Antenna grounding circuit, antenna structure and wearable device

Abstract

An embodiment of the present application provides an antenna grounding circuit, comprising a connecting end, a grounding end, a first branch and a second branch, wherein the connecting end is used to connect to the radiator of the antenna, and the grounding end is used to ground. The first branch comprises a first metal branch and a second metal branch, the first metal branch is electrically connected to the grounding end, the second metal branch is electrically connected to the grounding end, and at least a portion of the first metal branch and at least a portion of the second metal branch are arranged relative to each other to form a first capacitor. The second branch is connected in parallel with the first branch, and a first inductor is provided on the second branch. The antenna grounding circuit can not only achieve a grounding effect, but also form an equivalent capacitor structure through the first metal branch and the second metal branch, without the need to install a fixed capacitor, and the capacitance value can be easily adjusted, thereby adjusting the impedance value of the first branch. In addition, an embodiment of the present application also provides an antenna structure and a wearable device.

Description

Technical Field

[0001] The present application relates to the field of consumer electronic products, and in particular to an antenna grounding circuit, an antenna structure, and a wearable device. Background Art

[0002] At present, various wearable devices such as smart watches, virtual reality devices, and augmented reality devices have become widely popular. In addition to functions such as human-computer interaction, some current wearable devices can also communicate with other devices and servers. This requires wearable devices to be equipped with corresponding antennas, such as communication antennas, WiFi antennas, GPS antennas, etc.

[0003] As for the antenna structure, in order to ensure safety of use, it needs to be grounded. The current antenna structure mainly achieves grounding by setting a grounding circuit to connect to the "ground" on the wearable device. However, the current grounding circuit is relatively complex and requires the setting of multiple electrical components. These components will increase costs and require more space, which is not conducive to the lightweight and thinning of wearable devices. Summary of the Invention

[0004] The purpose of this application is to provide an antenna grounding circuit, an antenna structure and a wearable device to improve the above technical problems.

[0005] In a first aspect, an embodiment of the present application provides an antenna grounding circuit for use in a wearable device, comprising a connection end, a grounding end, a first branch, and a second branch. The connection end is used to connect to the radiator of the antenna, and the grounding end is used to ground. The first branch includes a first metal branch and a second metal branch. The first metal branch is electrically connected to the grounding end, and the second metal branch is electrically connected to the grounding end. At least a portion of the first metal branch and at least a portion of the second metal branch are arranged relative to each other to form a first capacitor. One end of the second branch is electrically connected to the connection end, and the other end is electrically connected to the grounding end, so that the second branch is connected in parallel with the first branch. A first inductor is provided on the second branch.

[0006] On the second aspect, an embodiment of the present application also provides an antenna structure for use in wearable devices. The antenna structure includes a radiator and the above-mentioned antenna grounding structure. The radiator has a grounding point, the connecting end is electrically connected to the grounding point, and the grounding end is electrically connected to the middle plate to ground the antenna structure.

[0007] In a third aspect, embodiments of the present application further provide a wearable device comprising a middle frame, a mainboard, and the aforementioned antenna grounding circuit. The middle frame comprises a middle plate and a frame, the frame being disposed around and connected to the middle plate. The frame is provided with a radiator having a grounding point and a feed point. The connection end is electrically connected to the grounding point, the grounding end is electrically connected to the middle plate to ground the antenna structure, the mainboard is disposed on the middle plate, and the feed point is electrically connected to the mainboard.

[0008] The antenna grounding circuit provided by the embodiment of the present application can not only achieve a grounding effect, but also form an equivalent capacitor structure through the first metal branch and the second metal branch, without the need to install a fixed capacitor, and by adjusting the area of the relatively arranged portion of the first metal branch and the second metal branch, the capacitance value can be conveniently adjusted, and then the impedance value of the first branch can be adjusted. Moreover, since the first metal branch and the second metal branch can be reasonably routed according to the space in the wearable device, the space utilization rate can be improved. In addition, by setting the first branch and the second branch in parallel with each other, the impedance selection of the antenna grounding circuit at different operating frequencies can be achieved by adjusting the inductance and impedance of the first branch and the second branch.

[0009] The antenna structure and wearable device provided in the embodiments of the present application can reasonably adjust the inductive impedance characteristic parameters of the antenna grounding circuit according to needs, and can more effectively utilize space, thereby achieving a lighter and thinner device.

[0010] These and other aspects of the present application will become more readily apparent from the description of the following embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0012] Figure 1 Schematic diagram of the structure of a wearable device shown in an embodiment of the present application.

[0013] Figure 2 This is a schematic diagram of the cross-sectional structure of a wearable device provided in an embodiment of the present application.

[0014] Figure 3 This is a schematic diagram of the antenna structure of a wearable device provided in an embodiment of the present application.

[0015] Figure 4 This is a circuit diagram of an antenna grounding circuit provided in an embodiment of the present application.

[0016] Figure 5 This is a structural diagram of the first branch in an antenna grounding circuit provided in an embodiment of the present application.

[0017] Figure 6 This is a schematic diagram of the connection structure between the first branch and the radiator in an antenna grounding circuit provided in an embodiment of the present application.

[0018] Figure 7 This is a schematic structural diagram of a first inductor in an antenna grounding circuit provided in an embodiment of the present application.

[0019] Figure 8 This is a schematic structural diagram of a second inductor in an antenna grounding circuit provided in an embodiment of the present application.

[0020] Figure 9 yes Figure 4 The impedance simulation diagram of the antenna ground circuit is shown.

[0021] Figure 10 This is a circuit diagram of another antenna grounding circuit provided in an embodiment of the present application.

[0022] Figure 11 yes Figure 10 The impedance simulation diagram of the antenna ground circuit is shown.

[0023] Figure 12 This is a circuit diagram of another antenna grounding circuit provided in an embodiment of the present application.

[0024] Figure 13 This is a schematic diagram of the structure of a second capacitor in an antenna grounding circuit provided in an embodiment of the present application.

[0025] Figure 14 This is a circuit diagram of another antenna grounding circuit provided in an embodiment of the present application. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0027] Current wearable devices, such as smartwatches, are increasingly equipped with various antennas. These can be one, two, or more. Each antenna typically utilizes a radiator within the wearable device's casing to radiate radio frequency signals. During operation, the antenna must be connected to a feed unit on the motherboard and grounded. However, due to the small size of wearable devices and limited internal space, the housing provides limited space for antenna placement. If a switch is used to adjust the frequency band for antenna grounding, the switch itself is large and consumes considerable PCB space. Power supply and control circuitry are also required to control the switch. Therefore, using a switch to control grounding requires a significant amount of board space for the switch module (switch, control, and power supply circuits). This is a significant drawback for electronic devices like smartwatches, where PCB space is extremely limited.

[0028] In the related art, for wearable electronic devices such as smart watches, some passband and band-blocking modules are used to replace the current use of switches to control the on and off of grounding, so as to reduce the space occupied by the grounding circuit. However, the existing passband and band-blocking modules still occupy a large space inside wearable devices such as smart watches, and the manufacturing cost is relatively high due to the need to set up additional capacitors, inductors and other components.

[0029] Based on this, the inventors of this application have proposed antenna grounding circuits, antenna structures, and wearable devices according to various embodiments of this application, in order to improve the above-mentioned defects. The following describes various embodiments of this application in detail with reference to the accompanying drawings.

[0030] Example

[0031] See Figure 1 This embodiment provides a wearable device 10, which is described using a smartwatch as an example. The wearable device 10 includes a wearable portion 20 and a main body 30. The wearable portion 20 is designed to be worn by a user, and the main body 30 can be used for functions such as human-computer interaction with the user. In this embodiment, the wearable portion 20 is configured as a watch strap, and the main body 30 is a watch dial. The main body 30 can be configured in any shape, such as a rectangle or a circle, without limitation. The wearable portion 20 can be made of materials such as fabric, leather, plastic, and metal, without limitation.

[0032] See also Figure 2 The main body 30 includes a middle frame 310, a display screen 320, a rear shell 330, a main board 340, etc. Figure 1 and Figure 2The display screen 320 and the rear cover 330 are respectively mounted on opposite sides of the middle frame 310. The rear cover 330 is mounted on the middle frame 310 to form a cavity for accommodating various components, such as a battery, camera, and motherboard 340. The display screen 320 is mounted on the middle frame 310 and is used to display images, text, and other information. It is understood that the display screen 320 can be a liquid crystal display screen 320 or an organic light-emitting diode display screen 320.

[0033] As used in the embodiments of the present application, the "wearable device 10" includes, but is not limited to, a device configured to receive / send communication signals via a wired line connection (such as via a Public Switched Telephone Network (PSTN), a Digital Subscriber Line (DSL), a digital cable, a direct cable connection, and / or another data connection / network) and / or via a wireless interface (for example, for a cellular network, a Wireless Local Area Network (WLAN), a digital television network such as a DVB-H network, a satellite network, an AM-FM broadcast transmitter, and / or another communication terminal).

[0034] Please also refer to Figure 2 and Figure 3 The middle frame 310 includes a frame 311 and a middle plate 313. It is understandable that the middle plate 313 can be a complete flat plate, or it can be formed by two or more plates separated from each other and connected to the frame 311, which will not be elaborated here. The frame 311 can be used to form an assembly with the rear shell 330 and the front shell, and the display screen 320 can be installed on the front shell. The motherboard 340 is arranged on the middle plate 313, and the motherboard 340 can integrate components such as processors and memories. The wearable device 10 also includes an antenna structure 350, and the antenna structure 350 is used to radiate radio frequency signals. It is understandable that in different embodiments, the antenna structure 350 can radiate communication signals, one or more of WiFi signals, GPS signals, etc., where the communication signals can be 3G, 4G or 5G signals, etc., which are not limited here.

[0035] Please continue reading Figure 3The antenna structure 350 includes a radiator 351 and an antenna ground circuit 353. As a method, the radiator 351 can be combined with the frame 311 in an integrally formed manner and can be exposed from the frame 311. In some embodiments, the radiator 351 can be formed by a portion of the frame 311, and the radiator 351 is isolated from the other parts of the frame 311 by providing a slit 315. It is understandable that the number of radiators 351 can be one or more, and one radiator 351 can be used to radiate one radio frequency signal or to radiate two or more radio frequency signals at the same time, which is not limited here. The radiator 351 can be set at any position of the frame 311 and can be configured into any shape.

[0036] The radiator 351 has a feeding point 3511 and a grounding point 3512, and the feeding point 3511 and the grounding point 3512 are arranged at intervals. A feeding unit 352 is also provided on the main board 340, and the feeding unit 352 is used to be electrically connected to the feeding point 3511 and control the radiator 351 to radiate radio frequency signals. The feeding unit 352 can also include a frequency band switching unit for switching different output frequency bands, thereby controlling the radiator 351 to radiate radio frequency signals of different frequency bands.

[0037] One end of the antenna grounding circuit 353 is electrically connected to the grounding point 3512, and the other end is connected to the middle plate 313 to ground the antenna structure 350. In one embodiment, the middle plate 313 can be made entirely or partially of a metal material or alloy, and the antenna grounding circuit 353 is directly electrically connected to the middle plate 313 to achieve grounding. In this embodiment, the wearable device 10 also includes a metal bracket. The metal bracket can be disposed on the middle plate 313, and a portion of the metal bracket can extend to the frame 311. The antenna grounding circuit 353 can achieve grounding by being electrically connected to the metal bracket.

[0038] Specifically, see Figure 4 The antenna grounding circuit 353 includes a connection terminal 3531, a grounding terminal 3532, a first branch 3533, and a second branch 3534. The connection terminal 3531 is electrically connected to the grounding point 3512. The grounding terminal 3532 is used to connect to the middle plate 313 and then to the ground. The first branch 3533 and the second branch 3534 are arranged in parallel. Figure 5 As shown, the first branch 3533 includes a first metal branch 3541 and a second metal branch 3543. The first metal branch 3541 is electrically connected to the ground terminal 3532, and the second metal branch 3543 is electrically connected to the ground terminal 3532. At least a portion of the first metal branch 3541 and at least a portion of the second metal branch 3543 are arranged relative to each other to form a first capacitor 354, wherein the first metal branch 3541 and the second metal branch 3543 are not directly electrically connected. Please refer to Figure 5 and Figure 6 The first metal branch 3541 has a first plate body 3542, and the second metal branch 3543 has a second plate body 3544. The first plate body 3542 and the second plate body 3544 are arranged opposite to each other, and the plane where the first plate body 3542 is located is roughly parallel to the plane where the middle plate 313 is located, and the plane where the second plate body 3544 is located is roughly parallel to the plane where the middle plate 313 is located, that is, the first plate body 3542 and the second plate body 3544 are arranged relatively spaced apart in the thickness direction of the shell, where the thickness direction of the shell refers to the direction perpendicular to the plane where the middle plate 313 is located.

[0039] The first plate 3542 and the second plate 3544 can have the same area, and in some embodiments, the orthographic projection of the first plate 3542 on the plane of the middle plate 313 can completely overlap with the orthographic projection of the second plate 3544 on the plane of the middle plate 313. The first capacitor 354 is formed by providing the first metal branch 3541 and the second metal branch 3543, which has the following advantages:

[0040] 1) The first metal branch 3541 and the second metal branch 3543 can be formed integrally with the radiator 351 , which reduces the number of process steps and eliminates the need to purchase additional capacitors, thereby reducing costs.

[0041] 2) The first metal branch 3541 and the second metal branch 3543 can be routed according to the spatial conditions of the setting position of the antenna grounding circuit 353, so they are less restricted by space. Therefore, the position of the grounding point 3512 of the radiator 351 does not need to be adjusted for the setting space of the antenna grounding circuit 353, thereby allowing the radiator 351 to be better configured and improving antenna performance.

[0042] In some embodiments, a dielectric may be disposed between the first plate 3542 and the second plate 3544 to enhance the capacitance of the first capacitor 354 , wherein the dielectric may be, for example, ceramic.

[0043] One end of the second branch 3534 is electrically connected to the connection terminal 3531, and the other end is electrically connected to the ground terminal 3532, thereby connecting the second branch 3534 in parallel with the first branch 3533. A first inductor 355 is provided on the second branch 3534, and the first inductor 355 and the first capacitor 354 are located on the two parallel circuits. The ground terminal 3532 is electrically connected to the middle plate 313 or the metal bracket to achieve grounding.

[0044] The first inductor 355 can be a commercially available inductor product. In this embodiment, Figure 7As shown, first inductor 355 includes a third metal branch 360 having a continuously reciprocating bending section 363. Third metal branch 360 is connected to second branch 3534. Reciprocating bending refers to a reciprocating change in the bending direction. Specifically, third metal branch 360 includes a first connecting portion 361, a bending section 363, and a second connecting portion 362. First connecting portion 361 and second connecting portion 362 are connected to opposite ends of bending section 363. When connected to second branch 3534, first connecting portion 361 is electrically connected to connection terminal 3531, and second connecting portion 362 is electrically connected to ground terminal 3532.

[0045] As just one example, the bending section 363 may have a serpentine bending structure, for example, the bending section 363 includes a first section 3631, a second section 3632, a third section 3633, a fourth section 3634, and a fifth section 3635. The first section 3631, the second section 3632, the third section 3633, the fourth section 3634, and the fifth section 3635 are sequentially connected end to end to form the bending section 363, forming a serpentine bending structure. The first section 3631, the second section 3632, the third section 3633, the fourth section 3634, and the fifth section 3635 may all be linear extensions, wherein the first section 3631, the third section 3633, and the fifth section 3635 are spaced apart from each other, the second section 3632 is connected between the first section 3631 and the third section 3633, the fourth section 3634 is connected between the third section 3633 and the fifth section 3635, and the second section 3632 and the fourth section 3634 are substantially parallel and staggered. In particular, the bending angle between any two adjacent segments of the first segment 3631, the second segment 3632, the third segment 3633, the fourth segment 3634, and the fifth segment 3635 can be substantially 90°. The end of the first segment 3631 away from the second segment 3632 is connected to the first connecting portion 361, and the end of the fifth segment 3635 away from the fourth segment 3634 is connected to the second connecting portion 362.

[0046] It is understandable that in other embodiments, the bending section 363 may have more bending times. And in another embodiment, the bending section 363 may also form a roughly "S"-shaped bending structure or a spiral routing structure. When powered on, the bending section 363 forms an equivalent inductor. By setting the first inductor 355 in the form of an equivalent inductor, the routing can be performed according to the spatial conditions of the setting position of the antenna grounding circuit 353, so that the space restriction is small. Therefore, the position of the grounding point 3512 of the radiator 351 does not need to be adjusted for the setting space of the antenna grounding circuit 353, thereby better configuring the radiator 351 and improving the antenna performance.

[0047] The first branch 3533 and the second branch 3534 connected in parallel are connected to the connection end 3531 , and the first branch 3533 and the second branch 3534 connected in parallel are connected to the ground end 3532 .

[0048] For different antenna structures 350, a single radiator 351 can achieve the radiation function of RF signals in multiple frequency bands. In related technologies, a switch needs to be set in the ground circuit to control the on / off of the ground circuit, thereby turning the ground circuit on / off at different operating frequencies to achieve the radiation of RF signals in different frequency bands. However, this method still has the problem of occupying a large space.

[0049] In one application scenario, the antenna grounding circuit 353 has a first operating frequency and a second operating frequency. At the first operating frequency, the antenna grounding circuit 353 has a first impedance value, and at the second operating frequency, the antenna grounding circuit 353 has a second impedance value. The first operating frequency is greater than the second operating frequency, and the first impedance value is less than the second impedance value. That is, when the antenna grounding circuit 353 is operating at a low frequency, the antenna grounding circuit 353 is not grounded or exhibits high impedance. When operating at a high frequency, the antenna grounding circuit 353 is grounded or exhibits low impedance. For example, the radiator 351 of the wearable device 10 has two operating frequencies, 1.575 GHz and 2.45 GHz. When operating at 1.575 GHz, the antenna grounding circuit 353 is not grounded or exhibits high impedance. When operating at 2.45 GHz, the antenna grounding circuit 353 is grounded or exhibits low impedance.

[0050] In order to achieve the goal of not setting a switch and realizing different working frequencies, the antenna grounding circuit 353 can also realize on / off. In a more specific embodiment, please refer to Figure 4 The antenna grounding circuit 353 also includes a second inductor 356, which is arranged in the first branch 3533 and is arranged in series with the first capacitor 354. The second inductor 356 can be a commercially available inductor product. In order to further reduce the space occupied by the antenna grounding circuit 353, the second inductor 356 can also adopt the same structure as the first inductor 355, that is, the second inductor 356 is formed in a manner of forming an equivalent inductor. The second inductor 356 includes a fourth metal branch 365, and the fourth metal branch 365 has a bending section 363 that is continuously bent back and forth, wherein the fourth metal branch 365 can have the same structure as the third metal branch 360. For the specific structural setting method, please refer to the above content and will not be repeated here.

[0051] The second inductor 356 is connected in series with the first capacitor 354 and then in parallel with the first inductor 355. By controlling the parameters of the first capacitor 354, the first inductor 355 and the second inductor 356, a simulation fitting is performed using the two operating frequencies of 1.575 GHz and 2.45 GHz as examples to obtain an impedance distribution diagram. In the diagram, 2 points represent 2.45 GHz and 1 point represents 1.575 GHz. Figure 9 As can be seen in the figure, at an operating frequency of 1.575 GHz (low frequency), the impedance of the entire antenna ground circuit 353 is relatively high, approximately 1514Ω, equivalent to an open circuit. However, at an operating frequency of 2.45 GHz (high frequency), the impedance of the entire antenna ground circuit 353 is very low, approximately 0Ω, equivalent to a short circuit in the antenna ground circuit 353, indicating ground continuity.

[0052] In another more specific embodiment, Figure 10 As shown, the antenna grounding circuit 353 also includes a second inductor 356, which is provided at the connection end 3531. That is, the first capacitor 354 and the first inductor 355 are connected in parallel and then in series with the second inductor 356. By controlling the parameters of the first capacitor 354, the first inductor 355 and the second inductor 356, a simulation fitting is performed using the two operating frequencies of 1.575 GHz and 2.45 GHz as examples to obtain an impedance value distribution diagram, in which 2 points represent 2.45 GHz and 1 point represents 1.575 GHz. Figure 11 As can be seen in the figure, at an operating frequency of 1.575 GHz (low frequency), the impedance of the entire antenna ground circuit 353 is relatively high, approximately 2670Ω, equivalent to an open circuit. However, at an operating frequency of 2.45 GHz (high frequency), the impedance of the entire antenna ground circuit 353 is very low, approximately 0Ω, equivalent to a short circuit in the antenna ground circuit 353, indicating ground continuity.

[0053] By providing a second inductor 356, the impedance characteristics of the antenna grounding circuit 353 can be set to high impedance at low frequencies and low impedance at high frequencies, depending on usage requirements. Furthermore, by configuring the second inductor 356 to have the same structure as the first inductor 355, the antenna grounding circuit 353 does not need a switch, reducing the PCB footprint. Furthermore, routing can be tailored to the spatial constraints of the antenna grounding circuit 353's location, minimizing space constraints. Therefore, the position of the grounding point 3512 of the radiator 351 does not need to be adjusted to accommodate the antenna grounding circuit 353's location, allowing for better configuration of the radiator 351 and improving antenna performance.

[0054] In another application scenario, the antenna grounding circuit 353 has a first operating frequency and a second operating frequency. At the first operating frequency, the antenna grounding circuit 353 has a first impedance value, and at the second operating frequency, the antenna grounding circuit 353 has a second impedance value. The first operating frequency is greater than the second operating frequency, and the first impedance value is greater than the second impedance value. That is, when the antenna grounding circuit 353 is operating at a high frequency, the antenna grounding circuit 353 is not grounded or exhibits high impedance. When operating at a low frequency, the antenna grounding circuit 353 is grounded or exhibits low impedance. For example, the radiator 351 of the wearable device 10 has two operating frequencies, 1.575 GHz and 2.45 GHz. When operating at 2.45 GHz, the antenna grounding circuit 353 is not grounded or exhibits high impedance. When operating at 1.575 GHz, the antenna grounding circuit 353 is grounded or exhibits low impedance.

[0055] In order to avoid setting a switch, the antenna grounding circuit 353 can also be turned on / off at different operating frequencies. Figure 12 Antenna grounding circuit 353 further includes a second capacitor 357, which is disposed in second branch 3534. Second capacitor 357 is connected in series with first inductor 355 and then in parallel with first capacitor 354. Second capacitor 357 can be a commercially available capacitor. To further reduce the footprint of antenna grounding circuit 353, second capacitor 357 can also employ the same structure as first capacitor 354, i.e., be configured to form an equivalent capacitor.

[0056] Specifically, such as Figure 13 As shown, the second capacitor 357 may include a fifth metal branch 3571 and a sixth metal branch 3573, and at least a portion of the fifth metal branch 3571 and at least a portion of the sixth metal branch 3573 are arranged relative to each other to form a first capacitor 354, wherein the fifth metal branch 3571 and the sixth metal branch 3573 are not directly electrically connected, and the fifth metal branch 3571 and the second metal branch 3543 are both connected as in the second branch 3534. The fifth metal branch 3571 has a third plate body 3572, and the sixth metal branch 3573 has a fourth plate body 3574. The third plate body 3572 and the fourth plate body 3574 are arranged opposite to each other, and the plane where the third plate body 3572 is located is roughly parallel to the plane where the middle plate 313 is located, and the plane where the fourth plate body 3574 is located is roughly parallel to the plane where the middle plate 313 is located, that is, the third plate body 3572 and the fourth plate body 3574 are relatively spaced apart in the thickness direction of the shell, where the thickness direction of the shell refers to the direction perpendicular to the plane where the middle plate 313 is located.

[0057] With this configuration, the fifth and sixth metal branches 3571, 3573 can be integrally formed with the radiator 351 and the second branch 3534, reducing process steps and eliminating the need for additional capacitors, thereby lowering costs and eliminating the need to occupy space on the motherboard 340. Furthermore, the fifth and sixth metal branches 3571, 3573 can be routed based on the spatial constraints of the antenna grounding circuit 353. Consequently, the position of the grounding point 3512 of the radiator 351 does not need to be adjusted to accommodate the antenna grounding circuit 353. This allows for better configuration of the radiator 351 and improves antenna performance.

[0058] In another more specific embodiment, see Figure 14 The antenna grounding circuit 353 further includes a second capacitor 357 , and the second capacitor 357 can also be set at the grounding terminal 3532 . At this time, the first capacitor 354 and the first inductor 355 are connected in parallel and then connected in series with the second capacitor 357 .

[0059] By providing second capacitor 357, the impedance characteristics of antenna ground circuit 353 can be set to low impedance at low frequencies and high impedance at high frequencies according to usage requirements. Furthermore, by configuring second capacitor 357 with the same structure as first capacitor 354, antenna ground circuit 353 does not need a switch, reducing PCB board space.

[0060] The antenna grounding circuit 353 and wearable device 10 described above utilize equivalent capacitance and equivalent inductance to form a grounding circuit, replacing the conventional method of providing a switch on the motherboard 340. This reduces the space occupied by the motherboard 340 and reduces the procurement cost of electrical components. Furthermore, this allows for more flexible wiring, adapting to the confined space within the wearable device 10, facilitating a more rational placement of the radiator 351, and making the wearable device 10 thinner and lighter.

[0061] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. An antenna grounding circuit, characterized in that: Applied to a wearable device, the antenna grounding circuit includes: A connecting end, the connecting end being used to connect to a radiator of an antenna; A grounding terminal, the grounding terminal being used for grounding; a first branch, the first branch including a first metal branch and a second metal branch, the first metal branch being electrically connected to the ground terminal, the second metal branch being electrically connected to the ground terminal, at least a portion of the first metal branch and at least a portion of the second metal branch being arranged relative to each other to form a first capacitor, the first branch being provided with a second inductor, the second inductor being provided in the first branch and being arranged in series with the first capacitor, or the second inductor being provided at the connection terminal, the second inductor including a fourth metal branch, the fourth metal branch having a bending section that continuously bends back and forth; and A second branch, one end of the second branch is electrically connected to the connection end, and the other end is electrically connected to the ground end, so that the second branch is connected in parallel with the first branch, and a first inductor is provided on the second branch, and the first inductor includes a third metal branch, and the third metal branch has a bending section that is continuously bent back and forth, and the third metal branch is connected to the second branch.

2. The antenna grounding circuit according to claim 1, wherein: The antenna grounding circuit has a first impedance value at a first operating frequency and a second impedance value at a second operating frequency. The first operating frequency is greater than the second operating frequency, and the first impedance value is less than the second impedance value.

3. The antenna grounding circuit according to claim 1, wherein: The antenna grounding circuit has a first impedance value at a first operating frequency and a second impedance value at a second operating frequency. The first operating frequency is greater than the second operating frequency, and the first impedance value is greater than the second impedance value.

4. The antenna grounding circuit according to claim 3, wherein: The antenna grounding circuit further includes a second capacitor, which is arranged in the second branch or the grounding end.

5. An antenna structure, characterized in that: Applied to wearable devices, the antenna structure includes: a radiator, wherein the radiator has a grounding point; The antenna grounding circuit according to any one of claims 1 to 4, wherein the connection end is electrically connected to the grounding point, and the grounding end is used to electrically connect to the midboard of the wearable device to ground the antenna structure.

6. The antenna structure according to claim 5, characterized in that: The antenna structure further includes a metal bracket, which is arranged on the middle plate, and the grounding end is electrically connected to the metal bracket.

7. A wearable device, characterized in that: include: A middle frame, the middle frame including a middle plate and a frame, the frame being arranged around the middle plate and connected to the middle plate, the frame being provided with a radiator, the radiator having a grounding point and a feeding point; The antenna grounding circuit according to any one of claims 1 to 4, wherein the connection end is electrically connected to the grounding point, and the grounding end is electrically connected to the middle plate to ground the antenna grounding circuit; and a main board, the main board is arranged on the middle plate, and the feeding point is electrically connected to the main board.

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