Dielectric plate, frequency selective surface, rear cover and electronic equipment

Abstract

The invention provides a dielectric plate, a frequency selection surface, a rear cover and electronic equipment, the dielectric plate comprises a first dielectric layer and a second dielectric layer which are stacked in a first direction, and the second dielectric layer comprises a plurality of dielectric units which are arranged at intervals. The gaps among the dielectric units can be filled with air, so that the air is mixed into the dielectric plate, and the overall effective dielectric constant of the dielectric plate is reduced. Compared with an existing scheme that the whole dielectric plate is of a solid plate-shaped structure, under the condition that it is guaranteed that the materials and the thickness of the dielectric plate are the same, the effective dielectric constant of the whole dielectric plate is reduced, wave impedance matching of the dielectric plate and air is facilitated, loss of electromagnetic waves in the dielectric plate is reduced, the transmission effect is better, and the service life of the dielectric plate is prolonged. The transmission coefficient of the dielectric plate is improved, so that the efficient transmission bandwidth can be further increased, the radiation performance of the antenna is improved, and the millimeter wave antenna is applied to electronic equipment with a high-dielectric-constant rear cover on the premise of ensuring the radiation performance.

Description

Technical Field

[0001] The present application relates to the field of communication technology, and in particular to a dielectric board, a frequency selective surface, a back cover and an electronic device. Background Art

[0002] 5G communication has the characteristics of high speed, low latency, and low bit error rate. With the commercialization and deployment of 5G communication systems, the millimeter wave band has gradually become the future of mobile communication technology due to its higher data transmission energy. In electronic devices with mobile communication functions such as mobile phones, the antenna is the only device for receiving signals. It is also the forefront of electronic devices and an important part of 5G mobile communications.

[0003] Current mobile phones and other terminals all have a shell with a certain physical strength, such as a glass back cover. However, this shell usually has a high dielectric constant and poor transmission performance, which will produce strong reflection and blocking effects on electromagnetic waves working in the millimeter wave band, causing large insertion losses for electronic devices, resulting in deterioration of the radiation performance of antennas (especially millimeter wave antennas) and narrow high-efficiency transmission bandwidth. Therefore, it is still a challenge to apply millimeter wave antennas under the back cover of electronic devices with high dielectric constants and maintain the original radiation performance.

[0004] It can be seen that in the prior art, the back cover of electronic devices made of high dielectric constant materials has poor transmission performance and a narrow high-efficiency transmission bandwidth, which leads to a decrease in antenna radiation performance and makes it difficult to apply millimeter wave antennas under the back cover of electronic devices with high dielectric constants. Summary of the invention

[0005] The dielectric plate, frequency selective surface, back cover and electronic device provided in the embodiments of the present application solve the problems in the prior art that the back cover of electronic devices made of high dielectric constant materials has poor transmission performance, narrow high-efficiency transmission bandwidth, resulting in reduced antenna radiation performance, and difficulty in applying millimeter wave antennas under the cover of electronic devices with high dielectric constants.

[0006] An embodiment of the present application provides a dielectric plate, comprising a first dielectric layer and a second dielectric layer stacked in a first direction, wherein the second dielectric layer comprises a plurality of dielectric units spaced apart from each other.

[0007] The dielectric plate provided in the embodiment of the present application can be used as a back cover of an electronic device, or integrated into the back cover of an electronic device. The first dielectric layer and the second dielectric layer are stacked, and the dielectric units in the second dielectric layer are spaced apart, which can be understood as: there are gaps between the multiple dielectric units in the second dielectric layer, and the first dielectric layer provides support for the multiple dielectric units in the second dielectric layer.

[0008] With this structure, part of the dielectric in the dielectric plate is removed (for example, the second dielectric layer is grooved, etc.) to form a gap between the dielectric units. The gap can be filled with air, so that the air is mixed into the dielectric plate. Since the dielectric constant of air is less than the dielectric constant of the dielectric plate itself, the equivalent dielectric constant of the dielectric plate as a whole is reduced. Therefore, compared with the solution in the prior art in which the dielectric plate is set as a solid plate structure as a whole, while ensuring that the material and thickness of the dielectric plate are the same, the equivalent dielectric constant of the dielectric plate as a whole in the present application is reduced, which is conducive to the wave impedance matching between the dielectric plate and the air. In addition, the reduction in relative dielectric constant can reduce the surface waves excited by the dielectric plate, and the surface groove treatment also has an inhibitory effect on the surface waves. Taking the above factors into consideration, the loss of electromagnetic waves in the dielectric plate will be reduced, the transmission effect will be better, and the transmission coefficient of the dielectric plate will be improved, thereby further increasing the bandwidth of efficient transmission and improving the radiation performance of the antenna. In particular, when the millimeter wave antenna is set below the back cover with a high dielectric constant, good radiation performance can also be guaranteed.

[0009] Therefore, the dielectric plate provided in the present application has a higher transmission coefficient, which can increase the bandwidth of the antenna's efficient transmission, and realize the application of millimeter wave antennas in electronic devices with a high dielectric constant back cover while ensuring radiation performance.

[0010] In some embodiments, at least a portion of the outer peripheral surface of each of the plurality of dielectric units is configured as a first transmission surface. The first transmission surface of each dielectric unit has a first end and a second end, and in a first direction, the second end is located between the first end and the first dielectric layer, and in a plane perpendicular to the first direction, the second end is located between the first end and an adjacent dielectric unit.

[0011] By adopting the above scheme, when there is a first transmission surface in the dielectric unit, there is an angle between the first transmission surface and the plane perpendicular to the first direction, and the electromagnetic wave emitted by the antenna is radiated onto the inclined first transmission surface, which changes the incident angle of the electromagnetic wave, that is, changes the boundary conditions of the incident field, so that the surface wave excitation of the dielectric plate changes, suppresses the propagation of the surface wave, and further improves the transmission effect of the dielectric plate.

[0012] In some embodiments, from the first end to the second end, the first transmission surface as a whole gradually extends toward the adjacent dielectric unit along a direction inclined to the first direction to form an outward expansion surface.

[0013] By adopting the above solution, the utilization rate of the surface of the medium unit can be improved.

[0014] In some embodiments, each dielectric unit is configured as a prism-shaped structure or a pyramid-shaped structure, the entire outer peripheral surface of the prism-shaped structure or the pyramid-shaped structure is configured as a first transmission surface, and the second end of the first transmission surface is located on the first surface of the first dielectric layer, wherein the first surface of the first dielectric layer faces the second dielectric layer.

[0015] By adopting the above solution, the utilization rate of the surface of the dielectric unit can be improved. When an antenna is arranged under the dielectric unit, the electromagnetic wave can irradiate any position of the first transmission surface.

[0016] In some embodiments, in each pyramid-shaped structure, the first end of the first transmission surface constitutes the tip of the pyramid-shaped structure. Each prism-shaped structure has a first bottom surface and a second bottom surface that are arranged opposite to each other and parallel in a first direction, the first bottom surface is connected to the first end of the first transmission surface and is configured as the second transmission surface, the second transmission surface is parallel to the first surface of the first dielectric layer, the second bottom surface is connected to the second end of the first transmission surface, and a portion of the first surface of the first dielectric layer constitutes the second bottom surface.

[0017] The first surface of the first dielectric layer is perpendicular to the first direction, and the angle between the first transmission surface of each prism-shaped structure and the first surface of the first dielectric layer is 25° to 60°, so that the transmission effect of the dielectric plate is optimal.

[0018] In some embodiments, the first bottom surface and the second bottom surface are both square, and the side length of the first bottom surface is p 1 , the side length of the second base is p 2 , 0 <p 1 / p 2 ≤1 / 2, so that the transmission effect of the dielectric plate is optimal.

[0019] In some embodiments, each dielectric unit is configured as a conical structure or a truncated cone structure, the entire outer circumference of each conical structure or truncated cone structure is configured as a first transmission surface, and the second end of the first transmission surface is located on the first surface of the first dielectric layer, wherein the first surface of the first dielectric layer faces the second dielectric layer.

[0020] By adopting the above solution, the utilization rate of the surface of the dielectric unit can be improved. When an antenna is arranged under the dielectric unit, the electromagnetic wave can irradiate any position of the first transmission surface.

[0021] In some embodiments, in the conical structure, the first end of the first transmission surface constitutes the tip of the conical structure. Each truncated cone structure has a first bottom surface and a second bottom surface that are arranged opposite to each other and parallel in the first direction, the first bottom surface is connected to the first end of the first transmission surface and is configured as the second transmission surface, the second transmission surface is parallel to the first surface of the first dielectric layer, the second bottom surface is connected to the second end of the first transmission surface, and a portion of the first surface of the first dielectric layer constitutes the second bottom surface. The radius of the first bottom surface is r1 , the radius of the second base is r 2 , 0 <r 1 / r 2 ≤1 / 2, so that the transmission effect of the dielectric plate is optimal.

[0022] In some embodiments, each dielectric unit is configured as a spherical structure, and the spherical surface of each spherical structure as a whole constitutes the outer peripheral surface of the dielectric unit and is configured as a first transmission surface.

[0023] By adopting the above solution, the utilization rate of the surface of the dielectric unit can be improved. When an antenna is arranged under the dielectric unit, the electromagnetic wave can irradiate any position of the first transmission surface.

[0024] In some embodiments, the diameter of each spherical structure is D, and the thickness of the second dielectric layer is h. 2 , 1 / 2≤h 2 / D≤2 / 3, so that the transmission effect of the dielectric plate 100 is optimal.

[0025] In some embodiments, the thickness of the first dielectric layer is h 1 , the thickness of the second dielectric layer is h 2 , 0 <h 1 / h 2 ≤1 / 3.

[0026] The second dielectric layer is a practical layer for reducing the dielectric constant of the dielectric plate and suppressing surface light waves. By adopting the above solution, the second dielectric layer accounts for a higher proportion in the dielectric plate than the first dielectric layer, which is more beneficial to the overall transmission effect of the dielectric plate.

[0027] In some embodiments, the sum of the thickness of the first dielectric layer and the second dielectric layer is 0.6 mm to 1 mm.

[0028] In some embodiments, the first dielectric layer and the second dielectric layer are an integrated structure, which can simplify the processing steps and facilitate production.

[0029] In some embodiments, the dielectric constant of the dielectric plate is 3-10.

[0030] In some embodiments, the dielectric plate is made of glass to meet the production requirements of applying the millimeter wave antenna under the glass back cover of the electronic device.

[0031] In some embodiments, the plurality of dielectric units are distributed in an array in the second direction and the third direction on a surface of the first dielectric layer facing the second dielectric layer, wherein the first direction, the second direction, and the third direction are perpendicular to each other.

[0032] The embodiment of the present application also provides a frequency selective surface, including a metal layer and a dielectric plate provided by any of the above embodiments. The advantages of the dielectric plate such as high transmittance are combined with the spatial filtering performance of the metal layer to obtain a frequency selective surface with excellent performance, which can effectively control the reflection and transmission of electromagnetic waves, and can exhibit obvious bandpass or bandstop filtering characteristics when interacting with electromagnetic waves.

[0033] In some embodiments, the metal layer is attached to the surface of the first dielectric layer facing the second dielectric layer and embedded between multiple dielectric units of the second dielectric layer. The metal layer surrounds the outer periphery of each dielectric unit to improve space utilization in the second dielectric layer.

[0034] In some embodiments, the metal layer is configured as a grid structure and includes a plurality of metal units arranged in an array on a surface of the first dielectric layer facing the second dielectric layer, the plurality of metal units corresponding one-to-one to the plurality of dielectric units, and each of the plurality of metal units surrounds the outer peripheral side of the corresponding dielectric unit.

[0035] In some embodiments, the orthographic projections of the plurality of dielectric units and the plurality of metal units on the first dielectric layer along the first direction cover the entire first dielectric layer. There is no gap between each dielectric unit and the surrounding metal units, which can maximize area utilization.

[0036] The embodiment of the present application also provides a back cover for an electronic device, including the dielectric plate or frequency selective surface provided by any of the above embodiments. The portion of the back cover corresponding to the antenna has a higher transmission coefficient, which can increase the bandwidth of the antenna's efficient transmission, and when the antenna is set as a millimeter wave antenna, the radiation performance of the antenna can be guaranteed.

[0037] An embodiment of the present application also provides an electronic device, including a shell, wherein the shell includes a back cover, which can increase the bandwidth of the antenna's efficient transmission and ensure the radiation performance of the millimeter wave antenna.

[0038] In some embodiments, the electronic device also includes an antenna, which is housed in the shell, and in a plane perpendicular to the first direction, the antenna is arranged corresponding to the central area of ​​the dielectric plate so that the dielectric plate is located within the effective radiation range of the antenna to the greatest extent, thereby improving the transmission effect of the antenna. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1a-1b Schematic diagrams of the structures of dielectric plates and millimeter wave antennas in some solutions;

[0040] Figure 2a Reflection curves obtained for simulation analysis of dielectric plates and millimeter wave antennas in some solutions;

[0041] Figure 2b-Figure 2cThe directional diagram obtained by simulating the effect of the dielectric plate and the millimeter wave antenna, where: Figure 2b is the orientation diagram of the y'z' plane, Figure 2c is the orientation diagram of the x'z' plane;

[0042] Figure 3a This is a schematic diagram of the structure of an electronic device according to an embodiment of the present application;

[0043] Figure 3b This is a schematic diagram of the structure of another implementation of the electronic device of the embodiment of the present application;

[0044] Figure 4 This is a schematic diagram of the three-dimensional structure of the dielectric plate of the embodiment of the present application;

[0045] Figure 5 This is a schematic diagram of the planar structure of the dielectric plate of the embodiment of the present application;

[0046] Figure 6a-6h This is a schematic diagram of the structure of a dielectric unit in a dielectric plate in an embodiment of the present application;

[0047] Figure 7 This is a schematic diagram of the arrangement of adjacent dielectric units in a dielectric plate according to an embodiment of the present application;

[0048] Figure 8a-8d This is a schematic structural diagram of a first implementation of a dielectric unit in a dielectric plate in an embodiment of the present application, wherein: Figure 8d for Figure 8b Sectional view in the AA direction;

[0049] Fig. 9 This is a schematic structural diagram of a second implementation of a dielectric unit in a dielectric plate in an embodiment of the present application;

[0050] Figure 10a-Figure 10b This is a schematic structural diagram of a third implementation mode of a dielectric unit in a dielectric plate according to an embodiment of the present application;

[0051] Fig.11 This is a schematic structural diagram of a fourth implementation mode of a dielectric unit in a dielectric plate according to an embodiment of the present application;

[0052] Fig.12a This is a schematic structural diagram of a fifth implementation mode of a dielectric unit in a dielectric plate according to an embodiment of the present application;

[0053] Figure 12b This is a structural schematic diagram of a sixth implementation mode of a dielectric unit in a dielectric plate in an embodiment of the present application;

[0054] Fig.13 This is a schematic diagram of the structure of the frequency selective surface according to an embodiment of the present application;

[0055] Fig.14This is a schematic diagram of the structure of the metal layer in the frequency selective surface of an embodiment of the present application;

[0056] Figure 15a-Figure 15d This is a schematic structural diagram of a first implementation of an FSS unit in a frequency selective surface according to an embodiment of the present application, wherein: Fig.15c for Fig.15a Cross-sectional view along the BB direction, Fig.15d for Fig.15c A partial enlarged view of part C in the middle;

[0057] Fig.16 This is a schematic structural diagram of a first implementation mode of a metal unit in a frequency selective surface according to an embodiment of the present application;

[0058] Fig.17a This is a schematic structural diagram of a second implementation of a metal unit in a frequency selective surface according to an embodiment of the present application;

[0059] Fig.17b This is a schematic structural diagram of a third implementation mode of a metal unit in a frequency selective surface according to an embodiment of the present application;

[0060] Fig.18 A transmission coefficient curve obtained by analyzing the simulation effect of the frequency selective surface of the embodiment of the present application;

[0061] Fig.19a This is a schematic structural diagram of a second implementation of an FSS unit in a frequency selective surface according to an embodiment of the present application;

[0062] Fig.19b It is a structural schematic diagram of a third implementation mode of the FSS unit in the frequency selective surface of the embodiment of the present application;

[0063] Fig. 20 This is a transmission coefficient curve obtained by analyzing the simulation effect of the frequency selective surface of the present application.

[0064] Description of reference numerals:

[0065] Existing technology:

[0066] 100': medium board;

[0067] 200': Antenna.

[0068] This application:

[0069] 100: dielectric plate;

[0070] 1: first dielectric layer; 11: first surface;

[0071] 2: second dielectric layer; 20: dielectric unit;

[0072] 201: first transmission surface; 2011: first end; 2012: second end;

[0073] 202: first bottom surface; 203: second bottom surface; 205: second transmission surface;

[0074] 200: frequency selective surface;

[0075] 3: metal layer; 30: metal unit;

[0076] 4: Connection layer;

[0077] 5: FSS unit;

[0078] 300: Electronic equipment;

[0079] 6: housing; 61: middle frame; 611: outer frame; 612: bottom plate; 62: back cover;

[0080] 71: display screen; 72: circuit board; 73: antenna;

[0081] z: first direction; x: second direction; y: third direction. DETAILED DESCRIPTION

[0082] The following specific embodiments illustrate the implementation of the present application, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. Although the description of the present application will be introduced in conjunction with some embodiments, this does not mean that the features of this application are limited to the implementation. On the contrary, the purpose of introducing the application in conjunction with the implementation is to cover other options or modifications that may be extended based on the claims of the present application. In order to provide a deep understanding of the present application, the following description will include many specific details. The present application can also be implemented without using these details. In addition, in order to avoid confusion or blurring the focus of the present application, some specific details will be omitted in the description. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0083] It should be noted that in this specification, similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings.

[0084] The following explains the terms that may appear in the embodiments of the present application.

[0085] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0086] In the description of this 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, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0087] Relative arrangement: can be understood as being arranged face to face (opposite to, or face to face) or being arranged with at least a partial overlap in a certain direction. In one embodiment, the two oppositely arranged radiators are arranged adjacently and no other radiator is arranged between them.

[0088] Ground / floor: can refer to at least a part of any grounding layer, grounding plate, or grounding metal layer in an electronic device (such as a mobile phone), or at least a part of any combination of any of the above grounding layers, grounding plates, or grounding components, etc., and "ground / floor" can be used for grounding components in electronic devices. In one embodiment, "ground / floor" can include any one or more of the following: the grounding layer of the circuit board of the electronic device, the grounding plate formed by the middle frame of the electronic device, the grounding metal layer formed by the metal film under the screen, the conductive grounding layer of the battery, and the conductive parts or metal parts electrically connected to the above grounding layer / grounding plate / metal layer. In one embodiment, the circuit board can be a printed circuit board (PCB), such as an 8-layer, 10-layer or 12-14-layer board with 8, 10, 12, 13 or 14 layers of conductive materials, or an element separated and electrically insulated by a dielectric layer or insulating layer such as glass fiber, polymer, etc. In one embodiment, the circuit board includes a dielectric substrate, a grounding layer and a wiring layer, and the wiring layer and the grounding layer are electrically connected through vias. In one embodiment, components such as a display, a touch screen, input buttons, a transmitter, a processor, a memory, a battery, a charging circuit, a system on chip (SoC) structure, etc. can be mounted on or connected to a circuit board; or electrically connected to a wiring layer and / or a ground layer in the circuit board. For example, a radio frequency source is disposed on the wiring layer.

[0089] Any of the above-mentioned grounding layers, grounding plates, or grounding metal layers are made of conductive materials. In one embodiment, the conductive material can be any of the following materials: copper, aluminum, stainless steel, brass and their alloys, copper foil on an insulating substrate, aluminum foil on an insulating substrate, gold foil on an insulating substrate, silver-plated copper, silver-plated copper foil on an insulating substrate, silver foil and tin-plated copper on an insulating substrate, cloth impregnated with graphite powder, graphite-coated substrates, copper-plated substrates, brass-plated substrates, and aluminum-plated substrates. It will be appreciated by those skilled in the art that the grounding layer / grounding plate / grounding metal layer can also be made of other conductive materials.

[0090] Antenna gain: It is used to characterize the degree to which the antenna radiates the input power. Generally, the narrower the main lobe of the antenna pattern and the smaller the side lobe, the higher the antenna gain.

[0091] Gain coefficient: The product of directivity coefficient and antenna efficiency, a parameter used to comprehensively measure the antenna energy conversion and directional characteristics.

[0092] Dielectric constant: the main parameter reflecting the dielectric properties or polarization properties of a dielectric under the action of an electrostatic field.

[0093] Relative dielectric constant: A physical parameter that characterizes the dielectric properties or polarization properties of dielectric materials. Its value is equal to the ratio of the capacitance of a capacitor of the same size made with the dielectric material as the medium to that made with vacuum as the medium. This value is also a characterization of the material's ability to store electricity. It is also called relative permittivity.

[0094] Dielectric loss tangent: A physical quantity that characterizes the dielectric loss of a dielectric material after an electric field is applied.

[0095] Surface waves: In physics, surface waves are mechanical waves that propagate along the interface between different media. Electromagnetic waves can also propagate as surface waves, as they can be guided along a refractive index gradient or along the interface between two media with different dielectric constants.

[0096] Transmittance: The ratio of the electromagnetic wave to the medium before and after it penetrates glass. The higher the transmittance, the more electromagnetic waves pass through the medium, and the lower the transmittance, the fewer electromagnetic waves pass through the medium.

[0097] Transmission coefficient: also called transmittance, refers to the ratio of transmitted luminous flux to incident luminous flux.

[0098] Reflection coefficient: The antenna reflection coefficient refers to the ratio of the signal received by the antenna in the reverse direction to the forward signal, which is the ratio of the reflected wave to the incident wave.

[0099] Antenna pattern: also called radiation pattern. It refers to the graph of the relative field strength (normalized modulus) of the antenna radiation field changing with direction at a certain distance from the antenna.

[0100] Standing wave ratio: the full name is voltage standing wave ratio, also known as VSWR and SWR, which is the abbreviation of Voltage Standing Wave Ratio in English. It refers to the ratio of the voltage at the antinode of the transmission line to the voltage at the trough, also known as the standing wave coefficient. When the standing wave ratio is equal to 1, it means that the impedance of the feeder and the antenna is completely matched. At this time, all high-frequency energy is radiated by the antenna, and there is no energy reflection loss; when the standing wave ratio is infinite, it means full reflection, no energy is radiated, and the reflection loss of electromagnetic waves is high.

[0101] Relative bandwidth: Relative bandwidth is defined as the ratio of signal bandwidth to center frequency and can be used to measure signal quality and performance.

[0102] The limitations such as colinearity, coaxiality, coplanarity, symmetry (e.g., axisymmetry, or center symmetry, etc.), parallelism, perpendicularity, sameness (e.g., same length, same width, etc.) mentioned in the embodiments of the present application are all for the current technological level, rather than an absolutely strict definition in a mathematical sense. There may be a deviation of a predetermined angle (e.g., ±5°, ±10°) between two structures that are parallel or perpendicular to each other.

[0103] In order to make the objectives, technical solutions and advantages of the present application clearer, the implementation methods of the present application will be further described in detail below in conjunction with the accompanying drawings.

[0104] 5G communication has the characteristics of high speed, low latency, and low bit error rate. With the commercialization and deployment of 5G communication systems, the millimeter wave band has gradually become the future of mobile communication technology due to its higher data transmission energy. In electronic devices with mobile communication functions such as mobile phones, the antenna is the only device for receiving signals. It is also the forefront of electronic devices and an important part of 5G mobile communications.

[0105] Current mobile phones and other terminals all have shells with a certain physical strength, such as a glass back cover. However, such shells usually have a high dielectric constant (permittivity) and poor transmission performance, which will produce strong reflection and blocking effects on electromagnetic waves working in the millimeter wave band, causing greater insertion loss for electronic equipment and leading to deterioration of the radiation performance of antennas (especially millimeter wave antennas).

[0106] See also Figure 1a-Figure 2c , Figure 1a-1b Schematic diagrams of the structures of dielectric plates and millimeter wave antennas in some solutions; Figure 2a Reflection curves obtained for simulation analysis of dielectric plates and millimeter wave antennas in some solutions; Figure 2b-Figure 2c The directional diagram obtained by simulating the effect of the dielectric plate and the millimeter wave antenna, where: Figure 2b is the orientation diagram of the y'z' plane, Figure 2c is the orientation diagram of the x'z' plane.

[0107] like Figure 1a-1b As shown, in the prior art, the back cover of the electronic device (also called the battery cover) can be regarded as a dielectric plate 100', which is usually a flat plate structure as a whole. In the figure, x' can represent the length direction of the dielectric plate 100', y' can represent the width direction of the dielectric plate 100', and z' can represent the thickness direction of the dielectric plate 100'. The electromagnetic waves radiated to the surrounding by the antenna 200' inside the electronic device pass through the dielectric plate 100' and enter the outside of the electronic device. As a propagation medium for electromagnetic waves, the material, structure and other characteristics of the dielectric plate 100' affect the radiation efficiency of the antenna. Taking the glass dielectric plate 100' and the millimeter wave antenna as an example, when a dielectric plate with a high dielectric constant is set within the radiation range of the antenna 200', the radiation field around it changes. The antenna pattern in different scenarios can be simulated by software to analyze the influence of the dielectric plate on its radiation performance.

[0108] like Figure 2aAs shown, the horizontal axis represents the frequency (Frequency, GHz) of the electromagnetic wave, the vertical axis represents the reflection coefficient (Reflective Coefficient, dB) of the antenna 200', the dotted line is the reflection coefficient curve of the antenna 200' when the glass dielectric plate 100' is not set, and the solid line is the reflection coefficient curve of the antenna when the glass dielectric plate 100' is set. According to international communication protocols, the 5G millimeter wave communication frequency band is mainly divided into three frequency bands: n257 (26.5~29.5GHz), n258 (24.25~27.5GHz), and n260 (37~43.5GHz). Figure 2a The analysis of electromagnetic waves from 20 to 25 GHz is consistent with the frequency band of millimeter waves. It can be seen from the figure that after adding the glass dielectric plate 100', the bandwidth of the antenna in a specific frequency band (for example, the bandwidth at -10db) is significantly narrowed, that is, the glass dielectric plate 100' has an impact on the bandwidth of the antenna, further increasing the standing wave ratio of the antenna, and the electronic wave has more reflection loss and low transmittance.

[0109] like Figure 2b-Figure 2c As shown, the vertical axis represents the gain coefficient (RealizedGain, dBi) of the electromagnetic wave at different incident angles, the dotted line is the directional pattern curve of the antenna 200' when the glass dielectric plate 100' is not set, and the solid line is the directional pattern curve of the antenna 200' when the glass dielectric plate 100' is set. It can be seen from the figure that after adding the glass dielectric plate 100', the azimuth pattern curves of the antenna 200' on the y'z' plane and the x'z' plane are changed, and are more tortuous than when the dielectric plate 100' is not set.

[0110] From the above simulation results, it can be seen that the high dielectric constant dielectric plate does have an adverse effect on the radiation performance of the millimeter wave antenna. If the back cover of an electronic device is made of a high dielectric constant material, it will cause problems such as poor transmission performance of the back cover, narrow high-efficiency transmission bandwidth, and reduced antenna radiation performance. It is difficult to apply millimeter wave antennas to the back cover of electronic equipment with a high dielectric constant.

[0111] To solve the above problems, some solutions are currently provided in the research of related fields (such as Chinese patent applications CN113497362A and CN115603057A), which usually involve attaching metal patterns on the surface of a dielectric plate to form a frequency selective surface with phase regulation function, also called an artificial magnetic conductor structure. Although this solution can reduce the energy loss of electromagnetic waves on the dielectric plate, improve the transmittance of electromagnetic waves, and increase the bandwidth of efficient transmission of the antenna, its structure is relatively complex and the production cost is high. In addition, its transmission regulation function for electromagnetic waves depends on the shape and layout of the metal pattern. Some solutions do not have obvious practical benefits in improving the transmittance of the dielectric plate and increasing the bandwidth of efficient transmission of the antenna.

[0112] However, in order to solve the above problems, the present application has made a pioneering improvement to the structure of the dielectric plate itself. By making grooves on the dielectric plate, a dielectric plate with a higher transmission coefficient can be obtained, which can increase the bandwidth of the antenna's efficient transmission, and achieve better application of millimeter wave antennas in electronic devices with high dielectric constant back covers while ensuring radiation performance. In addition, the structure is simple and the production cost is low.

[0113] The dielectric board provided in the embodiment of the present application is suitable for electronic devices with one or more of the following communication technologies: Bluetooth (BT) communication technology, global positioning system (GPS) communication technology, wireless fidelity (WiFi) communication technology, global system for mobile communications (GSM) technology, wideband code division multiple access (WCDMA) communication technology, long term evolution (LTE) communication technology, 5G communication technology, SUB-6G communication technology and other future communication technologies, etc. The electronic devices in the embodiment of the present application may include but are not limited to terminals such as mobile phones, tablet computers, laptop computers, smart bracelets, smart watches, and vehicle-mounted modules.

[0114] The following uses a mobile phone as an example to illustrate the application scenario of the media board.

[0115] See also Figure 3a-Figure 3b , Figure 3a This is a schematic diagram of the structure of an electronic device according to an embodiment of the present application; Figure 3b This is a schematic diagram of the structure of another implementation of the electronic device of the embodiment of the present application.

[0116] like Figure 3a-Figure 3bAs shown, an embodiment of the present application provides an electronic device 300, including a display screen 71, a circuit board 72, a middle frame 61, a back cover 62 and an antenna 73. The back cover 62 can be used as a battery cover of the electronic device 300. Among them, the middle frame 61 and the back cover 62 together constitute the shell 6 of the electronic device 300, and the middle frame 61 plays the role of supporting the whole machine, and its specific structure is not limited. In one embodiment, the middle frame 61 of the electronic device 300 may include an outer frame 611 and a bottom plate 612, and the bottom plate 612 can be used to support the display screen 71 and the components inside the shell 6. The outer frame 611 is the frame of the electronic device, which can be formed of conductive materials such as metal. In one implementation, the frame made of metal material can be directly used as the metal frame of the electronic device 300, forming the appearance of the metal frame, which is suitable for metal industrial design (industrial design, ID). In another implementation, the outer surface of the frame can also be a non-metallic material, such as a plastic frame, a glass frame, a ceramic frame, etc.

[0117] The back cover 62 is installed at one end of the outer frame 611, and together with the middle frame 61, it forms a receiving cavity, which is used to seal the components of the electronic device 300 inside the electronic device, and can also prevent dust, collision, and hardware scratches. The back cover 62 can be a back cover made of metal material (i.e., metal back cover); it can also be a back cover made of non-metallic material (i.e., non-metallic back cover), such as glass back cover, plastic back cover, etc. Non-metallic materials (such as glass) usually have a large dielectric constant. For example, the dielectric constant of glass is generally 6.6.

[0118] Furthermore, the display screen 71 is installed at the other end of the outer frame 611, which has an imaging function and may include a liquid crystal display (LCD), a light emitting diode (LED) display or an organic light-emitting semiconductor (OLED) display, etc., and the present application does not impose any restrictions on this.

[0119] The circuit board 72 is located inside the housing 6 and carries a plurality of electronic components, such as a radio frequency chip, a Bluetooth chip, a wireless fidelity chip, a capacitor, etc. The circuit board 72 can be a printed circuit board (PCB) or a flexible printed circuit board (FPC), etc., which is not limited in the present application.

[0120] The antenna 73 is used to realize the communication function, and its specific form is not limited. For example, the antenna 73 can be an antenna based on the flexible circuit board 72, an antenna based on laser direct structuring (LDS) or a microstrip disk antenna (MDA). Specifically, its type can be a wire antenna, a slot antenna, a loop antenna, a corrugated tube antenna, a patch antenna (or a patch antenna), and other specific forms of antennas.

[0121] The antenna 73 is accommodated in the housing 6, and its specific position and formation method are not limited. For example, it can be integrated into the circuit board 72, or it can be a transparent structure embedded in the display screen 71, so that the antenna 73 forms a transparent antenna unit embedded in the electronic device 300, etc. In one embodiment, the antenna 73 is a millimeter wave antenna integrated into the circuit board 72. The millimeter wave antenna can be an antenna of any frequency band among n257 (26.5GHz~29.5GHz), n258 (24.25GHz~27.5GHz), and n260 ((37GHz~43.5GHz)), and this application does not limit this. It should be noted that the formation method of the antenna 73 on the circuit board 72 is not limited. In an example scenario, a metal layer can be set on the circuit board 72, which can also be called a floor or grounding layer. The metal layer can be used for grounding components such as the antenna 73.

[0122] like Figure 3a As shown, the dielectric plate 100 is located on the back cover 62 of the electronic device 300. It can be understood that the dielectric plate 100 is a component of the back cover 62. For example, the dielectric plate 100 can be processed into the shape of the back cover 62, that is, the entire back cover 62 is used as the dielectric plate 100, or a part of the back cover 62 can be used as the dielectric plate 100, for example Figure 3a Only the dotted-line portion (the portion corresponding to the antenna 73) is the dielectric plate 100, and this application does not limit this. Figure 3a-Figure 3b In the direction of the arrow in the figure, the antenna 73 radiates electromagnetic waves in all directions, a part of which can be radiated into the air through the dielectric layer on the back cover 62. The portion of the back cover 62 corresponding to the antenna 73 provided in the embodiment of the present application has a high transmission coefficient, which can increase the bandwidth of the antenna's efficient transmission. When the antenna 73 is set as a millimeter wave antenna, the radiation performance of the antenna can be guaranteed.

[0123] It can be understood by those skilled in the art that the relative position of the antenna 73 and the dielectric plate 100 in the back cover 62 is not limited. In one embodiment, the antenna 73 is correspondingly arranged in the central area of ​​the dielectric plate 100, which can be understood as the antenna 73 is located in the central area of ​​the dielectric plate 100 as a whole on the plane where the back cover 62 is located (the plane perpendicular to the first direction z in the figure), so that the dielectric plate 100 is located in the effective radiation range of the antenna 73 to the greatest extent, which can improve the transmission effect of the antenna. It should be understood that since the antenna 73 and the dielectric plate 100 can be of various shapes, the antenna 73 does not absolutely correspond to the central area of ​​the dielectric plate 100, and there can be a certain range of deviations.

[0124] It should be noted that the medium plate 100 can be present in various forms on the rear cover 62, for example Figure 3a The dielectric plate 100 is directly applied to the rear cover 62, or a metal layer can be added to the dielectric plate 100 to form Figure 3b The frequency selective surface 200 shown can achieve the control effect on electromagnetic waves. The specific structure and working principle of the frequency selective surface 200 will be introduced later.

[0125] It should be understood that the structures of the electronic device 300 and the back cover 62 in the electronic device 300 are only examples to better illustrate the application scenarios of the medium board 100 in the electronic device 300, and do not limit the electronic device 300 and the back cover 62 provided in this application. In addition, the drawings provided in this application are only for illustration, and the electronic device 300 may include more or fewer devices than those shown in the drawings, for example, it may also include a battery, a speaker, a camera, etc. The structure of the back cover 62 and its matching relationship with other devices in the electronic device 300 are not limited to Figure 3a and Figure 3b The type shown in the figure.

[0126] The dielectric plate 100 provided in the present application is described in detail below with reference to the accompanying drawings.

[0127] See also Figure 4-Figure 7 , Figure 4 This is a schematic diagram of the three-dimensional structure of the dielectric plate of the embodiment of the present application; Figure 5 This is a schematic diagram of the planar structure of the dielectric plate of the embodiment of the present application; Figure 6a-6h This is a schematic diagram of the structure of a dielectric unit in a dielectric plate in an embodiment of the present application; Figure 7 Schematic diagram of arrangement of adjacent dielectric units in a dielectric plate according to an embodiment of the present application.

[0128] like Figure 4-Figure 7 As shown, the dielectric plate 100 includes a first dielectric layer 1 and a second dielectric layer 2 stacked in a first direction z, and the second dielectric layer 2 includes a plurality of dielectric units 20 arranged at intervals.

[0129] The second dielectric layer 2 includes a plurality of dielectric units 20 arranged at intervals, which can be understood as: there are gaps between the plurality of dielectric units 20 in the second dielectric layer 2, and the first dielectric layer 1 provides support for the plurality of dielectric units 20 in the second dielectric layer 2. With this structure, part of the dielectric in the dielectric plate 100 is removed, for example, the second dielectric layer 2 can be processed by slotting, etc., to form gaps between the dielectric units 20, and the gaps can be filled with air, so that the air is mixed into the dielectric plate 100, and because the dielectric constant of the air is less than the dielectric constant of the dielectric plate's own material, the equivalent dielectric constant of the dielectric plate 100 as a whole is reduced. For example, the dielectric constant of the dielectric plate's own material (for example, glass, ceramic, etc.) is usually between 3 and 10, while the dielectric constant of air is close to 1, so the mixing of air can reduce the equivalent dielectric constant of the dielectric plate. Therefore, compared with the solution in the prior art in which the dielectric plate is set as a solid plate structure as a whole, while ensuring that the material and thickness of the dielectric plate are the same, the equivalent dielectric constant of the dielectric plate 100 as a whole in the present application is reduced, which is conducive to the dielectric plate 100 and the air to achieve wave impedance matching. In addition, the reduction of the dielectric constant can reduce the surface waves excited by the dielectric plate 100. On the other hand, the surface grooving process allows the dielectric plate 100 to form a periodic structure similar to the electromagnetic band gap structure (EBG, Electromagnetic Band Gap). From the analysis of the dispersion properties, it can be seen that there is no mode of propagating waves in its transmission frequency band, and it also has an inhibitory effect on surface waves. Combining the above factors, the loss of electromagnetic waves in the dielectric plate 100 will be reduced, the transmission effect will be better, and the transmission coefficient of the dielectric plate 100 will be improved, thereby further increasing the bandwidth of efficient transmission and improving the radiation performance of the antenna. In particular, when the millimeter wave antenna is set below the back cover with a high dielectric constant, good radiation performance can also be guaranteed.

[0130] Therefore, the dielectric plate 100 provided in the present application has a higher transmission coefficient, which can increase the bandwidth of the antenna's efficient transmission, and achieve better application of the millimeter wave antenna in electronic devices with a high dielectric constant back cover while ensuring radiation performance.

[0131] When the dielectric plate 100 is used in the back cover 62 of the electronic device 300, the positional relationship between the first dielectric layer 1 and the second dielectric layer 2 is not limited. In one embodiment, the second dielectric layer 2 is located on the side of the first dielectric layer 1 close to the display screen 71, and the surface of the first dielectric layer 1 facing away from the second dielectric layer 2 can be used as the back appearance of the electronic device. In an alternative embodiment, the second dielectric layer 2 can also be arranged on the side of the first dielectric layer 1 away from the display screen 71. For the above two structures, the transmission effect of the dielectric plate 100 is similar or even the same.

[0132] It should be noted that the medium plate 100 provided in the present application can be set not only in the back cover of the electronic device, but also in other locations of the electronic device, such as the middle frame, display screen, etc. Moreover, in addition to electronic devices, the medium plate 100 provided in the present application can also be applied to terminal products in other fields, and the present application does not limit this.

[0133] It can be understood by those skilled in the art that the specific structure of the first dielectric layer 1 is not limited, as long as it can support the multiple dielectric units 20 in the second dielectric layer 2. In one embodiment, the first dielectric layer 1 is a solid plate-like structure, and its surface facing the second dielectric layer 2 is the first surface 11. In one embodiment, the second dielectric layer 2 is directly connected to the first surface 11 of the first dielectric layer 1. In other alternative embodiments, other structures can be provided between the first dielectric layer 1 and the second dielectric layer 2, for example, other dielectric layers can be provided, etc., and the present application does not limit this.

[0134] It will be understood by those skilled in the art that the specific arrangement of the plurality of dielectric units 20 in the second dielectric layer 2 is not limited. Figure 4-Figure 5 As shown, in one embodiment, a plurality of dielectric units 20 are distributed in an array on the surface of the first dielectric layer 1 facing the second dielectric layer 2 (i.e., the first surface 11) in the second direction x and the third direction y, wherein the first direction z, the second direction x, and the third direction y are mutually perpendicular. The second direction x and the third direction y may be the length direction and the width direction of the dielectric plate 100, and the plurality of dielectric units 20 are distributed in a rectangular array. It can be understood by those skilled in the art that the specific number of dielectric units 20 is not limited, and the number of dielectric units 20 arranged along the second direction x and the number of dielectric units 20 arranged along the third direction y are not limited. In other alternative embodiments, the plurality of dielectric units 20 may also be arranged in other forms, such as in a ring array, etc., which are not listed here one by one.

[0135] Those skilled in the art can understand that the second dielectric layer 2 is composed of a plurality of repeated dielectric units 20. The specific structure of each dielectric unit 20 is not limited, as long as there is a gap between adjacent dielectric units 20. The following describes the structure of the dielectric unit 20 in conjunction with the distance in the attached figure.

[0136] like Figure 6a-Figure 7 As shown, in one embodiment, at least part of the outer peripheral surface of each dielectric unit 20 is configured as a first transmission surface 201. The first transmission surface 201 of each dielectric unit 20 has a first end 2011 and a second end 2012, and in the first direction z, the second end 2012 is located between the first end 2011 and the first dielectric layer 1, and in a plane perpendicular to the first direction z, the second end 2012 is located between the first end 2011 and the adjacent dielectric unit 20.

[0137] The outer peripheral surface of each dielectric unit 20 refers to the outermost circumferential surface of each dielectric unit 20, which forms a certain angle with the first direction z. The first transmission surface 201 is one of the transmission surfaces of the dielectric unit 20, and all surfaces of the dielectric unit 20 that can transmit electromagnetic waves are transmission surfaces. In addition to the first transmission surface 201, the dielectric unit 20 may also include other transmission surfaces, such as the second transmission surface 205, etc., and the number of the first transmission surfaces 201 may be one or more, and the present application does not limit this.

[0138] The positional relationship between the first end 2011 and the second end 2012 of the first transmission surface 201 can be understood as follows: Figure 6a-Figure 7 In the viewing angle, the first end 2011 of the transmission surface of each dielectric unit 20 is located below the second end 2012, and the second end 2012 is closer to the dielectric unit 20 adjacent to the dielectric unit 20 than the first end 2011. For example, Figure 7 In the figure, O, P, and Q represent three adjacent dielectric units 20 arranged along the second direction x or the third direction y, respectively. It can be seen from the figure that the dielectric unit P has two first transmission surfaces 201 on the left and right sides. Among them, the first end 2011 of the first transmission surface 201 on the right side is located at the lower left of the second end 2012, and the second end 2012 is closer to the dielectric unit Q on the right side of the dielectric unit P than the first end 2011. Similarly, the first end 2011 of the first transmission surface 201 on the left side of the dielectric unit P is located as a whole at the lower right of the second end 2012, and the second end 2012 is closer to the dielectric unit O on the left side of the dielectric unit P than the first end 2011. A more intuitive method can be understood as follows: when an antenna 73 is placed under each dielectric unit 20, the area on the outer circumference of each dielectric unit 20 that can be radiated by electromagnetic waves is the first transmission surface 201.

[0139] With the above structure, when the dielectric unit 20 has a first transmission surface 201, an angle is formed between the first transmission surface 201 and a plane perpendicular to the first direction z, and the electromagnetic wave emitted by the antenna 73 is radiated onto the inclined first transmission surface 201, thereby changing the incident angle of the electromagnetic wave, that is, changing the boundary condition of the incident field, so that the surface wave excitation of the dielectric plate 100 changes, suppressing the propagation of the surface wave, and further improving the transmission effect of the dielectric plate 100.

[0140] Those skilled in the art will appreciate that the specific shape of the first transmission surface 201 in each dielectric unit 20 is not limited, and can extend along any one or more of a plane, a curved surface, an arc surface, or a curved surface. Figure 6a The middle medium unit 20 may be in the shape of a truncated cone or a prism. Figure 6bThe dielectric unit 20 may be conical or pyramidal. When the dielectric unit 20 is in the shape of a prism or pyramid, the side surfaces of the prism or pyramid are all first transmission surfaces 201, and each first transmission surface 201 is a plane. When the dielectric unit 20 is in the shape of a truncated cone or a cone, the entire outer circumference of the truncated cone or cone is the first transmission surface 201, and the first transmission surface 201 is a curved surface. Figure 6c The middle dielectric unit 20 is hemispherical, and the entire spherical surface is a first transmission surface 201 , and the first transmission surface 201 is a curved surface structure. Figure 6d The dielectric unit 20 is irregular in shape, and includes a plurality of first transmission surfaces 201 of different shapes. From the perspective of the figure, it can be seen that the first transmission surface 201 on the left side is a plane or curved surface structure, and the first transmission surface 201 on the right side is an irregular curved surface structure. Figure 6e The middle dielectric unit 20 may be a semi-conical structure, a prismatic structure or a pyramidal structure, etc. Its first transmission surface 201 is the outer peripheral surface on the right side in the viewing angle of the figure, and the first transmission surface 201 may be a curved surface or a flat surface. Figure 6f The middle dielectric unit 20 is a structure formed by splicing two prisms or frustums, and only a lower section of its outer circumference is a first transmission surface 201 (ie, the outer circumference of the prism or frustum located below).

[0141] like Figure 6g-6h As shown, Figure 6g and Figure 6h The outer peripheral surface of the dielectric unit 20 shown in the figure does not have a portion that can be used as the first transmission surface, so the dielectric units 20 of these two embodiments do not have the first transmission surface 201. It should be noted that Figure 6g and Figure 6h The structure shown is for Figure 6a-6f To form a contrast, so as to better illustrate the shape of the first transmission surface 201, but Figure 6g and Figure 6h This also meets the condition that the dielectric units 20 in the second dielectric layer 2 are arranged at intervals, and is also a structure that the dielectric units 20 can adopt. Those skilled in the art can understand that: Figure 6a-6h The structure of the first transmission surface 201 is only an example, and the shape of the dielectric unit 20 is not limited to the above-mentioned cases.

[0142] In order to improve the utilization rate of the surface of the dielectric unit 20, the proportion of the first transmission surface 201 in its outer circumference should be increased as much as possible to achieve the best transmission effect of the dielectric unit 20. Figure 6a-6c , Figure 6e-6fAs shown, in one embodiment, from the first end 2011 to the second end 2012, the first transmission surface 201 as a whole gradually extends toward the adjacent dielectric unit 20 along a direction inclined to the first direction z to form an outward expansion surface. It can be understood that the first transmission surface 201 as a whole diverges from the first end 2011 to the second end 2012 toward the surroundings of the dielectric unit 20. In conjunction with the graphic understanding, the slope of the first transmission surface 201 from the first end 2011 to the second end 2012 relative to the plane perpendicular to the first direction z remains in the same direction (always a positive slope or always a negative slope). With this structure, when an antenna 73 is provided below the dielectric unit 20, electromagnetic waves can irradiate any position of the first transmission surface 201. The following examples illustrate several typical structures for this solution.

[0143] See also Figure 8a-Figure 9 , Figure 8a-8d This is a schematic structural diagram of a first implementation of a dielectric unit in a dielectric plate in an embodiment of the present application, wherein: Figure 8d for Figure 8b Sectional view in the AA direction; Fig. 9 It is a structural schematic diagram of a second implementation mode of a dielectric unit in a dielectric plate in an embodiment of the present application.

[0144] like Figure 8a-Figure 9 As shown, in one embodiment, each dielectric unit 20 may be a prism-shaped structure ( Figure 8a-8d ) or pyramidal structures ( Fig. 9 ), the entire outer peripheral surface of the prism-shaped structure or the pyramid-shaped structure is configured as the first transmission surface 201. In addition, the second end 2012 of the first transmission surface 201 is located on the first surface 11 of the first dielectric layer 1, that is, the second end 2012 of the first transmission surface 201 is directly connected to the first dielectric layer 1.

[0145] like Figure 8a-8d As shown, in one embodiment, when the dielectric unit 20 is a prism-shaped structure, it can be a triangular prism, a quadrangular prism, a pentagonal prism, etc., and there is no specific limitation. The figure takes a quadrangular prism as an example, and the quadrangular prism can be a regular quadrangular prism or a special-shaped quadrangular prism, and the present application does not limit this. In one embodiment, each prism-shaped structure is a regular quadrangular prism, and has a first bottom surface 202 and a second bottom surface 203 that are opposite and parallel to each other in the first direction z, and the first bottom surface 202 and the second bottom surface 203 are both square. The first bottom surface 202 is connected to the first end 2011 of the first transmission surface 201, and is configured as a second transmission surface 205. The second transmission surface 205 is parallel to the first surface 11 of the first dielectric layer 1, and the second bottom surface 203 is connected to the second end 2012 of the first transmission surface 201, and a part of the surface of the first surface 11 of the first dielectric layer 1 constitutes the second bottom surface 203. Among them, the first transmission surface 201 and the second transmission surface 205 can both allow electromagnetic waves to pass through, but there are differences in the transmission effect.

[0146] Those skilled in the art will appreciate that the area ratio of the first bottom surface 202 to the second bottom surface 203 is not limited. In one embodiment, the side length of the first bottom surface 202 is p 1 , the side length of the second bottom surface 203 is p 2 , 0 <p 1 / p 2 ≤1 / 2.

[0147] Or, from another perspective, Figure 8a-8d The shape of the dielectric unit 20 shown is constrained, and the bottom angle of the quadrangular pyramid (the angle between the outer peripheral surface and the second bottom surface 203) is recorded as θ, and θ can be 25° to 60°, for example, 25°, 28°, 30°, 45°, 60°, etc., and the present application does not limit this. θ can also be understood as the angle between the first transmission surface 201 of the dielectric unit 20 and the first surface 11 of the first dielectric layer 1. In an example, the first surface 11 of the first dielectric layer 1 is perpendicular to the first direction z.

[0148] like Fig. 9 As shown, in one embodiment, when the dielectric unit 20 is a pyramid structure, it can be a triangular pyramid, a quadrangular pyramid, a pentagonal pyramid, etc., without limitation. The first end 2011 of the first transmission surface 201 constitutes the tip of the pyramid structure, which can be understood as the prism structure in the extreme case p 1 When is 0. In pyramidal and prism-shaped structures, 0 <p 1 / p 2 The solutions with a value of ≤1 / 2 can achieve the best transmission effect of the dielectric plate 100 .

[0149] See also Figure 10a-Figure 11 , Figure 10a-Figure 10b This is a schematic structural diagram of a third implementation mode of a dielectric unit in a dielectric plate according to an embodiment of the present application; Fig.11 It is a structural schematic diagram of a fourth implementation mode of a dielectric unit in a dielectric plate according to an embodiment of the present application.

[0150] like Figure 10a-Figure 11 As shown, in one embodiment, each dielectric unit 20 may be a conical structure ( Fig.11 ) or truncated cone structure ( Figure 10a-Figure 10b ), the entire outer circumference of each conical structure or truncated cone structure is configured as a first transmission surface 201. In addition, the second end 2012 of the first transmission surface 201 is located on the first surface 11 of the first dielectric layer 1, wherein the first surface 11 of the first dielectric layer 1 faces the second dielectric layer 2. That is, the second end 2012 of the first transmission surface 201 is directly connected to the first dielectric layer 1.

[0151] like Figure 10a-Figure 10bAs shown, in one embodiment, when the dielectric unit 20 is a truncated cone structure, each truncated cone structure has a first bottom surface 202 and a second bottom surface 203 that are opposite and parallel to each other in the first direction z, the first bottom surface 202 is connected to the first end 2011 of the first transmission surface 201, and is configured as a second transmission surface 205, the second transmission surface 205 is parallel to the first surface 11 of the first dielectric layer 1, the second bottom surface 203 is connected to the second end 2012 of the first transmission surface 201, and a part of the first surface 11 of the first dielectric layer 1 constitutes the second bottom surface 203. It can be understood by those skilled in the art that the radius ratio of the first bottom surface 202 and the second bottom surface 203 is not limited. In one embodiment, the radius of the first bottom surface 202 is r 1 , the radius of the second bottom surface 203 is r 2 , 0 <r 1 / r 2 ≤1 / 2.

[0152] like Fig.11 As shown, in one embodiment, when the dielectric unit 20 is a conical structure, the first end 2011 of the first transmission surface 201 constitutes the tip of the conical structure, which can be understood as the truncated cone structure in the extreme case r 1 When is 0. Conical structure Prismatic structure 0 <r 1 / r 2 The solutions with a value of ≤1 / 2 can also achieve the best transmission effect of the dielectric plate 100 .

[0153] See also Figure 12a-12b , Fig.12a This is a schematic structural diagram of a fifth implementation mode of a dielectric unit in a dielectric plate according to an embodiment of the present application; Figure 12b It is a structural schematic diagram of a sixth implementation mode of a dielectric unit in a dielectric plate according to an embodiment of the present application.

[0154] like Figure 12a-12b As shown, in one embodiment, each dielectric unit 20 is configured as a spherical structure, and the spherical surface of each spherical structure constitutes the outer peripheral surface of the dielectric unit 20 as a whole, and is configured as a first transmission surface 201. The spherical structure can be a hemisphere, a 1 / 3 sphere, a 2 / 3 sphere, a 3 / 4 sphere, etc., and is not specifically limited. The diameter of the spherical structure is denoted as D, and the thickness of the second dielectric layer 2 is denoted as h 2 , in one embodiment, 1 / 2≤h 2 / D≤2 / 3 to achieve the best transmission effect. Specifically, Fig.12a Medium 2 / D=1 / 2, that is, a hemispherical structure. Figure 12b Medium 2 / D=2 / 3, i.e. 2 / 3 spherical structure.

[0155] The above examples illustrate the structures that can be adopted by each dielectric unit 20 in the second dielectric layer 2 . The overall structure of the dielectric plate 100 will be expanded below.

[0156] Those skilled in the art will appreciate that the thickness of the first dielectric layer 1 and the second dielectric layer 2 are not limited.

[0157] like Figure 8c As shown, the thickness of the first dielectric layer 1 is recorded as h 1 In one embodiment, 0 <h 1 / h 2 ≤1 / 3. The second dielectric layer 2 is the actual layer for reducing the dielectric constant of the dielectric plate 100 and suppressing the surface light wave. Its proportion in the dielectric plate 100 is higher than that of the first dielectric layer 1, which is more beneficial to the overall transmission effect of the dielectric plate 100. At the same time, the first dielectric layer 1 also needs to have a certain thickness to ensure the structural strength of the dielectric plate 100. More specifically, in one example, h 1 / h 2 =1 / 3, that is, the thickness of the second dielectric layer 2 h 2 is the thickness of the first dielectric layer 1 h 1 Three times the thickness of the dielectric plate 100 can achieve a balance between the transmission effect and the structural strength of the dielectric plate 100.

[0158] In one embodiment, the sum of the thickness of the first dielectric layer 1 and the second dielectric layer 2 is 0.6 mm to 1 mm, that is, h 1 +h 2 =0.6mm~1mm. This range is the common thickness of the back cover of a mobile phone. In other alternative embodiments, h 1 +h 2 It can also be smaller than 0.6mm or larger than 1mm, depending on the actual application scenario.

[0159] It can be understood by those skilled in the art that the first dielectric layer 1 and the second dielectric layer 2 can be provided separately or integrally formed. Figure 8d As shown, in one embodiment, the first dielectric layer 1 and the second dielectric layer 2 are an integrated structure, that is, the first dielectric layer 1 and the second dielectric layer 2 are integrally formed, which can simplify the processing steps and facilitate production.

[0160] It can be understood by those skilled in the art that the specific material of the dielectric plate 100 is not limited, and the above structure can achieve the effect of reducing the dielectric constant and improving the transmittance of dielectric plates 100 of different materials, which can be determined according to the actual application scenario. In one embodiment, the dielectric constant of the dielectric plate 100 itself is 3 to 10, for example, it can be made of glass, ceramic, plastic, etc. More specifically, in one embodiment, the material of the dielectric plate 100 is glass to meet the production needs of applying the millimeter wave antenna under the glass back cover of the electronic device.

[0161] See also Figure 13-14 , Fig.13 This is a schematic diagram of the structure of the frequency selective surface according to an embodiment of the present application; Fig.14 This is a schematic diagram of the structure of the metal layer in the frequency selective surface according to an embodiment of the present application.

[0162] like Figure 13-14 As shown, the present application also provides a frequency selective surface 200 (Frequency Selective Surface, FSS), including a metal layer 3 and a dielectric plate 100 provided in any of the above embodiments. It can be understood that a metal layer 3 is added to the dielectric plate 100 to form a frequency selective surface 200. The frequency selective surface 200 is an electromagnetic structure with spatial filter characteristics. Through different electromagnetic parameter designs, it can meet the regulation requirements of electromagnetic wave transmission. It has a high application value in energy transmission, and the frequency selective surface 200 can also improve the transmittance of electromagnetic waves on the dielectric plate 100. Adding a metal layer 3 to the dielectric plate 100, combining the advantages of the high transmittance of the dielectric plate 100 with the spatial filtering performance of the metal layer 3, and adjusting the structure of the metal layer 3, the structure and arrangement of the dielectric unit 20 as needed, can obtain a frequency selective surface 200 with excellent performance, which can effectively control the reflection and transmission of electromagnetic waves, and can show obvious bandpass or bandstop filtering characteristics when interacting with electromagnetic waves. Among them, the specific material of the metal layer 3 is not limited, for example, it can be a metal such as copper.

[0163] See also Figure 15a-Figure 16 , Figure 15a-Figure 15d This is a schematic structural diagram of a first implementation of an FSS unit in a frequency selective surface according to an embodiment of the present application, wherein: Fig.15c for Fig.15a Cross-sectional view along the BB direction, Fig.15d for Fig.15c A partial enlarged view of part C in the middle; Fig.16 This is a schematic structural diagram of a first implementation of a metal unit in a frequency selective surface according to an embodiment of the present application.

[0164] It will be understood by those skilled in the art that the specific structure and position of the metal layer 3 are not limited. Figure 13-Figure 16 As shown, in one embodiment, the metal layer 3 is attached to the surface of the first dielectric layer 1 facing the second dielectric layer 2, that is, attached to the first surface 11, and is embedded between the plurality of dielectric units 20 of the second dielectric layer 2, and the metal layer 3 surrounds the outer periphery of each dielectric unit 20. In one embodiment, the metal layer 3 is arranged in a grid structure, and each grid wraps the outer periphery of a dielectric unit 20.

[0165] Furthermore, the metal layer 3 of the grid structure includes a plurality of metal units 30 arranged in an array (one metal unit 30 corresponds to one grid), and each metal unit 30 surrounds the outer peripheral side of the corresponding dielectric unit 20. Among them, one metal unit 30, the dielectric unit 20 surrounded by the metal unit 30, and the first dielectric layer 1 where the metal unit 30 and the dielectric unit 20 are located together constitute an FSS unit 5, and the frequency selective surface 200 can be regarded as an array structure formed by arranging multiple repeated FSS units 5. Figure 15a-Figure 15d The structure of a FSS unit 5 is shown schematically from different angles. Fig.16 The structure of the metal unit 30 in the FSS unit 5 is shown schematically. Figure 15a-Figure 15d The array distribution of FSS unit 5 can be obtained Fig.13 A frequency selective surface 200 is shown.

[0166] Those skilled in the art will appreciate that the specific location of the metal layer 3 is not limited. Figure 15c-15d As shown, in one embodiment, a connection layer 4 is still provided between each dielectric unit 20 and the first dielectric layer 1, and the metal layer 3 is embedded between a plurality of connection layers 4 corresponding to the plurality of dielectric units 20, so that the metal layer 3 is more firmly installed in the second dielectric layer 2. In other alternative embodiments, a connection layer 4 may not be provided between each dielectric unit 20 and the first dielectric layer 1, for example, the metal layer 3 is directly installed between a plurality of dielectric units 20, etc., which are not listed one by one in this application.

[0167] See also Figure 17a-17b , Fig.17a This is a schematic structural diagram of a second implementation mode of a metal unit in a frequency selective surface according to an embodiment of the present application; Fig.17b It is a schematic structural diagram of a third implementation mode of a metal unit in a frequency selective surface according to an embodiment of the present application.

[0168] It can be understood by those skilled in the art that the metal unit 30 and the dielectric unit 20 can be matched in any way, and their shapes can correspond or not correspond. When the shapes of the metal unit 30 and the dielectric unit 20 correspond, the two can be closely matched to improve space utilization. For example, Fig.16 The metal unit 30 with a square frame corresponds to the dielectric unit 20 with a regular quadrangular pyramid shape and can be attached to the four sides of the dielectric unit 20. For dielectric units 20 with other shapes, the shape of the metal unit 30 can also be adjusted. For example, when the dielectric unit 20 is conical, truncated, or spherical, the metal unit 30 can be Fig.17a When the dielectric unit 20 is in the shape of a hexagonal pyramid or a hexagonal pyramid, the metal unit 30 may be Fig.17bFor the structure shown, for dielectric units 20 of other shapes, metal units 30 of corresponding shapes may also be used, which will not be listed one by one in this application.

[0169] like Figure 13-14 , Fig.15a As shown, in one embodiment, the orthographic projections of the plurality of dielectric units 20 and the plurality of metal units 30 on the first dielectric layer 1 along the first direction z cover the entire first dielectric layer 1. Or it can be understood that the metal layer 3 and the second dielectric layer 2 together cover the entire first surface 11 of the first dielectric layer 1. With this structure, there is no gap between each dielectric unit 20 and the surrounding metal units 30, which can maximize the area utilization. In other alternative embodiments, a certain gap can also be reserved between each dielectric unit 20 and the surrounding metal units 30, and this application is not limited to this.

[0170] like Figure 13-Figure 16 As shown, taking a specific implementation as an example, the shape, material and specific size of each FSS unit 5 of the frequency selective surface 200 are as follows:

[0171] The dielectric plate 100 is made of glass with a dielectric constant of 6.6 and a loss tangent of 0.002, and the metal layer 3 is a copper sheet. Each dielectric unit 20 in the second dielectric layer 2 is a regular quadrangular pyramid structure with a bottom angle θ=28°. The side length p of the first bottom surface 202 is 1 =1.66mm, the side length p of the second bottom surface 203 2 =2.6mm. The metal layer 3 is a square grid structure, and each metal unit 30 is a square frame structure, and its frame width w=0.1mm. The total width p of the FSS unit 5 is 2.8mm.

[0172] The frequency selective surface 200 in the above embodiment is simulated by using software to obtain a corresponding transmission coefficient curve, which is interpreted below.

[0173] See also Fig.18 , Fig.18 This is a transmission coefficient curve obtained by analyzing the simulation effect of the frequency selective surface in the embodiment of the present application.

[0174] like Fig.18 As shown, the horizontal axis represents the frequency of the electromagnetic wave, the vertical axis represents the transmission coefficient (dB), and different curves represent the incident angle of the electromagnetic wave. Among them, theta = 0 means vertical incidence, that is, the electromagnetic wave is incident along the first direction z, theta = 10 means that the electromagnetic wave is incident along the direction with an angle of 10° to the first direction z, theta = 20 means that the electromagnetic wave is incident along the direction with an angle of 20° to the first direction z, and theta = 30 means that the electromagnetic wave is incident along the direction with an angle of 30° to the first direction z.

[0175] from Fig.18 It can be seen from the figure that when the incident angle of the electromagnetic wave is 0 and the frequency is between 20GHz-45GHz, the transmission coefficient of the frequency selective surface 200 can basically be maintained above -2dB. When theta=30, the bandwidth of the transmission coefficient above -2dB is: 21GHz~43.8GHz, and the relative bandwidth is 70.37% after calculation. It can be seen from the figure that when theta=20, theta=10, and theta=0, the transmission coefficient of the frequency selective surface 200 in the bandwidth range of 20GHz~45GHz is all above -2dB, and as the incident angle decreases, the bandwidth corresponding to -2dB increases successively. It can be seen that when theta=20, theta=10, and theta=0, the relative bandwidth of the frequency selective surface 200 is higher than 70.37%. It can be seen that the relative bandwidth of the frequency selective surface 200 is relatively high when the incident angle of the electromagnetic wave is 0°~30°.

[0176] See also Figure 19a-Figure 20 , Fig.19a This is a schematic structural diagram of a second implementation of an FSS unit in a frequency selective surface according to an embodiment of the present application; Fig.19b It is a structural schematic diagram of a third implementation mode of the FSS unit in the frequency selective surface of the embodiment of the present application; Fig. 20 This is a transmission coefficient curve obtained by analyzing the simulation effect of the frequency selective surface of the present application.

[0177] like Figure 19a-Figure 20 As shown, in addition to simulating the frequency selective surface 200 with a quadrangular pyramid-shaped dielectric unit 20, the present application also simulates the frequency selective surface 200 with a hemispherical ( Fig.19a ), cone( Fig.19b ) The same simulation experiment was conducted on the dielectric unit 20, and the second dielectric layer 2 was set to be free of grooves (i.e. Figure 1a-1b The experiment of the solution that the medium plate 100 as a whole adopts a solid plate structure) is used as a control group, and the results obtained are as follows:

[0178] like Fig. 20 As shown in the figure, the horizontal axis represents the frequency of the electromagnetic wave, the vertical axis represents the transmission coefficient, and different curves represent the frequency selective surface 200 when the dielectric unit 20 is in different shapes, wherein the dotted line represents the frequency selective surface 200 of the second dielectric plate 100 without slotting. It can be seen from the figure that when the second dielectric plate 100 is slotted and contains multiple dielectric units 20, no matter the dielectric unit 20 is in the shape of a quadrangular pyramid, a hemisphere or a cone, the transmission coefficient of the frequency selective surface 200 is higher than that of a solid plate structure without slotting, and can be maintained above -2dB. Therefore, slotting the dielectric plate 100 can improve its overall transmission coefficient, and the performance of the frequency selective surface is also more excellent.

[0179] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A dielectric plate, characterized in that: The invention comprises a first dielectric layer and a second dielectric layer stacked in a first direction, wherein the second dielectric layer comprises a plurality of dielectric units arranged at intervals.

2. The dielectric plate according to claim 1, characterized in that: At least a portion of the outer peripheral surface of each of the plurality of dielectric units is configured as a first transmission surface; The first transmission surface of each of the dielectric units has a first end and a second end. In the first direction, the second end is located between the first end and the first dielectric layer, and in a plane perpendicular to the first direction, the second end is located between the first end and the adjacent dielectric unit.

3. The dielectric plate according to claim 2, characterized in that: From the first end to the second end, the first transmission surface as a whole gradually extends toward the adjacent dielectric unit along a direction inclined to the first direction to form an outward expansion surface.

4. The dielectric plate according to claim 2 or 3, characterized in that: Each of the dielectric units is arranged into a prism-shaped structure or a pyramid-shaped structure, the entire outer peripheral surface of the prism-shaped structure or the pyramid-shaped structure is configured as the first transmission surface, and the second end of the first transmission surface is located on the first surface of the first dielectric layer, wherein the first surface of the first dielectric layer faces the second dielectric layer.

5. The dielectric plate according to claim 4, characterized in that: In each of the pyramidal structures, the first end of the first transmission surface constitutes a tip of the pyramidal structure; Each of the prism-shaped structures has a first bottom surface and a second bottom surface which are arranged opposite to each other and in parallel in the first direction, the first bottom surface is connected to the first end of the first transmission surface and is configured as a second transmission surface, the second transmission surface is parallel to the first surface of the first dielectric layer, the second bottom surface is connected to the second end of the first transmission surface, and a portion of the first surface of the first dielectric layer constitutes the second bottom surface; the first surface of the first dielectric layer is perpendicular to the first direction, and the angle between the first transmission surface of each of the prism-shaped structures and the first surface of the first dielectric layer is 25° to 60°.

6. The dielectric plate according to claim 5, characterized in that: The first bottom surface and the second bottom surface are both square, the side length of the first bottom surface is p1, the side length of the second bottom surface is p2, <p1 / p2≤1 / 2。 7. The dielectric plate according to claim 2 or 3, characterized in that: Each of the dielectric units is configured as a conical structure or a truncated cone structure, the entire outer circumferential surface of each of the conical structure or the truncated cone structure is configured as the first transmission surface, and the second end of the first transmission surface is located on the first surface of the first dielectric layer, wherein the first surface of the first dielectric layer faces the second dielectric layer.

8. The dielectric plate according to claim 7, characterized in that: In the conical structure, the first end of the first transmission surface constitutes a tip of the conical structure; Each of the truncated cone structures has a first bottom surface and a second bottom surface which are arranged opposite to each other and in parallel in the first direction, the first bottom surface is connected to the first end of the first transmission surface and is configured as a second transmission surface, the second transmission surface is parallel to the first surface of the first dielectric layer, the second bottom surface is connected to the second end of the first transmission surface, and a part of the first surface of the first dielectric layer constitutes the second bottom surface; the radius of the first bottom surface is r1, the radius of the second bottom surface is r2, and the radius of the second bottom surface is r3. <r1 / r2≤1 / 2。 9. The dielectric plate according to claim 2 or 3, characterized in that: Each of the dielectric units is configured as a spherical structure, and the spherical surface of each of the spherical structures as a whole constitutes the outer peripheral surface of the dielectric unit and is configured as the first transmission surface.

10. The dielectric plate according to claim 9, characterized in that: The spherical diameter of each of the spherical structures is D, the thickness of the second dielectric layer is h2, and 1 / 2≤h2 / D≤2 / 3.

11. The dielectric plate according to any one of claims 1 to 10, characterized in that: The thickness of the first dielectric layer is h1, and the thickness of the second dielectric layer is h2. <h1 / h2≤1 / 3。 12. The dielectric plate according to any one of claims 1 to 11, characterized in that: The sum of the thickness of the first dielectric layer and the second dielectric layer is 0.6 mm to 1 mm.

13. The dielectric plate according to any one of claims 1 to 12, characterized in that: The first dielectric layer and the second dielectric layer are an integrated structure.

14. The dielectric plate according to any one of claims 1 to 13, characterized in that: The dielectric constant of the dielectric plate is 3-10.

15. The dielectric plate according to any one of claims 1 to 14, characterized in that: The material of the medium plate is glass.

16. The dielectric plate according to any one of claims 1 to 15, characterized in that: The plurality of dielectric units are distributed in an array in a second direction and a third direction on a surface of the first dielectric layer facing the second dielectric layer, wherein the first direction, the second direction, and the third direction are perpendicular to each other.

17. A frequency selective surface, characterized in that: The invention comprises a metal layer and a dielectric plate as claimed in any one of claims 1 to 15.

18. The frequency selective surface according to claim 17, characterized in that The metal layer is attached to the surface of the first dielectric layer facing the second dielectric layer and is embedded between the plurality of dielectric units of the second dielectric layer. The metal layer surrounds the outer circumference of each dielectric unit.

19. The frequency selective surface according to claim 17 or 18, characterized in that The metal layer is arranged in a grid structure and includes a plurality of metal units arranged in an array on a surface of the first dielectric layer facing the second dielectric layer, the plurality of metal units corresponding one to one to the plurality of dielectric units, and each of the plurality of metal units surrounds the outer peripheral side of the corresponding dielectric unit.

20. The frequency selective surface according to claim 19, characterized in that Orthographic projections of the plurality of dielectric units and the plurality of metal units on the first dielectric layer along the first direction cover the entire first dielectric layer.

21. A back cover for an electronic device, characterized in that: It comprises the dielectric plate according to any one of claims 1 to 16 or the frequency selective surface according to any one of claims 17 to 20.

22. An electronic device, comprising a housing, characterized in that: The housing comprises a rear cover as claimed in claim 21.

23. The electronic device according to claim 22, characterized in that: The electronic device further includes an antenna, which is accommodated in the housing and is disposed correspondingly in a central area of ​​the dielectric plate in a plane perpendicular to the first direction.

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