can exhibit different relative permittivities upon application of a bias voltage, thereby altering electromagnetic parameters such as the antenna structure's phase and radiation pattern, thereby achieving reconfigurable antenna structure characteristics.

[0019] In one possible implementation, the first and second dielectric layers are formed of alumina. Alumina has a high relative permittivity. When stacked with a tuning layer having a lower relative permittivity, a distributed Bragg reflector can be formed. This allows a signal to be reflected more strongly after passing through the partially reflective layer, thereby improving signal strength.

[0020] In one possible implementation, the reflective portion is formed of at least one of gold, copper, and aluminum.

[0021] In one possible implementation, the third dielectric layer is formed of cyclic olefin copolymer. Cyclic olefin copolymer has a low relative dielectric constant, close to that of the tuning layer. This reduces signal loss during signal radiation from the third dielectric layer toward the tuning layer, thereby improving the radiation efficiency of the antenna structure.

[0022] In one possible implementation, the metal patch is shaped like at least one of a rectangle, a circle, a triangle, or a trapezoid. By flexibly adjusting the shape and arrangement of the metal patches, different reflective and hollow structures can be achieved, helping to optimize the structural parameters of the frequency selective layer and increase the beam scanning range of the antenna structure.

[0023] In one possible implementation, the through hole has a shape of at least one of a rectangle, a circle, a triangle, or a trapezoid.

[0024] In one possible implementation, the thickness of the tuning layer is an odd integer multiple of one-quarter of the wavelength of the medium of the tuning layer, where the wavelength of the medium of the tuning layer is the wavelength of the signal propagating within the tuning layer. This allows for higher propagation efficiency of the signal within the tuning layer, reduces signal loss, and helps improve the overall signal radiation efficiency of the antenna structure.

[0025] In one possible implementation, the thickness of the first dielectric layer is an odd multiple of one-quarter of the dielectric wavelength of the first dielectric layer, and the dielectric wavelength of the first dielectric layer is the wavelength of the signal propagating in the first dielectric layer; this can enable the signal to have a higher propagation efficiency in the first dielectric layer, help reduce the loss of the signal in the first dielectric layer, and thus effectively improve the radiation efficiency of the antenna structure.

[0026] The thickness of the second dielectric layer is an odd integer multiple of one-quarter of the dielectric wavelength of the second dielectric layer, where the dielectric wavelength of the second dielectric layer is the wavelength of the signal propagating within the second dielectric layer. This allows for higher signal propagation efficiency within the second dielectric layer, helps reduce signal loss within the second dielectric layer, and thereby effectively improves the radiation efficiency of the antenna structure.

[0027] A second aspect of the present application provides a communication device comprising any of the aforementioned antenna structures. By including the aforementioned antenna structure in the communication device, the space occupied by the antenna structure within the communication device can be effectively reduced, the rationality of the antenna structure's layout within the communication device can be improved, and this can contribute to the miniaturization of the communication device. Furthermore, this can help reduce the difficulty and cost of producing the communication device.

[0028] In one possible implementation, the communication device further includes a control circuit, which is electrically connected to a tuning layer in the antenna structure; and the control circuit is configured to apply a bias voltage to the tuning layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] FIG1 is a schematic structural diagram of an antenna structure provided in an embodiment of the present application;

[0030] FIG2 is a schematic structural diagram of a frequency selective layer provided in an embodiment of the present application;

[0031] FIG3 is a schematic structural diagram of another frequency selective layer provided in an embodiment of the present application;

[0032] FIG4 is a schematic structural diagram of another antenna structure provided in an embodiment of the present application;

[0033] FIG5 is a transmission line model diagram of an antenna structure provided in an embodiment of the present application;

[0034] FIG6 is a simulation diagram of the dispersion characteristics of an antenna structure provided in an embodiment of the present application;

[0035] FIG7 is a dispersion simulation diagram of an antenna structure when no frequency selective layer is provided in the related art;

[0036] FIG8 is a directional diagram of an antenna structure provided in an embodiment of the present application and an antenna structure in related art;

[0037] FIG9 is a directional diagram of another antenna structure provided in an embodiment of the present application and an antenna structure in related art.

[0038] Explanation of the reference numerals: 100 - antenna structure; 110 - feeding structure; 120 - ground layer group; 121 - metal floor; 122 - third dielectric layer; 130 - partial reflection layer group; 131 - first dielectric layer; 132 - tuning layer; 133 - second dielectric layer; 140 - frequency selection layer; 141 - hollow portion; 142 - reflection portion. DETAILED DESCRIPTION

[0039] The terms used in the implementation section of this application are only used to explain the specific embodiments of this application and are not intended to limit this application.

[0040] A leaky wave antenna is a structure that continuously radiates electromagnetic waves as they propagate along a traveling wave structure. This type of structure is called a leaky wave antenna. By varying the frequency, a leaky wave antenna can achieve beam scanning, enabling the antenna to provide signal coverage over a wider range. Generally speaking, leaky wave antennas require a wide spectral bandwidth to achieve complete beam scanning. However, with the continuous advancement of antenna technology, the introduction of tunable materials (such as liquid crystal) into leaky wave antennas has enabled them to achieve beam scanning at a fixed frequency, effectively extending their propagation range.

[0041] A related art provides a reconfigurable leaky-wave antenna. This antenna comprises a stacked high-dielectric-constant layer and a low-dielectric-constant liquid crystal layer. A control circuit is provided on the liquid crystal layer. The control circuit applies a bias voltage to the liquid crystal layer to change its relative dielectric constant, thereby altering the antenna's electromagnetic parameters and achieving reconfigurable characteristics. However, due to the limited tuning range of the relative dielectric constant of liquid crystal materials, the fixed-frequency beam scanning range of leaky-wave antennas implemented using liquid crystal materials is often limited, reducing the antenna's reconfigurable characteristics.

[0042] In order to solve the above problems, the researchers thought of improving the structure of the antenna by setting a frequency selective layer in the antenna structure. The frequency selective layer includes a hollow part and a reflective part. A phase delay can occur between the signal radiated outward through the hollow part and the signal reflected by the reflective part and then radiated outward. By amplifying the phase change of the signal, a wider range of phase tuning can be obtained, enabling the antenna structure to achieve a wider range of beam scanning and improving the reconfigurable characteristics of the antenna structure.

[0043] The antenna structure and communication device provided in this application are described in detail below with reference to the accompanying drawings.

[0044] FIG1 is a schematic structural diagram of an antenna structure provided in an embodiment of the present application.

[0045] Embodiments of the present application provide an antenna structure and a communication device including the same. The antenna structure can be a high-frequency leaky-wave antenna, for example, capable of radiating electromagnetic wave signals in the microwave, millimeter-wave, and terahertz frequency bands. The antenna structure can be applied to communication base station platform antenna feed systems, millimeter-wave radars, smart home devices, and other communication devices.

[0046] As shown in FIG1 , the antenna structure 100 may include a feed structure 110 and a stacked ground layer group 120, a partially reflective layer group 130, and a frequency selective layer 140. The feed structure 110 may be electrically connected to the ground layer group 120, and the partially reflective layer group 130 may be located between the ground layer group 120 and the frequency selective layer 140. The feed structure 110 may feed power or input power to the antenna structure 100, so that a signal may be fed into the antenna structure 100 through the feed structure 110. For example, the feed structure 110 may be a waveguide structure, such as a rectangular waveguide. The feed structure 110 may be electrically connected to the ground layer group 120 by welding or metal springs, so that the feed structure 110 may feed power to the ground layer group 120. Alternatively, the feed structure 110 and the ground layer group 120 may feed power to the ground layer group 120 through slot coupling. Specifically, the specific structural form and feeding method of the feeding structure 110 can be selected and set according to the specific application scenario. The embodiment of the present application does not limit the feeding method and electrical connection method of the feeding structure 110.

[0047] Among them, the partial reflection layer group 130 can be used to realize the reconfigurable characteristics of the antenna structure 100. For example, a tuning device can be provided in the partial reflection layer group 130. When a bias voltage is applied to the partial reflection layer group 130, the dielectric constant in the partial reflection layer group 130 can change to change the overall electromagnetic parameters of the antenna structure 100, so that the phase and radiation pattern of the antenna structure 100 change, thereby realizing the reconfigurable characteristics of the antenna structure 100.

[0048] The frequency selective layer 140 may include a hollow portion 141 and a reflective portion 142, wherein the hollow portion 141 may be used to allow signals to pass through, and the reflective portion 142 may be used to reflect the signals. For example, the reflective portion 142 may be a metal layer. When the signal is projected onto the metal layer, the metal layer may reflect the signal to change the propagation direction of the signal. For example, when a signal is transmitted from the partially reflective layer group 130 to the frequency selective layer 140, a portion of the signal may pass through the hollow portion 141 and radiate outward, while another portion may be reflected again by the reflective portion 142 and returned to the partially reflective layer group 130. Then, the signal reflected to the partially reflective layer group 130 may be reflected again by the partially reflective layer group 130 to the hollow portion 141 and radiate outward through the hollow portion 141 to form a leaky wave mode.

[0049] For example, during a specific operation, after the feeding structure 110 feeds a signal into the ground layer group 120, the signal can pass through the ground layer group 120 to reach the partially reflective layer group 130. A portion of the signal reaching the partially reflective layer group 130 can pass through the partially reflective layer group 130, and another portion can be reflected by the partially reflective layer group 130 to the ground layer group 120. At this time, the ground layer group 120 can reflect all of the signal reflected back from the partially reflective layer group 130 back to the partially reflective layer group 130. After multiple reflections between the partially reflective layer group 130 and the ground layer group 120, the signal finally passes through the partially reflective layer group 130 and propagates to the frequency selective layer 140. Among them, after the signal passes through the partial reflection layer group 130, a part of it can be radiated outward through the hollow portion 141 of the frequency selective layer 140. Outward radiation means that the signal is radiated through the hollow portion 141 toward the side of the frequency selective layer 140 facing away from the partial reflection layer group 130, and the other part can be reflected by the reflecting portion 142 onto the partial reflection layer group 130, and after multiple reflections between the reflecting portion 142 and the partial reflection layer group 130, it is finally reflected by the partial reflection layer group 130 and then radiated outward through the hollow portion 141.

[0050] Compared with the fixed-frequency beam scanning scheme of the antenna achieved by liquid crystal materials in the related art, the embodiment of the present application sets a frequency selection layer 140 on the partial reflection layer group 130. A phase delay can occur between the signal radiated outward through the hollow portion 141 of the frequency selection layer 140 and the signal reflected by the reflection portion 142 and the partial reflection layer group 130 and then radiated outward through the hollow portion 141. The signal can be reflected multiple times between the ground layer group 120, the partial reflection layer group 130 and the frequency selection layer 140, and multiple phase delays can occur. In this way, the phase change of the entire signal can be amplified, and a wider range of phase tuning can be obtained, so that the antenna structure 100 can achieve a wider range of beam scanning, thereby improving the reconfigurable characteristics of the antenna structure 100.

[0051] 1 , the partially reflective layer group 130 may include a first dielectric layer 131, a tuning layer 132, and a second dielectric layer 133 that are stacked. For example, the first dielectric layer 131 may be disposed on a side of the tuning layer 132 that faces the frequency selective layer 140, and the second dielectric layer 133 may be disposed on a side of the tuning layer 132 that faces the ground layer group 120. The frequency selective layer 140 may be disposed on the first dielectric layer 131.

[0052] The relative permittivity of the first dielectric layer 131 and the second dielectric layer 133 can both be greater than the relative permittivity of the tuning layer 132 under a bias voltage. The relative permittivity is a physical parameter that characterizes the dielectric or polarization properties of a dielectric material. Its value is equal to the ratio of the dielectric constant of the dielectric material to the dielectric constant of a vacuum.

[0053] For example, a bias voltage can be applied to the tuning layer 132, and the relative dielectric constant of the tuning layer 132 can change under the action of the bias voltage to change the overall electromagnetic parameters of the antenna structure 100, so that the phase and radiation pattern of the antenna structure 100 change, thereby realizing the reconfigurable characteristics of the antenna structure 100.

[0054] It should be noted that the bias voltage can be greater than or equal to 0V. When the bias voltage is 0V, it can be understood that no bias voltage is applied to the tuning layer 132. When the bias voltage is greater than 0V, it can be understood that a bias voltage is applied to the tuning layer 132. That is, in the partially reflective layer group 130, the relative dielectric constant of the tuning layer 132 changes under the bias voltage, but its relative dielectric constant value is always smaller than the relative dielectric constants of the first dielectric layer 131 and the second dielectric layer 133.

[0055] For example, a control circuit may be provided in the communication device, and the control circuit may be electrically connected to the tuning element to apply a bias voltage to the tuning layer 132 to change the relative dielectric constant of the tuning layer 132 .

[0056] The stacked first dielectric layer 131, tuning layer 132 and second dielectric layer 133 can form a distributed Bragg reflector (DBR). The distributed Bragg reflector is composed of a periodic arrangement of basic reflection units. By adjusting the relevant parameters of the basic reflection units, for example, adjusting the material, structural thickness and refractive index of the reflection units, the reflection of the corresponding frequency can be enhanced to obtain a stronger reflection signal. Specifically, when electromagnetic waves pass through different media, they will be reflected at the interface, and the magnitude of the reflectivity will be related to the dielectric constant between the media. Therefore, if thin films with different dielectric constants are stacked together periodically, when the electromagnetic waves pass through these thin films with different dielectric constants, the electromagnetic waves reflected from each layer will constructively interfere due to the change in phase angle, and then combine with each other to obtain a strong reflected electromagnetic wave. In this way, when the signal is fed from the feeding structure 110 and enters the partial reflection layer group 130 formed by the first dielectric layer 131, the tuning layer 132 and the second dielectric layer 133, the partial reflection layer group 130 can reflect or radiate stronger signal waves outward, which helps to improve the signal strength.

[0057] An asymmetric Fabry-Perot cavity (FPC) can be formed between the partially reflective layer group 130 and the frequency selective layer 140. In this case, the first dielectric layer 131 can be considered a resonant cavity, and the DBR formed by the frequency selective layer 140, the tuning layer 132, and the second dielectric layer 133 is asymmetric with respect to the first dielectric layer 131. The asymmetric FPC structure exhibits an overcoupling effect, causing incident light (or electromagnetic wave signals) to be reflected with a significant phase delay, thereby amplifying phase changes.

[0058] Continuing with FIG1 , the ground layer group 120 may include a metal floor 121 and a third dielectric layer 122 disposed on the metal floor 121. The feed structure 110 may be electrically connected to the metal floor 121, and the partially reflective layer group 130 may be disposed on the third dielectric layer 122. The metal floor 121 may reflect signals to reflect all signals fed by the feed structure 110 into the partially reflective layer group 130. Furthermore, after the partially reflective layer group 130 reflects part of the signal back, the metal floor 121 may continue to reflect the reflected signal back into the partially reflective layer group 130. This effectively reduces or prevents the signal from being projected toward the outside of the metal floor 121 (i.e., the side of the metal floor 121 facing away from the partially reflective layer group 130), thereby causing signal loss and helping to improve the signal radiation efficiency of the antenna structure 100.

[0059] The third dielectric layer 122 can provide space for signal reflection between the partially reflective side and the metal floor 121. At this time, the third dielectric layer 122 can also be understood as a resonant cavity, and the metal floor 121 is a full-emission surface. Through the mirror theory, the resonant cavity formed between the partially reflective layer group 130 and the metal floor 121 can be equivalent to a symmetrical FPC resonant cavity.

[0060] In the embodiment of the present application, referring to FIG1 , the thickness of the tuning layer 132 may be L1, and the value of L1 may be an odd multiple of one-quarter of the wavelength of the medium of the tuning layer 132. The wavelength of the medium of the tuning layer 132 refers to the wavelength of the signal propagating within the tuning layer 132. For the same electromagnetic wave, the frequency remains unchanged when propagating in different media, while the propagation speed and wavelength may change. By comparison with the propagation of electromagnetic waves in a vacuum, the wavelength of the wave propagating in the medium can be derived using the following formula:

[0061]

[0062] Where λ is the wavelength of the wave propagating in the medium, λ0 is the wavelength of the wave propagating in a vacuum, and n is the refractive index of the medium material. From the above formula, it can be seen that the wavelength of the medium in which the signal propagates in the tuning layer 132 can be calculated using the refractive index of the tuning layer 132 material and the wavelength of the wave in a vacuum.

[0063] When the thickness of the tuning layer 132 is an odd multiple of a quarter of the dielectric wavelength, the signal can have a higher propagation efficiency when propagating in the tuning layer 132, which can reduce signal loss and help improve the overall signal radiation efficiency of the antenna structure 100.

[0064] Continuing with FIG. 1 , the thickness of the first dielectric layer 131 may be L2, and the value of L2 may be an odd multiple of one-quarter of the dielectric wavelength of the first dielectric layer 131, where the dielectric wavelength of the first dielectric layer 131 is the wavelength of the signal propagating within the first dielectric layer 131. This allows for higher propagation efficiency of the signal within the first dielectric layer 131, helps reduce signal loss within the first dielectric layer 131, and thereby effectively improves the radiation efficiency of the antenna structure 100.

[0065] Continuing with FIG1 , the second dielectric layer 133 may have a thickness L3, where the value of L3 may be an odd multiple of one-quarter of the dielectric wavelength of the second dielectric layer 133, where the dielectric wavelength of the second dielectric layer 133 is the wavelength of the signal propagating within the second dielectric layer 133. This allows for higher propagation efficiency of the signal within the second dielectric layer 133, helps reduce signal loss within the second dielectric layer 133, and thereby effectively improves the radiation efficiency of the antenna structure 100.

[0066] In an embodiment of the present application, the tuning layer 132 can be a liquid crystal layer, a vanadium dioxide layer, a ferrite layer, a graphene layer or a diode. The above materials and devices can exhibit different relative dielectric constants after applying a bias voltage, and can change the electromagnetic parameters such as the phase and radiation pattern of the antenna structure 100, thereby realizing the reconfigurable characteristics of the antenna structure 100.

[0067] For example, when the tuning layer 132 comprises a liquid crystal layer and a vanadium dioxide layer, a bias voltage can be applied to the upper and lower surfaces of the tuning layer 132. Changing the bias voltage can cause the relative dielectric constant of the tuning layer 132 to change under the action of the bias voltage. When the tuning layer 132 comprises a ferrite layer, a graphene layer, or a diode, the bias voltage can be applied to the tuning layer 132 in other ways to change the relative dielectric constant of the tuning layer 132. Specifically, the bias voltage application method can be selected and set based on the configuration of the tuning layer 132.

[0068] The first dielectric layer 131 and the second dielectric layer 133 may be formed of alumina, which has a relatively high relative dielectric constant. By being stacked with the tuning layer 132 having a lower relative dielectric constant, a distributed Bragg reflector can be formed, which enables the signal to obtain a stronger reflected signal after passing through the partial reflection layer, thereby helping to improve the signal strength.

[0069] It should be noted that, depending on the configuration of the tuning layer 132, the materials of the first dielectric layer 131 and the second dielectric layer 133 may also vary, as long as the relative dielectric constants of the first dielectric layer 131 and the second dielectric layer 133 are both greater than the relative dielectric constant of the tuning layer 132 under a bias voltage. In specific applications, the materials of the first dielectric layer 131 and the second dielectric layer 133 can be selected based on the configuration of the tuning layer 132 or the specific application scenario.

[0070] The third dielectric layer 122 may be formed of a cyclic olefin copolymer (Zeonor). Cyclic olefin copolymer has a low relative dielectric constant, which is close to that of the tuning layer 132. This reduces signal loss during signal radiation from the third dielectric layer 122 toward the tuning layer 132, thereby improving the radiation efficiency of the antenna structure 100.

[0071] It should be noted that, depending on the different configurations of the tuning layer 132 , the molding material of the third dielectric layer 122 may also be different, as long as the relative dielectric constant of the third dielectric layer 122 is close to the relative dielectric constant of the tuning layer 132 , thereby reducing signal loss and improving the radiation efficiency of the antenna structure 100 .

[0072] FIG2 is a schematic structural diagram of a frequency selective layer provided in an embodiment of the present application.

[0073] As shown in FIG2 , in one possible implementation, the frequency selective layer 140 may include a plurality of metal patches arranged in an array, with gaps between adjacent metal patches. The metal patches may form the reflective portion 142 of the frequency selective layer 140, and the gaps may form the hollow portion 141 of the frequency selective layer 140. For example, the metal patches may be attached to the first dielectric layer 131 of the partially reflective layer group 130 by bonding, snapping, or snapping. For example, the metal patches may be arranged in a rectangular array of M rows by N columns, where M and N may both be greater than or equal to 2. Alternatively, in some examples, the metal patches may be arranged in other array configurations, for example, in a circular or triangular array. Specifically, the arrangement of the metal patches may be selected and set based on the shape of the antenna structure 100, the shape of the metal patches, and the specific application scenario.

[0074] When the signal propagates from the partially reflective layer group 130 to the frequency selective layer 140, part of the signal can radiate outward through the gaps between the metal patches, while another part of the signal can be reflected by the metal patches to the partially reflective layer group 130, and reflected again into the gaps through the partially reflective layer group 130 to radiate outward through the gaps, thereby amplifying the phase change of the signal radiation.

[0075] The shape of the metal patch can be at least one of a rectangle, a circle, a triangle, or a trapezoid. For example, the shapes of the multiple metal patches can all be the same, such as a rectangle, a circle, a triangle, or a trapezoid. Alternatively, in some examples, the shapes of the metal patches can be different. For example, the shape of some metal patches can be one shape, while the shape of another part of the metal patches can be a different shape.

[0076] By flexibly setting the shape and arrangement of the metal patch, it is possible to obtain reflective portions 142 and hollow portions 141 of different structural forms, which helps to optimize the structural parameters of the frequency selection layer 140, effectively improve the intensity of the overcoupling effect of the asymmetric FPC structure, and enhance the influence of the phase change generated by the tuning layer 132 under different bias voltages, thereby effectively improving the beam scanning range of the antenna structure 100.

[0077] FIG3 is a schematic structural diagram of another frequency selective layer provided in an embodiment of the present application.

[0078] Alternatively, in another possible implementation, as shown in FIG3 , the frequency selective layer 140 may include a metal layer having a plurality of through holes arranged in an array. The through holes may form a hollow portion 141, and the metal layer outside the through holes may form a reflective portion 142. For example, the through holes may be formed in the metal layer by laser cutting or other methods.

[0079] For example, the through holes may be arranged in a rectangular array of M rows × N columns, where the values ​​of M and N may both be greater than or equal to 2. Alternatively, in some examples, depending on the shape of the metal layer, the through holes may be arranged in other arrays, for example, in a circular or triangular array. Specifically, the arrangement of the through holes may be selected and set based on the shape of the antenna structure 100, the shape of the metal layer, and the specific application scenario.

[0080] When the signal propagates from the partially reflective layer group 130 to the frequency selective layer 140, a portion of the signal can be radiated outward through the through hole, while another portion of the signal can be reflected by the metal layer outside the through hole to the partially reflective layer group 130, and then reflected again into the through hole through the partially reflective layer group 130 to radiate outward through the through hole, thereby amplifying the phase change of the signal radiation.

[0081] Among them, the shape of the through hole can also be at least one of a rectangle, a circle, a triangle or a trapezoid. For example, through holes of all the same shape can be opened on the metal layer, and each through hole can be arranged in a rectangular array, a circular array or a triangular array. Alternatively, in some instances, each through hole can also be combined in different shapes. For example, the shape of a part of the through holes can be rectangular, and the shape of another part of the through holes can be circular. Alternatively, the shape of a part of the through holes can be circular, and the shape of another part of the through holes can be triangular. Specifically, the shape of each through hole can be selected and set according to the specific application scenario.

[0082] By opening through holes of different shapes and sizes on the metal layer, hollow portions 141 and reflective portions 142 of different structural forms can be obtained, and the structural parameters of the frequency selection layer 140 can be optimized to increase the overcoupling effect strength of the asymmetric FPC structure and enhance the influence of the phase change generated by the tuning layer 132 under different bias voltages, thereby effectively improving the beam scanning range of the antenna structure 100.

[0083] The reflector 142 can be formed of at least one of gold, copper, or aluminum. For example, the reflector 142 can be a structural component made of any of these materials, or the radiator can be a structural component made of a mixture of any two or more of these materials. These materials have good electrical conductivity, which helps improve the signal reflection efficiency of the frequency selective layer 140 and enhances the signal radiation efficiency of the antenna structure 100.

[0084] FIG4 is a schematic structural diagram of another antenna structure provided in an embodiment of the present application.

[0085] In one possible implementation, as shown in FIG4 , the partially reflective layer group 130 may include multiple tuning layers 132 and multiple second dielectric layers 133. The multiple tuning layers 132 and the multiple second dielectric layers 133 may be interlaced between the first dielectric layer 131 and the ground layer group 120. For example, as shown in FIG4 , the number of tuning layers 132 and the number of second dielectric layers 133 may each be three. The three tuning layers 132 and the three second dielectric layers 133 may be interlaced and stacked between the first dielectric layer 131 and the ground layer group 120. By increasing the number of tuning layers 132 and the number of second dielectric layers 133, the tuning layers 132 can effectively improve their ability to control the beam scanning range, enabling the antenna structure 100 to achieve a wider range of phase control, thereby enabling the antenna structure 100 to achieve a wider range of beam scanning, effectively extending the beam scanning range of the antenna structure 100.

[0086] The beam scanning performance of the antenna structure 100 provided in the embodiment of the present application is verified below with reference to the accompanying drawings. This experiment is conducted using a structure in which the tuning layer 132 and the second dielectric layer 133 are both one layer (ie, the structure in FIG1 ) as an example.

[0087] FIG5 is a transmission line model diagram of an antenna structure provided in an embodiment of the present application.

[0088] First, the antenna structure 100 is equivalent to the transmission line model shown in FIG5 through a transverse equivalent network. Then, the dispersion characteristics of the antenna structure 100 are calculated and analyzed, and the following dispersion equation can be obtained: Y0+Y FSS +Y TL (Y H ,Y LC ,Y sub )=0

[0089] Where Y0 is the admittance corresponding to the free space wave, and its value is usually 1 / 377, and Y FSS is the admittance corresponding to the frequency selective layer 140, Y H is the admittance corresponding to the second dielectric layer 133, Y LC is the admittance corresponding to the tuning layer 132, Y sub The admittance corresponding to the ground layer group 120 is related to the propagation constant of the antenna structure 100 in the leaky wave mode. TL (Y H , Y LC , Y sub ) is the admittance corresponding to the short-circuited transmission line, and its value can be calculated using transmission line theory.

[0090] The above equation is a transcendental equation with the propagation constant of the leaky wave mode generated by the antenna structure 100 as an unknown variable. It can be iteratively solved according to methods such as Muller root finding or Pade root finding to obtain the admittance value of the frequency selective layer 140, thereby achieving good impedance matching. Based on the admittance value of the frequency selective layer 140, the structure of the frequency selective layer 140 that meets the admittance value can be designed. For example, after obtaining the admittance value of the frequency selective layer 140, the dimensions of the reflective portion 142 and the hollow portion 141 in the frequency selective layer 140 can be calculated based on the admittance value. In this example, the reflective portion 142 is selected as a square metal patch as an example, and the following parameters are selected after calculation for testing.

[0091] The total antenna height L (see Figure 1) refers to the distance from the upper surface of the frequency selective layer 140 to the lower surface of the metal floor 121 in the antenna structure 100. The thickness L4 of the ground layer group 120 (see Figure 1) is the sum of the thicknesses of the metal floor 121 and the third dielectric layer 122. The width d1 of the reflective portion 142 (see Figure 2) is the side length of the square metal patch. The width d2 of the hollow portion 141 (see Figure 2) is the gap width between two adjacent square metal patches. By inputting the above parameters into the simulation software, a dispersion characteristic simulation curve of the antenna structure 100 can be obtained.

[0092] FIG6 is a simulation diagram of the dispersion characteristics of an antenna structure provided in an embodiment of the present application.

[0093] Refer to Figure 6, which shows a simulated dispersion characteristic curve when the antenna structure 100 is the structure shown in Figure 1, that is, after the frequency selective layer 140 is provided in the antenna structure 100. The abscissa in Figure 6 represents the normalized frequency f / f0, and the ordinate represents α / k0 or β / k0, where α is the attenuation constant, β is the phase constant, and k0 is the free-space wave number. For ease of comparison, the abscissa in the figure is normalized, with f representing the operating frequency and f0 being the optimal operating frequency at which the phase constant β equals the attenuation constant α when the bias voltage is 0V, resulting in maximum antenna gain. Curve 1 in Figure 6 shows the ratio of the phase constant β to the free-space wave number k0 (i.e., β / k0) when the bias voltage is 0. Curve 2 shows the ratio of the attenuation constant α to the free-space wave number k0 (i.e., α / k0) when the bias voltage is 0. Curve 3 shows the ratio of the phase constant β to the free-space wave number k0 when the bias voltage is 15V. Curve 4 is the ratio of the attenuation constant α to the free space wave number k0 when the bias voltage is 15V.

[0094] It can be concluded from curve 1 and curve 2 in Figure 6 that when the normalized frequency is 1 and the bias voltage on the tuning layer 132 is 0, as mentioned above, the two curves α / k0 and β / k0 intersect, and the values ​​of α / k0 and β / k0 are equal, that is, the attenuation constant α is equal to the phase constant β. At this time, according to the leaky wave antenna theory, it can be seen that the beam pointing angle θ of the antenna structure 100 is 0 degrees.

[0095] From curves 3 and 4 in FIG6 , it can be seen that when the normalized frequency is 1 and the bias voltage on the tuning layer 132 is 15V, the values ​​of the two curves α / k0 and β / k0 on the horizontal axis differ greatly, with the value of β / k0 being much greater than the value of α / k0, that is, β>>α. At this time, according to leaky wave antenna theory, the beam pointing angle θ satisfies the following formula: sinθ=β / k0

[0096] According to the inverse trigonometric function, we can conclude that: θ = sin -1 β / k0

[0097] From curve 3 in the figure, we can see that the value of β / k0 is approximately 0.46, and therefore the beam pointing angle θ is approximately 27.5 degrees. Therefore, it can be seen that when the bias voltage increases from 0V to 15V, the beam pointing angle θ of the antenna structure 100 changes from 0 degrees to 27.5 degrees, that is, the beam scanning range of the antenna structure 100 is 27.5 degrees.

[0098] FIG7 is a dispersion simulation diagram of the antenna structure when no frequency selective layer is provided in the related art.

[0099] FIG7 shows a simulated dispersion characteristic curve of an antenna structure without a frequency selective layer 140. Curve 1 in FIG7 shows the ratio of the phase constant β to the free-space wave number k0 (i.e., β / k0) when the bias voltage is 0. Curve 2 shows the ratio of the attenuation constant α to the free-space wave number k0 (i.e., α / k0) when the bias voltage is 0. Curve 3 shows the ratio of the phase constant β to the free-space wave number k0 when the bias voltage is 15V. Curve 4 shows the ratio of the attenuation constant α to the free-space wave number k0 when the bias voltage is 15V.

[0100] It can be concluded from curve 1 and curve 2 in Figure 7 that when the normalized frequency is 1 and the bias voltage on the tuning layer 132 is 0, the two curves α / k0 and β / k0 intersect, and the values ​​of α / k0 and β / k0 are equal, that is, the attenuation constant α is equal to the phase constant β. At this time, according to the leaky wave antenna theory, it can be seen that the beam pointing angle θ of the antenna structure 100 is 0 degrees.

[0101] From curves 3 and 4 in the figure, it can be seen that when the frequency is 1 and the bias voltage on the tuning layer 132 is 15V, the values ​​of the α / k0 and β / k0 curves on the horizontal axis are very different. The value of β / k0 is much larger than the value of α / k0, that is, β>>α. At this time, according to leaky wave antenna theory, the beam pointing angle θ satisfies the following formula: sinθ=β / k0

[0102] At this point, the value of the beam pointing angle θ can be obtained based on the inverse trigonometric function. From Curve 3 in the figure, it can be determined that the value of β / k0 is approximately 0.33, so the beam pointing angle θ can be determined to be approximately 19.5 degrees. Therefore, it can be seen that when the bias voltage increases from 0V to 15V, the beam pointing angle θ of the antenna structure 100 without the frequency selective layer 140 changes from 0 degrees to 19.5 degrees. In other words, the beam scanning range of the antenna structure 100 without the frequency selective layer 140 is 19.5 degrees.

[0103] The experimental results show that compared with the antenna structure without a frequency selection layer, after the frequency selection layer 140 is set in the antenna structure 100, the beam scanning range of the antenna structure 100 increases from 19.5 degrees to 27.5 degrees, that is, the beam scanning range of the antenna structure 100 increases by 8 degrees. The beam scanning range has been significantly increased, which effectively increases the beam scanning effect of the antenna structure 100.

[0104] In the following, a simulation test is conducted on the directional pattern of the antenna structure 100 with reference to the accompanying drawings.

[0105] FIG8 is a directional diagram of the antenna structure provided in an embodiment of the present application and an antenna structure in related art.

[0106] Referring to FIG8 , the horizontal axis represents the beam pointing angle, and the vertical axis represents the directivity coefficient. Curve 1 in FIG8 is a directional pattern curve when the antenna structure 100 is provided with a frequency selective layer 140 and the bias voltage is 0V. Curve 2 is a directional pattern curve when the antenna structure 100 is provided with a frequency selective layer 140 and the bias voltage is 15V. Curve 3 is a directional pattern curve when the antenna structure 100 is not provided with a frequency selective layer 140 and the bias voltage is 0V. Curve 4 is a directional pattern curve when the antenna structure 100 is not provided with a frequency selective layer 140 and the bias voltage is 15V.

[0107] When the directivity reaches its maximum value, the value corresponding to the horizontal axis is the beam pointing angle of the antenna structure 100. From curves 1 and 2 in FIG8 , it can be seen that when the frequency selective layer 140 is provided on the antenna structure 100, the beam pointing angle of the antenna structure 100 is 0 degrees when the bias voltage is 0V, and the beam pointing angle of the antenna structure 100 is approximately 27.7 degrees when the bias voltage is 15V, which is close to the beam pointing angle of 27.5 degrees obtained from the experimental dispersion simulation diagram (i.e., FIG6 ). From curves 3 and 4 , it can be seen that when the frequency selective layer 140 is not provided on the antenna structure 100, the beam pointing angle of the antenna structure 100 is 0 degrees when the bias voltage is 0V, and the beam pointing angle of the antenna structure 100 is approximately 20.8 degrees when the bias voltage is 15V, which is close to the beam pointing angle of 19.5 degrees obtained from the experimental dispersion simulation diagram (i.e., FIG7 ).

[0108] The experimental results show that compared with the antenna structure 100 without the frequency selection layer 140, after the frequency selection layer 140 is set in the antenna structure 100, the beam scanning range of the antenna structure 100 increases from 20.8 degrees to 27.7 degrees, that is, the beam scanning range of the antenna structure 100 increases by 6.9 degrees. The beam scanning range has been significantly increased, which effectively increases the beam scanning effect of the antenna structure 100, which is consistent with the conclusion drawn from the dispersion simulation diagram test.

[0109] In the following, with reference to the accompanying drawings, a simulation experiment is conducted on the directional patterns when both the tuning layer 132 and the second dielectric layer 133 in the antenna structure 100 are three layers.

[0110] FIG9 is a directional diagram of another antenna structure provided in an embodiment of the present application and an antenna structure in related art.

[0111] Referring to FIG. 9 , Curve 1 in FIG. 9 shows the directional pattern of the antenna structure 100 when the frequency selective layer 140 is provided and the bias voltage is 0V. Curve 2 shows the directional pattern of the antenna structure 100 when the frequency selective layer 140 is provided and the bias voltage is 15V. Curve 3 shows the directional pattern of the antenna structure 100 when the frequency selective layer 140 is not provided and the bias voltage is 0V. Curve 4 shows the directional pattern of the antenna structure 100 when the frequency selective layer 140 is not provided and the bias voltage is 15V.

[0112] When the directivity coefficient reaches its maximum value, the value corresponding to the horizontal axis is the beam pointing angle of the antenna structure 100. It can be seen from curves 1 and 2 in Figure 9 that when the frequency selective layer 140 is provided in the antenna structure 100, when the bias voltage is 0V, the beam pointing angle of the antenna structure 100 is 0 degrees. When the bias voltage is 15V, the beam pointing angle of the antenna structure 100 is approximately 34.6 degrees. It can be seen from curves 3 and 4 that when the frequency selective layer 140 is not provided in the antenna structure 100, when the bias voltage is 0V, the beam pointing angle of the antenna structure 100 is 0 degrees. When the bias voltage is 15V, the beam pointing angle of the antenna structure 100 is approximately 26.7 degrees.

[0113] It can be concluded from the experimental results that when the number of layers of the tuning layer 132 and the second dielectric layer 133 are both three, compared with the antenna structure 100 without the frequency selection layer 140, after the frequency selection layer 140 is set in the antenna structure 100, the beam scanning range of the antenna structure 100 increases from 26.7 degrees to 34.6 degrees, and the beam scanning range of the antenna structure 100 increases by 7.9 degrees. The beam scanning range has a significant increase, which effectively increases the beam scanning effect of the antenna structure 100.

[0114] In addition, a comparison of Figures 8 and 9 shows that when the number of layers of the tuning layer 132 and the second dielectric layer 133 is one, after the frequency selective layer 140 is added, the beam scanning range of the antenna structure 100 is 27.7 degrees. However, by increasing the number of layers of the tuning layer 132 and the second dielectric layer 133 and not providing the frequency selective layer 140, the beam scanning range of the antenna structure 100 is 26.7 degrees. This shows that compared with the method of increasing the beam scanning range by providing the frequency selective layer 140, the method of increasing the beam scanning range by providing the frequency selective layer 140 can significantly increase the beam scanning range and has a better phase amplification effect. Moreover, it can also effectively reduce the thickness of the antenna structure 100, which is conducive to the miniaturization design of the antenna structure 100.

[0115] The present application also provides a communication device that can include the antenna structure 100 for any of the aforementioned scenarios. The communication device can be a communication base station platform antenna feed system, a millimeter-wave radar, a smart home, or the like. Including the antenna structure 100 in the communication device effectively reduces the space occupied by the antenna structure 100 within the communication device, improving the rationality of the antenna structure 100's layout within the communication device and facilitating the miniaturization of the communication device. Furthermore, it helps reduce the difficulty and cost of manufacturing the communication device.

[0116] In the description of the embodiments of the present application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, or it can be an indirect connection through an intermediate medium, or it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances. The terms "first", "second", "third", "fourth", etc. (if any) are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0117] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the embodiments of the present application, rather than to limit them. Although the embodiments of the present application have been described in detail with reference to the aforementioned embodiments, ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. These modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. An antenna structure, characterized in that: It includes a feeding structure, and a ground layer group, a partial reflection layer group and a frequency selection layer which are stacked; The feeding structure is electrically connected to the ground layer group, and the partial reflection layer group is located between the ground layer group and the frequency selection layer; The ground layer group is used to reflect signals, and the partial reflection layer group is used to allow part of the signals to pass through and reflect the rest of the signals; The frequency selection layer includes a hollow portion and a reflection portion, the hollow portion is used for allowing signals to pass through, and the reflection portion is used for reflecting the signals.

2. The antenna structure according to claim 1, characterized in that: The partial reflection layer group comprises a first dielectric layer, a tuning layer, and a second dielectric layer which are stacked in sequence, and the frequency selection layer is located on the first dielectric layer; The relative dielectric constants of the first dielectric layer and the second dielectric layer are both greater than the relative dielectric constant of the tuning layer under a bias voltage; The tuning layer is used to change the relative dielectric constant under the action of applied bias voltage.

3. The antenna structure according to claim 1 or 2, characterized in that: The frequency selection layer includes a plurality of metal patches arranged in an array, and there is a gap between two adjacent metal patches; The metal patch forms the reflecting portion, and the gap forms the hollow portion.

4. The antenna structure according to any one of claims 1 to 3, characterized in that: The frequency selection layer comprises a metal layer, and a plurality of through holes arranged in an array are provided on the metal layer; The through hole forms the hollow portion, and the metal layer outside the through hole forms the reflective portion.

5. The antenna structure according to any one of claims 1 to 4, characterized in that: The grounding layer group includes a metal floor and a third dielectric layer arranged on the metal floor; The feeding structure is electrically connected to the metal floor, and the partial reflection layer group is arranged on the third dielectric layer.

6. The antenna structure according to claim 2, characterized in that: The partial reflection layer group includes a plurality of the tuning layers and a plurality of the second dielectric layers; The plurality of tuning layers and the plurality of the second dielectric layers are alternately arranged between the first dielectric layer and the ground layer group.

7. The antenna structure according to claim 2 or 6, characterized in that: The tuning layer is a liquid crystal layer, a vanadium dioxide layer, a ferrite layer, a graphene layer or a diode layer.

8. The antenna structure according to any one of claims 2, 6 or 7, characterized in that: The first dielectric layer and the second dielectric layer are formed of aluminum oxide.

9. The antenna structure according to any one of claims 1 to 8, characterized in that: The reflecting part is formed of at least one of gold, copper and aluminum.

10. The antenna structure according to claim 5, characterized in that: The third dielectric layer is formed of cycloolefin copolymer.

11. The antenna structure according to claim 3, characterized in that: The shape of the metal patch is at least one of a rectangle, a circle, a triangle or a trapezoid.

12. The antenna structure according to claim 4, characterized in that: The through hole has a shape of at least one of a rectangle, a circle, a triangle or a trapezoid.

13. The antenna structure according to any one of claims 2, 6 to 8, characterized in that: The thickness of the tuning layer is an odd multiple of one quarter of a medium wavelength of the tuning layer, where the medium wavelength of the tuning layer is a wavelength of a signal propagating in the tuning layer.

14. The antenna structure according to any one of claims 2, 6 to 8, characterized in that: The thickness of the first dielectric layer is an odd multiple of one quarter of the dielectric wavelength of the first dielectric layer, and the dielectric wavelength of the first dielectric layer is the wavelength of the signal propagating in the first dielectric layer; The thickness of the second dielectric layer is an odd multiple of one quarter of a dielectric wavelength of the second dielectric layer, and the dielectric wavelength of the second dielectric layer is a wavelength of a signal propagating in the second dielectric layer.

15. A communication device, characterized in that: It comprises the antenna structure described in any one of claims 1 to 14.

16. The communication device according to claim 15, characterized in that: The communication device further comprises a control circuit, wherein the control circuit is electrically connected to the tuning layer in the antenna structure; The control circuit is used to apply a bias voltage to the tuning layer.

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