An antenna structure and a communication device

Abstract

The embodiment of the application provides an antenna structure and a communication device, and belongs to the technical field of antennas. The antenna structure comprises a feeding structure, a ground layer group, a partial reflection layer group and a frequency selection layer which are sequentially stacked. The ground layer group is used for reflecting signals, and the partial reflection layer group is used for allowing part of the signals to pass through and reflecting the remaining part of the signals. The frequency selection layer comprises a hollow part and a reflection part. The hollow part is used for allowing signals to pass through, and the reflection part is used for reflecting signals. The signals radiated outward through the hollow part and the signals radiated outward after being reflected by the reflection part can be delayed in phase. The signals can be reflected multiple times between the ground layer group, the partial reflection layer group and the frequency selection layer, can be delayed in phase multiple times, can be amplified in phase variation of the whole signal, and a larger range of phase tuning can be obtained, so that the antenna structure can realize a larger range of beam scanning.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of antennas, and in particular to an antenna structure and a communication device. BACKGROUND

[0002] An antenna is a device that converts energy and directs electromagnetic waves in wireless communication, and is widely used in radio communication, broadcasting, radar, navigation, remote sensing and other engineering systems. For example, an antenna is applied in electronic devices such as mobile phones, notebook computers, tablet computers, netbooks, wearable devices, etc. The electronic devices can transmit signals through the antenna. Among them, a reconfigurable leaky-wave antenna can realize fixed-frequency beam scanning and effectively increase the radiation range of the antenna, and is also widely used in the technical field of antennas.

[0003] In related technologies, the reconfigurable leaky-wave antenna usually includes high dielectric constant layers and low dielectric constant liquid crystal layers arranged alternately. A control circuit is arranged 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, so that the electromagnetic parameters such as the phase and the directional diagram of the antenna change, thereby realizing the reconfigurable characteristics of the leaky-wave antenna, enabling the antenna to realize fixed-frequency beam scanning and reducing the dependence of antenna scanning on a wide frequency band.

[0004] However, in the above-mentioned antenna, the fixed-frequency beam scanning of the antenna is realized by using liquid crystal materials, and the scanning range is usually small, which reduces the reconfigurable characteristics of the antenna. SUMMARY

[0005] 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 improve the reconfigurable characteristics of the antenna.

[0006] A first aspect of the present application provides an antenna structure, comprising a feeding structure, and a ground layer group, a partial reflection layer group and a frequency selection layer arranged in layers;

[0007] 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.

[0008] The ground layer group is used for reflecting signals, and the partial reflection layer group is used for allowing part of the signals to pass through and reflecting the remaining part of the signals.

[0009] The frequency selection layer includes a hollow part and a reflection part, the hollow part is used for allowing signals to pass through, and the reflection part is used for reflecting the signals.

[0010] The application sets a frequency selection layer, the signals radiated outward through the hollow part of the frequency selection layer and the signals radiated outward through the hollow part after being reflected by the reflection part and the partial reflection layer group can have phase delay, the signals can be reflected multiple times between the ground layer group, the partial reflection layer group and the frequency selection layer, multiple phase delays can occur, the phase change of the whole signal can be amplified, a larger range of phase tuning can be obtained, so that the antenna structure realizes a larger range of beam scanning and improves the reconfigurable characteristics of the antenna structure.

[0011] In a possible implementation, the partial reflection layer group includes a first dielectric layer, a tuning layer and a second dielectric layer which are sequentially stacked, 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 the bias voltage; and the tuning layer is configured to change the relative dielectric constant under the bias voltage. The first dielectric layer, the tuning layer and the second dielectric layer which are stacked can form a distributed Bragg reflector, and when the signal passes through the partial reflection layer group, a stronger signal wave can be radiated, which helps to improve the strength of the signal.

[0012] In a possible implementation, the frequency selection layer includes a plurality of arrayed metal patches, and adjacent two metal patches have a gap therebetween; the metal patches form the reflection part, and the gaps form the hollow part. When the signal propagates from the partial reflection layer group to the frequency selection layer, a part of the signal can be radiated outward through the gaps between the metal patches, and another part of the signal can be reflected to the partial reflection layer group through the metal patches, and then reflected to the gaps again through the partial reflection layer group to be radiated outward through the gaps, so as to amplify the phase change of the signal radiation.

[0013] In a possible implementation, the frequency selection layer includes a metal layer, and a plurality of arrayed through holes are formed in the metal layer; the through holes form the hollow part, and the metal layer other than the through holes forms the reflection part. When the signal propagates from the partial reflection layer group to the frequency selection layer, a part of the signal can be radiated outward through the through holes in the metal layer, and another part of the signal can be reflected to the partial reflection layer group through the metal layer other than the through holes, and then reflected to the through holes again through the partial reflection layer group to be radiated outward through the through holes, so as to amplify the phase change of the signal radiation.

[0014] In a possible implementation, the ground layer set includes a metal floor and a third dielectric layer disposed on the metal floor; the feeding structure is electrically connected to the metal floor, and the partial reflection layer set is disposed on the third dielectric layer. The metal floor can reflect signals to reflect all signals fed by the feeding structure into the partial reflection layer set, thereby effectively reducing or avoiding the signals from being projected to the outside of the metal floor (i.e., the side of the metal floor facing away from the partial reflection layer set), and further causing signal loss, which helps to improve the signal radiation efficiency of the antenna structure.

[0015] In a possible implementation, the partial reflection layer set includes a plurality of the tuning layers and a plurality of the second dielectric layers; the plurality of the tuning layers and the plurality of the second dielectric layers are alternately disposed between the first dielectric layer and the ground layer set. By increasing the number of the tuning layers and the second dielectric layers, the tuning ability of the tuning layers to the beam scanning range can be effectively improved, so that the antenna structure can achieve a larger range of phase control, thereby enabling the antenna structure to achieve a larger range of beam scanning, and effectively improving the beam scanning range of the antenna structure.

[0016] In a possible implementation, the tuning layer is a liquid crystal layer, a vanadium dioxide layer, a ferrite layer, a graphene layer, or a diode layer. The above materials and devices can exhibit different relative dielectric constants after a bias voltage is applied, and can change the electromagnetic parameters such as the phase and the radiation pattern of the antenna structure, thereby achieving the reconfigurable characteristics of the antenna structure.

[0017] In a possible implementation, the forming material of the first dielectric layer and the second dielectric layer is aluminum oxide. Aluminum oxide has a relatively high relative dielectric constant, and can form a distributed Bragg reflector by being stacked with the tuning layer having a relatively low relative dielectric constant, so as to enable the signal to obtain a relatively strong reflected signal after passing through the partial reflection layer set, and help to improve the strength of the signal.

[0018] In a possible implementation, the forming material of the reflection portion is at least one of gold, copper, and aluminum.

[0019] In a possible implementation, the forming material of the third dielectric layer is cyclic olefin copolymer. Cyclic olefin copolymer has a relatively low relative dielectric constant, and is relatively close to the relative dielectric constant of the tuning layer, so that the loss of the signal can be reduced in the process of radiating from the third dielectric layer to the tuning layer, which is beneficial to improve the radiation efficiency of the antenna structure.

[0020] In a possible implementation, the metal patch is at least one of a rectangle, a circle, a triangle, or a trapezoid. By flexibly setting the shape and arrangement of the metal patch, a reflection part and a hollow part of different structures can be obtained, which helps to optimize the structural parameters of the frequency selection layer and improve the beam scanning range of the antenna structure.

[0021] In a possible implementation, the through hole is at least one of a rectangle, a circle, a triangle, or a trapezoid.

[0022] In a possible implementation, the thickness of the tuning layer is an odd multiple of a quarter of a dielectric wavelength of the tuning layer, and the dielectric wavelength of the tuning layer is a wavelength of a signal propagating in the tuning layer. In this way, the signal can have a high propagation efficiency when propagating in the tuning layer, and the loss of the signal can be reduced, thereby improving the overall radiation efficiency of the antenna structure.

[0023] In a possible implementation, the thickness of the first dielectric layer is an odd multiple of a quarter of a dielectric wavelength of the first dielectric layer, and the dielectric wavelength of the first dielectric layer is a wavelength of a signal propagating in the first dielectric layer. In this way, the signal can have a high propagation efficiency in the first dielectric layer, and the loss of the signal in the first dielectric layer can be reduced, thereby effectively improving the radiation efficiency of the antenna structure.

[0024] The thickness of the second dielectric layer is an odd multiple of a 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. In this way, the signal can have a high propagation efficiency in the second dielectric layer, and the loss of the signal in the second dielectric layer can be reduced, thereby effectively improving the radiation efficiency of the antenna structure.

[0025] The second aspect of the present application provides a communication device including the antenna structure described above. By including the antenna structure described above, the space occupied by the antenna structure in the communication device can be effectively reduced, the rationality of the layout of the antenna structure in the communication device can be improved, and the miniaturization design of the communication device can be improved. Moreover, the production difficulty and production cost of the communication device can also be reduced.

[0026] In a possible implementation, the communication device further includes a control circuit electrically connected to the tuning layer in the antenna structure, and the control circuit is configured to apply a bias voltage to the tuning layer. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 FIG. 1 is a structural schematic diagram of an antenna structure provided by an embodiment of the present application;

[0028] Figure 2A structure diagram of a frequency selection layer provided by an embodiment of the present application;

[0029] Figure 3 A structure diagram of another frequency selection layer provided by an embodiment of the present application;

[0030] Figure 4 A structure diagram of another antenna structure provided by an embodiment of the present application;

[0031] Figure 5 A transmission line model diagram of an antenna structure provided by an embodiment of the present application;

[0032] Figure 6 A dispersion characteristic simulation diagram of an antenna structure provided by an embodiment of the present application;

[0033] Figure 7 A dispersion simulation diagram of an antenna structure without a frequency selection layer in the related art;

[0034] Figure 8 A radiation pattern of an antenna structure provided by an embodiment of the present application and an antenna structure in the related art;

[0035] Figure 9 A radiation pattern of another antenna structure provided by an embodiment of the present application and an antenna structure in the related art.

[0036] Explanation of reference signs:

[0037] 100-antenna structure;

[0038] 110-feed structure;

[0039] 120-ground layer group; 121-metal floor; 122-third dielectric layer;

[0040] 130-partial reflection layer group; 131-first dielectric layer; 132-tuning layer; 133-second dielectric layer;

[0041] 140-frequency selection layer; 141-hollow part; 142-reflective part. DETAILED DESCRIPTION

[0042] The terms used in the embodiment part of the present application are only used for explaining the specific embodiments of the present application, and are not intended to limit the present application.

[0043] Leakage wave antenna refers to that when electromagnetic waves propagate along a traveling wave structure, if radiation is continuously generated along the structure, the radiated wave is called leakage wave. The structure that generates leakage wave is called leakage wave antenna. By changing the frequency, the leakage wave antenna can realize beam scanning, and can enable the antenna to realize a larger range of signal coverage. Generally speaking, the leakage wave antenna usually needs a relatively wide frequency spectrum bandwidth to realize complete beam scanning. With the continuous development of antenna technology, by introducing tunable materials (such as liquid crystal) in the leakage wave antenna, the leakage wave antenna can realize beam scanning at a fixed frequency, thereby effectively improving the propagation range of the leakage wave antenna.

[0044] In the related art, a reconfigurable leakage wave antenna is provided, which includes a high dielectric constant layer and a low dielectric constant liquid crystal layer arranged in a stack, and a regulation circuit is arranged on the liquid crystal layer. The regulation 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 to realize the reconfigurable characteristic of the leakage wave antenna. However, due to the limited tuning range of the relative dielectric constant of the liquid crystal material, the fixed frequency beam scanning range of the leakage wave antenna realized by the liquid crystal material is often small, which reduces the reconfigurable characteristic of the antenna.

[0045] In order to solve the above problems, the researchers thought of improving the structure of the antenna, by arranging a frequency selection layer in the antenna structure, the frequency selection layer includes a hollow part and a reflection part, the phase delay can occur between the signals radiated outward through the hollow part and the signals radiated outward after being reflected by the reflection part, the phase change of the signals is amplified, a larger range of phase tuning can be obtained, the antenna structure can realize a larger range of beam scanning, and the reconfigurable characteristic of the antenna structure is improved.

[0046] The antenna structure and the communication device provided by the present application are described in detail below with reference to the accompanying drawings.

[0047] Figure 1 A structural schematic diagram of an antenna structure provided by an embodiment of the present application.

[0048] The antenna structure provided by the embodiment of the present application and the communication device including the antenna structure can be a high-frequency leakage wave antenna, for example, the antenna structure can radiate electromagnetic wave signals in the microwave, millimeter wave, and terahertz frequency bands. The antenna structure can be applied to a communication base station platform feed system, a millimeter wave radar, a smart home, and the like.

[0049] Reference is made to Figure 1As shown, the antenna structure 100 can include a feed structure 110, and a ground layer group 120, a partial reflection layer group 130 and a frequency selection layer 140 arranged in a stack. The feed structure 110 can be electrically connected to the ground layer group 120, and the partial reflection layer group 130 can be arranged between the ground layer group 120 and the frequency selection layer 140. The feed structure 110 can feed or power the antenna structure 100, so that signals can be fed into the antenna structure 100 through the feed structure 110. For example, the feed structure 110 can be a waveguide structure, for example, the waveguide structure can be a rectangular waveguide. The feed structure 110 can be electrically connected to the ground layer group 120 by welding or metal spring, so that the feed structure 110 can feed the ground layer group 120. Alternatively, the feed structure 110 and the ground layer group 120 can also feed the ground layer group 120 by means of gap coupling. Specifically, the specific structure form and feeding mode of the feed structure 110 can be selected and set according to the specific application scenario, and the feeding mode and electrical connection mode of the feed structure 110 are not limited in the present application.

[0050] 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 arranged 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, so as to change the electromagnetic parameters of the whole antenna structure 100, so that the phase and the directional pattern of the antenna structure 100 change, thereby realizing the reconfigurable characteristics of the antenna structure 100.

[0051] The frequency selection layer 140 can include a hollow part 141 and a reflection part 142. The hollow part 141 can be used for signal transmission, and the reflection part 142 can be used for signal reflection. For example, the reflection part 142 can be a metal layer, which can reflect the signal when the signal is projected onto the metal layer, so as to change the propagation direction of the signal. For example, when the signal is transmitted from the partial reflection layer group 130 to the frequency selection layer 140, part of the signal can pass through the hollow part 141 and be radiated outward, and the other part can be reflected by the reflection part 142 to the partial reflection layer group 130 again. Then, the signal reflected to the partial reflection layer group 130 can be reflected to the hollow part 141 again through the partial reflection layer group 130, and then be radiated outward through the hollow part 141, so as to form a leaky wave mode.

[0052] For example, in the process of specific work, after the feeding structure 110 feeds the signal into the ground layer group 120, the signal can pass through the ground layer group 120 to the partial reflection layer group 130. Part of the signal on the partial reflection layer group 130 can pass through the partial reflection layer group 130, and the other part can be reflected by the partial reflection layer group 130 to the ground layer group 120. At this time, the ground layer group 120 can reflect the signal reflected by the partial reflection layer group 130 to the partial reflection layer group 130 again. After the signal is repeatedly reflected between the partial reflection layer group 130 and the ground layer group 120 for multiple times, the signal finally passes through the partial reflection layer group 130 and propagates to the frequency selection layer 140. Among them, part of the signal passing through the partial reflection layer group 130 can be radiated outward through the hollow part 141 of the frequency selection layer 140. The outward radiation refers to the signal radiating through the hollow part 141 towards the side of the frequency selection layer 140 away from the partial reflection layer group 130. The other part can be reflected to the partial reflection layer group 130 through the reflection part 142, and after multiple reflections between the reflection part 142 and the partial reflection layer group 130, it finally passes through the partial reflection layer group 130 and is radiated outward through the hollow part 141 after reflection.

[0053] Compared with the scheme for realizing the fixed-frequency beam scanning of the antenna by the liquid crystal material in the related art, the frequency selection layer 140 is arranged on the partial reflection layer group 130 in the embodiment of the application. The phase delay can occur between the signal radiated outward through the hollow part 141 of the frequency selection layer 140 and the signal radiated outward through the hollow part 141 after being reflected by the reflection part 142 and the partial reflection layer group 130. 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 the phase delay can occur multiple times. In this way, the phase change of the entire signal can be amplified, a larger range of phase tuning can be obtained, and thus the antenna structure 100 can realize a larger range of beam scanning and improve the reconfigurable characteristics of the antenna structure 100.

[0054] Continuing to refer to Figure 1 As shown in the figure, the partial reflection layer group 130 can include the first dielectric layer 131, the tuning layer 132 and the second dielectric layer 133 arranged in layers. For example, the first dielectric layer 131 can be arranged on the side of the tuning layer 132 facing the frequency selection layer 140, and the second dielectric layer 133 can be arranged on the side of the tuning layer 132 facing the ground layer group 120. The frequency selection layer 140 can be arranged on the first dielectric layer 131.

[0055] Among them, the relative dielectric constant of the first dielectric layer 131 and the second dielectric layer 133 can be greater than the relative dielectric constant of the tuning layer 132 under the bias voltage. The relative dielectric constant is a physical parameter representing 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 the vacuum.

[0056] For example, a bias voltage can be applied to the tuning layer 132. Under the action of the bias voltage, the relative permittivity of the tuning layer 132 can change, thereby changing the overall electromagnetic parameters of the antenna structure 100, causing the phase and radiation pattern of the antenna structure 100 to change, thus realizing the reconfigurable characteristics of the antenna structure 100.

[0057] 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 partial reflective layer group 130, the relative permittivity of the tuning layer 132 changes under the bias voltage, but its relative permittivity value is always less than the relative permittivity of the first dielectric layer 131 and the second dielectric layer 133.

[0058] For example, a control circuit can be provided in the communication device. The control circuit can be electrically connected to the tuning element to apply a bias voltage to the tuning layer 132 to change the relative permittivity of the tuning layer 132.

[0059] The stacked first dielectric layer 131, tuning layer 132, and second dielectric layer 133 can form a distributed bragg reflector (DBR). The DBR is composed of periodically arranged basic reflective units. By adjusting the relevant parameters of the basic reflective units, such as the material, structural thickness, and refractive index, the reflection at a corresponding frequency can be enhanced to obtain a stronger reflected signal. Specifically, when electromagnetic waves pass through different media, they are reflected at the interface, and the reflectivity is related to the dielectric constant between the media. Therefore, if thin films with different dielectric constants are periodically stacked together, when electromagnetic waves pass through these films with different dielectric constants, the electromagnetic waves reflected back from each layer undergo constructive interference due to the change in phase angle, and then combine together to obtain a strong reflected electromagnetic wave. When the signal is fed in from the feeding structure 110, it 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.

[0060] The partial reflection layer group 130 and the frequency selection layer 140 can form an asymmetric Fabry-Perot cavity structure (FPC for short), and at this time, the first dielectric layer 131 can be regarded as a resonant cavity, and the frequency selection layer 140 and the DBR composed of the tuning layer 132 and the second dielectric layer 133 are asymmetric structures with respect to the first dielectric layer 131. The asymmetric FPC structure has an overcoupling effect, which can make the incident light (or electromagnetic wave signal) reflect back with a very strong phase delay, thereby realizing the amplification of phase change.

[0061] Continuing to refer to Figure 1 As shown, the ground layer group 120 can include a metal floor 121 and a third dielectric layer 122 disposed on the metal floor 121, the feed structure 110 can be electrically connected with the metal floor 121, and the partial reflection layer group 130 can be disposed on the third dielectric layer 122. The metal floor 121 can reflect signals to reflect all signals fed by the feed structure 110 into the partial reflection layer group 130, and after the partial reflection layer group 130 reflects part of the signals back, the metal floor 121 can continue to reflect the reflected signals into the partial reflection layer group 130 again, which can effectively reduce or avoid the signals from being projected outwards of the metal floor 121 (i.e., the side of the metal floor 121 facing away from the partial reflection layer group 130), thereby reducing signal loss and improving the signal radiation efficiency of the antenna structure 100.

[0062] The third dielectric layer 122 can provide space for signal reflection between the partial reflection side and the metal floor 121, and at this time, the third dielectric layer 122 can also be understood as a resonant cavity, and the metal floor 121 is a full reflection surface. According to the mirror theory, the resonant cavity formed between the partial reflection layer group 130 and the metal floor 121 can be equivalent to a symmetric FPC resonant cavity.

[0063] In the embodiments of the present application, continuing to refer to Figure 1 As shown, the thickness of the tuning layer 132 can be L1, and the value of L1 can be an odd multiple of one quarter of the dielectric wavelength of the tuning layer 132. The dielectric wavelength of the tuning layer 132 refers to the wavelength of the signal propagating in the tuning layer 132. For the same electromagnetic wave, the frequency remains unchanged when propagating in different media, but the propagation speed and wavelength change. Compared with the propagation of electromagnetic waves in vacuum, the wavelength of waves propagating in a medium can be obtained by the following formula:

[0064]

[0065] In the formula, λ is the wavelength of the wave propagating in the medium, λ0 is the wavelength of the wave propagating in vacuum, and n is the refractive index of the medium material. From the above formula, it can be deduced that the wavelength of the signal propagating 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 vacuum.

[0066] When the thickness of the tuning layer 132 is an odd multiple of a quarter of the dielectric wavelength, the signal can have higher propagation efficiency when propagating within the tuning layer 132, which can reduce signal loss and help improve the overall radiation efficiency of the antenna structure 100.

[0067] See also Figure 1 As shown, the thickness of the first dielectric layer 131 can be L2, and the value of L2 can 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 at which the signal propagates within the first dielectric layer 131. This allows the signal to have higher propagation efficiency within the first dielectric layer 131, helps to reduce signal loss within the first dielectric layer 131, and thus effectively improves the radiation efficiency of the antenna structure 100.

[0068] See also Figure 1 As shown, the thickness of the second dielectric layer 133 can be L3, and the value of L3 can 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 at which the signal propagates within the second dielectric layer 133. This allows the signal to have higher propagation efficiency within the second dielectric layer 133, helps to reduce signal loss within the second dielectric layer 133, and thus effectively improves the radiation efficiency of the antenna structure 100.

[0069] In this embodiment, the tuning layer 132 can be a liquid crystal layer, a vanadium dioxide layer, a ferrite layer, a graphene layer, or a diode. These materials and devices can exhibit different relative permittivity after a bias voltage is applied, which can change the phase and radiation pattern and other electromagnetic parameters of the antenna structure 100, thereby realizing the reconfigurable characteristics of the antenna structure 100.

[0070] For example, when the tuning layer 132 is 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. By changing the magnitude of the bias voltage, the relative permittivity of the tuning layer 132 can be changed under the influence of the bias voltage. When the tuning layer 132 is 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 permittivity of the tuning layer 132. Specifically, the method of applying the bias voltage can be selected and set according to the configuration of the tuning layer 132.

[0071] The forming material of the first dielectric layer 131 and the second dielectric layer 133 can be alumina. Alumina has a relatively high relative dielectric constant. By being stacked with the tuning layer 132 having a relatively low relative dielectric constant, a dispersive Bragg reflector can be formed, which can make the signal get a stronger reflected signal after passing through part of the reflection group layer, and help to improve the strength of the signal.

[0072] It should be noted that, according to the form of the tuning layer 132, the material of the first dielectric layer 131 and the second dielectric layer 133 can also be different. In order to meet the requirement that the relative dielectric constant of the first dielectric layer 131 and the second dielectric layer 133 is greater than the relative dielectric constant of the tuning layer 132 under the bias voltage. In the specific application process, the forming material of the first dielectric layer 131 and the second dielectric layer 133 can be selected and set according to the setting mode of the tuning layer 132 or the specific application scene.

[0073] The forming material of the third dielectric layer 122 can be Zeonor. Zeonor has a relatively low relative dielectric constant, which is close to the relative dielectric constant of the tuning layer 132. In this way, the signal loss can be reduced during the signal radiation from the third dielectric layer 122 to the tuning layer 132, which is beneficial to improve the radiation efficiency of the antenna structure 100.

[0074] It should be noted that, according to the form of the tuning layer 132, the material of the third dielectric layer 122 can also be different. In order to meet the requirement that the relative dielectric constant of the third dielectric layer 122 is close to the relative dielectric constant of the tuning layer 132, so as to reduce the signal loss and improve the radiation efficiency of the antenna structure 100.

[0075] Figure 2 A structure diagram of a frequency selection layer provided in an embodiment of the present application.

[0076] Referring to Figure 2As shown, in a possible implementation manner, the frequency selection layer 140 can include a plurality of array-arranged metal patches, and gaps between adjacent two metal patches. Among them, the metal patches can form the reflection part 142 of the frequency selection layer 140, and the gaps can form the hollow part 141 of the frequency selection layer 140. For example, the metal patches can be attached on the first dielectric layer 131 of the partial reflection layer group 130 by bonding, clamping or buckling and the like. For example, the metal patches can be arranged in a rectangular array in the form of M rows and N columns, where the values of M and N can both be greater than or equal to 2. Alternatively, in some examples, the metal patches can also be arranged in other array forms, for example, the metal patches can be arranged in an array along a circular, triangular or the like. Specifically, the arrangement manner of the metal patches can be selected and set according to the shape of the antenna structure 100, the shape of the metal patches and the specific application scenario.

[0077] When the signal propagates from the partial reflection layer group 130 to the frequency selection layer 140, part of the signal can be radiated outward through the gaps between the metal patches, and another part of the signal can be reflected to the partial reflection layer group 130 through the metal patches, and then reflected to the gaps again through the partial reflection layer group 130, so as to be radiated outward through the gaps, thereby amplifying the phase change of signal radiation.

[0078] Among them, 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 plurality of metal patches can all be the same, being a rectangle, a circle, a triangle or a trapezoid and the like. Alternatively, in some examples, the shapes of the metal patches can also be different, for example, a part of the metal patches can have one shape, and another part of the metal patches can have another different shape.

[0079] By flexibly setting the shape and arrangement manner of the metal patches, the reflection part 142 and the hollow part 141 of different structural forms can be obtained, which is helpful for optimizing the structural parameters of the frequency selection layer 140, effectively improving the strength of the over-coupling effect of the asymmetric FPC structure, enhancing 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.

[0080] Figure 3 Another structural schematic diagram of a frequency selection layer provided by an embodiment of the present application.

[0081] Alternatively, in another possible implementation manner, referring to Figure 3 As shown, the frequency selection layer 140 can include a metal layer, and a plurality of array-arranged through holes can be formed on the metal layer, wherein the through holes can form the hollow part 141, and the metal layer other than the through holes can form the reflection part 142. For example, the through holes can be formed on the metal layer by laser cutting or the like.

[0082] For example, the through holes can also be arranged in a rectangular array in M rows by N columns, where M and N can each be greater than or equal to 2. Alternatively, in some examples, the through holes can also be arranged in other array manners according to different shapes of the metal layer, for example, the through holes can be arranged in a circular, triangular, or other form. Specifically, the arrangement manner of the through holes can be selected and set according to the shape of the antenna structure 100, the shape of the metal layer, and the specific application scenario.

[0083] When the signal propagates from the partially reflective layer group 130 to the frequency selective layer 140, part of the signal can be radiated outward through the through holes, and another part of the signal can be reflected to the partially reflective layer group 130 through the metal layer other than the through holes, and then reflected to the through holes again through the partially reflective layer group 130 to be radiated outward through the through holes, thereby amplifying the phase change of signal radiation.

[0084] The shape of the through hole can also be at least one of a rectangle, a circle, a triangle, or a trapezoid. For example, the through holes on the metal layer can all have the same shape, and the through holes can be arranged in a rectangular array, a circular array, or a triangular array. Alternatively, in some examples, the through holes can also be combined in different shapes, for example, part of the through holes can have a rectangular shape, and part of the through holes can have a circular shape. Alternatively, part of the through holes can have a circular shape, and part of the through holes can have a triangular shape. Specifically, the shape of each through hole can be selected and set according to the specific application scenario.

[0085] By opening through holes with different shapes and sizes on the metal layer, the hollow part 141 and the reflection part 142 with different structural forms can be obtained, the structural parameters of the frequency selective layer 140 can be optimized, the overcoupling effect strength of the asymmetric FPC structure can be improved, the influence of the phase change generated by the tuning layer 132 under different bias voltages can be enhanced, and thus the beam scanning range of the antenna structure 100 can be effectively improved.

[0086] The forming material of the reflection part 142 can be at least one of gold, copper, or aluminum. For example, the reflection part 142 can be a structural member made of any of the above materials, or the radiator can also be a structural member mixed from any two or more of the above materials. The above materials have good electrical conductivity, which helps to improve the reflection efficiency of the frequency selective layer 140 to the signal and improve the radiation efficiency of the antenna structure 100 to the signal.

[0087] Figure 4 Another structural schematic diagram of an antenna structure provided by an embodiment of the present application.

[0088] In one possible implementation manner, referring to Figure 4As shown, the partial reflection layer group 130 can include a plurality of tuning layers 132 and a plurality of second dielectric layers 133, which can be interleaved between the first dielectric layer 131 and the ground layer group 120. For example, referring to Figure 4 As shown, the number of tuning layers 132 and second dielectric layers 133 can each be three layers, and the three layers of tuning layers 132 and the three layers of second dielectric layers 133 can be interleaved and stacked between the first dielectric layer 131 and the ground layer group 120. By increasing the number of layers of tuning layers 132 and second dielectric layers 133, the tuning ability of the tuning layers 132 to the beam scanning range can be effectively improved, so that the antenna structure 100 can achieve a larger range of phase control, thereby enabling the antenna structure 100 to achieve a larger range of beam scanning, and effectively improving the beam scanning range of the antenna structure 100.

[0089] The beam scanning performance of the antenna structure 100 provided by the embodiments of the present application is verified below in combination with the drawings. The experiment is performed on the structure in which the number of layers of tuning layers 132 and second dielectric layers 133 is one (i.e., the structure in Figure 1

[0090] Figure 5 A transmission line model diagram of an antenna structure provided by the embodiments of the present application.

[0091] First, the antenna structure 100 is equivalent to the transmission line model shown in Figure 5 by 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:

[0092] Y0+Y FSS +Y TL (Y H ,Y LC ,Y sub )=0

[0093] In the formula, Y0is the admittance corresponding to the free space wave, which is usually 1 / 377, 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, and Y sub is the admittance corresponding to the ground layer group 120, and the above values are related to the propagation constant of the antenna structure 100 in the leaky mode. Y TL (Y H , Y LC , Y sub ) is the admittance corresponding to the short-circuit transmission line, which can be calculated by the transmission line theory.

[0094] ​The above equation is a transcendental equation with the propagation constant of the leaky mode generated by the antenna structure 100 as the unknown, which can be solved iteratively according to the Muller root-finding or Pade root-finding method to obtain the admittance value of the frequency selective layer 140, so as to obtain good impedance matching. According to the admittance value of the frequency selective layer 140, the structure of the frequency selective layer 140 satisfying the admittance value can be designed, for example, after the admittance value of the frequency selective layer 140 is obtained, the size of the reflecting part 142 and the hollow part 141 in the frequency selective layer 140 can be calculated according to the admittance value. In this example, the reflecting part 142 is taken as a square metal patch, and the following parameters are selected for testing after calculation.

[0095]

[0096] wherein the total height L of the antenna (refer to Figure 1 ) is the distance between the upper surface of the frequency selective layer 140 and the lower surface of the metal floor 121 in the antenna structure 100. The thickness L4 of the ground layer group 120 (refer to Figure 1 ) is the sum of the thicknesses of the metal floor 121 and the third dielectric layer 122. The width d1 of the reflecting part 142 (refer to Figure 2 ) is the side length of the square metal patch. The width d2 of the hollow part 141 (refer to Figure 2 ) is the gap width between two adjacent square metal patches. By inputting the above parameters into the simulation software, the dispersion characteristic simulation curve of the antenna structure 100 can be obtained.

[0097] Figure 6 is a dispersion characteristic simulation diagram of an antenna structure provided by an embodiment of the present application.

[0098] Referring to Figure 6 , it can be seen that Figure 6 is a dispersion characteristic simulation curve diagram of the antenna structure 100 when the antenna structure 100 is in the structure shown in Figure 1 , that is, after the frequency selective layer 140 is arranged in the antenna structure 100. Figure 6 The abscissa in is the normalized frequency f / f0, and the ordinate is a / k0 or b / k0, wherein a is the attenuation constant, b is the phase constant, and k0 is the free space wave number. In order to facilitate comparison, the abscissa in the figure is normalized, f is the working frequency, and f0 is the best working frequency when the phase constant b is equal to the attenuation constant a when the bias voltage is 0V, at which time the antenna has the maximum gain. Figure 6Curve 1 in the diagram represents the ratio of the phase constant β to the free space wavenumber k0 (β / k0) when the bias voltage is 0. Curve 2 represents the ratio of the attenuation constant α to the free space wavenumber k0 (α / k0) when the bias voltage is 0. Curve 3 represents the ratio of the phase constant β to the free space wavenumber k0 when the bias voltage is 15V. Curve 4 represents the ratio of the attenuation constant α to the free space wavenumber k0 when the bias voltage is 15V.

[0099] from Figure 6 From curves 1 and 2, we can conclude that when the normalized frequency is 1 and the bias voltage on the tuning layer 132 is 0, as mentioned earlier, 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 theory of leaky wave antennas, the beam pointing angle θ of the antenna structure 100 is 0 degrees.

[0100] from Figure 6 Curves 3 and 4 show that when the normalized frequency is 1 and the bias voltage on the tuning layer 132 is 15V, the values ​​of α / k0 and β / k0 on the horizontal axis differ significantly, with β / k0 being much larger than α / k0, i.e., β >> α. At this point, according to leaky-wave antenna theory, the beam pointing angle θ satisfies the following formula:

[0101] sinθ=β / k0

[0102] According to the inverse trigonometric function, we can derive: θ = sin -1 β / k0

[0103] From curve 3 in the figure, we can deduce that the value of β / k0 is approximately 0.46, and therefore the beam pointing angle θ is approximately 27.5 degrees. Thus, it can be seen that when the bias voltage increases from 0V to 15V, the beam pointing θ of the antenna structure 100 changes from 0 degrees to 27.5 degrees, meaning the beam scanning range of the antenna structure 100 is 27.5 degrees.

[0104] Figure 7 This is a dispersion simulation diagram of the antenna structure when no frequency selection layer is set in the relevant technology.

[0105] See Figure 7 As shown, Figure 7 The simulation curves show the dispersion characteristics of the antenna structure without a frequency selection layer of 140. Figure 7 Curve 1 in the diagram represents the ratio of the phase constant β to the free space wavenumber k0 (β / k0) when the bias voltage is 0. Curve 2 represents the ratio of the attenuation constant α to the free space wavenumber k0 (α / k0) when the bias voltage is 0. Curve 3 represents the ratio of the phase constant β to the free space wavenumber k0 when the bias voltage is 15V. Curve 4 represents the ratio of the attenuation constant α to the free space wavenumber k0 when the bias voltage is 15V.

[0106] from Figure 7 From curves 1 and 2, we can conclude 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 theory of leaky wave antenna, the beam pointing angle θ of the antenna structure 100 is 0 degrees.

[0107] 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 α / k0 and β / k0 on the horizontal axis differ significantly, with β / k0 being much larger than α / k0, i.e., β >> α. At this point, according to leaky-wave antenna theory, the beam pointing angle θ satisfies the following formula:

[0108] sinθ=β / k0

[0109] At this point, the beam pointing angle θ can be obtained using the inverse trigonometric function. From curve 3 in the figure, the value of β / k0 is approximately 0.33, therefore the beam pointing angle θ is approximately 19.5 degrees. Thus, 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 selection layer 140 changes from 0 degrees to 19.5 degrees, meaning the beam scanning range of the antenna structure 100 without the frequency selection layer 140 is 19.5 degrees.

[0110] The experimental results show that, compared with the antenna structure without a frequency selection layer, after setting the frequency selection layer 140 in the antenna structure 100, the beam scanning range of the antenna structure 100 increased from 19.5 degrees to 27.5 degrees, which is 8 degrees. The beam scanning range has been significantly increased, effectively improving the beam scanning effect of the antenna structure 100.

[0111] The radiation pattern of antenna structure 100 is simulated below with reference to the attached figures.

[0112] Figure 8 The antenna structure provided in the embodiments of this application is a radiation pattern of the antenna structure in the related art.

[0113] See Figure 8 As shown, Figure 8 The horizontal axis represents the beam pointing angle, and the vertical axis represents the direction factor. Figure 8Curve 1 is the directional diagram curve of the antenna structure 100 when the frequency selective layer 140 is arranged and the bias voltage is 0V. Curve 2 is the directional diagram curve of the antenna structure 100 when the frequency selective layer 140 is arranged and the bias voltage is 15V. Curve 3 is the directional diagram curve of the antenna structure 100 when the frequency selective layer 140 is not arranged and the bias voltage is 0V. Curve 4 is the directional diagram curve of the antenna structure 100 when the frequency selective layer 140 is not arranged and the bias voltage is 15V.

[0114] When the directional coefficient reaches the maximum value, the value corresponding to the abscissa is the beam pointing angle of the antenna structure 100. From the curve 1 and the curve 2 in the Figure 8 , it can be concluded that when the frequency selective layer 140 is arranged in the antenna structure 100, the beam pointing angle of the antenna structure 100 is 0 degree when the bias voltage is 0V, and the beam pointing angle of the antenna structure 100 is about 27.7 degrees when the bias voltage is 15V, which is close to the degree 27.5 degrees of the beam pointing angle obtained by the experiment of the dispersion simulation diagram (i.e. Figure 6 ) described above. From the curve 3 and the curve 4, it can be concluded that when the frequency selective layer 140 is not arranged in the antenna structure 100, the beam pointing angle of the antenna structure 100 is 0 degree when the bias voltage is 0V, and the beam pointing angle of the antenna structure 100 is about 20.8 degrees when the bias voltage is 15V, which is close to the degree 19.5 degrees of the beam pointing angle obtained by the experiment of the dispersion simulation diagram (i.e. Figure 7 ) described above.

[0115] It can be concluded from the experimental results that compared with the antenna structure 100 without the frequency selective layer 140, the beam scanning range of the antenna structure 100 is increased from 20.8 degrees to 27.7 degrees after the frequency selective layer 140 is arranged in the antenna structure 100, that is, the beam scanning range of the antenna structure 100 is increased by 6.9 degrees, and the beam scanning range is obviously increased, which effectively increases the beam scanning effect of the antenna structure 100, which is consistent with the conclusion obtained by the experiment of the dispersion simulation diagram.

[0116] The directional diagram of the antenna structure 100 when the tuning layer 132 and the second dielectric layer 133 are both three layers is simulated and tested as follows in combination with the drawings.

[0117] Figure 9 Another antenna structure provided by the embodiment of the present application and the directional diagram of the antenna structure in the related art.

[0118] Referring to FIG. 1, Figure 9 , the directional diagram of the antenna structure 100 when the tuning layer 132 and the second dielectric layer 133 are both three layers is simulated and tested as follows in combination with the drawings. Figure 9Curve 1 is the directional diagram of the antenna structure 100 when the frequency selective layer 140 is provided and the bias voltage is 0 V. Curve 2 is the directional diagram of the antenna structure 100 when the frequency selective layer 140 is provided and the bias voltage is 15 V. Curve 3 is the directional diagram of the antenna structure 100 when the frequency selective layer 140 is not provided and the bias voltage is 0 V. Curve 4 is the directional diagram of the antenna structure 100 when the frequency selective layer 140 is not provided and the bias voltage is 15 V.

[0119] When the directional coefficient reaches the maximum value, the value corresponding to the abscissa is the beam pointing angle of the antenna structure 100. From Figure 9 It can be seen from Curve 1 and Curve 2 in FIG. 1 that when the frequency selective layer 140 is provided, the beam pointing angle of the antenna structure 100 is 0 degree when the bias voltage is 0 V. When the bias voltage is 15 V, the beam pointing angle of the antenna structure 100 is about 34.6 degrees. It can be seen from Curve 3 and Curve 4 that when the frequency selective layer 140 is not provided, the beam pointing angle of the antenna structure 100 is 0 degree when the bias voltage is 0 V. When the bias voltage is 15 V, the beam pointing angle of the antenna structure 100 is about 26.7 degrees.

[0120] It can be seen from the experimental results that when the number of layers of the tuning layer 132 and the second dielectric layer 133 is three, compared with the antenna structure 100 without the frequency selective layer 140, the beam scanning range of the antenna structure 100 is increased from 26.7 degrees to 34.6 degrees after the frequency selective layer 140 is provided in the antenna structure 100, the beam scanning range of the antenna structure 100 is increased by 7.9 degrees, the beam scanning range is obviously increased, and the beam scanning effect of the antenna structure 100 is effectively increased.

[0121] In addition, the comparison between Figure 8 and Figure 9 shows that when the number of layers of the tuning layer 132 and the second dielectric layer 133 is one, the beam scanning range of the antenna structure 100 is 27.7 degrees after the frequency selective layer 140 is provided. When the number of layers of the tuning layer 132 and the second dielectric layer 133 is increased and the frequency selective layer 140 is not provided, the beam scanning range of the antenna structure 100 is 26.7 degrees. It is shown that compared with the method of increasing the beam scanning range by increasing the tuning layer 132 and the second dielectric layer 133, the method of setting the frequency selective layer 140 can increase the beam scanning range more and has a better phase amplification effect. Moreover, the thickness of the antenna structure 100 can be effectively reduced, which is beneficial to the miniaturization design of the antenna structure 100.

[0122] The embodiment of the present application further provides a communication device, which can include the antenna structure 100 in any of the above scenarios, and can be a communication base station platform feed system, a millimeter wave radar, a smart home, etc. By making the communication device include the antenna structure 100, the space occupied by the antenna structure 100 in the communication device can be effectively reduced, the rationality of the layout of the antenna structure 100 in the communication device is improved, and the miniaturization design of the communication device is facilitated. Moreover, the production difficulty and cost of the communication device are also reduced.

[0123] In the description of the embodiments of the present application, it should be explained that, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connection" should be understood in a broad sense, for example, can be fixed connection, can be indirectly connected through an intermediate medium, can be the internal communication of two elements or the interaction relationship of two elements. For those skilled in the art, the specific meaning 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" and the like (if any) are used to distinguish similar objects, and do not necessarily be used to describe a specific order or sequence.

[0124] Finally, it should be pointed out that: the above embodiments are only used to illustrate the technical solutions of the embodiments of the present application, and not to limit them; although the embodiments of the present application have been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. An antenna structure, characterized by The antenna structure comprises a feeding structure, a ground layer group, a partial reflection layer group and a frequency selection layer which are arranged in layers; The feeding structure is electrically connected with the ground layer group, and the partial reflection layer group is arranged between the ground layer group and the frequency selection layer; The ground layer group is configured to reflect signals, and the partial reflection layer group is configured to allow part of the signals to pass through and reflect the rest of the signals; The frequency selection layer comprises a hollow part and a reflection part, the hollow part is configured to allow signals to pass through, and the reflection part is configured to reflect signals; The partial reflection layer group comprises a tuning layer, and the tuning layer is configured to change relative permittivity under the action of an applied bias voltage.

2. The antenna structure of claim 1, wherein, The partial reflection layer group further comprises a first dielectric layer and a second dielectric layer, the first dielectric layer, the tuning layer and the second dielectric layer are arranged in layers in sequence, and the frequency selection layer is arranged on the first dielectric layer; The relative permittivity of the first dielectric layer and the second dielectric layer is greater than the relative permittivity of the tuning layer under the bias voltage.

3. The antenna structure of claim 1 or 2, wherein, The frequency selection layer comprises a plurality of arrayed metal patches, and adjacent two metal patches have a gap therebetween; The metal patches form the reflection part, and the gap forms the hollow part.

4. The antenna structure of claim 1 or 2, wherein, The frequency selection layer comprises a metal layer, and a plurality of arrayed through holes are formed in the metal layer; The through holes form the hollow part, and the metal layer other than the through holes forms the reflection part.

5. The antenna structure of any one of claims 1 to 4, wherein, The ground layer group comprises a metal ground plate and a third dielectric layer arranged on the metal ground plate; The feeding structure is electrically connected with the metal ground plate, and the partial reflection layer group is arranged on the third dielectric layer.

6. The antenna structure of claim 2, wherein, The partial reflection layer group comprises a plurality of tuning layers and a plurality of second dielectric layers; The plurality of tuning layers and the plurality of second dielectric layers are arranged in layers in sequence between the first dielectric layer and the ground layer group.

7. The antenna structure of claim 2 or 6, wherein, The tuning layer is a liquid crystal layer, a vanadium dioxide layer, a ferrite layer, a graphene layer or a diode layer.

8. An antenna structure according to any one of claims 2, 6 or 7, characterised in that, The first dielectric layer and the second dielectric layer are made of alumina.

9. The antenna structure of any of claims 1 to 8, wherein, The reflection part is made of at least one of gold, copper and aluminum.

10. The antenna structure of claim 5, wherein, The third dielectric layer is made of cyclic olefin copolymer.

11. The antenna structure of claim 3, wherein, The shape of the metal patch is at least one of a rectangle, a circle, a triangle and a trapezoid.

12. The antenna structure of claim 4, wherein, The shape of the through hole is at least one of a rectangle, a circle, a triangle and a trapezoid.

13. The antenna structure of any of claims 2, 6-8, wherein, The thickness of the tuning layer is an odd multiple of one quarter of the dielectric wavelength of the tuning layer, and the dielectric wavelength of the tuning layer is the wavelength of the signal propagating in the tuning layer.

14. The antenna structure of any one of claims 2, 6-8, wherein, 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 the dielectric wavelength of the second dielectric layer, and the dielectric wavelength of the second dielectric layer is the wavelength of the signal propagating in the second dielectric layer.

15. A communications device, characterized by The antenna structure comprises the antenna structure of any one of claims 1 to 14.

16. The communication apparatus according to claim 15, wherein The communication device further comprises a control circuit, and the control circuit is electrically connected with the tuning layer in the antenna structure; The control circuit is configured to apply a bias voltage to the tuning layer.

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