Antenna ground structure and electronic device

Abstract

The application provides an antenna grounding structure and an electronic device, wherein the antenna grounding structure comprises a first mainboard, an antenna and a flexible circuit board; the first mainboard is provided with a mainboard ground; the flexible circuit board comprises at least a signal layer and a ground layer; the antenna is connected with the first mainboard through a first connecting structure; the flexible circuit board is connected with the first mainboard through a second connecting structure, so that the ground layer of the flexible circuit board is in electrical conduction with the mainboard ground of the first mainboard; wherein the ground layer is an extension of the mainboard ground, and the length of the ground layer is determined according to the length of the mainboard ground of the first mainboard and the working wavelength of the antenna. The technical scheme can significantly improve the antenna radiation capacity of the antenna without increasing the overall volume.

Description

Technical Field

[0001] This application relates to the field of electronic equipment technology, and in particular to an antenna grounding structure and electronic equipment. Background Technology

[0002] As a crucial component in communication, the performance of an antenna is highly dependent on an effective ground plane. In traditional designs, the antenna's ground plane primarily relies on the antenna body and the motherboard ground.

[0003] However, as electronic devices, especially smart wearable devices (such as smart glasses and AR / VR headsets), become thinner and smaller, the size of the motherboard connected to the antenna and the size of the antenna itself are strictly limited, resulting in insufficient size of the ground plane available for the antenna. When the ground plane is insufficient, antenna performance deteriorates significantly, manifesting as low radiation efficiency, narrowed operating bandwidth, and distortion of the radiation pattern (which shows the strength distribution of electromagnetic waves radiated by the antenna in various directions of space).

[0004] In related technologies, increasing the motherboard size is sometimes attempted to extend the ground plane, but this runs counter to the trend of device miniaturization; alternatively, a dedicated component for antenna grounding is added, but this increases assembly complexity and cost, and is difficult to implement when space is limited. Therefore, how to effectively extend the antenna ground plane within a limited space has become a pressing technical problem to be solved in order to improve the wireless performance of compact devices. Utility Model Content

[0005] This application provides an antenna grounding structure and electronic device, aiming to solve the technical problem of antenna performance degradation caused by insufficient grounding plane size in compact electronic devices.

[0006] In a first aspect, an antenna grounding structure is provided, comprising: a first motherboard, an antenna, and a flexible circuit board; a motherboard ground is provided on the first motherboard; the flexible circuit board includes at least a signal layer and a ground layer; the antenna is connected to the first motherboard through a first connection structure; the flexible circuit board is connected to the first motherboard through a second connection structure, such that the ground layer of the flexible circuit board is electrically connected to the motherboard ground of the first motherboard; wherein the ground layer is an extension of the motherboard ground, and the length of the ground layer is determined according to the length of the motherboard ground of the first motherboard and the operating wavelength of the antenna.

[0007] This antenna grounding structure cleverly utilizes the wiring space of the flexible circuit board to effectively extend the motherboard ground plane in three-dimensional space by introducing a flexible circuit board and connecting its ground layer to the motherboard ground through a connection structure. By rationally designing the length of the flexible circuit board's ground layer, it forms a sufficiently long overall grounding reference plane with the motherboard ground that meets the antenna's operating wavelength requirements. This design significantly improves the antenna's grounding conditions without significantly increasing the device's size and complexity, thereby enhancing key performance characteristics such as radiation efficiency and bandwidth. It is particularly suitable for space-constrained electronic devices.

[0008] In conjunction with the first aspect, in one possible implementation, the first connecting structure is a metal spring and / or a coaxial line.

[0009] In conjunction with the first aspect, in one possible implementation, the second connection structure is any of the following: board-to-board connector, zero-insertion-force connector, flexible circuit board connector, solder joint.

[0010] The above connection structure provides flexible and reliable connection and mechanical fixation options, which can be adapted to different product structures and manufacturing processes.

[0011] In conjunction with the first aspect, in one possible implementation, the antenna grounding structure further includes: a second main board; the flexible circuit board is connected to the second main board via a third connection structure. This design allows the flexible circuit board to span between two or more main boards, extending the grounding plane and potentially enabling signal transmission, thus achieving structural reuse and further improving space utilization.

[0012] In conjunction with the first aspect, in one possible implementation, the third connection structure is any of the following: board-to-board connector, zero-insertion-force connector, flexible circuit board connector, solder joint.

[0013] In conjunction with the first aspect, in one possible implementation, the antenna is any one of an inverted-F antenna, a loop antenna, or a monopole antenna. The grounding structure extension scheme provided in this application is particularly suitable for these common antenna types that are sensitive to ground plane length.

[0014] In conjunction with the first aspect, in one possible implementation, the length of the ground plane is determined based on the length of the motherboard ground of the first motherboard and the operating wavelength of the antenna, specifically: the sum of the length of the ground plane and the length of the motherboard ground of the first motherboard is not less than one-quarter of the operating wavelength of the antenna.

[0015] This quantitative design principle ensures that the total electrical length of the combined ground plane can support the antenna to work effectively in the target operating frequency band.

[0016] In conjunction with the first aspect, in one possible implementation, the antenna grounding structure is disposed in the smart glasses, and the first main board and the second main board are respectively disposed in one side temple of the smart glasses.

[0017] In conjunction with the first aspect, in one possible implementation, the flexible circuit board includes at least one signal layer and at least one ground layer; when the number of ground layers is greater than or equal to two, the length of the ground layer refers to the length of the ground layer with the best radiation performance, and the ground layer with the best radiation performance includes at least one of the following: the longest ground layer, the ground layer at the bottom layer, and the ground layer at the top layer.

[0018] In a second aspect, an electronic device is provided, the electronic device including an antenna grounding structure as described in any one of the first aspects.

[0019] In conjunction with the second aspect, in one possible implementation, the electronic device is a smart glasses, with a first motherboard and a flexible circuit board of an antenna grounding structure disposed inside one temple of the smart glasses.

[0020] In conjunction with the second aspect, in one possible implementation, the electronic device is a smart glasses, with the first motherboard and the second motherboard of the antenna grounding structure respectively disposed inside one side of the temple of the smart glasses, and the flexible circuit board passing through the frame of the smart glasses.

[0021] This application achieves the following technical effects: by introducing a flexible circuit board and extending its ground plane as an extension of the main board ground, the grounding reference plane of the antenna is expanded. Through reasonable length design of the flexible circuit board's ground plane, the sum of the length of the flexible circuit board's ground plane and the length of the antenna body can meet the wavelength requirements of the antenna radiation, effectively improving the antenna's impedance matching and radiation characteristics. This compact and flexible structure is particularly suitable for devices with extremely limited space, such as smart glasses, significantly improving the antenna's radiation capability without increasing the overall volume. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of an antenna grounding structure provided in an embodiment of this application; Figure 2 A front view and a side view of a flexible circuit board provided for embodiments of this application; Figure 3 This is a schematic diagram of another antenna grounding structure provided in an embodiment of this application; Figure 4 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application; Figure 5 This is a schematic diagram illustrating another antenna grounding structure layout provided in this application embodiment when used in smart glasses. Figure 6 This is a schematic diagram of another antenna grounding structure layout provided in this application embodiment when used in smart glasses. Detailed Implementation

[0023] The technical solutions in the embodiments of this application will now be described with reference to the accompanying drawings.

[0024] The technical solution of this application is applicable to the field of electronic device technology, especially to electronic devices with strict limitations on internal space, including but not limited to smart glasses, AR / VR headsets, etc. The electronic device includes the antenna grounding structure shown in this application.

[0025] The following is a detailed description of an antenna grounding structure provided in this application.

[0026] like Figure 1 As shown in the figure, this application embodiment provides an antenna grounding structure 10. The antenna grounding structure 10 includes: a first main board 102, an antenna 103, and a flexible circuit board 101.

[0027] As a feasible implementation, the first motherboard 102 can be a rigid printed circuit board, and its substrate can be FR-4, high-frequency board, etc.

[0028] A motherboard ground 1021 is provided on the first motherboard 102. As a possible implementation, the motherboard ground 1021 can be a copper layer that is laid out over a large area on the first motherboard 102, which can serve as a common reference potential point for the entire circuit system, including as part of the ground plane of the antenna 103.

[0029] As a feasible implementation method, the first motherboard 102 may also be equipped with a radio frequency module.

[0030] The antenna 103 can be placed in a suitable position inside an electronic device (such as smart glasses) and connected to the first motherboard 102 through the first connection structure 104.

[0031] In one possible design, antenna 103 can be any one of an inverted-F antenna (PIFA antenna), a loop antenna, or a monopole antenna.

[0032] In one possible design, the first connection structure 104 is a metal spring and / or a coaxial line.

[0033] For example, if antenna 103 is an inverted-F antenna, the first connection structure 104 may include two metal springs, which connect the feed point and ground point of antenna 103 to the RF module pads and motherboard ground 1021 on the first motherboard 102, respectively. As another example, the first connection structure 104 may be a coaxial cable, with its core wire soldered to the antenna feed point and its outer conductor shielding layer soldered to the antenna ground point and motherboard ground 1021.

[0034] The flexible circuit board 101 can be a multilayer structure, including at least a signal layer 1011 and a ground layer 1012. As a possible implementation, the ground layer 1012 can be a large-area copper layer, used to provide return paths and electromagnetic shielding for the traces of the signal layer 1011.

[0035] For example, please see Figure 2 The images provided are a front view and a side view of a flexible circuit board according to an embodiment of this application.

[0036] like Figure 2 As shown in the front view, the flexible circuit board 101 can be presented as a strip or sheet structure of a specific shape to adapt to the spatial layout inside the device.

[0037] like Figure 2 As can be seen from the side view, the flexible circuit board 101 may include at least two layers: a signal layer 1011 and a ground layer 1012. The ground layer 1012 serves as an extension of the motherboard ground 1021 of the first motherboard, and its length is determined based on the length of the motherboard ground 1021 and the operating wavelength of the antenna. However, the structure involved in this application is not limited to this specific number of layers. In other embodiments, depending on the complexity of the circuit design and performance requirements (such as increasing wiring density, enhancing shielding, or achieving specific impedance), the flexible circuit board 101 may further include at least two signal layers and / or at least two ground layers. For example, a multilayer flexible board design with "signal-ground-signal" or alternating stacked layers can be adopted, wherein one ground layer is connected to the motherboard ground of the first motherboard of this application through a second connection structure, together forming the ground plane of the antenna.

[0038] In one possible design, the flexible circuit board 101 includes at least one signal layer and at least one ground layer; when the number of ground layers is greater than or equal to two, the length of the ground layer refers to the length of the ground layer with the best radiation performance, and the ground layer with the best radiation performance includes at least one of the following: the longest ground layer, the ground layer located at the bottom layer, and the ground layer located at the top layer.

[0039] It should be noted that the longest stratum is the one whose length exceeds that of all other strata. A longer length generally means a better grounding area and a longer RF signal return path, potentially resulting in better radiation efficiency for antenna 103. For example, a larger, more complete stratum typically performs better when providing a return reference for the antenna 103 body.

[0040] The bottommost ground layer can refer to the side of the flexible circuit board 101 furthest from the antenna 103 body in the stacked structure (i.e., the side closest to the internal motherboard or support structure of the product). The importance of this ground layer lies in the fact that it can be the main layer for connecting and physically fixing the flexible circuit board 101 to the motherboard ground 1021, and its stability and integrity are very important for ensuring the grounding quality of the entire antenna grounding structure 10.

[0041] The topmost ground layer can refer to the side of the flexible circuit board 101 closest to the external environment or the antenna 103 itself. This ground layer may be more directly coupled to the radiator of the antenna 103, and has a significant impact on the near-field distribution and final radiation performance of the antenna 103.

[0042] It should also be noted that the stratum with the best radiation performance may possess only one of the aforementioned characteristics, or it may possess multiple characteristics simultaneously. In practical design, simulation and testing can be used to determine which stratum plays a decisive role in the performance of antenna 103, and the stratum with the best radiation performance can be determined based on the simulation and test results.

[0043] In one embodiment, the length of the ground layer 1012 is determined based on the length of the motherboard ground 1021 of the first motherboard and the operating wavelength of the antenna 103. Specifically, the sum of the length of the ground layer 1012 and the length of the motherboard ground 1021 of the first motherboard is not less than one-quarter of the operating wavelength of the antenna 103.

[0044] For example, suppose the operating frequency of antenna 103 is 2.4 GHz (its operating wavelength λ is approximately 125 mm). Measurements or simulations show that the length (primarily the effective length) L1 of the motherboard ground 1021 on the first motherboard is 20 mm. If this is used as the sole reference ground, the grounding length of antenna 103 is much less than λ / 4 (approximately 31.25 mm), resulting in poor radiation performance of antenna 103. In this case, by introducing a flexible circuit board 101 and extending its ground plane 1012 as a grounding extension, designing its length L2 (primarily the effective length) to be at least 12 mm, the total grounding length L_Total reaches 32 mm (greater than 31.25 mm). This allows the combined grounding plane to meet the λ / 4 length requirement, thereby significantly optimizing the performance of antenna 103 in the 2.4 GHz band.

[0045] In one possible design, the total ground length L_Total can be equal to or slightly greater than λ / 4, and the resonant point of the antenna 103 can be fine-tuned by adjusting the precise length of the ground layer 1012 of the flexible circuit board 101.

[0046] In one possible design, the second connection structure 105 can be any of the following: board-to-board connector, zero-insertion-force connector, flexible circuit board connector, or solder joint.

[0047] It should be noted that the specific type of the second connection structure 105 can be selected based on the overall design of the electronic device, the manufacturing and assembly process, and reliability requirements. Different connection structures have their own characteristics in terms of electrical performance, mechanical reliability, space occupation, and maintainability.

[0048] It should be further explained that, regardless of the specific second connection structure chosen, the core design objective is to ensure a near-zero impedance, highly stable connection between the ground plane 1012 of the flexible circuit board 101 and the mainboard ground 1021 of the first mainboard. This makes them electrically equivalent to a continuous, sized extended ground plane, meeting the grounding size requirements of the antenna 103 related to its operating wavelength, and ultimately optimizing the radiation performance of the antenna 103. In practical design, electromagnetic simulation and actual measurements can be used to verify the impact of the small parasitic parameters introduced by different connection structures on the key performance indicators of the antenna 103 (such as resonant frequency, efficiency, and bandwidth), and a final selection can be made accordingly.

[0049] As one feasible implementation, the flexible circuit board 101 may be provided with pads or contacts for connection. For example, a first ground connection point may be provided at the end or a specific location of the ground layer 1012, and this first ground connection point is connected to a corresponding ground point on the first motherboard through a second connection structure. The end of the signal layer 1011 may be provided with a signal connection point for transmitting radio frequency signals or control signals. This flexible characteristic of the flexible circuit board allows its ground layers to be extended and arranged in three-dimensional space, thereby enabling it to pass through structural gaps inside the device or fit onto non-planar housings, effectively expanding the physical dimensions and electrical performance of the antenna ground plane without increasing the size of the motherboard.

[0050] As can be seen, the antenna grounding structure shown in this application expands the antenna grounding reference plane by introducing a flexible circuit board and extending its ground plane as an extension of the main board ground. Furthermore, by designing the ground plane of the flexible circuit board with a reasonable length, the sum of the length of the ground plane of the flexible circuit board and the length of the antenna body can meet the wavelength requirements of the antenna radiation, effectively improving the impedance matching and radiation characteristics of the antenna. This structure is compact and flexible, and is particularly suitable for devices with extremely limited space, such as smart glasses. It significantly improves the antenna radiation capability without increasing the overall volume.

[0051] Please see Figure 3 This is another antenna grounding structure provided in the embodiments of this application. Figure 3 The antenna grounding structure 30 shown includes: a first main board 302, a second main board 306, an antenna 303, and a flexible circuit board 301.

[0052] The first motherboard 302 has a motherboard ground 3021; ​​the flexible circuit board 301 includes at least a signal layer 3011 and a ground layer 3012.

[0053] Antenna 303 is connected to the first motherboard 302 through the first connection structure 304.

[0054] Among them, the ground layer 3012 is an extension of the motherboard ground 3021, and the length of the ground layer 3012 is determined according to the length of the motherboard ground 3021 of the first motherboard 302 and the operating wavelength of the antenna 303.

[0055] It should be noted that the above description of the first motherboard 302, antenna 303, flexible circuit board 301 and their related connection structures can be referred to the foregoing embodiments, and will not be repeated here.

[0056] As one possible implementation, the second motherboard 306 can be a separate electronic component or module that carries a specific function. For example, the second motherboard 306 can be a sub-board used to expand system interfaces (such as USB-C interface modules, speaker modules) or carry some peripheral circuits; it can also be a display driver board specifically used to drive the display screen; or it can be a sensor module board, such as a circuit board integrating a distance sensor, an ambient light sensor, etc.

[0057] One end of the flexible circuit board 301 is connected to the first motherboard 302 through the second connection structure 305, so that the ground layer 3012 of the flexible circuit board 301 is electrically connected to the motherboard ground 3021 of the first motherboard 302. The other end of the flexible circuit board 301 is connected to the second motherboard 306 through the third connection structure 307.

[0058] It should be noted that the function of the third connection structure 307 is to connect the other end of the flexible circuit board 301 to the second motherboard 306. In one possible design, the third connection structure 307 can be any of the following: board-to-board connector, zero-insertion-force connector, flexible circuit board connector, or solder joint.

[0059] In terms of specific form, the third connection structure 307 can be the same as the second connection structure 305, or it can differ depending on the interface type and space constraints of the connected object (the second motherboard). For example, since the second connection structure 305 connects to the system motherboard, it may use a high-precision board-to-board connector, while the third connection structure 307, which connects to a simple sensor board, may use a more economical flexible circuit board 301 connector or direct soldering.

[0060] For example, the first motherboard 302 and the second motherboard 306 can be physically separated. For instance, when the antenna 303 grounding structure based on the flexible circuit board 301 is placed on smart glasses, the first motherboard 302 (assuming it's the main system board) can be located inside the left temple of the smart glasses, responsible for core computing, wireless communication (such as Bluetooth / Wi-Fi), and power management; while the second motherboard 306 (such as a driver board or camera processing board carrying a near-eye display micro-projection engine) can be located inside the right temple. The first motherboard 302 and the second motherboard 306 are connected via the flexible circuit board 301. Specifically, the first motherboard 302 is connected to one end of the flexible circuit board 301 via a second connection structure 305, and the second motherboard 306 is connected to the other end of the flexible circuit board 301 via a third connection structure 307.

[0061] As can be seen, the embodiments shown in this application introduce a second motherboard and utilize a flexible circuit board and the connection structures at its two ends (second and third connection structures) to effectively connect the first motherboard and the second motherboard. This ensures that the antenna system can be provided with a flexible and space-efficient extended grounding solution, while also expanding the functionality of the antenna grounding structure.

[0062] Please see Figure 4 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Figure 4 The electronic device 40 shown includes: an antenna grounding structure 401.

[0063] It should be noted that the relevant description of the antenna grounding structure 401 can be found in the aforementioned embodiments, and will not be repeated here.

[0064] In one embodiment, the electronic device 40 is a smart glasses, and the first motherboard and flexible circuit board of the antenna grounding structure 401 are disposed inside one side temple of the smart glasses.

[0065] As a feasible implementation, in one temple of the smart glasses, the first main board (usually the main circuit board) and the flexible circuit board of the antenna grounding structure 40 can be directly arranged in the same temple. The first main board is connected to the antenna through the connection structure between the antenna and the main board 1 (i.e., the first connection structure), and the first main board and the flexible circuit board are connected through connection structures such as board-to-board connectors, zero-insertion-force connectors, flexible circuit board connectors, and solder points.

[0066] For example, please refer to Figure 5 This is a schematic diagram illustrating another antenna grounding structure layout provided in this application embodiment when used in smart glasses. When this antenna grounding structure is installed in the smart glasses, the main board 1 (i.e., the first main board) can be specifically located inside one side of the temple. It is connected to the main board 1 through a connection structure between the antenna and the main board 1 (i.e., the first connection structure), and connected to the FPC through a connection structure between the main board 1 and the flexible circuit board (i.e., the FPC) (i.e., the second connection structure). The FPC extends downwards and can be connected to other devices located further down the temple (such as the second main board, sensors, batteries, or interface modules, etc.) through a connection structure between the FPC and other devices.

[0067] In one embodiment, the electronic device 40 is a smart glasses, and the first motherboard and the second motherboard of the antenna grounding structure 401 are respectively disposed in one side of the temple of the smart glasses, and the flexible circuit board passes through the frame of the smart glasses.

[0068] For example, the first motherboard, as the main system board, can integrate core components such as a central processing unit, wireless communication chip, and power management unit, and is connected to an antenna; while the second motherboard can carry specific functional units such as speaker modules, touch sensor arrays, or biometric sensors.

[0069] For example, the flexible circuit board can be laid in the frame of smart glasses. In some embodiments, it can also be laid in the frame and temples, and its shape can be adapted to the curved space of the temples for wiring. One end of the ground plane of the flexible circuit board is connected to the motherboard ground of the first motherboard through a second connection structure, and the other end is connected to the second motherboard through a third connection structure.

[0070] For example, please refer to Figure 6This is a schematic diagram illustrating another antenna grounding structure layout provided in this application embodiment when used in smart glasses. When this antenna grounding structure is installed in the smart glasses, the antenna can be connected to the mainboard 1 (i.e., the first mainboard) via a connection structure (i.e., the first connection structure). The mainboard 1 can be located in the temple 1. The temple 2 also houses the mainboard 2 (i.e., the second mainboard). The mainboard 1 and mainboard 2 are respectively connected to the flexible circuit board via connection structures. Specifically, a second connection structure is installed between the flexible circuit board and the mainboard 1, and a third connection structure is installed between the flexible circuit board and the mainboard 2. The flexible circuit board can pass through the frame of the smart glasses.

[0071] As can be seen, the electronic device of this application embodiment, such as smart glasses, provides an efficient and flexible grounding scheme optimization method in a dense and compact space by configuring this antenna grounding structure, without significantly increasing the overall size and complexity of the device. This scheme enables the antenna to maximize the utilization of the grounding plane by utilizing the available grounding area inside the device.

[0072] The above-disclosed embodiments are merely preferred embodiments of this application and should not be construed as limiting the scope of this application. Therefore, any equivalent variations made in accordance with the claims of this application shall still fall within the scope of this application.

Claims

1. An antenna grounding structure, characterized in that, include: A first motherboard, an antenna, and a flexible circuit board; the first motherboard has a motherboard ground; the flexible circuit board includes at least a signal layer and a ground layer; The antenna is connected to the first motherboard via a first connection structure; The flexible circuit board is connected to the first motherboard through a second connection structure, so that the ground layer of the flexible circuit board is electrically connected to the motherboard ground of the first motherboard; The ground layer serves as an extension of the motherboard ground, and its length is determined based on the length of the motherboard ground of the first motherboard and the operating wavelength of the antenna.

2. The antenna grounding structure as described in claim 1, characterized in that, The first connection structure is a metal spring and / or a coaxial line.

3. The antenna grounding structure as described in claim 1, characterized in that, The second connection structure can be any of the following: board-to-board connector, zero insertion force connector, flexible circuit board connector, or solder joint.

4. The antenna grounding structure as described in claim 1, characterized in that, The antenna grounding structure also includes: a second motherboard; The flexible circuit board is connected to the second motherboard via a third connection structure.

5. The antenna grounding structure as described in claim 1, characterized in that, The sum of the length of the ground layer and the length of the motherboard ground of the first motherboard is greater than or equal to one-quarter of the operating wavelength of the antenna.

6. The antenna grounding structure as described in claim 1, characterized in that, The flexible circuit board includes at least one signal layer and at least one ground layer; When the number of strata is greater than or equal to two, the length of the strata refers to the length of the stratum with the best radiation performance. The stratum with the best radiation performance includes at least one of the following: the longest stratum, the bottommost stratum, and the topmost stratum.

7. An electronic device, characterized in that, The electronic device includes the antenna grounding structure as described in any one of claims 1 to 6.

8. The electronic device as claimed in claim 7, characterized in that, The electronic device is a smart glasses, and the first main board and flexible circuit board of the antenna grounding structure are disposed inside one side of the temple of the smart glasses.

9. The electronic device as claimed in claim 7, characterized in that, The electronic device is a smart glasses. The first main board and the second main board of the antenna grounding structure are respectively disposed in the temple of one side of the smart glasses, and the flexible circuit board passes through the frame of the smart glasses.

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