Cavity antenna and electronic device

Abstract

The application provides a cavity antenna and an electronic device, which can reduce the influence of the surrounding environment on the antenna, avoid the change of the working frequency of the antenna, and ensure the wireless communication of the electronic device. The cavity antenna comprises a metal back plate, a dielectric substrate and a flexible circuit board. The dielectric substrate and the flexible circuit board are both mounted on the inner side of the metal back plate. The flexible circuit board covers part of the dielectric substrate and is electrically connected with the metal back plate. The flexible circuit board comprises a body part and a folding strip. The body part is provided with a avoiding hole which penetrates the body part along the thickness direction of the body part and is arranged in a spaced manner with the peripheral surface of the body part. The folding strip is fixedly connected to the hole wall of the avoiding hole and can be folded relative to the body part. When the folding strip is folded relative to the body part, the folding strip extends into the inside of the cavity antenna and is electrically connected with the metal back plate.

Description

Cavity antennas and electronic devices

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on November 15, 2023, with application number 202323105787.1 and application name “Cavity Antenna and Electronic Device”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the technical field of electronic equipment, and in particular to a cavity antenna and electronic equipment. Background Art

[0003] With the continuous advancement of science and technology, electronic devices such as tablets are widely used in people's daily lives and work, becoming indispensable daily necessities. To achieve wireless communication in electronic devices, current electronic devices often incorporate numerous antennas. However, antennas can be affected by their surroundings, causing variations in their operating frequency and impacting wireless communication.

[0004] Summary of the Invention

[0005] The present application provides a cavity antenna and electronic equipment, which can reduce the impact of the antenna's surrounding environment on the antenna, avoid changes in the antenna's operating frequency, and ensure wireless communication of the electronic equipment.

[0006] In the first aspect, the present application provides a cavity antenna, comprising a metal backplate, a dielectric substrate and a flexible circuit board, wherein the dielectric substrate and the flexible circuit board are both installed on the inner side of the metal backplate, the flexible circuit board covers a portion of the dielectric substrate, and is electrically connected to the metal backplate, and forms a cavity antenna with the metal backplate, the flexible circuit board comprises a main body and a folding strip, the main body is provided with an avoidance hole, the avoidance hole passes through the main body along the thickness direction of the main body, and is spaced apart from the circumferential surface of the main body, the folding strip is fixedly connected to the hole wall of the avoidance hole, and can be folded relative to the main body.

[0007] When the folding strip is folded relative to the main body, the folding strip extends into the interior of the cavity antenna and is electrically connected to the metal back plate.

[0008] In the cavity antenna described in this application, a flexible circuit board can wrap around a dielectric substrate and be electrically connected to a metal backplane to form a cavity antenna. The cavity antenna is used for wireless communication in electronic devices. The flexible circuit board is designed with a folding strip. By designing the structure and dimensions of the folding strip, a wide range of fine tuning of the cavity antenna's operating frequency can be achieved without modifying the cavity antenna's structure. This reduces the impact of the surrounding environment on the cavity antenna, prevents changes in the cavity antenna's operating frequency, and ensures wireless communication in electronic devices.

[0009] In one embodiment, when the folding strip is folded relative to the main body, it is directly electrically connected or coupled electrically connected to the metal backplate. The resonant frequency of the cavity antenna differs when the folding strip is directly electrically connected to the metal backplate or when it is coupled electrically connected to the metal backplate. Depending on the target frequency of the cavity antenna, the cavity antenna can be selected to determine whether to use the folding strip directly electrically connected to the metal backplate or coupled electrically connected to the metal backplate, so that the resonant frequency of the cavity antenna approaches the target frequency. This can reduce the impact of the surrounding environment on the cavity antenna, prevent changes in the operating frequency of the cavity antenna, and ensure wireless communication of the electronic device.

[0010] In one embodiment, when the folding strip is unfolded relative to the main body, the resonant frequency f of the cavity antenna is r satisfy:

[0011] Where w1 represents the length of the cavity antenna, w2 represents the width of the cavity antenna, c represents the speed of light, and ε r represents the relative dielectric constant of the dielectric substrate, and f0 represents the target frequency.

[0012] When f r is less than f0, and when the folding strip is folded relative to the main body, the folding strip is directly electrically connected to the metal back plate to achieve direct grounding, which can increase the resonant frequency f of the cavity antenna. r , the resonant frequency f of the cavity antenna r Tuning to the target frequency f0 can reduce the impact of the surrounding environment on the cavity antenna, avoid changes in the operating frequency of the cavity antenna, and ensure wireless communication of electronic equipment.

[0013] When f r When the folding strip is folded relative to the main body, the folding strip is electrically coupled with the metal back plate to achieve coupling grounding, which can reduce the resonant frequency f of the cavity antenna. r , the resonant frequency f of the cavity antenna r Tuning to the target frequency f0 can reduce the impact of the surrounding environment on the cavity antenna, avoid changes in the operating frequency of the cavity antenna, and ensure wireless communication of electronic equipment.

[0014] In one embodiment, there are multiple avoidance holes and multiple folding strips, with the multiple avoidance holes spaced apart from each other, and each folding strip fixedly connected to the wall of a avoidance hole. By using one or more folding strips and folding them relative to the main body, the resonant frequency of the cavity antenna can be adjusted to approach the target frequency, achieving tuning of the cavity antenna. This can reduce the impact of the surrounding environment on the cavity antenna, prevent changes in the operating frequency of the cavity antenna, and ensure wireless communication of the electronic device.

[0015] In one embodiment, there are two avoidance holes and two folding strips, namely a first avoidance hole and a second avoidance hole, and two folding strips, namely a first folding strip and a second folding strip, with the first folding strip fixedly connected to the wall of the first avoidance hole, and the second folding strip fixedly connected to the wall of the second avoidance hole. By using the first folding strip and / or the second folding strip, the first folding strip and / or the second folding strip can be folded relative to the main body to bring the resonant frequency of the cavity antenna closer to the target frequency, achieving tuning of the cavity antenna. This can reduce the impact of the surrounding environment on the cavity antenna, prevent changes in the operating frequency of the cavity antenna, and ensure wireless communication of the electronic device.

[0016] In one embodiment, the cavity antenna has a resonant frequency of 2.45 GHz. That is, the cavity antenna can transmit WiFi signals. The operating frequency band of the cavity antenna is the WiFi 2.4 GHz band, with an operating frequency of 2.415 GHz to 2.485 GHz and a center frequency of 2.45 GHz.

[0017] In one embodiment, the cavity antenna can transmit Bluetooth signals.

[0018] In one embodiment, the length of the cavity antenna w1 = 55 mm, the width of the cavity antenna w2 = 25 mm, and the relative dielectric constant ε of the dielectric substrate r =3.15, the first folding strip and the second folding strip are both folded relative to the main body, and are both directly electrically connected to the metal back plate, the width L1 of the first folding strip is =3mm, the width L2 of the second folding strip is =5mm or the width L1 of the first folding strip is =5mm, the width L2 of the second folding strip is =2mm.

[0019] When the cavity antenna uses the first folding strip and the second folding strip at the same time, the resonant frequency of the cavity antenna can be finely tuned by using folding strips of different widths, so that the resonant frequency of the cavity antenna approaches the target frequency. The tuning of the cavity antenna can reduce the impact of the surrounding environment on the cavity antenna, avoid changes in the operating frequency of the cavity antenna, and ensure wireless communication of electronic equipment.

[0020] In one embodiment, the length of the cavity antenna w1 = 55 mm, the width of the cavity antenna w2 = 25 mm, and the relative dielectric constant ε of the dielectric substrate r =3.0, the first folding strip is folded relative to the main body and is directly electrically connected to the metal back plate, and the width L1 of the first folding strip is =3mm.

[0021] When the relative dielectric constant ε of the dielectric substrate in the cavity antenna is rWhen adjusted to 3.0, the first folding strip can be used instead of the second folding strip without changing the size of the cavity antenna, and the width of the first folding strip can be adjusted to L1 = 3mm. The resonant frequency of the cavity antenna can be tuned to the target frequency f0 = 2.45GHz, which can reduce the impact of the surrounding environment on the cavity antenna, avoid changes in the operating frequency of the cavity antenna, and ensure wireless communication of electronic equipment.

[0022] In one embodiment, the cavity antenna includes a first circumferential surface, a second circumferential surface, and a chamfered circumferential surface, wherein the chamfered circumferential surface is connected between the first circumferential surface and the second circumferential surface. In other words, a corner of the cavity antenna is cut off.

[0023] The length of the cavity antenna w1 = 55 mm, the width of the cavity antenna w2 = 25 mm, and the relative dielectric constant ε of the dielectric substrate r =3.15, the first folding strip and the second folding strip are both folded relative to the main body and are both directly electrically connected to the metal back plate, the width L1 of the first folding strip is L1 = 3 mm, and the width L2 of the second folding strip is L2 = 2 mm.

[0024] When a corner of the cavity antenna is cut off, the first folding strip and the second folding strip can be used without changing the other dimensions of the cavity antenna, and the width of the first folding strip can be adjusted to L1 = 3mm, and the width of the second folding strip can be adjusted to L2 = 2mm. The resonant frequency of the cavity antenna can be tuned to the target frequency f0 = 2.45GHz, which can reduce the impact of the surrounding environment on the cavity antenna, avoid changes in the operating frequency of the cavity antenna, and ensure wireless communication of electronic equipment.

[0025] In one embodiment, the folding strip includes an electrical connection portion and a foldable portion, the electrical connection portion is spaced apart from the main body, and the foldable portion is fixedly connected between the hole wall of the avoidance hole and the electrical connection portion.

[0026] When the folding strip is folded relative to the main body, the electrical connection part is located between the main body and the metal back plate, and is arranged opposite to the main body and electrically connected to the metal back plate. The foldable part is bent relative to the main body and the electrical connection part.

[0027] In one embodiment, when the folding strip is unfolded relative to the main body, the electrical connection portion and the foldable portion are located in the avoidance hole. The avoidance hole can avoid the folding strip, preventing the hole wall of the avoidance hole from affecting the folding of the folding strip relative to the main body.

[0028] In one embodiment, the flexible circuit board also includes a mounting portion and a bending portion. The mounting portion is located between the main body portion and the metal back plate, and is spaced apart from and arranged opposite to the main body portion. It is also electrically connected to the metal back plate. The bending portion is fixedly connected between the hole wall of the avoidance hole and the mounting portion, and is bent relative to the main body portion and the mounting portion.

[0029] In one embodiment, the cavity antenna further includes a first conductive adhesive layer, which is electrically connected between the mounting portion and the metal backplate to achieve electrical connection between the flexible circuit board and the metal backplate.

[0030] In one embodiment, when the flexible circuit board is in the unfolded state, the main body and the folding strip are in the same plane.

[0031] In one embodiment, the body further includes a notch extending through the body along its thickness and circumference, and spaced apart from the avoidance hole. The notch connects the interior and exterior of the cavity antenna, leaving the interior of the cavity antenna open. The notch allows for signal radiation from the cavity antenna.

[0032] In a second aspect, the present application provides an electronic device comprising any of the above-mentioned cavity antennas, a processor and connecting wires, wherein the processor and the connecting wires are both installed on the inner side of a metal backplate, and the connecting wires are electrically connected between the processor and a flexible circuit board.

[0033] In the electronic device shown in the present application, a folding strip is designed on the flexible circuit board. Without improving the structure of the cavity antenna, the relevant design of the structure and size of the folding strip can achieve a wider range and fine tuning of the operating frequency of the cavity antenna, which can reduce the impact of the surrounding environment on the cavity antenna, avoid changes in the operating frequency of the cavity antenna, and ensure wireless communication of the electronic device.

[0034] The connecting wire is electrically connected to the position of the main body near the notch. The area of ​​the main body near the notch can be used as the feeding area of ​​the cavity antenna to facilitate coupled feeding or direct feeding of the cavity antenna.

[0035] In one embodiment, the electronic device further includes a frame, the metal back plate is mounted on one side of the frame, and the dielectric substrate and the flexible circuit board are both mounted on the inner side of the frame.

[0036] In one embodiment, the electronic device further includes a display screen, which is mounted on the side of the frame facing away from the metal back plate. The display screen includes a display panel and a metal support plate, which is mounted on the non-display side of the display panel and electrically connected to the main body.

[0037] In one embodiment, the electronic device further includes a second conductive adhesive layer, which is electrically connected between the main body and the metal support plate to achieve electrical connection between the flexible circuit board and the metal support plate.

[0038] In the electronic device described in this application, a flexible circuit board can wrap around a dielectric substrate and be electrically connected to a metal backplane to form a cavity antenna. The cavity antenna is used for wireless communication in the electronic device. The flexible circuit board is designed with a folding strip. By designing the structure and dimensions of the folding strip, a wide range of fine tuning of the cavity antenna's operating frequency can be achieved without modifying the cavity antenna's structure. This reduces the impact of the surrounding environment on the cavity antenna, prevents changes in the cavity antenna's operating frequency, and ensures wireless communication in the electronic device. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be described below.

[0040] FIG1 is a schematic structural diagram of an electronic device provided in an embodiment of the present application;

[0041] FIG2 is a schematic diagram of the exploded structure of the electronic device shown in FIG1 ;

[0042] FIG3 is a schematic structural diagram of a flexible circuit board and a second conductive adhesive layer in the electronic device shown in FIG2 ;

[0043] FIG4 is a schematic structural diagram of the flexible circuit board and the first conductive adhesive layer in the electronic device shown in FIG2 at another angle;

[0044] FIG5 is a schematic structural diagram of the flexible circuit board in the electronic device shown in FIG2 in an unfolded state;

[0045] FIG6 is a schematic diagram of a simplified structure of a cavity antenna in the electronic device shown in FIG2 under a first embodiment;

[0046] FIG7 is a schematic cross-sectional view of the cavity antenna shown in FIG6 when using the first folding strip;

[0047] FIG8 is a graph showing S11 of the cavity antenna shown in FIG6 under different usage conditions;

[0048] FIG9 is a simplified structural diagram of a cavity antenna in the electronic device shown in FIG2 under a second embodiment;

[0049] FIG10 is a graph showing S11 of the cavity antenna shown in FIG9 in the first to fifth embodiments;

[0050] FIG11 is a graph showing S11 of the cavity antenna shown in FIG9 in the fifth to ninth embodiments;

[0051] FIG12 is a schematic diagram of a simplified structure of a cavity antenna in the electronic device shown in FIG2 according to a third embodiment;

[0052] FIG13 is a schematic cross-sectional view of the cavity antenna shown in FIG12 ;

[0053] FIG14 is an S11 graph of the cavity antenna shown in FIG12 in the first to fourth embodiments;

[0054] FIG15 is a schematic diagram of a simplified structure of a cavity antenna in the electronic device shown in FIG2 according to a fourth embodiment;

[0055] FIG16 is a graph showing S11 of the cavity antenna shown in FIG15 ;

[0056] FIG17 is a schematic diagram of a simplified structure of a cavity antenna in the electronic device shown in FIG2 according to a fifth embodiment;

[0057] FIG18 is a graph showing the S11 curve of the cavity antenna shown in FIG17 . DETAILED DESCRIPTION

[0058] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application.

[0059] Please refer to Figures 1 and 2. Figure 1 is a structural diagram of an electronic device 1000 provided in an embodiment of the present application, and Figure 2 is a schematic diagram of the exploded structure of the electronic device 1000 shown in Figure 1.

[0060] The electronic device 1000 can be an electronic product with wireless communication function, such as a tablet computer, a mobile phone, a laptop computer, a car computer, a smart watch, a smart bracelet, a POS machine (point of sales terminal, point of sales terminal). Next, the embodiment of the present application is described by taking the electronic device 1000 as a tablet computer as an example. For the convenience of description, the width direction of the electronic device 1000 is defined as the X-axis direction, the length direction of the electronic device 1000 is defined as the Y-axis direction, and the thickness direction of the electronic device 1000 is defined as the Z-axis direction. The X-axis direction, the Y-axis direction, and the Z-axis direction are perpendicular to each other.

[0061] It should be noted that the qualifiers such as parallel and perpendicular mentioned in the embodiments of the present application regarding relative positional relationships are all based on the current state of the art, rather than being absolutely strict definitions in a mathematical sense. A small amount of deviation is allowed, and both approximately parallel and approximately perpendicular are acceptable. For example, A and B are parallel, which means that A and B are parallel or approximately parallel, and the angle between A and B can be between 0 degrees and 10 degrees. For example, A and B are perpendicular, which means that A and B are perpendicular or approximately perpendicular, and the angle between A and B can be between 80 degrees and 100 degrees.

[0062] The electronic device 1000 includes a housing 100, a circuit board 200, a processor (not shown), a display screen 300, a dielectric substrate (not shown), a flexible printed circuit board 400 and connecting wires 500. The circuit board 200, the processor, the display screen 300, the dielectric substrate, the flexible printed circuit (FPC) 400 and the connecting wires 500 are all installed in the housing 100.

[0063] The housing 100 includes a frame 110 and a metal backplate 120, which is mounted on one side of the frame 110. The metal backplate 120 can be made of a metal material such as iron or aluminum. For example, the frame 110 and the metal backplate 120 can be integrally formed to ensure the overall strength of the housing 100. In other embodiments, the frame 110 and the metal backplate 120 can be assembled to form an integrated structure, or the metal backplate 120 can be detachably mounted on the frame 110 to facilitate the maintenance and replacement of internal components or modules of the electronic device 1000.

[0064] The circuit board 200 and the processor are both mounted on the inner side of the frame 110. The processor can be mounted on the circuit board 200 and electrically connected to the circuit board 200. The circuit board 200 can be the mainboard of the electronic device 1000, and the processor can be the CPU (central processing unit) of the electronic device 1000. It should be noted that the directional terms such as "inside" and "outside" involved in this application are all described with reference to the orientation shown in Figure 1, with the interior of the electronic device 1000 being referred to as "inside" and the exterior of the electronic device 1000 being referred to as "outside". It does not indicate or imply 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 a limitation on this application.

[0065] The display screen 300 is mounted on the other side of the frame 110. Specifically, the display screen 300 is mounted on the side of the frame 110 that is away from the metal back plate 120. That is, the display screen 300 and the metal back plate 120 are respectively mounted on opposite sides of the frame 110. When the user uses the electronic device 1000, the display screen 300 is placed toward the user and the metal back plate 120 is placed away from the user. The display screen 300 is electrically connected to the circuit board 200 to achieve electrical connection with the processor. The display screen 300 can receive a display signal sent by the processor through the circuit board 200, and display information such as images or text based on the display signal.

[0066] Display screen 300 includes a display panel and a metal support plate. The metal support plate is mounted on the non-display side of the display panel and supports the display panel. For example, display screen 300 may be a liquid crystal display (LCD) panel or an organic light-emitting diode (OLED) panel. The metal support plate may be an iron frame.

[0067] The dielectric substrate, flexible circuit board 400, and connecting wire 500 are all mounted on the inner sides of the frame 110 and the metal backplate 120. Specifically, the dielectric substrate, flexible circuit board 400, and connecting wire 500 are all located in the upper left corner of the frame 110. The dielectric substrate can be supported by an insulating material. The flexible circuit board 400 partially covers the dielectric substrate and is electrically connected to both the metal backplate 120 and the display screen 300. The connecting wire 500 is electrically connected between the feed point of the flexible circuit board 400 and the circuit board 200 to achieve an electrical connection between the flexible circuit board 400 and the processor.

[0068] In one embodiment, electronic device 1000 includes a cavity antenna 600, which includes a metal backplate 120, a dielectric substrate, and a flexible circuit board 400. In other words, the flexible circuit board 400, the dielectric substrate, and the metal backplate 120 can be combined to form the cavity antenna 600. The metal layer within the flexible circuit board 400 can be combined with the dielectric substrate and the metal backplate 120 to form the cavity antenna 600. The cavity antenna 600 can transmit Bluetooth or WiFi signals.

[0069] The processor can transmit antenna signals to the connecting wire 500 via the circuit board 200. The connecting wire 500 can transmit the antenna signals sent by the processor to the cavity antenna 600 from the feeding point of the flexible circuit board 400. The cavity antenna 600 can radiate signals to the outside of the electronic device 1000 based on the antenna signals sent by the processor, thereby realizing signal transmission of the electronic device 1000. The cavity antenna 600 can also receive antenna signals from outside the electronic device 1000 and transmit the received external antenna signals from the feeding point of the flexible circuit board 400 to the connecting wire 500. The connecting wire 500 transmits the external antenna signals from the circuit board 200 to the processor, thereby realizing signal reception of the electronic device 1000. In this way, wireless communication of the electronic device 1000 is realized.

[0070] It should be noted that the directional terms such as "up", "down", "left" and "right" involved in this application are all described with reference to the directions shown in Figure 1, with the direction towards the positive direction of the Y-axis being "up", the direction towards the negative direction of the Y-axis being "down", the direction towards the positive direction of the X-axis being "right", and the direction towards the negative direction of the X-axis being "left". They do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on this application.

[0071] In addition, electronic device 1000 also includes a first conductive adhesive layer (not shown) and a second conductive adhesive layer 800. The first conductive adhesive layer is located between the flexible circuit board 400 and the metal backplate 120 and is electrically connected thereto, thereby achieving an electrical connection between the flexible circuit board 400 and the metal backplate 120. The first conductive adhesive layer includes a plurality of first sub-conductive adhesive portions, which are spaced apart and located between the flexible circuit board 400 and the metal backplate 120 and are electrically connected thereto. The second conductive adhesive layer 800 is located between the flexible circuit board 400 and the metal support plate of the display screen 300 and is electrically connected thereto, thereby achieving a single connection between the flexible circuit board 400 and the display screen 300. The second conductive adhesive layer 800 includes a plurality of second conductive adhesive sub-sections 810. The plurality of second conductive adhesive sub-sections 810 are spaced apart and positioned between the flexible circuit board 400 and the metal support plate of the display screen 300, and are electrically connected between the flexible circuit board 400 and the metal support plate. Exemplarily, both the first conductive adhesive layer and the second conductive adhesive layer 800 are conductive foam adhesive.

[0072] It should be noted that during use of the electronic device 1000, the cavity antenna 600 may be affected by the surrounding environment, causing the operating frequency of the cavity antenna 600 to change, thereby affecting the wireless communication function of the electronic device 1000. Generally, the operating frequency of the cavity antenna 600 can be tuned by modifying the size of the cavity antenna 600. However, due to the very precise internal structure of the electronic device 1000, the size change of the cavity antenna 600 may affect other components of the electronic device 1000.

[0073] In the electronic device 1000 shown in this embodiment, the operating frequency of the cavity antenna 600 can be finely tuned without changing the size of the cavity antenna 600, thereby reducing the impact of the surrounding environment on the cavity antenna 600, preventing changes in the operating frequency of the cavity antenna 600, and ensuring the wireless communication function of the electronic device 1000. Next, the cavity antenna 600 of the electronic device 1000 is described in detail.

[0074] Please refer to Figures 3 to 5. Figure 3 is a structural schematic diagram of the flexible circuit board 400 and the second conductive adhesive layer 800 in the electronic device 1000 shown in Figure 2. Figure 4 is a structural schematic diagram of the flexible circuit board 400 and the first conductive adhesive layer 700 in the electronic device 1000 shown in Figure 2 at another angle. Figure 5 is a structural schematic diagram of the flexible circuit board 400 in the electronic device 1000 shown in Figure 2 in an unfolded state.

[0075] The flexible circuit board 400 includes a main body 10, a mounting portion 20, a bending portion 30, and a folding strip 40. The mounting portion 20 is located on the bottom side of the main body 10 and is spaced apart from and opposite to the main body 10. The folding portion 30 is fixedly connected between the main body 10 and the mounting portion 20. The folding strip 40 is fixedly connected to the main body 10 and can be folded relative to the main body 10. It is spaced apart from both the mounting portion 20 and the folding portion 30. The main body 10, mounting portion 20, bending portion 30, and folding strip 40 can be integrally formed.

[0076] It should be noted that the directional terms such as "top" and "bottom" involved in this application are all described with reference to the orientation shown in Figure 4, with the direction facing the positive direction of the Z axis as "top" and the direction facing the negative direction of the Z axis as "bottom". They do not indicate or imply 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 a limitation on this application.

[0077] The main body 10 is provided with a notch 101, an avoidance hole 102 and a positioning hole 103. The notch 101, the avoidance hole 102 and the positioning hole 103 all penetrate the main body 10 along the thickness direction of the main body 10 (Z-axis direction in the figure). Specifically, the notch 101 is located at the edge of the main body 10 and penetrates the circumference of the main body 10. The notch 101 can connect the inside and outside of the cavity antenna 600, so that the inside of the cavity antenna 600 is in an open state, and the notch 101 can be used for signal radiation of the cavity antenna 600. Exemplarily, the notch 101 is located at the upper part of the main body 10, and a feeding point is also provided at the upper part of the main body 10, and the feeding point is arranged close to the notch 101. At this time, the upper part of the main body 10 can be used as the feeding area of ​​the cavity antenna 600 to facilitate coupled feeding or direct feeding of the cavity antenna 600. In some other embodiments, the notch 101 may also be located at the lower part, left part or right part of the main body 10 . The present application does not impose any specific limitation on the position of the notch 101 .

[0078] The avoidance hole 102 is located in the middle of the main body 10, and is spaced apart from the notch 101 and the circumference of the main body 10. There are two avoidance holes 102, and the two avoidance holes 102 are spaced apart from each other. The two avoidance holes 102 are respectively a first avoidance hole 102a and a second avoidance hole 102b. Exemplarily, the first avoidance hole 102a and the second avoidance hole 102b are both rectangular holes, and the length direction of the first avoidance hole 102a is parallel to the Y-axis direction, and the length direction of the second avoidance hole 102b is parallel to the X-axis direction. In some other embodiments, there may be one or more than three avoidance holes 102, and the present application does not impose any specific restrictions on the number and shape of the avoidance holes 102.

[0079] The positioning holes 103 are spaced apart from the notch 101 and the avoidance hole 102. The positioning holes 103 can be used to install fasteners such as screws or bolts, or they can be used for mounting and positioning. For example, there are three positioning holes 103, spaced apart from each other. In other embodiments, there may be fewer than two or more than four positioning holes 103. This application does not impose any specific restrictions on the number and location of the positioning holes 103.

[0080] Along the Z-axis direction, the mounting portion 20 is spaced apart from and opposite to the main body 10, and is electrically connected to the metal backplate 120. Exemplarily, the mounting portion 20 is parallel to the XY plane. There are two mounting portions 20, and the two mounting portions 20 are spaced apart from each other. The two mounting portions 20 are respectively a first mounting portion 20a and a second mounting portion 20b. The first mounting portion 20a is spaced apart from and opposite to the lower portion of the main body 10, and is electrically connected to the metal backplate 120. The first mounting portion 20a includes two first sub-mounting portions 21a, and along the X-axis direction, the two first mounting portions 20a are spaced apart from each other, and are both electrically connected to the metal backplate 120. The second mounting portion 20b is spaced apart from and opposite to the right portion of the main body 10, and is electrically connected to the metal backplate 120. The second mounting portion 20b includes two second sub-mounting portions 21b, and along the X-axis direction, the two second mounting portions 20b are spaced apart from each other, and are both electrically connected to the metal backplate 120. In some other embodiments, there may be one or more than three mounting portions 20 . This application does not impose any specific limitation on the number and position of the mounting portions 20 .

[0081] The bending portion 30 is fixedly connected between the circumferential surface of the main body 10 and the circumferential surface of the mounting portion 20, and is bent relative to both the main body 10 and the mounting portion 20. There are two bending portions 30, and the two bending portions 30 are spaced apart from each other. The two bending portions 30 are respectively a first bending portion 30a and a second bending portion 30b. The first bending portion 30a is fixedly connected between the lower portion of the main body 10 and the first mounting portion 20a. The first bending portion 30a includes two first sub-bending portions 31a, each of which is fixedly connected between the main body 10 and a first sub-mounting portion 21a. Along the X-axis direction, the two first sub-bending portions 31a are spaced apart. The second bending portion 30b is fixedly connected between the right portion of the main body 10 and the second mounting portion 20b. In some other embodiments, there may be one or more than three bending portions 30, and this application does not impose any specific restrictions on the number and position of the bending portions 30.

[0082] The folding strip 40 is fixedly connected to the hole wall of the avoidance hole 102 and can be folded relative to the main body 10. The folding strip 40 includes an electrical connection portion 41 and a foldable portion 42. The electrical connection portion 41 is spaced apart from the main body 10, and the foldable portion 42 is fixedly connected between the electrical connection portion 41 and the hole wall of the avoidance hole 102. The folding strip 40 has an unfolded state and a folded state. When the folding strip 40 is in the unfolded state, as shown in Figure 5, the folding strip 40 is unfolded relative to the main body 10, and the foldable portion 42 is unfolded relative to the main body 10. Both the electrical connection portion 41 and the foldable portion 42 can be located within the avoidance hole 102. At this time, the folding strip 40 can be in the same plane as the main body 10. As shown in Figure 5, when the flexible circuit board 400 is in the unfolded state, the main body 10, the mounting portion 20, the bending portion 30 and the folding strip 40 are all in the same plane.

[0083] When the folding strip 40 is in the folded position, as shown in Figures 3 and 4 , it is folded relative to the main body 10, extending into the cavity antenna 600 and electrically connected to the metal backplate 120. The electrical connection portion 41 is located on the bottom side of the main body 10, spaced from and opposite to the main body 10, and the foldable portion 42 is bent relative to the main body 10 and the electrical connection portion 41. In this state, the electrical connection portion 41 of the folding strip 40 is directly electrically connected to the metal backplate 120 or electrically coupled thereto.

[0084] There are two folding strips 40, and the two folding strips 40 are spaced apart from each other. The two folding strips 40 are respectively a first folding strip 40a and a second folding strip 40b. The first folding strip 40a is fixedly connected to the hole wall of the first avoidance hole 102a, and the second folding strip 40b is fixedly connected to the hole wall of the second avoidance hole 102b. Exemplarily, when the first folding strip 40a and the second folding strip 40b are in the unfolded state, the first folding strip 40a and the second folding strip 40b are both rectangular, and the length direction of the first folding strip 40a is parallel to the length direction of the first avoidance hole 102a, and the length direction of the second folding strip 40b is parallel to the length direction of the second avoidance hole 102b. In some other embodiments, there may be one or more than three folding strips 40, and the present application does not impose any specific restrictions on the number and position of the folding strips 40.

[0085] Illustratively, the first conductive adhesive layer 700 includes five first sub-conductive adhesive portions 710, and the second conductive adhesive layer 800 includes four second sub-conductive adhesive portions 810. One first sub-conductive adhesive portion 710 is disposed on the bottom surface of two first sub-mounting portions 21a in the first mounting portion 20a and electrically connects the first mounting portion 20a to the metal backplate 120. Two first sub-conductive adhesive portions 710 are respectively disposed on the bottom surface of two second sub-mounting portions 21b in the second mounting portion 20b and electrically connect the second mounting portion 20b to the metal backplate 120. Two first sub-conductive adhesive portions 710 are respectively disposed on the bottom surface of the electrical connection portions 41 in the two folding strips 40. The four second sub-conductive adhesive portions 810 are all disposed on the top surface of the main body 10, spaced apart from each other, and electrically connect between the main body 10 and the metal support plate of the display screen 300.

[0086] Next, taking the WiFi 2.4 GHz frequency band as an example, the structure of the cavity antenna 600 is described in detail. The operating frequency of the cavity antenna 600 is 2.415 GHz to 2.485 GHz, with a center frequency of 2.45 GHz.

[0087] Please refer to Figures 6 and 7. Figure 6 is a simplified structural diagram of the cavity antenna 600 in the electronic device 1000 shown in Figure 2 under the first embodiment, and Figure 7 is a cross-sectional structural diagram of the cavity antenna 600 shown in Figure 6 when using the first folding strip 40a.

[0088] In this embodiment, the cavity antenna 600 includes a first circumferential surface 601 and a second circumferential surface 602, which are directly connected. The length of the cavity antenna 600 is W1, the width is W2, and the relative dielectric constant of the dielectric substrate 900 is ε r Among them, W1=55mm, W2=25mm, ε r =3.15. The feeding point 610 of the cavity antenna 600 is disposed on the flexible printed circuit board 400 .

[0089] Please refer to Figure 8, which is a graph of S11 under different usage conditions of the cavity antenna 600 shown in Figure 6. It should be understood that in the graph shown in Figure 8, the horizontal axis represents the resonant frequency in GHz, and the vertical axis represents the energy reflection coefficient in dB.

[0090] In the first embodiment, the cavity antenna 600 uses the first folding strip 40a but not the second folding strip 40b. Specifically, the first folding strip 40a is folded relative to the main body 10 and directly electrically connected to the metal backplate 120, while the second folding strip 40b is unfolded relative to the main body 10. The first folding strip 40a can be directly electrically connected to the metal backplate 120 via the first sub-conductive adhesive portion.

[0091] In the second embodiment, the cavity antenna 600 utilizes a first folding strip 40a and a second folding strip 40b. Specifically, the first folding strip 40a and the second folding strip 40b are both folded relative to the main body 10 and electrically connected to the metal backplate 120. The first folding strip 40a and the second folding strip 40b are both directly electrically connected to the metal backplate 120 via the first sub-conductive adhesive portion.

[0092] In the third embodiment, the cavity antenna 600 does not utilize the first folding strip 40a, but instead utilizes the second folding strip 40b. Specifically, the first folding strip 40a is extended relative to the main body 10, while the second folding strip 40b is folded relative to the main body 10 and electrically connected to the metal backplate 120. Furthermore, the second folding strip 40b can be directly electrically connected to the metal backplate 120 via the first sub-conductive adhesive portion.

[0093] In the fourth embodiment, the cavity antenna 600 does not use the first folding strip 40 a and the second folding strip 40 b , that is, the first folding strip 40 a and the second folding strip 40 b are both extended relative to the main body 10 and spaced apart from the metal back plate 120 .

[0094] As shown in Figure 8, when the cavity antenna 600 uses the first folding strip 40a but not the second folding strip 40b, the resonant frequency of the cavity antenna 600 is 2.42 GHz. When the cavity antenna 600 uses the first folding strip 40a and the second folding strip 40b, the resonant frequency of the cavity antenna 600 is 2.48 GHz. When the cavity antenna 600 does not use the first folding strip 40a but uses the second folding strip 40b, the resonant frequency of the cavity antenna 600 is 2.38 GHz. When the cavity antenna 600 does not use the first folding strip 40a and the second folding strip 40b, the resonant frequency of the cavity antenna 600 is 2.33 GHz. In summary, while the structure of the cavity antenna 600 remains unchanged, the resonant frequency of the cavity antenna 600 can be tuned over a wide range depending on whether the folding strip 40 is used.

[0095] Please refer to FIG. 9 , which is a simplified structural diagram of the cavity antenna 600 in the electronic device 1000 shown in FIG. 2 under a second embodiment.

[0096] The cavity antenna 600 shown in this embodiment differs from the cavity antenna 600 shown in the first embodiment described above in that the cavity antenna 600 uses a first folding strip 40a and a second folding strip 40b. Specifically, the first folding strip 40a and the second folding strip 40b are both folded relative to the main body 10 and are both electrically connected to the metal back plate 120. The first folding strip 40a and the second folding strip 40b can both be directly electrically connected to the metal back plate 120 via the first sub-conductive adhesive portion. In addition, the width of the first folding strip 40a is L1, and the width of the second folding strip 40b is L2. L1 and L2 are both greater than or equal to 1 mm and less than or equal to 5 mm.

[0097] Please refer to Figures 10 and 11. Figure 10 is a graph of the S11 values ​​of the cavity antenna 600 shown in Figure 9 in the first through fifth embodiments, and Figure 11 is a graph of the S11 values ​​of the cavity antenna 600 shown in Figure 9 in the fifth through ninth embodiments. It should be understood that in the graphs shown in Figures 10 and 11, the abscissa represents the resonant frequency in GHz, and the ordinate represents the energy reflection coefficient in dB.

[0098] In the first embodiment, L1 = 1 mm, L2 = 5 mm. In the second embodiment, L1 = 2 mm, L2 = 5 mm. In the third embodiment, L1 = 3 mm, L2 = 5 mm. In the fourth embodiment, L1 = 4 mm, L2 = 5 mm. In the fifth embodiment, L1 = 5 mm, L2 = 5 mm. In the sixth embodiment, L1 = 5 mm, L2 = 1 mm. In the seventh embodiment, L1 = 5 mm, L2 = 2 mm. In the eighth embodiment, L1 = 5 mm, L2 = 3 mm. In the ninth embodiment, L1 = 5 mm, L2 = 4 mm.

[0099] As shown in Figure 10, when the width L2 of the second folding strip 40b remains unchanged at 5mm and the width L1 of the first folding strip 40a varies from 1mm to 5mm, the resonant frequency of the cavity antenna 600 can be tuned from 2.42GHz to 2.48GHz, achieving fine tuning of the resonant frequency of the cavity antenna 600. Specifically, when L1 = 3mm, the resonant frequency of the cavity antenna 600 is tuned to the target frequency of 2.45GHz. As shown in Figure 11, when the width L1 of the first folding strip 40a remains unchanged at 5mm and the width L2 of the second folding strip 40b varies from 1mm to 5mm, the resonant frequency of the cavity antenna 600 can be tuned from 2.44GHz to 2.48GHz, achieving fine tuning of the resonant frequency of the cavity antenna 600. Specifically, when L2 = 2mm, the resonant frequency of the cavity antenna 600 is tuned to the target frequency of 2.45GHz. Therefore, when L1 = 3 mm, L2 = 5 mm or L1 = 5 mm, L2 = 2 mm, the resonant frequency of the cavity antenna 600 can be tuned to the target frequency of 2.45 GHz. In summary, it can be seen that by using folding strips 40 of different widths, the resonant frequency of the cavity antenna 600 can be finely tuned, so that the resonant frequency of the cavity antenna 600 approaches the target frequency, and the tuning of the cavity antenna 600 can be achieved, which can reduce the impact of the surrounding environment on the cavity antenna 600, avoid changes in the operating frequency of the cavity antenna 600, and ensure wireless communication of the electronic device 1000.

[0100] 12 and 13 , FIG12 is a simplified structural diagram of the cavity antenna 600 in the electronic device 1000 shown in FIG2 under a third embodiment, and FIG13 is a cross-sectional structural diagram of the cavity antenna 600 shown in FIG12 . FIG13 does not show the dielectric substrate.

[0101] The difference between the cavity antenna 600 shown in this embodiment and the cavity antenna 600 shown in the first embodiment mentioned above is that the cavity antenna 600 uses a first folding strip 40a instead of a second folding strip 40b. Specifically, the first folding strip 40a is folded relative to the main body 10, and the first folding strip 40a is coupled to the metal back plate 120. In the thickness direction of the cavity antenna 600 (Z-axis direction in the figure), the spacing of the coupling gap between the electrical connection part 42 of the first folding strip 40a and the metal back plate 120 is h, and h is greater than 0 and less than or equal to 1 mm. Exemplarily, h is greater than or equal to 0.4 mm and less than or equal to 1 mm. In addition, the width L1 of the first folding strip 40a is 5 mm.

[0102] Please refer to Figure 14, which is a graph of S11 for the first to fourth embodiments of the cavity antenna 600 shown in Figure 12. It should be understood that in the graph shown in Figure 14, the abscissa represents the resonant frequency in GHz, and the ordinate represents the energy reflection coefficient in dB.

[0103] As can be seen from Figure 14, when the cavity antenna 600 uses the first fold strip 40a but not the second fold strip 40b, the width L1 of the first fold strip 40a remains unchanged at 5mm, and the distance h of the coupling gap between the first fold strip 40a and the metal backplate 120 changes from 0.4mm to 1mm, the resonant frequency of the cavity antenna 600 can be tuned from 2.18GHz to 2.31GHz.

[0104] Combining the first through third embodiments above, it can be seen that when the cavity antenna 600 does not use the folding strip 40, the resonant frequency of the cavity antenna 600 is 2.33 GHz. When the cavity antenna 600 uses the folding strip 40 and the folding strip 40 is directly electrically connected to the metal backplate 120, the resonant frequency of the cavity antenna 600 is higher than the resonant frequency of the cavity antenna 600 without the folding strip 40. When the cavity antenna 600 uses the folding strip 40 and the folding strip 40 is coupled and electrically connected to the metal backplate 120, the resonant frequency of the cavity antenna 600 is lower than the resonant frequency of the cavity antenna 600 without the folding strip 40. Therefore, based on the comparison between the resonant frequency of the cavity antenna 600 without the folding strip 40 and the target frequency f0, it can be determined whether the folding strip 40 is directly electrically connected to the metal backplate 120 or coupled and electrically connected to the metal backplate 120 when the cavity antenna 600 uses the folding strip 40. Among them, f0=2.45GHz.

[0105] It should be understood that when the cavity antenna 600 does not use the folding strip 40, the resonant frequency f of the cavity antenna 600 can be obtained. r satisfy:

[0106] Wherein, w1 represents the length of the cavity antenna 600, w2 represents the width of the cavity antenna 600, c represents the speed of light, and ε r It should be understood that in the above formula, "≈" can mean "equal to", "slightly less than" and "slightly greater than", for example, "≈" includes three cases: equal to, slightly less than and slightly greater than.

[0107] When the cavity antenna 600 does not use the folding strip 40, the resonant frequency f r The resonant frequency f0 of the cavity antenna 600 can be increased by using the folding strip 40 and directly electrically connecting the folding strip 40 to the metal back plate 120 to achieve direct grounding. r , the resonant frequency f of the cavity antenna 600 r Tuning to the target frequency f0 to achieve tuning of the cavity antenna 600 can reduce the impact of the surrounding environment on the cavity antenna 600, avoid changes in the operating frequency of the cavity antenna 600, and ensure wireless communication of the electronic device 1000.

[0108] If the cavity antenna 600 does not use the folding strip 40, the resonant frequency f r The resonant frequency f0 of the cavity antenna 600 can be reduced by using the folding strip 40, which is electrically coupled to the metal back plate 120 to achieve coupling grounding. r , the resonant frequency f of the cavity antenna 600 r Tuning to the target frequency f0 to achieve tuning of the cavity antenna 600 can reduce the impact of the surrounding environment on the cavity antenna 600, avoid changes in the operating frequency of the cavity antenna 600, and ensure wireless communication of the electronic device 1000.

[0109] Please refer to FIG. 15 , which is a simplified structural diagram of the cavity antenna 600 in the electronic device 1000 shown in FIG. 2 according to a fourth embodiment.

[0110] The difference between the cavity antenna 600 shown in this embodiment and the cavity antenna 600 shown in the first embodiment is that the relative dielectric constant ε of the dielectric substrate 900 is r =3.0. Specifically, the cavity antenna 600 uses the first folding strip 40a but not the second folding strip 40b. The first folding strip 40a is folded relative to the main body 10 and is directly electrically connected to the metal backplate 120. Furthermore, the width L1 of the first folding strip 40a is 3 mm.

[0111] Please refer to Figure 16, which is a graph of S11 of the cavity antenna 600 shown in Figure 15. It should be understood that in the graph shown in Figure 16, the abscissa represents the resonant frequency in GHz, and the ordinate represents the energy reflection coefficient in dB.

[0112] It is understandable that when the relative dielectric constant ε of the dielectric substrate 900 in the cavity antenna 600 is r After the change, the resonant frequency of the cavity antenna 600 will also change, and the size of the cavity antenna 600 needs to be adjusted to adjust the resonant frequency to the target frequency f0. As shown in FIG16, when the relative dielectric constant ε of the dielectric substrate 900 in the cavity antenna 600 is r When adjusted to 3.0, the first folding strip 40a can be used instead of the second folding strip 40b without changing the size of the cavity antenna 600, and the width of the first folding strip 40a can be adjusted to L1 = 3mm, so that the resonant frequency of the cavity antenna 600 can be tuned to the target frequency f0 = 2.45GHz to achieve the tuning of the cavity antenna 600, reduce the impact of the surrounding environment on the cavity antenna 600, avoid changes in the operating frequency of the cavity antenna 600, and ensure wireless communication of the electronic device 1000.

[0113] Please refer to FIG. 17 , which is a simplified structural diagram of the cavity antenna 600 in the electronic device 1000 shown in FIG. 2 under a fifth embodiment.

[0114] The cavity antenna 600 shown in this embodiment differs from the cavity antenna 600 shown in the first embodiment in that the cavity antenna 600 includes a first circumferential surface 601, a second circumferential surface 602, and a chamfered circumferential surface 603, with the chamfered circumferential surface 603 connecting the first circumferential surface 601 and the second circumferential surface 602. In other words, compared to the cavity antenna 600 shown in the first embodiment, the cavity antenna 600 shown in this embodiment has a corner cut off.

[0115] Specifically, the cavity antenna 600 utilizes a first folding strip 40a and a second folding strip 40b. Both the first folding strip 40a and the second folding strip 40b are folded relative to the main body 10 and are directly electrically connected to the metal backplate 120. Furthermore, the width L1 of the first folding strip 40a is 3 mm, and the width L2 of the second folding strip 40b is 2 mm.

[0116] Please refer to Figure 18, which is a graph of S11 of the cavity antenna 600 shown in Figure 17. It should be understood that in the graph shown in Figure 18, the abscissa represents the resonant frequency in GHz, and the ordinate represents the energy reflection coefficient in dB.

[0117] It is understandable that when the local structure of the cavity antenna 600 changes, the resonant frequency of the cavity antenna 600 will generally change as well, and the dimensions of the cavity antenna 600 need to be adjusted to adjust the resonant frequency to the target frequency f0. As shown in Figure 18, when a corner of the cavity antenna 600 is cut off, the resonant frequency of the cavity antenna 600 can be tuned to the target frequency f0 = 2.45 GHz by using the first folding strip 40a and the second folding strip 40b without changing the other dimensions of the cavity antenna 600. By adjusting the width of the first folding strip 40a to L1 = 3 mm and the width of the second folding strip 40b to L2 = 2 mm, the resonant frequency of the cavity antenna 600 can be tuned to the target frequency f0 = 2.45 GHz, thereby achieving tuning of the cavity antenna 600. This can reduce the impact of the surrounding environment on the cavity antenna 600, avoid changes in the operating frequency of the cavity antenna 600, and ensure wireless communication of the electronic device 1000.

[0118] In the electronic device 1000 shown in this application, a flexible circuit board 400 can wrap around a dielectric substrate 900 and be electrically connected to a metal backplane 120, forming a cavity antenna 600. Cavity antenna 600 is used for wireless communication of electronic device 1000. A folding strip 40 is designed on the flexible circuit board 400. By designing the structure and dimensions of the folding strip 40 without modifying the structure of cavity antenna 600, a wide range of fine tuning of the operating frequency of cavity antenna 600 can be achieved. This reduces the impact of the surrounding environment on cavity antenna 600, prevents changes in the operating frequency of cavity antenna 600, and ensures wireless communication of electronic device 1000.

[0119] The above description is only a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by any person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application; the embodiments of this application and the features of the embodiments can be combined with each other unless there is a conflict. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A cavity antenna, characterized in that: The invention comprises a metal back plate, a dielectric substrate and a flexible circuit board, wherein the dielectric substrate and the flexible circuit board are both installed on the inner side of the metal back plate, the flexible circuit board covers a part of the dielectric substrate and is electrically connected to the metal back plate, the flexible circuit board comprises a main body and a folding strip, the main body is provided with an avoidance hole, the avoidance hole penetrates the main body along the thickness direction of the main body and is spaced apart from the circumference of the main body, the folding strip is fixedly connected to the hole wall of the avoidance hole and can be folded relative to the main body; When the folding strip is folded relative to the main body, the folding strip extends into the interior of the cavity antenna and is electrically connected to the metal back plate.

2. The cavity antenna according to claim 1, characterized in that: When the folding strip is folded relative to the main body, the folding strip is directly electrically connected or coupled electrically connected to the metal back plate.

3. The cavity antenna according to claim 2, characterized in that: When the folding strip is unfolded relative to the main body, the resonant frequency f of the cavity antenna is r satisfy: Wherein, w1 represents the length of the cavity antenna, w2 represents the width of the cavity antenna, c represents the speed of light, ε r represents the relative dielectric constant of the dielectric substrate, and f0 represents the target frequency; When the f r is smaller than f0, and when the folding strip is folded relative to the main body, the folding strip is directly electrically connected to the metal back plate; When the f r is greater than f0, and when the folding strip is folded relative to the main body, the folding strip is coupled and electrically connected to the metal back plate.

4. The cavity antenna according to claim 3, characterized in that: There are a plurality of the avoidance holes and the folding strips, the plurality of avoidance holes are arranged at intervals from each other, and each of the folding strips is fixedly connected to a hole wall of the avoidance hole.

5. The cavity antenna according to claim 4, characterized in that: There are two avoidance holes and two folding strips, the two avoidance holes are respectively the first avoidance hole and the second avoidance hole, the two folding strips are respectively the first folding strip and the second folding strip, the first folding strip is fixedly connected to the hole wall of the first avoidance hole, and the second folding strip is fixedly connected to the hole wall of the second avoidance hole.

6. The cavity antenna according to claim 5, characterized in that: The resonant frequency of the cavity antenna is 2.45 GHz.

7. The cavity antenna according to claim 6, characterized in that: The length w1 of the cavity antenna is 55 mm, the width w2 of the cavity antenna is 25 mm, and the relative dielectric constant ε of the dielectric substrate is r =3.15, the first fold strip and the second fold strip are both folded relative to the main body, and are both directly electrically connected to the metal back plate, the width L1 of the first fold strip is =3mm, the width L2 of the second fold strip is =5mm or the width L1 of the first fold strip is =5mm, the width L2 of the second fold strip is =2mm.

8. The cavity antenna according to claim 6, characterized in that: The length w1 of the cavity antenna is 55 mm, the width w2 of the cavity antenna is 25 mm, and the relative dielectric constant ε of the dielectric substrate is r =3.0, the first folding strip is folded relative to the main body and is directly electrically connected to the metal back plate, and the width L1 of the first folding strip is =3mm.

9. The cavity antenna according to claim 6, characterized in that: The cavity antenna comprises a first circumferential surface, a second circumferential surface and a chamfered circumferential surface, wherein the chamfered circumferential surface is connected between the first circumferential surface and the second circumferential surface; The length w1 of the cavity antenna is 55 mm, the width w2 of the cavity antenna is 25 mm, and the relative dielectric constant ε of the dielectric substrate is r =3.15, the first folding strip and the second folding strip are both folded relative to the main body, and are both directly electrically connected to the metal back plate, the width L1 of the first folding strip is =3mm, and the width L2 of the second folding strip is =2mm.

10. The cavity antenna according to any one of claims 1 to 9, characterized in that: The foldable strip comprises an electrical connection portion and a foldable portion, the electrical connection portion is spaced apart from the main body portion, and the foldable portion is fixedly connected between the hole wall of the avoidance hole and the electrical connection portion; When the folding strip is folded relative to the main body, the electrical connection part is located between the main body and the metal back plate, and is arranged opposite to the main body and electrically connected to the metal back plate, and the foldable part is bent relative to the main body and the electrical connection part.

11. The cavity antenna according to claim 10, characterized in that: When the folding strip is unfolded relative to the main body, the electrical connection portion and the foldable portion are located in the avoidance hole.

12. The cavity antenna according to any one of claims 1 to 9, characterized in that: The flexible circuit board also includes a mounting portion and a bending portion. The mounting portion is located between the main body portion and the metal back plate, and is spaced apart from and arranged opposite to the main body portion, and is also electrically connected to the metal back plate. The bending portion is fixedly connected between the hole wall of the avoidance hole and the mounting portion, and is bent relative to the main body portion and the mounting portion.

13. The cavity antenna according to claim 12, characterized in that: The cavity antenna further includes a first conductive adhesive layer, and the first conductive adhesive layer is electrically connected between the mounting portion and the metal back plate.

14. The cavity antenna according to claim 1, characterized in that: When the flexible circuit board is in an unfolded state, the main body and the folding strip are in the same plane.

15. The cavity antenna according to claim 1, characterized in that: The main body is further provided with a notch, which penetrates the main body along the thickness direction of the main body and the peripheral surface of the main body and is spaced apart from the avoidance hole.

16. An electronic device, characterized in that: It comprises a cavity antenna, a processor and a connecting wire as described in any one of claims 1 to 15, wherein the processor and the connecting wire are both installed on the inner side of the metal backplate, one end of the connecting wire is electrically connected to the processor, and the other end is electrically connected to the flexible circuit board.

17. The electronic device according to claim 16, characterized in that: The electronic device further comprises a frame, the metal back plate is mounted on one side of the frame, and the dielectric substrate and the flexible circuit board are both mounted on the inner side of the frame.

18. The electronic device according to claim 16 or 17, characterized in that: The electronic device also includes a display screen, which is installed on the side of the frame away from the metal back plate. The display screen includes a display panel and a metal support plate, which is installed on the non-display side of the display panel and is electrically connected to the main body.

19. The electronic device according to claim 18, characterized in that: The electronic device further includes a second conductive adhesive layer, and the second conductive adhesive layer is electrically connected between the main body and the metal support plate.

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