Cavity antenna and electronic device

Abstract

This application provides a cavity antenna and electronic device, relating to the field of wireless communication design technology. The cavity antenna includes a semi-enclosed metal resonant cavity and at least two feeding structures; wherein: the at least two feeding structures are respectively disposed at electric field weakness points corresponding to different frequency bands within the metal resonant cavity, forming the feeding points of the cavity antenna, and the electric field strength at the electric field weakness points is less than a preset threshold. By setting multiple feeding structures in the cavity antenna, different frequency bands of the multi-frequency cavity antenna are excited respectively, realizing multi-band operation of a single antenna, reducing system complexity. By placing multiple feeding structures at electric field weakness points of different frequency bands, the requirement that a single feeding point location cannot simultaneously meet the electric field weakness requirements of multiple frequency bands is solved, improving the impedance matching of the cavity antenna at multiple frequency bands, thereby improving antenna radiation efficiency, achieving multi-band, high-performance radiation characteristics, and meeting the communication needs of multi-frequency wireless communication devices.

Description

Technical Field

[0001] This application relates to the field of wireless communication design technology, and in particular to a cavity antenna and electronic device. Background Technology

[0002] Currently, tablets, laptops, and other terminal devices commonly adopt an all-metal design for aesthetics and a premium feel. However, this all-metal casing significantly impacts antenna performance, rendering traditional antenna solutions (such as monopole antennas, loop antennas, and inverted-F antennas) unsuitable for such environments. To address the challenges of antenna design within an all-metal casing, resonant cavity antennas are currently the primary approach. These antennas utilize electromagnetic field resonance within a cavity to radiate or receive signals. At the resonant point, a specific mode distribution exists, primarily manifested as the electric and magnetic fields distributed within the cavity.

[0003] In related technologies, a single feeding structure is used to introduce radio frequency signals into the cavity through a single feeding point, thereby exciting the cavity antenna. The feeding point is usually located at a weak electric field point inside the cavity.

[0004] However, the cavity antennas mentioned above are insufficient to meet the communication requirements of multi-frequency wireless communication devices. Summary of the Invention

[0005] This application provides a cavity antenna and an electronic device to solve the problem that cavity antennas in the related art cannot meet the communication requirements of multi-frequency wireless communication devices.

[0006] In a first aspect, this application provides a cavity antenna, comprising: a semi-enclosed metallic resonant cavity and at least two feeding structures; wherein:

[0007] At least two feeding structures are respectively set at the electric field weak points corresponding to different frequency bands in the metal resonant cavity to form the feeding points of the cavity antenna, and the electric field strength of the electric field weak points is less than a preset threshold.

[0008] In one possible implementation, the number of feeding structures is equal to the number of frequency bands included in the multi-frequency radio frequency signal transmitted by the cavity antenna.

[0009] In one possible implementation, different feed structures are each connected to a feed line, and the feed structure is used to receive signals of the corresponding frequency band through the correspondingly connected feed line.

[0010] In one possible implementation, the cavity antenna further includes a combiner, which includes one input port and a number of output ports corresponding to the feed structure. The input port is used to connect to the feed line, and the output ports are connected to the corresponding feed structure.

[0011] In one possible implementation, the metal resonant cavity is formed by welding a metal shell assembly and a printed circuit board.

[0012] In one possible implementation, the combiner is mounted on a printed circuit board.

[0013] In one possible implementation, the cavity antenna has a cuboid structure, a cube structure, a sphere structure, or a cylinder structure.

[0014] In one possible implementation, the number of power supply structures is two. The metal resonant cavity includes an open surface perpendicular to the printed circuit board. The two power supply structures are disposed on the side of the open surface opposite to the printed circuit board and are connected to the output port of the combiner through structural components.

[0015] In one possible implementation, the number of power feeding structures is 2. The metal resonant cavity includes two adjacent open surfaces, both of which are perpendicular to the printed circuit board. The two power feeding structures are respectively disposed on the sides of the two open surfaces opposite to the printed circuit board and are connected to the output port of the combiner through structural components.

[0016] Secondly, this application provides an electronic device including the cavity antenna of the first aspect.

[0017] In one possible implementation, the electronic device includes a metal frame or a metal housing, and the semi-enclosed metal resonant cavity of the cavity antenna is formed by a portion of the metal frame or the portion of the metal housing of the electronic device.

[0018] The cavity antenna and electronic device provided in this application include a semi-enclosed metallic resonant cavity and at least two feeding structures. The at least two feeding structures are respectively located at electric field weakness points corresponding to different frequency bands within the metallic resonant cavity, forming the feeding points of the cavity antenna. The electric field strength at these weak points is less than a preset threshold. By setting multiple feeding structures within the cavity antenna, different frequency bands of the multi-frequency cavity antenna are excited, enabling multi-band operation of a single antenna, reducing system complexity. Positioning multiple feeding structures at electric field weakness points in different frequency bands solves the problem that a single feeding point location cannot simultaneously meet the requirements of electric field weakness points for multiple frequency bands, improving the impedance matching of the cavity antenna at multiple frequency bands, thereby increasing antenna radiation efficiency and achieving multi-band, high-performance radiation characteristics. This is particularly suitable for miniaturized antenna designs and also meets the communication requirements of multi-frequency wireless communication devices. Furthermore, the semi-enclosed structure can radiate resonant energy in a directional manner while suppressing energy leakage in non-radiating directions, thus improving antenna gain. Attached Figure Description

[0019] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0020] Figure 1The electric field distribution diagram of the resonant cavity WiFi antenna provided in the embodiments of this application;

[0021] Figure 2 Electric field distribution diagram of miniaturized resonant cavity WiFi antenna provided in the embodiments of this application;

[0022] Figure 3 A schematic diagram of the cavity antenna provided in the embodiments of this application. Figure 1 ;

[0023] Figure 4 A schematic diagram of the cavity antenna provided in the embodiments of this application. Figure 2 ;

[0024] Figure 5 The return loss curves of the resonant cavity antenna at different positions provided in the embodiments of this application are shown.

[0025] Figure 6 Simulation amplitude curve of a 1-to-2 WiFi combiner provided in the embodiments of this application;

[0026] Figure 7 The return loss curve of the dual-feed resonant cavity antenna provided in the embodiments of this application;

[0027] Figure 8 A schematic diagram of the cavity antenna provided in the embodiments of this application. Figure 3 ;

[0028] Figure 9 This is a schematic diagram of a dual-feed resonant cavity antenna provided in an embodiment of this application;

[0029] Figure 10 This is a partial schematic diagram of a dual-feed resonant cavity antenna provided in an embodiment of this application;

[0030] Figure 11 A schematic diagram of the cavity antenna provided in the embodiments of this application. Figure 4 .

[0031] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0032] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0033] The terms “first,” “second,” etc., used in the specification and claims of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, products, or apparatus.

[0034] In related technologies, resonant cavity antenna schemes generally employ a single feed structure, meaning that the radio frequency signal is introduced into or extracted from the cavity through a single feed point. To excite the cavity antenna, the feed point typically needs to be placed at a weak electric field (i.e., a strong current point). This is because the current is stronger at weak electric field points, making it easier to form good coupling with the feed structure, thus effectively exciting the cavity resonance. However, modern wireless communication devices (such as devices supporting dual-band WiFi) need to operate on multiple frequency bands, such as WiFi 2.4GHz and WiFi 5.8GHz. At the same location, the electric field distribution at different resonant points (e.g., 2.4GHz and 5.8GHz) is different. This means that a location might be a weak electric field point at 2.4GHz but a strong electric field point at 5.8GHz. For ease of understanding, [further explanation needed]. Figure 1 and Figure 2 The electric field distribution of the resonant cavity WiFi antenna is explained.

[0035] Figure 1 The electric field distribution diagram of the resonant cavity WiFi antenna provided in the embodiments of this application is as follows: Figure 1 As shown, Figure 1 In Figure (a), the electric field distribution corresponding to WiFi 2.4 GHz inside the resonant cavity is shown. Figure 1Figure (b) shows the electric field distribution within the resonant cavity corresponding to WiFi 5.8GHz. Dark areas represent points with strong electric fields, and light areas represent points with weak electric fields. Antenna theory dictates that to achieve antenna resonance and good impedance matching, the feed port (i.e., the feed point) needs to be positioned where the electric field is weak (resistance is relatively small). To achieve resonance and good impedance matching for WiFi 2.4GHz, the feed point needs to be positioned... Figure 1 At position 102 in (a), there is a weak point in the electric field, and... Figure 1 As shown in (b), position 102 corresponds to the point of strong electric field for WiFi 5.8GHz, while position 101 is the point of weak electric field for WiFi 5.8GHz. If the feed point is set at position 102, it is difficult to achieve matching for WiFi 5.8GHz, and the resonance of WiFi 5.8GHz cannot be effectively excited. If the feed point is set at position 101, it is difficult to achieve matching for WiFi 2.4GHz, and the resonance of WiFi 2.4GHz cannot be effectively excited.

[0036] Figure 2 The electric field distribution diagram of the miniaturized resonant cavity WiFi antenna provided in the embodiments of this application is as follows: Figure 2 As shown, Figure 2 In Figure (a), the electric field distribution corresponding to WiFi 2.4 GHz inside the resonant cavity is shown. Figure 2 (b) shows the electric field distribution within the resonant cavity corresponding to WiFi 5.8GHz. Dark areas represent strong electric field points, and light areas represent weak electric field points. Position 103 represents a weak electric field point for WiFi 2.4GHz, and position 104 represents a strong electric field point for WiFi 2.4GHz. The opposite is true for WiFi 5.8GHz. Therefore, for miniaturized cavity antennas, it is more difficult to obtain the same location for the weak electric field points of WiFi 2.4GHz and WiFi 5.8GHz. In practice, due to limitations such as antenna size and environment, the weak electric field points of many cavity antennas of various sizes cannot coincide well across multiple frequency bands, making matching more difficult.

[0037] Furthermore, with increasingly compact internal spaces in modern electronic products, it is often difficult to provide a large area for cavity antennas. Therefore, miniaturization of cavity antenna design is necessary. However, miniaturization of cavity antennas can lead to problems where a single feed point cannot match multiple resonant frequency bands.

[0038] In summary, because it is impossible to adequately address the electric field weaknesses of both WiFi 2.4GHz and WiFi 5.8GHz at the feed point location, it is difficult for the feed point location to simultaneously meet the electric field weakness requirements of multiple frequency bands. This makes it difficult for the cavity antenna to achieve optimal impedance matching at multiple frequency bands simultaneously. Poor matching will further reduce the antenna radiation efficiency, making it difficult to meet the communication needs of multi-frequency wireless communication devices.

[0039] To address the aforementioned technical issues, the cavity antenna provided in this application places multiple feeding structures at electric field weaknesses in different frequency bands, thereby exciting the corresponding frequency bands. This solves the problem that a single feeding structure cannot simultaneously excite electric field weaknesses corresponding to different frequency bands, improves the impedance matching of the cavity antenna in multiple frequency bands, and thus improves the antenna radiation efficiency, meeting the requirements of miniaturization design and the communication needs of multi-frequency wireless communication devices.

[0040] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0041] Figure 3 A schematic diagram of the cavity antenna provided in the embodiments of this application. Figure 1 It should be noted that, Figure 3 This is merely an illustration and does not constitute a specific limitation on the shape or structure of the cavity antenna provided in the embodiments of this application. Figure 3 As shown, the cavity antenna 30 includes: a semi-enclosed metal resonant cavity 31 and at least two feeding structures 32; wherein: at least two feeding structures 32 are respectively disposed at electric field weak points corresponding to different frequency bands in the metal resonant cavity 31 to form feeding points of the cavity antenna, and the electric field strength of the electric field weak points is less than a preset threshold.

[0042] The cavity antenna 30 is made of metal material, forming a semi-enclosed space (metal resonant cavity). The semi-enclosed structure can effectively limit the propagation range of electromagnetic waves, so that the electromagnetic waves resonate in the cavity, thereby enhancing the radiation performance of the antenna.

[0043] The metal resonant cavity 31 can be a regular geometric shape such as a cuboid, cylinder, cube, cone, or sphere, or an irregular geometric shape. For example, the cavity antenna 30 includes a cuboid metal resonant cavity with M open faces, where M is 1, 2, or 3. The open faces are used to radiate electromagnetic waves. As one example, if there is one open face, the other 5 faces are closed, such as... Figure 3 The central open surface 10. The configuration of the metal resonant cavity 31 is not limited to laser direct forming (LDS) technology, nano-injection molding (NMT) technology, metal injection molding (MIM) technology, or using a support frame as an auxiliary structure, and is constructed by multiple metal plate components, etc.

[0044] The cavity antenna 30 provided in this embodiment can be used to effectively convert the high-frequency current energy (multi-frequency radio frequency signal) output by the transmitting device into electromagnetic energy in space and radiate it out through an open surface. The multi-frequency radio frequency signal contains multiple different frequency bands. In the metal resonant cavity, the electric field distribution under different frequency bands is different, and there are regions with relatively weak electric field strength.

[0045] For example, before setting the feeding structure, simulation software can be used to analyze the electric field distribution of multi-frequency radio frequency signals in the cavity antenna, thereby determining the specific locations of electric field weaknesses in different frequency bands. Electric field weaknesses can be considered as locations where the electric field strength is less than a preset threshold. For cavity antennas of different sizes, open surfaces, or application environments, the number and placement of the required feeding structures may differ during simulation analysis. For instance, there may be scenarios where electric field weaknesses overlap in some frequency bands or where electric field weaknesses in different frequency bands do not overlap at all. Taking a multi-frequency radio frequency signal containing N frequency bands as an example, for the two frequency bands where electric field weaknesses overlap, a feeding structure is set at the overlapping electric field weakness point to form a feeding point, which can also be called a feeding port or feeding end; feeding structures are then set at the electric field weaknesses corresponding to the other N-2 frequency bands, meaning that N-1 feeding structures are needed. For scenarios where the electric field weaknesses of N frequency bands do not overlap, a feeding structure is set at the electric field weakness point of each frequency band, meaning that N feeding structures are needed. This allows multi-frequency radio frequency signals to be introduced into the cavity antenna through different feeding points, achieving effective excitation of different frequency bands.

[0046] Multi-frequency radio frequency signals can be dual-frequency signals, tri-frequency signals, quad-frequency signals, etc. The cavity antenna in this application embodiment supports Bluetooth bands (such as 2.4GHz to 2.485GHz), WiFi 2.4G bands (such as 2.4GHz to 2.5GHz), WiFi 5G bands (such as 5.15 to 5.85GHz), and LTE bands including band 38, band 39, band 40, and band 41.

[0047] In a specific example, the multi-frequency radio frequency signal is a dual-band WiFi signal. The electric field weaknesses of WiFi 2.4GHz and WiFi 5.8GHz are obtained through simulation software analysis. Feeding structures are set at these two electric field weaknesses to form feed points. The feed points are used to connect feed lines, which are used to transmit the multi-frequency signal emitted by the transmitting device to the cavity antenna with minimal loss through the feed points. For example, two feed points can be independently connected to different feed lines. Feed point a is connected to feed line A, and feed point b is connected to feed line B. The dual-band radio frequency signal output from the transmitting device is processed so that feed line A is used to transmit a 2.4GHz signal, and feed line B is used to transmit a 5.8GHz signal. Alternatively, the two feed points and feed lines can be connected via a 1-to-2 combiner. The input of the combiner is connected to the feed line that transmits a dual-band WiFi signal. One output of the combiner is connected to feed point A, and only the 2.4GHz signal passes through this output. The other output is connected to feed point B, and only the 5.8GHz signal passes through this output. This achieves independent power supply through the 1-to-2 combiner.

[0048] It should be noted that the embodiments of this application do not limit the connection method between the power supply point and the power supply line, and are not limited to the two methods listed above.

[0049] It should also be noted that the geometry, size, number of open surfaces, and location of the open surfaces of the metal resonant cavity 31 can affect the resonant frequency and radiation characteristics of the cavity antenna 30 to a certain extent, and the structural morphology of the metal resonant cavity 31 will affect the antenna performance. Therefore, in practical applications, the geometry, size, number of open surfaces, and location of the open surfaces of the metal resonant cavity 31 can be determined according to design requirements and application scenarios, and this application does not impose any restrictions on this. In addition, based on the principle of electric field distribution, the electric field weakness points corresponding to each frequency band may be a certain region rather than a specific point. When setting up the feeding structure, a specific location can be selected from the electric field weakness region to set up the feeding structure according to design requirements, application scenarios, and other factors. It should be understood that the specific location of the feeding point (or electric field weakness point) can be obtained through simulation or determined through multiple adjustments.

[0050] This application embodiment achieves multi-band operation of a single antenna by setting multiple feeding structures in the cavity antenna to excite different frequency bands of the multi-frequency cavity antenna, thus reducing system complexity. By placing multiple feeding structures at the electric field weaknesses of different frequency bands, the requirement that a single feeding point location cannot simultaneously meet the electric field weaknesses of multiple frequency bands is addressed. This improves the impedance matching of the cavity antenna at multiple frequency bands, thereby increasing antenna radiation efficiency and achieving multi-band, high-performance radiation characteristics to meet the communication needs of multi-frequency wireless communication devices. Furthermore, the semi-enclosed structure can radiate resonant energy in a directional manner while suppressing energy leakage in non-radiative directions, thus improving antenna gain.

[0051] For scenarios where the electric field weaknesses of different frequency bands in a cavity antenna do not overlap, it is necessary to set up feeding structures at the electric field weakness points of different frequency bands. Multi-frequency radio frequency signals are introduced into the cavity antenna through different feeding points to achieve effective excitation of different frequency bands. Therefore, in some embodiments, the number of feeding structures is equal to the number of frequency bands included in the multi-frequency radio frequency signals transmitted by the cavity antenna.

[0052] For example, a cavity antenna supports the transmission of tri-band radio frequency signals, which include three frequency bands. The electric field weaknesses of each frequency band in the cavity antenna do not overlap. The required number of feeding structures is three, and the three feeding structures are respectively set at the electric field weaknesses corresponding to the three frequency bands.

[0053] In some embodiments, different feed structures are each connected to a feed line, and the feed structure is used to receive signals of the corresponding frequency band through the corresponding feed line.

[0054] For example, filters can be added to the feed lines to allow different feed lines to transmit signals of a specific frequency band. In a tri-band cavity antenna, three feed points (feed structures) are connected to feed lines for low frequency (e.g., 700MHz), intermediate frequency (e.g., 1.8GHz), and high frequency (e.g., 2.6GHz), respectively. Optionally, the signal for each frequency band can be adjusted for power, phase control, etc., through independent feed lines, thereby optimizing antenna performance.

[0055] The feeder is not limited to coaxial line, microstrip line, stripline, etc. For example, the feeder is a coaxial line. The inner conductor (inner core) of the coaxial line is connected to the feeding structure, and the outer conductor is connected to the metal wall of the metal resonant cavity. The excitation signal is transmitted to the metal resonant cavity through the inner conductor to excite the electromagnetic resonance in the metal resonant cavity.

[0056] In this embodiment, signals of different frequency bands are transmitted through independent feeders, and signals of different frequency bands are transmitted to the corresponding feeder structures respectively, avoiding signal coupling and interference. This is especially suitable for scenarios that are sensitive to inter-frequency interference (such as satellite communication and radar systems) and require independent control of signals of each frequency band (such as Wi-Fi routers and base station antennas).

[0057] In some embodiments, the cavity antenna 30 further includes a combiner 33, which includes one input port and a number of output ports corresponding to the feed structure 32. The input port is used to connect to the feed line, and the output ports are connected to the corresponding feed structure 32.

[0058] Among them, the combiner 33 is used to distribute and isolate multi-frequency radio frequency signals, combining signals from multiple frequency bands into a common port (input port), or separating them from the common port to multiple output ports (corresponding to the power supply structure).

[0059] For example, the input port is connected to the feed line to receive multi-band radio frequency signals from the radio frequency front end (such as the transmitting device) and distribute the signals to the corresponding feed structure of the cavity antenna (such as feed points of different frequency bands).

[0060] by Figure 4 Let's take an example to illustrate. Figure 4 A schematic diagram of the cavity antenna provided in the embodiments of this application. Figure 2 .like Figure 4 The diagram shows a dual-fed resonant cavity antenna. The side 10 of the metal resonant cavity 31 of the cavity antenna 30 is non-metallic and open (open surface) for radiating electromagnetic waves. Feed points 101 and 102 are set on the side 10. The two output ports of the combiner 33 are connected to feed points 101 and 102 respectively. The input port 100 of the combiner 33 is connected to the feed line to receive dual-frequency radio frequency signals. After passing through the combiner 33, the dual-frequency radio frequency signals reach feed point 101 as only WiFi 5.8GHz signals and reach feed point 102 as only WiFi 2.4GHz signals. Since the signals of the two feed ports exist independently, they do not interfere with each other, thereby improving the antenna radiation efficiency. At the same time, it achieves simultaneous feeding at the weak electric field points of WiFi 2.4GHz and WiFi 5.8GHz, thereby achieving good impedance matching in the two frequency bands.

[0061] It should be noted that the combiner 33 can exist independently of the cavity antenna 30, or it can be set at a certain position on the cavity antenna 30 (integrated into or near the cavity antenna). For example, the combiner circuit can be embedded in the metal resonant cavity of the cavity antenna 30 and connected to the feed structure through a microstrip line or coaxial line to reduce the feed line length and loss.

[0062] In this embodiment, a combiner is used to connect the feed line and the power supply structure to achieve efficient transmission of multi-band signals, ensuring that the signals of each band do not interfere with each other, and simultaneously powering the electric field weaknesses of different band signals to achieve good impedance matching of multiple bands and improve the radiation efficiency of the cavity antenna.

[0063] To verify the performance of the combiner proposed in this application embodiment in terms of signal distribution and frequency band isolation, simulation analysis can be performed through multiple sets of experiments. These multiple sets of experiments are all based on... Figure 4 The cavity antenna implementation shown can be, for example, fed at feed point 101 and feed point 102 using a calibration vector network analyzer (VNA), or using electromagnetic simulation software, programming tools, etc.

[0064] Example 1: Without a combiner, the same multi-frequency signal was used to feed the antenna at different feeding positions (feeding point 101 and feed point 102), and the resonance curves of the resonant cavity antenna under different feeding positions were tested, such as... Figure 5The return loss curves of the resonant cavity antenna at different locations provided in this application embodiment are shown in the figure. The horizontal axis represents the frequency in GHz, and the vertical axis represents the return loss in dB. The return loss directly reflects the amplitude change of the S-parameter S11. The lower the amplitude value (the more negative), the better the matching. The dashed line represents the return loss curve corresponding to the excitation at feed point 102 (corresponding to fed_pos=16 in the figure), and the solid line represents the return loss curve corresponding to the excitation at feed point 101 (corresponding to fed_pos=10 in the figure). Figure 5 As can be seen, feed point 102 has relatively good matching for the WiFi 5.8GHz bandwidth, but poor matching for WiFi 2.4GHz, while feed point 101 has good matching for WiFi 2.4GHz, but poor matching for WiFi 5.8GHz. Therefore, in order to achieve good matching for both WiFi 2.4GHz and WiFi 5.8GHz, a dual-feed structure (dual feed points) needs to be set on the resonant cavity antenna.

[0065] Example 2: A dual-feed point is set on the resonant cavity antenna, and the two feed points are connected to a combiner, which simultaneously feeds the antenna. For example... Figure 6 The simulation amplitude curve of the 1-to-2 WiFi combiner provided in this application embodiment is shown in the figure. The horizontal axis represents frequency in GHz, and the vertical axis represents amplitude response in dB. The curves represent the amplitude response of the combiner at different frequencies. The dashed line represents the amplitude response corresponding to WiFi 5.8GHz (feed point 102), and the solid line represents the amplitude response corresponding to WiFi 2.4GHz (feed point 101). Figure 6 As can be seen, there are significant peaks around 2.4 GHz and 5.8 GHz, indicating that the signal transmission efficiency is high at these frequencies. At other frequencies, the amplitude response is low, meaning that the signal transmission efficiency is low or suppressed. Therefore, the combiner essentially achieves frequency division power supply for WiFi 2.4 GHz and WiFi 5.8 GHz.

[0066] Furthermore, based on Example 2, through Figure 7 The return loss at different locations of the resonant cavity antenna with a combiner is represented. Figure 7 The return loss curve of the dual-feed resonant cavity antenna provided in the embodiments of this application is from... Figure 7 It can be seen that the S-parameter S11 shows obvious troughs (i.e. the curve drops to a lower value) around 2.4 GHz and 5.8 GHz, which indicates that the antenna has low return loss and good matching at these frequencies; at other frequencies, the S11 value is higher, which means that the antenna matching effect is poor and the reflected signal is larger.

[0067] Through the above experiments, it can be determined that the dual-fed cavity antenna provided in this application embodiment achieves good bandwidth impedance matching for WiFi 2.4GHz and WiFi 5.8GHz.

[0068] In some embodiments, the metal resonant cavity is formed by welding a metal shell assembly and a printed circuit board.

[0069] The metal housing components come in various forms. For example, a metal housing component can be obtained by wrapping a plastic support with a flexible printed circuit board (FPC); or, a metal housing component can be obtained by laser engraving a plastic support combined with electroplating, spraying, or other methods to achieve metallization; and so on. Additionally, the metal housing component can also be made of highly conductive metals (such as copper or aluminum) or alloys (such as stainless steel), and the surface can be plated with gold / silver to reduce losses. The metal housing component provides electromagnetic shielding, reduces radiation leakage, and forms a semi-enclosed resonant cavity with the printed circuit board (PCB) to control the electromagnetic field distribution. The metal housing component can be precision machined, stamped, or cast to ensure dimensional accuracy of the cavity; for example, the metal housing component can be a metal shielding cover. Below the metal housing component is the PCB, and the metal housing component and the PCB can be welded together using various methods such as laser welding and resistance welding. Specifically, the metal housing component is welded to the ground plane of the PCB, for example, to form a cavity antenna with an open surface.

[0070] In this embodiment, radio frequency front-end circuits can be integrated on the PCB to reduce interconnection losses. For example, in some embodiments, the combiner can also be set on the printed circuit board, and multiple feed structures on the metal housing assembly are respectively connected to multiple output ports of the combiner on the PCB to form feed points, thereby realizing the distribution of signals of different frequency bands to the corresponding feed structures.

[0071] In this embodiment, by integrating the combiner onto the printed circuit board of the cavity antenna, the additional connection (such as coaxial cable or connector) between the independent combiner and the cavity antenna is eliminated, reducing losses in the transmission path and simplifying the structure. At the same time, it enables the miniaturization design of the cavity antenna, saving space and cost.

[0072] In some embodiments, the cavity antenna has a cuboid structure, a cube structure, a sphere structure, or a cylindrical structure.

[0073] Cavity antennas with cuboid, cube, spherical, or cylindrical structures offer more uniform current distribution, reducing additional losses caused by uneven current distribution. This allows all parts of the cavity antenna to effectively participate in radiation, thereby improving the overall radiation efficiency. Geometric symmetry also simplifies the analysis and design of electromagnetic field distribution. Furthermore, they are easier to manufacture and have a more stable hardware structure.

[0074] As a specific embodiment, when the cavity antenna is a dual-band antenna, the number of feeding structures is 2. The metal resonant cavity includes an open surface perpendicular to the printed circuit board. The two feeding structures are arranged on the side of the open surface opposite to the printed circuit board and are connected to the output port of the combiner through structural components.

[0075] like Figure 8 A schematic diagram of the cavity antenna provided in the embodiments of this application. Figure 3 As shown, the cavity antenna 30 has a cuboid structure. The metal resonant cavity 31 of the cavity antenna 30 is formed by welding a metal shell assembly and a printed circuit board. The metal resonant cavity 31 includes a non-metallic open surface 10, wherein the open surface 10 is perpendicular to the printed circuit board (e.g., Figure 8 (Lower surface of the middle). There are two power supply structures, corresponding to power supply point 102 and power supply point 101 respectively. The power supply structures are respectively set on the side 11 of the open surface 10 and connected to the two output ports of the combiner through structural components.

[0076] pass Figure 9 and Figure 10 The location and connection relationship of the combiner and the power supply structure are shown more clearly. Figure 9 This is a schematic diagram of a dual-feed resonant cavity antenna provided in an embodiment of this application. Figure 10 This is a partial schematic diagram of a dual-feed resonant cavity antenna provided in an embodiment of this application.

[0077] like Figure 9 As shown, the metal resonant cavity consists of a metal shell assembly (metal cover) and a PCB (dark gray area). A combiner (dashed coil in the figure) is mounted on the PCB, and this combiner includes one input terminal and two output terminals. Figure 11 As shown, two protruding structures (structural components) are clearly visible on the side 11 of the open surface. These two protruding structures are connected to the two output ports of the combiner, forming cavity power supply position 1 (power supply point 101) and cavity power supply position 2 (power supply point 102). The main power supply port is used to connect to the feeder.

[0078] As another specific embodiment, when the cavity antenna is a miniaturized dual-band antenna, in some embodiments, the number of feeding structures is 2. The metal resonant cavity includes 2 adjacent open surfaces, both of which are perpendicular to the printed circuit board. The 2 feeding structures are respectively arranged on the sides of the 2 open surfaces opposite to the printed circuit board and are connected to the output port of the combiner through structural components.

[0079] like Figure 11 A schematic diagram of the cavity antenna provided in the embodiments of this application. Figure 4As shown, the cavity antenna 30 has a cuboid structure. The metal resonant cavity 31 of the cavity antenna 30 is formed by welding a metal shell assembly and a printed circuit board. The metal resonant cavity 31 includes two non-metallic open surfaces 20 and 21, wherein the open surfaces 20 and 21 are adjacent to each other and are both perpendicular to the printed circuit board (e.g., ...). Figure 11 (Lower surface of the middle). There are two power supply structures, corresponding to power supply points 202 and 201 respectively. One power supply structure is set on the side 211 of the open surface 20, and the other power supply structure is set on the side 212 of the open surface 21. They are connected to the two output ports of the combiner 33 through structural components. The input port 200 of the combiner is connected to the feeder.

[0080] It should be noted that the specific location of the power supply structure on the opposite side of the printed circuit board in the open surface is related to the location of the electric field weakness, and this application does not impose any restrictions on this.

[0081] Finally, the cavity antenna provided in this application embodiment can be applied to electronic devices. This application embodiment provides an electronic device that includes the cavity antenna described in the above embodiment.

[0082] For example, the electronic device may be a tablet computer, laptop computer, wireless headphones, wearable devices (such as smartwatches, smart bracelets, smart helmets, smart glasses, etc.), in-vehicle devices, augmented reality (AR) / virtual reality (VR) devices, personal digital assistants (PDAs), and other multi-frequency wireless communication devices. The electronic device may also be a handheld device with wireless communication capabilities, a computing device, or other processing devices connected to a wireless modem, a terminal device in a 5G network, or a terminal device in a future evolved public terrestrial mobile network (PLMN), etc., and this application embodiment is not limited in this respect.

[0083] Cavity antennas are disposed in electronic devices. In some embodiments, the electronic device includes a metal frame or a metal shell, and the semi-enclosed metal resonant cavity of the cavity antenna is formed by part of the metal frame or part of the metal shell of the electronic device.

[0084] Optionally, the electronic device includes an insulating frame or an insulating housing, and the cavity antenna can be disposed on the insulating frame or the insulating housing.

[0085] It should be noted that the specific location of the cavity antenna within the electronic device can be designed according to the structure of the electronic device, and this application does not impose any restrictions on this. Applying the cavity antenna provided in this application to electronic devices can meet the communication requirements of multi-frequency wireless communication devices.

[0086] In summary, this application has at least the following advantages:

[0087] I. By incorporating multiple feeding structures within the cavity antenna, different frequency bands of the multi-frequency cavity antenna can be excited separately, enabling single-antenna multi-band operation and reducing system complexity. Positioning multiple feeding structures at electric field weaknesses in different frequency bands addresses the challenge of a single feeding point simultaneously meeting the requirements of multiple frequency bands' electric field weaknesses. This improves the impedance matching of the cavity antenna across multiple frequency bands, thereby enhancing antenna radiation efficiency and achieving multi-band, high-performance radiation characteristics, meeting the needs of miniaturized antenna design and multi-frequency wireless communication devices. Furthermore, the semi-enclosed structure allows for directional radiation of resonant energy while suppressing energy leakage in non-radiative directions, thus improving antenna gain.

[0088] Second, by transmitting signals of different frequency bands through independent feeders, signals of different frequency bands are transmitted to the corresponding feeder structures respectively, avoiding signal coupling and interference. This is especially suitable for scenarios that are sensitive to inter-frequency interference (such as satellite communication and radar systems) and require independent control of signals of each frequency band (such as Wi-Fi routers and base station antennas).

[0089] Third, by connecting the feed line and the power supply structure through a combiner, efficient transmission of multi-band signals is achieved, ensuring that the signals of each band do not interfere with each other, and simultaneously powering the electric field weaknesses of different band signals to achieve good impedance matching of multiple bands and improve the radiation efficiency of the cavity antenna.

[0090] Fourth, by integrating the combiner onto the printed circuit board of the cavity antenna, the additional connection between the independent combiner and the cavity antenna (such as coaxial cable or connector) is eliminated, reducing the loss in the transmission path, simplifying the structure, and enabling the miniaturization of the cavity antenna, saving space and cost.

[0091] 5. Cavity antennas with cuboid or cubic structures offer more uniform current distribution, reducing additional losses caused by uneven current distribution. This allows all parts of the cavity antenna to effectively participate in radiation, thereby improving the overall radiation efficiency. Geometric symmetry also simplifies the analysis and design of electromagnetic field distribution. Furthermore, they are easier to manufacture and have a more stable hardware structure.

[0092] Finally, it should be noted that other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This invention is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein, and is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

Claims

1. A cavity antenna, characterized in that, include: A semi-enclosed metal resonant cavity and at least two feeding structures; wherein: The at least two feeding structures are respectively disposed at electric field weak points corresponding to different frequency bands in the metal resonant cavity, forming the feeding points of the cavity antenna, and the electric field strength of the electric field weak points is less than a preset threshold; the semi-enclosed metal resonant cavity includes at least one open surface, and the different frequency bands all form an electric field distribution based on the overall space of the metal resonant cavity.

2. The cavity antenna according to claim 1, characterized in that, The number of feeding structures is equal to the number of frequency bands included in the multi-frequency radio frequency signal transmitted by the cavity antenna.

3. The cavity antenna according to claim 1 or 2, characterized in that, Each of the aforementioned feeding structures is connected to a feed line, and the feeding structure is used to receive signals of the corresponding frequency band through the corresponding feed line.

4. The cavity antenna according to claim 1 or 2, characterized in that, The cavity antenna also includes a combiner, which has one input port and a number of output ports corresponding to the feeding structure. The input port is used to connect to the feed line, and the output port is connected to the corresponding feeding structure.

5. The cavity antenna according to claim 4, characterized in that, The metal resonant cavity is formed by welding a metal shell assembly and a printed circuit board.

6. The cavity antenna according to claim 5, characterized in that, The combiner is mounted on the printed circuit board.

7. The cavity antenna according to claim 6, characterized in that, The cavity antenna has a cuboid structure, a cube structure, a sphere structure, or a cylindrical structure.

8. The cavity antenna according to claim 7, characterized in that, The number of power feeding structures is 2. The metal resonant cavity includes an open surface perpendicular to the printed circuit board. The two power feeding structures are arranged on the side of the open surface opposite to the printed circuit board and are connected to the output port of the combiner through structural components.

9. The cavity antenna according to claim 7, characterized in that, The number of power feeding structures is 2. The metal resonant cavity includes 2 adjacent open surfaces. Both open surfaces are perpendicular to the printed circuit board. The 2 power feeding structures are respectively disposed on the sides of the 2 open surfaces opposite to the printed circuit board and are connected to the output port of the combiner through structural components.

10. An electronic device, characterized in that, Includes a cavity antenna as described in any one of claims 1 to 9.

11. The electronic device according to claim 10, characterized in that, The electronic device includes a metal frame or a metal casing, and the semi-enclosed metal resonant cavity of the cavity antenna is formed by part of the metal frame or part of the metal casing of the electronic device.

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