Flat panel antenna and electronic device

Abstract

The present disclosure provides a flat plate antenna and electronic equipment, which belong to the technical field of antennas, and can solve the problems of low aperture utilization, uneven radiation amplitude and difficulty in realizing multi-frequency coverage of existing flat plate antennas. The flat plate antenna comprises a waveguide structure, a first dielectric substrate, a radiation layer and a plurality of switch units. The radiation layer has a plurality of slit openings. The switch units are arranged one by one corresponding to the slit openings and are configured to control the switch state of the corresponding slit openings. The radiation layer is divided into a middle region and a peripheral region. Part of the plurality of slit openings located in the middle region is divided into a plurality of groups. Each group of slit openings includes at least a plurality of first slit openings. The sizes of the first slit openings located in different groups are different, and the sizes of the first slit openings in the group closer to the center of the middle region are larger. The flat plate antenna has the advantages of high aperture utilization, multi-frequency coverage and uniform radiation amplitude.

Description

Flat panel antennas and electronic devices Technical Field

[0001] This disclosure belongs to the field of antenna technology, specifically relating to a flat panel antenna and an electronic device. Background Technology

[0002] As a type of aperture antenna, planar slot array antennas offer easy control over the amplitude distribution within the antenna aperture plane. They boast high aperture plane utilization, small size, and light weight, enabling the achievement of low or extremely low sidelobes. Furthermore, due to their low profile and small size, planar slot array antennas are well-suited for integration into various electronic devices and communication systems. In addition, planar slot array antennas offer the advantage of frequency adjustability. Therefore, in recent years, planar slot array antennas have been widely used in wireless communication, radar systems, and satellite communication.

[0003] Functionally, a planar slot array antenna mainly consists of a radiating section and a feeding section. Physically, it mainly consists of a feeding structure, a reference electrode layer, a waveguide structure, a dielectric layer, and a radiating layer stacked sequentially. The waveguide structure has a feeding port for connecting the antenna to the feeding structure, allowing the microwave signal emitted by the feed source to be fed into the waveguide structure; this part is called the feeding section. The radiating layer has multiple slits for radiating the electromagnetic waves transmitted in the waveguide structure into external space; this part is called the radiating section.

[0004] As can be seen, practical planar slot array antennas are typically array antennas composed of multiple excitation slots opened on a conductor plate with a limited area. Each slot is equivalent to an array element. The radiation characteristics of the array antenna depend on factors such as the properties, number, arrangement, and current amplitude and phase distribution of the array elements. Therefore, in order to improve the bandwidth, gain, aperture utilization, and reconfigurability of planar slot array antennas, it is necessary to calculate and design the properties, number, and arrangement of the slots. Summary of the Invention

[0005] This invention aims to at least solve one of the technical problems existing in the prior art. On one hand, it provides a planar antenna, comprising a waveguide structure, a first dielectric substrate, a radiating layer, and a plurality of switching units sequentially disposed on the waveguide structure; wherein the radiating layer has a plurality of slit openings extending along its thickness direction; the switching units are arranged one-to-one with the slit openings, and the switching units are configured to control the switching state of the corresponding slit openings; the radiating layer is divided into a central region and a peripheral region surrounding the central region; the portion of the plurality of slit openings located in the central region is divided into multiple groups, and each group of slit openings is sequentially nested; each group of slit openings includes at least a plurality of first slit openings, and at least some of the first slit openings in different groups have different sizes, with the first slit openings in the group closer to the center of the central region having larger sizes.

[0006] As an alternative embodiment, each group of slit openings includes at least one ring of slit openings, and the first slit openings in the same group of slit openings are of the same size.

[0007] As an optional embodiment, each slit opening further includes a second slit opening, and the size of the second slit opening is smaller than the size of the first slit opening.

[0008] As an optional embodiment, each ring of slit openings includes a plurality of slit openings arranged clockwise, and every two adjacent slit openings constitute a first unit; for any first unit, the extension line of one slit opening along its length is a first straight line, and the line connecting the center of the slit opening and the center of the intermediate region is a third straight line; the extension line of the other slit opening along its length is a second straight line, and the line connecting the center of the slit opening and the center of the intermediate region is a fourth straight line; the angle between the first straight line and the third straight line is -45°, and the angle between the second straight line and the fourth straight line is 45°.

[0009] As an optional embodiment, the portion of the slit opening located in the peripheral region is divided into a plurality of second units; the slit opening in the second unit includes at least the first slit opening.

[0010] As an optional embodiment, the number of the second units is four, and the line connecting the center of two of the second units to the center of the intermediate region is a fifth straight line, and the line connecting the center of the other two second units to the center of the intermediate region is a sixth straight line; the fifth straight line and the sixth straight line are orthogonal.

[0011] As an optional embodiment, the slit opening in the second unit further includes a second slit opening, the size of which is smaller than the size of the first slit opening.

[0012] As an optional embodiment, the planar antenna includes four sets of slit openings nested in sequence, wherein the first slit openings in the same set are all the same size, and the ratio of the size of the first slit openings in each set away from the center of the intermediate region is 6.3:6.2:6:5.0.

[0013] As an optional embodiment, the portion of the plurality of slit openings located in the middle region is divided into multiple rings, with each ring of slit openings arranged clockwise at intervals; the distance between two adjacent rings of slit openings is between 0.1λ and 0.5λ, where λ is the wavelength of free space corresponding to the operating frequency of the planar antenna.

[0014] As an optional embodiment, the portion of the plurality of slit openings located in the middle region is divided into multiple rings, with each ring of slit openings arranged clockwise at intervals; in the ring of slit openings closest to the center of the middle region, the distance between the centers of two adjacent slit openings is between 0.24λ and 0.30λ, where λ is the wavelength in free space corresponding to the operating frequency of the planar antenna.

[0015] As an optional embodiment, the portion of the plurality of slit openings located in the middle region is divided into multiple rings, with each ring of slit openings arranged clockwise at intervals; the distance between the slit opening closest to the center of the middle region and the center of the middle region is not less than 0.30λ, where λ is the wavelength of free space corresponding to the operating frequency of the planar antenna.

[0016] As an optional embodiment, it further includes a metasurface structure located on the side of the radiating layer opposite to the first dielectric substrate; the orthographic projection of the metasurface structure on the waveguide structure at least covers the orthographic projection of the radiating layer on the waveguide structure.

[0017] As an optional embodiment, the metasurface structure includes: a second dielectric substrate having a first surface and a second surface, the first surface being closer to the radiating layer; and a plurality of metasurface units arranged in an array on the second surface side of the second dielectric substrate.

[0018] As an optional embodiment, the metasurface unit is square with a side length between 0.16λ and 0.174λ, and the spacing between any two adjacent metasurface units is between 0.18λ and 0.195λ, where λ is the wavelength in free space corresponding to the operating frequency of the flat panel antenna.

[0019] As an optional embodiment, the switching unit includes any one of a PIN diode, a variable reactance diode, a liquid crystal switch, and a MEMS switch.

[0020] As an optional embodiment, a feeding structure is also included, configured to feed microwave signals into the waveguide structure.

[0021] As an optional embodiment, the power supply structure includes a coaxial probe.

[0022] Secondly, the present invention provides an electronic device including the flat panel antenna described in any of the above embodiments. Attached Figure Description

[0023] Figure 1 is a schematic diagram of a planar slot array antenna in related technologies.

[0024] Figure 2 is a top perspective view of the planar slot array antenna shown in Figure 1.

[0025] Figure 3 is a front perspective view of the flat panel antenna provided in an embodiment of this disclosure.

[0026] Figure 4 is a top perspective view of the flat panel antenna provided in an embodiment of this disclosure.

[0027] Figure 5 is a distribution diagram of the first slit opening and the second slit opening in the planar antenna provided in the embodiments of this disclosure.

[0028] Figure 6 is a schematic diagram of the first unit consisting of two slit openings.

[0029] Figure 7 is a schematic diagram of the spacing between the two slit openings.

[0030] Figure 8 shows the radiation simulation diagram of the first slit opening of different sizes in the planar antenna shown in Figure 3.

[0031] Figure 9 shows the simulation results of the return loss of the planar antenna shown in Figure 3.

[0032] Figure 10 shows the simulation results of the radiation pattern of the flat panel antenna shown in Figure 3 at 12.7 GHz.

[0033] Figure 11 shows the simulation results of the left-hand circular polarization axial ratio of the flat panel antenna shown in Figure 3 in the 12GHz-13GHz frequency band.

[0034] Figure 12 shows the simulation results of the gain curve of the flat panel antenna shown in Figure 3 in the 12GHz-13GHz frequency band.

[0035] Figure 13 is a front perspective view of a planar antenna with an added metasurface structure.

[0036] Figure 14 is a top perspective view of the flat panel antenna shown in Figure 13.

[0037] Figure 15 shows the simulation results of the planar antenna shown in Figure 13 at 12.7 GHz.

[0038] Figure 16 shows the simulation results of the left-hand circular polarization axial ratio of the flat panel antenna shown in Figure 13 in the 12GHz-13GHz frequency band.

[0039] Figure 17 shows the simulation results of the gain curve of the flat panel antenna shown in Figure 13 in the 12GHz-13GHz frequency band.

[0040] Figure 18 is a schematic diagram of the structure when a PIN diode is used as a switching unit.

[0041] Figure 19 is a schematic diagram of the structure when an LCD switch is used as the switching unit.

[0042] Figure 20 is a schematic diagram of the structure when a MEMS switch is used as the switching unit.

[0043] The attached figures are labeled as follows:

[0044] 101. Waveguide structure; 102. First dielectric substrate; 103. Radiation layer; 104. Feeding structure; 106. Switching unit; 201. Slit opening; R1. Middle region; R2. Peripheral region; 1021. Third dielectric substrate; 1022. Air dielectric layer; G1. First group; G2. Second group; G3. Third group; G4. Fourth group; 2011. First slit opening; 2012. Second slit opening; L1. First straight line; L2. Second straight line; L3. Third straight line; L4. Fourth straight line; L5. Fifth straight line; L6. Sixth straight line; 401. First unit; 107. Metasurface structure; 1071. Second dielectric substrate; 1072. Metasurface unit; 108. Liquid crystal layer; 109. Opposing substrate; 110. Control electrode; 111. Patch electrode. Detailed Implementation

[0045] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0046] Unless otherwise defined, the technical or scientific terms used in this disclosure shall have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms “first,” “second,” and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms “an,” “a,” or “the,” and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms “including,” “comprising,” or “containing,” and similar terms mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. The terms “connected,” “linked,” or similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The terms “upper,” “lower,” “left,” and “right,” etc., are used only to indicate relative positional relationships, and these relative positional relationships may change accordingly when the absolute position of the described objects changes.

[0047] As used herein, “parallel” and “perpendicular” include the described situation and situations that are similar to the described situation, within an acceptable range of deviation, which is determined by those skilled in the art taking into account the measurement under discussion and the error associated with the measurement of a particular quantity (i.e., the limitations of the measurement system). For example, “parallel” includes absolute parallelism and approximate parallelism, where an acceptable range of deviation for approximate parallelism may be, for example, within 5°; “perpendicular” includes absolute perpendicularity and approximate perpendicularity, where an acceptable range of deviation for approximate perpendicularity may also be, for example, within 5°.

[0048] It should be understood that when a layer or element is referred to as being on another layer or substrate, it can mean that the layer or element is directly on the other layer or substrate, or that there is an intermediate layer between the layer or element and the other layer or substrate.

[0049] This document describes exemplary embodiments with reference to sectional views and / or plan views, which are idealized exemplary drawings. In the drawings, the thickness of layers and regions is enlarged for clarity. Therefore, variations in shape relative to the drawings are contemplated due to, for example, manufacturing techniques and / or tolerances. Therefore, exemplary embodiments should not be construed as limited to the shapes of the regions shown herein, but rather include shape deviations due to, for example, manufacturing processes. Thus, the regions shown in the drawings are schematic in nature, and their shapes are not intended to show the actual shapes of the regions of the device, nor are they intended to limit the scope of the exemplary embodiments.

[0050] Reconfigurability, as a new requirement for modern antennas, can greatly improve the reusability of antennas and reduce the cost and complexity of antenna systems. For example, a frequency-reconfigurable antenna can operate at several frequency points; a polarization-reconfigurable antenna can realize multiple polarization modes; and a beam-reconfigurable antenna can switch between multiple beam directions, possessing the function of a phased scanning array.

[0051] Figures 1 and 2 are schematic diagrams of a planar slot array antenna in related technologies. Figure 1 is a front perspective view of the planar slot array antenna, and Figure 2 is a top perspective view of the planar slot array antenna. As shown in Figure 1, a typical planar slot array antenna includes a feed structure 104, a waveguide structure 101, a first dielectric substrate 102, a radiating layer 103, and multiple switching units 106 sequentially disposed on the waveguide structure 101. The waveguide structure 101 and the radiating layer 103 can be made of metallic materials, such as aluminum or copper. A through-hole penetrating the thickness of the waveguide structure 101 is provided, called a feed port, for connecting the feed structure 104 to the waveguide structure 101, allowing the microwave signal emitted by the feed source to be transmitted into the waveguide structure 101. As shown in Figure 2, the radiating layer 103 has multiple slit openings 201 of the same size. Switching units 106 are configured to correspond one-to-one with each slit opening 201, and the switching units 106 are configured to control the switching state of their respective slit openings 201. Referring again to Figure 2, the radiating layer 103 can be divided into a central region R1 and a peripheral region R2 surrounding the central region R1. In related technologies, multiple slit openings 201 of the same size are all located in the central region R1. The operation of this planar slot array antenna is roughly as follows: microwave signals are transmitted through the feed structure 104 into the waveguide structure 101, propagating from the feed port in a direction away from the feed port; subsequently, the microwave signals propagating within the waveguide structure 101 are radiated into external space through the slit openings 201.

[0052] Due to structural limitations, the planar slot array antennas in the related technologies shown in Figures 1-2 typically suffer from the following technical problems:

[0053] 1. Low Aperture Utilization. Aperture utilization is a crucial performance parameter in antenna design, used to evaluate the antenna's radiation efficiency and performance. Aperture utilization refers to the ratio between the antenna's effective radiating area and its physical aperture, expressed by the formula: Aperture Utilization = Effective Radiating Area / (π * (Aperture / 2)^2). The value typically ranges from 0 to 1. A higher aperture utilization indicates higher antenna radiation efficiency, meaning it can more effectively convert input power into radiated power. The effective radiating area refers to the actual area of ​​the antenna used for transmitting and receiving signals, excluding areas where signals cannot be radiated. In related technologies, the slit opening 201 that can radiate signals is often concentrated only in the central region R1. The surrounding region R2, located around the central region R1, usually does not have slit openings 201. Therefore, the effective radiating area of ​​planar slot array antennas in related technologies is relatively small, resulting in low aperture utilization.

[0054] 2. Uneven overall antenna radiation amplitude. Typically, the feed port of a planar slot array antenna is located at the center of the waveguide structure 101. If the center of the waveguide structure 101 is the center of a circle, the energy of the electromagnetic field propagating within the waveguide structure 101 gradually weakens with distance from the center. Since the slit openings 201 of the planar slot array antenna in related technologies are all of the same size, meaning that each slit opening 201 has the same ability to radiate energy into the external space, in this case, the energy radiated into the external space by the entire radiating layer 103 of the planar slot array antenna weakens with distance from the center, thus resulting in uneven overall antenna radiation amplitude.

[0055] 3. Difficulty in achieving multi-frequency coverage. The size design of the slit opening 201 directly affects the antenna's radiation performance. For example, studies have shown that the length of the slit opening 201 has a significant impact on the antenna's resonant frequency, while the width of the slit opening 201 has a very significant impact on the antenna's bandwidth and input impedance, and can cause the antenna's resonant frequency to drift. In related technologies, the size of each slit opening 201 in the planar slot array antenna is the same, which limits the antenna's bandwidth to a certain frequency corresponding to the size of that slit opening 201, making it difficult to achieve multi-frequency coverage.

[0056] In summary, planar slot antennas in related technologies suffer from drawbacks such as low aperture utilization, uneven overall radiation amplitude, and difficulty in achieving multi-frequency coverage, resulting in a lack of reconfigurability and poor radiation performance. Therefore, there is still room for improvement.

[0057] To address at least one of the aforementioned technical problems, in a first aspect, this disclosure provides a planar antenna. Figure 3 shows a front perspective view of the planar antenna provided in this disclosure, and Figure 4 shows a top perspective view of the planar antenna provided in this disclosure. Referring to Figure 3, the planar antenna provided in this disclosure includes a waveguide structure 101, a first dielectric substrate 102, a radiating layer 103, and a plurality of switching units 106 sequentially disposed on the waveguide structure 101. Referring to Figure 4, the radiating layer 103 has a plurality of slit openings 201 penetrating its thickness, and the switching units 106 are correspondingly disposed with respect to the slit openings 201. The switching units 106 are configured to control the switching state of the corresponding slit openings 201. In some examples, the switching units 106 may be liquid crystal switches. Figure 19 is a schematic diagram of the structure of a liquid crystal switch. Referring to Figures 3 and 19, the liquid crystal switch includes a first dielectric substrate 102 and a counter substrate 109 opposite to the first dielectric substrate 102. The counter substrate 109 may be a glass substrate. A control electrode 110 is provided on the side of the opposing substrate 109 near the radiating layer 103. A liquid crystal layer 108 is provided between the layer containing the control electrode 110 and the layer containing the radiating layer 103. By changing the voltage applied to the control electrode 110, the deflection angle of the liquid crystal molecules in the liquid crystal layer 108 can be changed, thereby controlling the opening and closing state of the slit opening 201. Referring again to FIG4, the radiating layer 103 can be divided into a central region R1 and a peripheral region R2 surrounding the central region R1; a portion of the plurality of slit openings 201 is located in the central region R1, and the remainder is located in the peripheral region R2. The slit openings 201 located in the central region R1 can be divided into multiple groups, with each group of slit openings 201 nested sequentially. Each group of slit openings 201 includes at least a plurality of first slit openings 2011. At least some of the first slit openings 2011 located in different groups have different sizes, and the first slit openings 2011 in the group of slit openings closer to the center of the central region R1 are larger.

[0058] Those skilled in the art will understand that in a planar slot array antenna, the slot openings 201 formed on the radiating layer 103 typically include two different types: active slots and inactive slots, whose operating states are controlled by corresponding switching units 106. An active slot is one that is excited or used to radiate signals. When current passes through an active slot, a radiation field is generated at the location of the active slot, thus realizing the antenna's radiation function. Active slots are typically designed with a specific size and shape to achieve specific radiation characteristics and frequency response. Inactive slots are those that are not excited or used to radiate signals. Inactive slots do not generate radiation, i.e., they do not have the ability to radiate energy, but they play a supporting and isolating role in the overall antenna structure. Inactive slots are typically designed to be spaced apart from active slots to maintain the stability and performance of the antenna structure. It should be noted that, in the embodiments of this disclosure, the first slit opening 2011 refers to the working slit opening, and the second slit opening 2012 refers to the non-working slit opening.

[0059] Figure 5 shows a schematic diagram of the number and position of the first slit opening 2011 and the second slit opening 2012 in the radiating layer 103 among multiple slit openings 201, where "0" represents a non-working slit opening and "1" represents a working slit opening. Taking Figure 5 as an example, the first slit opening 2011 and the second slit opening 2012 are specifically explained. As shown in Figure 5, in the multiple slit openings 201 of the planar antenna provided in this disclosure, the first ring of slit openings 201 (the ring of slit openings closest to the center of the central region R1) includes 6 first slit openings 2011, the second ring of slit openings 201 (adjacent to the first ring of slit openings) includes 8 first slit openings 2011, the third ring of slit openings 201 includes 11 first slit openings 2011, and so on. The arrangement of the first slit openings 2011 and the second slit openings 2012 can be seen in Figure 5, and will not be listed here individually.

[0060] In other words, in the planar antenna provided in this embodiment, the slit opening 201 located in the middle region R1 can be divided into multiple groups, and each group of slit openings 201 is nested sequentially. Each group of slit openings 201 includes at least multiple working slit openings (first slit openings 2011). At least some of the working slit openings in different groups have different sizes, and the working slit openings in the group of slit openings 201 closer to the center of the middle region R1 have larger sizes. This arrangement can achieve at least the following beneficial effects: On the one hand, the planar antenna can realize multi-bit modulation and weight the energy amplitude radiated at different positions of the radiating layer 103. In practical applications, the size of the working slit openings at different positions can be adjusted according to actual needs to make the energy amplitude radiated by the entire radiating layer 103 more uniform, thereby improving the gain of the planar antenna; on the other hand, the resonant frequencies corresponding to working slit openings of different sizes are different. Therefore, by combining working slit openings of various sizes, the antenna can achieve multi-frequency coverage, expand the antenna bandwidth, and realize frequency reconfigurability. In addition, in the planar antenna provided in this embodiment, a portion of the plurality of slit openings 201 are located in the central region R1, while the remaining portion is located in the peripheral region R2. This arrangement is equivalent to increasing the area of ​​the effective radiation region in the planar antenna without changing the physical aperture size of the planar antenna. Therefore, the aperture utilization rate of the antenna can be effectively improved.

[0061] Specifically, in the planar antenna provided in this embodiment, each group of slit openings 201 includes at least one ring of slit openings 201. In some examples, the size of the first slit opening 2011 in different rings of slit openings 201 within the same group can be different, or even the size of the first slit opening 2011 in each ring of slit openings can be different, that is, in a gradual form. For example, the size of the first slit opening 2011 in different rings can be between 0.1λ and 0.4λ, where λ is the wavelength of free space corresponding to the operating frequency of the planar antenna; for example, the operating frequency band of the planar antenna provided in this embodiment is 11GHz-13GHz, which is in the high-frequency electromagnetic wave range. However, in some other examples, the size of the first slit opening 2011 in the same group of slit openings 201 can be the same.

[0062] Both of the above examples can achieve multi-bit modulation, which can make the overall radiation amplitude of the flat panel antenna more uniform and improve the gain. However, compared with the first example, the fabrication process of the flat panel antenna in the second example is simpler, so the manufacturing cost is lower.

[0063] Furthermore, in some examples, each ring of slit opening 201 also includes a second slit opening 2012 (i.e., the non-working slit opening mentioned above, the location and number of which can be seen in Figure 5), and the size of the second slit opening 2012 is smaller than the size of the first slit opening 2011. It should be noted that in some other examples, each ring of slit opening 201 may only include the first slit opening 2011, without including the second slit opening 2012. In other words, no slit opening 201 is opened at the position indicated by "0" in Figure 5.

[0064] In the two examples described above, compared to the structure without the second slit opening 2012 in the latter example, the planar antenna with the second slit opening 2012 in the former example has the following additional advantages: On the one hand, it can effectively reduce the effective length and weight of the radiating layer 103, thereby contributing to the compactness and lightweighting of the planar antenna structure; on the other hand, by rationally designing the position and size of the inactive slit opening, the impedance matching of the planar antenna can be adjusted, allowing the antenna to better adapt to specific operating frequencies and system requirements. Furthermore, since the planar antenna provided in this embodiment operates at a high frequency, setting the size of the inactive slit opening to be smaller than the size of the active slit opening prevents it from radiating high-frequency electromagnetic waves; that is, its operating state is "off," thus avoiding interference with the radiation performance of the active slit opening.

[0065] The following provides several examples of the tilt angle settings for the slit openings 201. Figure 6 shows an example of the arrangement of a ring of slit openings 201. As shown in Figure 6, each ring of slit openings 201 includes multiple slit openings 201 arranged clockwise, and every two adjacent slit openings 201 constitute a first unit 401. For any first unit 401, the extension line of one slit opening 201 in the length direction is a first straight line L1, and the line connecting the center of this slit opening 201 and the center of the intermediate region R1 is a third straight line L3; the extension line of the other slit opening 201 in the length direction is a second straight line L2, and the line connecting the center of this slit opening 201 and the center of the intermediate region R1 is a fourth straight line L4. The angle θ1 between the first straight line L1 and the third straight line L3 is -45°, and the angle θ2 between the second straight line L2 and the fourth straight line L4 is 45°.

[0066] In the above example, the electromagnetic waves radiated by the two slit openings 201 in any first unit 401 have polarization directions of 45° and -45°, respectively. Positive and negative 45° are two mutually orthogonal linear polarization directions. Therefore, multiple slit openings 201 at positive and negative 45° can radiate signals with arbitrary polarization directions. Thus, the planar antenna provided in the above example has great flexibility and can easily realize polarization signals in various directions, thereby achieving polarization reconstruction and making its application scenarios more extensive. Of course, for any first unit 401, the angle θ1 between the first line L1 and the third line L3, and the angle θ2 between the second line L2 and the fourth line L4 can also be other values. For example, the angle θ1 between the first line L1 and the third line L3 can be 40°, and correspondingly, the angle θ2 between the second line L2 and the fourth line L4 can be 50°. In this case, for another example, the angle θ1 between the first line L1 and the third line L3 can be 30°, and correspondingly, the angle θ2 between the second line L2 and the fourth line L4 can be 60°. It can be understood that in any of the above examples, the polarization directions of the electromagnetic waves radiated by the two slit openings 201 in any first unit 401 are two mutually orthogonal linear polarization directions, and therefore can also constitute signals with arbitrary polarization directions.

[0067] Referring again to Figure 4, in some examples, the portion of the slit opening 201 located in the peripheral region R2 can be divided into multiple second units, for example, four second units. These four second units satisfy the following conditions: the line connecting the center of two of the second units to the center of the intermediate region R1 is a fifth straight line L5; the line connecting the center of the other two second units to the center of the intermediate region R1 is a sixth straight line L6; the fifth straight line L5 and the sixth straight line L6 are orthogonal to each other, or the angle between the fifth straight line L5 and the sixth straight line L6 is within the range of 85°-95°. Furthermore, as shown in Figure 5, each slit opening 201 in each second unit includes at least a first slit opening 2011. Of course, in some examples, each slit opening 201 in each second unit may also include a second slit opening 2012.

[0068] In the example above, it is equivalent to setting slit openings 201 at the upper left, lower left, upper right, and lower right corners of the radiating layer 103 of the flat panel antenna. The upper left and lower right corners form a diagonal pair, and the two second units located at these diagonals are symmetrical. Similarly, the lower left and upper right corners also form a diagonal pair, and the two second units located at these diagonals are also symmetrical. This arrangement achieves the following beneficial effects: Firstly, it can maximize the area of ​​the effective radiating region in the radiating layer 103, thereby improving aperture utilization. Secondly, the symmetrical radiating regions help reduce the sidelobes of the radiated wave from the flat panel antenna, improving the directivity of the radiation. Thirdly, the symmetrical radiating structure simplifies the antenna design and manufacturing process, thereby reducing cost and complexity.

[0069] Furthermore, when the slit opening 201 in the second unit also includes a second slit opening 2012, the size of the second slit opening 2012 is smaller than the size of the first slit opening 2011. In this case, the second slit opening 2012 is in an "off" state for the planar antenna operating in the high-frequency band, that is, it cannot play a radiation role, thus avoiding interference with the radiation effect of the first slit opening 2011.

[0070] Based on the above inventive concept, two specific embodiments of flat panel antennas are provided below.

[0071] In the first specific embodiment, the portion of the multiple slit openings 201 located in the middle region R1 is divided into multiple rings. The size of the first slit opening 2011 located in different rings is different, and the size of the first slit opening 2011 closer to the center of the middle region R1 is larger. Specifically, the length of each ring of slit openings 201 can be between 0.1λ and 0.4λ (approximately 2.4mm to 9.4mm), and the width can be between 0.48mm and 0.52mm, preferably 0.5mm.

[0072] In the second specific embodiment, referring to Figure 4, the planar antenna may include four nested sets of slit openings 201. Along the direction away from the center of the central region R1, the four sets of slit openings 201 are designated as a first set G1, a second set G2, a third set G3, and a fourth set G4. The first set G1, the second set G2, and the third set G3 each include four rings of slit openings 201, and the fourth set G4 includes five rings of slit openings 201. The dimensions of the first slit openings 2011 within the same set are all the same, and the ratio of the dimensions of the first slit openings 2011 in each set away from the center of the central region R1 is: 6.3; 6.2; 6; 5.8. Meanwhile, the dimensions of the first slit openings 2011 located in the peripheral region R2 are smaller than the dimensions of the first slit openings 2011 located in the central region R1, and the dimensions of the second slit openings 2012 at different locations are all the same and smaller than the dimensions of any of the first slit openings 2011.

[0073] For example, the length of the first slit opening 2011 located in the first group G1 can be 0.23λ-0.27λ, for example, 6.3 mm, and its width can be 0.5 mm; the length of the first slit opening 2011 located in the second group G2 can be 0.22λ-0.26λ, for example, 6.2 mm, and its width can be 0.5 mm; the length of the first slit opening 2011 located in the third group G3 can be 0.219λ-0.259λ, for example, 6 mm, and its width can be 0.5 mm; the length of the first slit opening 2011 located in the fourth group G4 can be 0.212λ-0.25λ, for example, 5.8 mm, and its width can be 0.5 mm. The length of the first slit opening 2011 located in the peripheral region R2 can be 0.208λ-0.246λ, for example, 5.7 mm, and its width can be 0.5 mm. The length of the second slit opening 2012 at any location can be 0.15λ-0.17λ, for example, 4 mm, and its width can be 0.5 mm.

[0074] Furthermore, in some examples, as shown in Figure 7, the distance d1 between two adjacent rings of slit openings 201 is 0.1λ-0.5λ, preferably 5mm. The distance d1 between two adjacent rings of slit openings 201 is explained below. The ring of slit openings 201 closest to the center of the central region R1 is called the first ring, and the other is called the second ring. Those skilled in the art will understand that the center O1 of the central region R1, the center O2 of the slit opening 201 in the first ring, and the center O3 of the slit opening 201 in the second ring can be located on the same straight line. In this case, the line connecting O1 and O2 is defined as the first line segment, and the line connecting O1 and O3 is called the second line segment. Therefore, the distance d1 between two adjacent rings of slit openings 201 is the difference in length between the second line segment and the first line segment.

[0075] Furthermore, still referring to Figure 7, in some examples, the distance d2 between the ring of slit openings 201 closest to the center O1 of the intermediate region R1 and the center O1 of the intermediate region R1 is not less than 0.30λ, for example, it can be 12mm. For the ring of slit openings 201 closest to the center O1 of the intermediate region R1, the distance d8 between the centers of two adjacent slit openings 201 in this ring is between 0.24λ and 0.30λ, for example, it can be 6mm to 7mm.

[0076] In some examples, as shown in Figure 3, the planar antenna further includes a third dielectric substrate 1021 and an air dielectric layer 1022 located between the first dielectric substrate 102 and the waveguide structure 101, wherein the air dielectric layer 1022 is located between the third dielectric substrate 1021 and the first dielectric substrate 102. The waveguide structure 101 and the radiating layer 103 can be made of metallic materials. For example, the waveguide structure 101 can be, but is not limited to, aluminum or aluminum alloy, and the material of the radiating layer 103 can be, but is not limited to, copper, with a thickness of 0.002 mm. The first dielectric substrate 102 and the third dielectric substrate 1021 can be slow-wave dielectric materials. For example, the first dielectric substrate 102 can be, but is not limited to, a glass substrate, with a thickness of 0.5 mm. The third dielectric substrate 1021 can be, but is not limited to, polytetrafluoroethylene (PTFE), PCB, PET, and other polymer low-loss dielectric materials, with a thickness of 2.5 mm. The thickness of the air dielectric layer 1022 can be 1.2 mm. The overall dimensions of the planar antenna are approximately 200 mm × 200 mm × 7 mm.

[0077] Figures 8-12 show the simulation results of the radiation performance of the planar antenna provided in the second embodiment described above. Figure 8 shows the simulation results of the radiation from the first slit opening 2011 with different sizes. As can be seen from Figure 8, the frequency of the electromagnetic wave radiated when the first slit opening 2011 with different sizes has optimal radiation performance is different, meaning that the planar antenna provided in this embodiment can achieve multi-frequency coverage. Figure 9 shows the return loss S of the planar antenna provided in this embodiment. 11 As shown in Figure 9, the impedance matching of the planar antenna provided in this disclosure is good. Figure 10 shows the radiation pattern of the planar antenna provided in this disclosure at 12.7 GHz, demonstrating its good operating performance. Figures 11 and 12 show the left-hand circular polarization axial ratio and gain curves of the planar antenna provided in this disclosure in the 12 GHz-13 GHz frequency band, respectively. As seen in Figures 11-12, the planar antenna provided in this disclosure exhibits good polarization and gain characteristics. In summary, the planar antenna provided in this disclosure offers reconfigurability in terms of frequency and polarization, and possesses good transmission performance, meeting the requirements of communication operations.

[0078] Furthermore, in some examples, the planar antenna provided in this disclosure also includes a metasurface structure 107 located on the side of the radiating layer 103 facing away from the first dielectric substrate 102. Figure 13 shows a front perspective view of the planar antenna including the metasurface structure 107, and Figure 14 shows a top perspective view of the planar antenna shown in Figure 13. As shown in Figures 13 and 14, the orthographic projection of the metasurface structure 107 onto the waveguide structure 101 at least covers the orthographic projection of the radiating layer 103 onto the waveguide structure 101. The metasurface structure 107 includes a second dielectric substrate 1071 and a plurality of metasurface units 1072, wherein the second dielectric substrate 1071 has a first surface and a second surface, and the first surface is closer to the radiating layer 103; the plurality of metasurface units 1072 are arrayed on the second surface side of the second dielectric substrate 1071. As shown in Figure 14, the metasurface unit 1072 can be square, with a side length between 0.16λ and 0.174λ, preferably 4 mm. That is, the size of the metasurface unit 1072 is 4 mm × 4 mm, and the distance between any two adjacent metasurface units 1072 can be between 0.18λ and 0.195λ, preferably 4.5 mm. Those skilled in the art will understand that the distance between two adjacent metasurface units 1072 refers to the distance between the centers of the two metasurface units 1072.

[0079] Figures 15-17 show the simulation results of the planar antenna after adding the metasurface structure 107. Figure 15 shows the radiation pattern of the planar antenna at 12.7 GHz; Figures 16 and 17 show the simulation results of the left-hand circular polarization axial ratio and gain curve of the planar antenna in the 12 GHz-13 GHz frequency band, respectively. As can be seen from Figures 15-17, after adding the metasurface structure 107, the circular polarization axial ratio of the planar antenna remains good, and the gain is significantly improved. The gain improvement of the planar antenna is greater than 2 dB across the entire frequency band. Therefore, the above example demonstrates that by adding the metasurface structure 107 above the radiating layer 103, the antenna gain can be effectively improved without affecting the antenna polarization performance.

[0080] It should be noted that the second dielectric substrate 1071 of the aforementioned metasurface structure 107 can be a PCB board, a glass substrate, or a thin film, etc. Among them, the PCB board has better support and is easier to arrange electronic components; the glass substrate has excellent optical properties and can be used to realize transparent or translucent metasurface structures 107, while also having good weather resistance and mechanical strength; the thin film, due to its flexibility, can be flexibly prepared into various shapes. This disclosure does not limit the material of the second dielectric substrate 1071, and it can be selected according to actual needs. In addition, the shape of the metasurface unit 1072 is not limited to a square. Those skilled in the art can select other shapes or patterns of metasurface units according to actual needs, and this disclosure does not limit the shape of the metasurface unit.

[0081] In some examples, the switching unit 106 can be any of a PIN diode, a variable reactance diode (Varactor), a liquid crystal switch, or a MEMS switch. The following is a brief introduction to various types of switching units 106.

[0082] Figure 18 is a schematic diagram of the switching unit 106 when a PIN diode or a variable reactance diode (Varactor) is used as the switching unit 106. As shown in Figure 18, in this case, the PIN diode or Varactor and the slit opening 201 can be integrated to control the switching state of the slit opening 201. Taking the PIN diode as an example, the bias voltage input to the PIN diode is controlled to control the forward / reverse bias of the PIN diode. When the slit opening 201 needs to be in the open state, the bias voltage input to the PIN diode is greater than its conduction threshold, and the PIN diode conducts; when the slit opening 201 needs to be in the closed state, the bias voltage input to the PIN diode is less than its conduction threshold, and the PIN diode is turned off.

[0083] Figure 19 is a schematic diagram of the switching unit 106 when a liquid crystal switch is used as the switching unit 106. As shown in Figure 19, in this case, a counter substrate 109 is provided opposite to the first dielectric substrate 102, and a control electrode 110 is provided on the side of the counter substrate 109 near the radiating layer 103. A liquid crystal layer 108 is provided between the layer containing the control electrode 110 of the counter substrate 109 and the radiating layer 103. By changing the voltage applied to the control electrode 110, the deflection angle of the liquid crystal molecules in the liquid crystal layer 108 is changed, thereby controlling the switching state of the slit opening 201, and thus controlling the amplitude of the radio frequency signal radiated from it.

[0084] Figure 20 is a schematic diagram of the structure of the switching unit 106 when a MEMS switch is used as the switching unit 106. As shown in Figure 20, in this case, a counter substrate 109 is provided opposite to the first dielectric substrate 102. The counter substrate 109 is a flexible substrate. A patch electrode 111 is provided on the side of the counter substrate 109 close to the first dielectric substrate 102, and the patch electrode 111 is provided in a one-to-one correspondence with the slit opening 201. At this time, by applying a voltage to the patch electrode 111, the distance between the patch electrode 111 and the slit opening 201 is adjusted under the action of the electric field force, thereby realizing the control of the switching state of the slit opening 201, so as to regulate the radiation amplitude of the radio frequency signal radiated by the slit opening 201.

[0085] In some examples, referring to FIG3, the planar antenna further includes a feed structure 104 configured to feed microwave signals into the waveguide structure 101. Exemplarily, the feed structure 104 includes a coaxial probe, which includes, but is not limited to, an SMA. Specifically, the waveguide structure 101 has at least a feed port, and the inner core of the coaxial probe in the feed structure 104 can be inserted into the waveguide structure 101 for feeding microwave signals into the waveguide structure 101.

[0086] In summary, the planar antenna provided in this disclosure has advantages such as reconfigurable polarization, reconfigurable frequency (i.e., multi-frequency coverage), high aperture utilization, and high gain. Therefore, it can be widely used in satellite communication or mobile communication and other fields.

[0087] Secondly, embodiments of this disclosure provide an electronic device including the aforementioned flat panel antenna. The electronic device further includes a transceiver unit, a radio frequency transceiver, a signal amplifier, a power amplifier, and a filtering unit. The flat panel antenna can function as both a transmitting and receiving antenna. The transceiver unit may include a baseband and a receiving end. The baseband provides signals in at least one frequency band, such as 2G, 3G, 4G, and 5G signals, and transmits these signals to the radio frequency transceiver. After receiving the signal, the transparent antenna in the communication system processes it through the filtering unit, power amplifier, signal amplifier, and radio frequency transceiver before transmitting it to the receiving end in the transceiver unit. The receiving end may be, for example, a smart gateway.

[0088] Furthermore, the RF transceiver is connected to the transceiver unit and is used to modulate the signals transmitted by the transceiver unit, or to demodulate the signals received by the transparent antenna before transmitting them to the transceiver unit. Specifically, the RF transceiver may include a transmitting circuit, a receiving circuit, a modulation circuit, and a demodulation circuit. After the transmitting circuit receives various types of signals provided by the baseband, the modulation circuit can modulate the various types of signals provided by the baseband before transmitting them to the antenna. The transparent antenna receives the signals and transmits them to the receiving circuit of the RF transceiver. The receiving circuit then transmits the signals to the demodulation circuit, which demodulates the signals before transmitting them to the receiving end.

[0089] Furthermore, the RF transceiver is connected to a signal amplifier and a power amplifier, which are then connected to a filtering unit. The filtering unit is connected to at least one antenna. During signal transmission in the communication system, the signal amplifier improves the signal-to-noise ratio (SNR) of the RF transceiver's output signal before transmitting it to the filtering unit; the power amplifier amplifies the power of the RF transceiver's output signal before transmitting it to the filtering unit. The filtering unit may specifically include a duplexer and a filtering circuit. The filtering unit combines the signals output from the signal amplifier and power amplifier, filters out clutter, and transmits them to the transparent antenna, which radiates the signal. During signal reception in the communication system, the antenna receives the signal and transmits it to the filtering unit. The filtering unit filters out clutter from the received signal and transmits it to the signal amplifier and power amplifier. The signal amplifier increases the gain of the received signal, improving the SNR; the power amplifier amplifies the power of the received signal. The signal received by the antenna, after processing by the power amplifier and signal amplifier, is transmitted to the RF transceiver, which then transmits it to the transceiver unit.

[0090] In some examples, the signal amplifier may include various types of signal amplifiers, such as low-noise amplifiers, without limitation.

[0091] In some examples, the antenna provided in this disclosure also includes a power management unit connected to a power amplifier to provide voltage to the power amplifier for amplifying signals.

[0092] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of the present invention, and the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A planar antenna, comprising a waveguide structure, a first dielectric substrate, a radiating layer, and a plurality of switching units sequentially disposed on the waveguide structure; wherein, The radiative layer has a plurality of slit openings extending through its thickness. The switching unit is provided in a one-to-one correspondence with the slit opening, and the switching unit is configured to control the switching state of the corresponding slit opening; The radiation layer is divided into a central region and a peripheral region surrounding the central region; The portion of the plurality of slit openings located in the middle region is divided into multiple groups, and the slit openings in each group are nested sequentially; each group of slit openings includes at least a plurality of first slit openings, and the size of the first slit openings located in at least some of the different groups is different, and the size of the first slit opening in the group of slit openings closer to the center of the middle region is larger.

2. The flat panel antenna according to claim 1, wherein, Each group of slit openings includes at least one ring of slit openings, and the first slit openings in the same group of slit openings are of the same size.

3. The flat panel antenna according to claim 2, wherein, Each slit opening also includes a second slit opening, and the size of the second slit opening is smaller than the size of the first slit opening.

4. The flat panel antenna according to claim 2, wherein, Each slit opening includes a plurality of slit openings arranged clockwise, and every two adjacent slit openings constitute a first unit; For any one of the first units, the extension line of one of the slit openings along its length is a first straight line, and the line connecting the center of the slit opening and the center of the intermediate region is a third straight line; the extension line of the other slit opening along its length is a second straight line, and the line connecting the center of the slit opening and the center of the intermediate region is a fourth straight line. The angle between the first line and the third line is -45°, and the angle between the second line and the fourth line is 45°.

5. The flat panel antenna according to claim 1, wherein, The portion of the slit opening located in the peripheral region is divided into multiple second units; the slit opening in the second unit includes at least the first slit opening.

6. The flat panel antenna according to claim 5, wherein, The number of the second unit is four, and the line connecting the center of two of the second units to the center of the middle region is the fifth straight line, and the line connecting the center of the other two second units to the center of the middle region is the sixth straight line; The fifth line and the sixth line are orthogonal.

7. The flat panel antenna according to claim 5, wherein, The slit opening in the second unit further includes a second slit opening, the size of which is smaller than the size of the first slit opening.

8. The flat panel antenna according to any one of claims 1-7, wherein, The slit openings are nested in four groups, with the first slit openings in the same group having the same size. The size ratio of the first slit openings in each group away from the center of the intermediate region is 6.3:6.2:6:5.

8.

9. The flat panel antenna according to any one of claims 1-7, wherein, The portion of the plurality of slit openings located in the middle region is divided into multiple rings, with the slit openings in each ring arranged at clockwise intervals. The spacing between two adjacent rings of slit openings is between 0.1λ and 0.5λ, where λ is the wavelength in free space corresponding to the operating frequency of the planar antenna.

10. The flat panel antenna according to any one of claims 1-7, wherein, The portion of the plurality of slit openings located in the middle region is divided into multiple rings, with the slit openings in each ring arranged at clockwise intervals. In the ring of slit openings closest to the center of the central region, the distance between the centers of two adjacent slit openings is between 0.24λ and 0.30λ, where λ is the wavelength in free space corresponding to the operating frequency of the planar antenna.

11. The flat panel antenna according to any one of claims 1-7, wherein, The portion of the plurality of slit openings located in the middle region is divided into multiple rings, with the slit openings in each ring arranged at clockwise intervals. The distance between the slit openings closest to the center of the intermediate region and the center of the intermediate region is not less than 0.30λ, where λ is the wavelength in free space corresponding to the operating frequency of the planar antenna.

12. The flat panel antenna according to claim 1, wherein, It also includes a metasurface structure located on the side of the radiating layer opposite to the first dielectric substrate; the orthogonal projection of the metasurface structure onto the waveguide structure at least covers the orthogonal projection of the radiating layer onto the waveguide structure.

13. The flat panel antenna according to claim 12, wherein, The metasurface structure includes: A second dielectric substrate having a first surface and a second surface, wherein the first surface is closer to the radiating layer; Multiple metasurface units are arranged in an array on the second surface side of the second dielectric substrate.

14. The flat panel antenna according to claim 13, wherein, The metasurface unit is square with a side length between 0.16λ and 0.174λ, and the distance between any two adjacent metasurface units is between 0.18λ and 0.195λ, where λ is the wavelength in free space corresponding to the operating frequency of the flat panel antenna.

15. The flat panel antenna according to claim 1, wherein, The switching unit includes any one of a PIN diode, a variable reactance diode, a liquid crystal switch, or a MEMS switch.

16. The flat panel antenna according to claim 1, wherein, It also includes a feeding structure configured to feed microwave signals into the waveguide structure.

17. The flat panel antenna according to claim 16, wherein, The power supply structure includes a coaxial probe.

18. An electronic device comprising the flat panel antenna according to any one of claims 1-17.

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