Method, apparatus and electronic device for reducing sar

Abstract

The application discloses a method, device and electronic equipment. A first radiator comprises a first grounding point, a feeding point and a first free end arranged in sequence. A second radiator comprises a second free end and a second grounding point arranged in sequence. The second free end is coupled with the first free end through a coupling gap. A signal source is electrically connected with the feeding point. The signal source is used for exciting a first resonance mode and a second resonance mode. The resonance frequency point of the first resonance mode is smaller than the resonance frequency point of the second resonance mode. The current intensity of the first resonance mode on the first radiator is greater than the current intensity on the second radiator. The resonance frequency point of the first resonance mode belongs to a target frequency band. The target frequency band falls into a preset frequency band configured by an antenna assembly. The SAR value of the antenna assembly working in the target frequency band is smaller than or equal to the SAR value of a frequency band other than the target frequency band in the preset frequency band. The application can reduce the SAR value.

Description

Technical Field

[0001] This application relates to the field of communication technology, and specifically to a method, apparatus, and electronic device for reducing SAR. Background Technology

[0002] As communication requirements increase in mobile phones and other electronic devices, the number of antennas required on these devices also increases. How to reduce the overall distribution of the Specific Absorption Rate (SAR) of antenna components on these devices, improve SAR transmission pass rates, or reduce unnecessary power back-off has become a technical problem that needs to be solved. Summary of the Invention

[0003] This application provides a method, apparatus, and electronic device for reducing the SAR value of an antenna assembly on an electronic device.

[0004] In a first aspect, this application provides an electronic device, including an antenna assembly, the antenna assembly comprising:

[0005] The first radiator includes a first grounding point, a feed point and a first free end arranged in sequence, wherein the first grounding point is grounded;

[0006] The second radiator includes a second free end and a second grounding point arranged sequentially, the second free end being coupled to the first free end through a coupling gap, and the second grounding point being grounded; and

[0007] A signal source electrically connected to the feed point is used to excite the first radiator and the second radiator to jointly form a first resonant mode and a second resonant mode. The resonant frequency of the first resonant mode is lower than that of the second resonant mode. The current intensity of the first resonant mode on the first radiator is greater than that on the second radiator. The resonant frequency of the first resonant mode is configured as a frequency point in a target frequency band. The target frequency band falls within a preset frequency band in which the antenna assembly is configured. The SAR value of the antenna assembly when operating in the target frequency band is less than or equal to the SAR value of the antenna assembly when operating in a frequency band other than the target frequency band in the preset frequency band.

[0008] Secondly, this application provides a method for reducing SAR, the method being applied to an electronic device having an antenna assembly, the antenna assembly including a first radiator, a second radiator, and a signal source, the first radiator including a first grounding point, a feed point, and a first free end arranged sequentially, the first grounding point being grounded; the second radiator including a second free end and a second grounding point arranged sequentially, the second free end being coupled to the first free end through a coupling gap, the second grounding point being grounded; the signal source being electrically connected to the feed point, the signal source being used to excite the first radiator and the second radiator to jointly form a first resonant mode and a second resonant mode, the resonant frequency of the first resonant mode being lower than the resonant frequency of the second resonant mode, and the current intensity of the first resonant mode on the first radiator being greater than the current intensity on the second radiator; the method includes:

[0009] A target frequency band is determined within a preset frequency band in which the antenna assembly is configured, wherein the target frequency band falls within the preset frequency band in which the antenna assembly is configured; the SAR value of the antenna assembly when operating in the target frequency band is less than or equal to the SAR value of the antenna assembly when operating in a frequency band other than the target frequency band within the preset frequency band.

[0010] Configure the resonant frequency of the first resonant mode as a frequency point in the target frequency band.

[0011] Thirdly, this application provides a device for reducing SAR, characterized in that the device is applied to an electronic device having an antenna assembly, the antenna assembly including a first radiator, a second radiator, and a signal source; the first radiator includes a first grounding point, a feed point, and a first free end arranged sequentially, the first grounding point being grounded; the second radiator includes a second free end and a second grounding point arranged sequentially, the second free end being coupled to the first free end through a coupling gap, the second grounding point being grounded; the signal source is electrically connected to the feed point, the signal source being used to excite the first radiator and the second radiator to jointly form a first resonant mode and a second resonant mode, the resonant frequency of the first resonant mode being lower than the resonant frequency of the second resonant mode, and the current intensity of the first resonant mode on the first radiator being greater than the current intensity on the second radiator; the device includes:

[0012] A determination module is configured to determine a target frequency band within a preset frequency band in which the antenna assembly is configured, wherein the target frequency band falls within the preset frequency band in which the antenna assembly is configured; the SAR value of the antenna assembly operating in the target frequency band is less than or equal to the SAR value of the antenna assembly operating in a frequency band other than the target frequency band within the preset frequency band.

[0013] The configuration module is used to configure the resonant frequency of the first resonant mode as a frequency point in the target frequency band.

[0014] Fourthly, this application provides an electronic device including a memory and a processor. The memory is used to store a computer program, and the processor is used to call and run the computer program stored in the memory to execute the method for reducing SAR.

[0015] The SAR reduction method, apparatus, and electronic device provided in this application include an antenna assembly comprising a first radiator, a second radiator, and a signal source. The first radiator includes a first grounding point, a feed point, and a first free end arranged sequentially. The first grounding point is grounded. The second radiator includes a second free end and a second grounding point arranged sequentially. The second free end is coupled to the first free end via a coupling gap. The second grounding point is grounded. The signal source is electrically connected to the feed point. The signal source is used to excite the first and second radiators to jointly form a first resonant mode and a second resonant mode. The resonant frequency of the first resonant mode is greater than the resonant frequency of the second resonant mode. The current intensity of the first resonant mode on the first radiator is greater than the current intensity on the second radiator. The resonant frequency of the first resonant mode is configured as a frequency point within a target frequency band. The target frequency band falls within a preset frequency band configured for the antenna assembly. The SAR value of the antenna assembly operating in the target frequency band is less than or equal to the SAR value of the antenna assembly operating in a frequency band other than the target frequency band within the preset frequency band, thereby reducing the SAR value of the antenna assembly operating in the first resonant mode. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly described below.

[0017] Figure 1 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application;

[0018] Figure 2 yes Figure 1 A partially exploded view of the provided electronic device;

[0019] Figure 3 yes Figure 1 A schematic diagram of the frame, reference ground system, and antenna assembly of the provided electronic device;

[0020] Figure 4 This is a current distribution diagram of the first resonant mode of the antenna assembly provided in the embodiments of this application;

[0021] Figure 5 This is a current distribution diagram of the second resonant mode of the antenna assembly provided in the embodiments of this application;

[0022] Figure 6 This is a schematic diagram of the first possible location distribution of the center frequency point of the first resonant mode of the antenna assembly provided in this application embodiment;

[0023] Figure 7 This is a schematic diagram of a second location distribution of the center frequency point of the first resonant mode of the antenna assembly provided in the embodiments of this application;

[0024] Figure 8 This is a SAR intensity distribution map on a reference ground system provided in the embodiments of this application;

[0025] Figure 9 This is a first positional layout diagram of the antenna assembly on the reference ground system provided in the embodiments of this application;

[0026] Figure 10 This is a current distribution diagram of the antenna assembly provided in this application embodiment, where the first resonant frequency point is located in the first sub-band of a preset frequency band;

[0027] Figure 11 This is a SAR distribution map of the antenna assembly provided in this application, located at the first resonant frequency point in the first sub-band of the preset frequency band, and a SAR distribution map on the reference ground system.

[0028] Figure 12 This is an overall SAR distribution map formed by the SAR distribution of the antenna assembly at the first resonant frequency point in the first sub-band of the preset frequency band and the SAR distribution on the reference ground system, as provided in the embodiments of this application.

[0029] Figure 13 This is a current distribution diagram of the second sub-band of the antenna assembly provided in this application embodiment, where the first resonant frequency point is located in a preset frequency band;

[0030] Figure 14 This is a SAR distribution map of the antenna assembly provided in this application, located at the first resonant frequency point in the second sub-band of the preset frequency band, and a SAR distribution map on the reference ground system.

[0031] Figure 15 This is an overall SAR distribution map formed by the SAR distribution of the antenna assembly located at the first resonant frequency point in the second sub-band of the preset frequency band and the SAR distribution on the reference ground system provided in the embodiments of this application;

[0032] Figure 16 This is a current distribution diagram of the antenna assembly provided in this application embodiment, where the first resonant frequency point is located in the third sub-band of a preset frequency band;

[0033] Figure 17 This is a SAR distribution map of the antenna assembly provided in this application, located at the first resonant frequency point in the third sub-band of the preset frequency band, and a SAR distribution map on the reference ground system.

[0034] Figure 18 This is an overall SAR distribution map formed by the SAR distribution of the antenna assembly located at the first resonant frequency point in the third sub-band of the preset frequency band and the SAR distribution on the reference ground system, as provided in the embodiments of this application.

[0035] Figure 19 This is a SAR hotspot simulation diagram when the antenna assembly provided in the embodiments of this application supports the B3 band and the first resonant frequency is 1.75 GHz, 1.85 GHz, and 1.95 GHz.

[0036] Figure 20 These are the S-parameter curves of the antenna assembly provided in this application embodiment when in a free scene and when close to a human body;

[0037] Figure 21 This is a SAR hotspot simulation diagram when the antenna assembly provided in this application supports the B1 band and the first resonant frequency is 1.85 GHz, 1.95 GHz, and 2.05 GHz.

[0038] Figure 22 This application provides a second location layout of the antenna assembly on the reference ground system and a current distribution and SAR hotspot map of the first sub-band of the first resonant frequency point located in the preset frequency band, as provided in the embodiments of this application.

[0039] Figure 23 This application provides a second location layout of the antenna assembly on the reference ground system and a current distribution and SAR hotspot map of the second sub-band where the first resonant frequency point is located in a preset frequency band, as provided in the embodiments of this application.

[0040] Figure 24 This application provides a second location layout of the antenna assembly on the reference ground system and a current distribution and SAR hotspot map of the third sub-band where the first resonant frequency point is located in a preset frequency band.

[0041] Figure 25 This is a third location layout diagram of the antenna assembly on the reference ground system provided in the embodiments of this application;

[0042] Figure 26 This is a schematic diagram of the electrical connection between the controller and the antenna assembly's tuning circuit and matching circuit, provided in an embodiment of this application.

[0043] Figure 27 This is a schematic diagram of a method for reducing SAR provided in an embodiment of this application;

[0044] Figure 28 yes Figure 27 Detailed step-by-step diagrams of the provided method;

[0045] Figure 29 yes Figure 28 A schematic diagram illustrating a detailed step of step S110 in the provided method;

[0046] Figure 30 yes Figure 28 A schematic diagram of another detailed step in step S110 of the provided method;

[0047] Figure 31 This is a schematic diagram of an embodiment following step S200 provided in the embodiments of this application;

[0048] Figure 32 This is a schematic diagram of another embodiment following step S200 provided in the embodiments of this application;

[0049] Figure 33 This is a schematic diagram of an apparatus for reducing SAR provided in an embodiment of this application;

[0050] Figure 34 This is a schematic diagram of an electronic device including a processor and a memory provided in an embodiment of this application.

[0051] Explanation of icon numbers:

[0052] Electronic device 1000; antenna assembly 100; display screen 200, middle frame 300; back cover 400; middle plate 310; frame 320; top edge 321; bottom edge 322; first side edge 323; second side edge 324; reference ground system 500; signal source 20; first radiator 11; second radiator 12; first grounding point 112; feed point A; first free end 111; second free end 122; second grounding point 121; first reference edge 510; second reference edge 520; third reference edge 530; fourth reference edge 540; preset frequency band F0; first sub-frequency band F01; second sub-frequency band F02; third sub-frequency band F03; SAR strong area N1; SAR weak area N2; tuning circuit T; switching unit K; tuning branch T1; determination module 610; configuration module 620; memory 700; processor 800. Detailed Implementation

[0053] The technical solution of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the embodiments described in this application are only a part of the embodiments, and not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments provided in this application without creative effort are within the protection scope of this application.

[0054] In this application, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment to other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this application can be combined with other embodiments.

[0055] The terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish different objects, not to describe a particular order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, an assembly or device comprising one or more components is not limited to the one or more components listed, but may optionally also include one or more components not listed but inherent to the exemplified product, or one or more components that it should have based on the described function.

[0056] Please see Figure 1 , Figure 1 This is a schematic diagram of the structure of an electronic device 1000 provided in an embodiment of this application. The electronic device 1000 includes, but is not limited to, mobile phones, wearable devices, virtual reality (VR) controllers, VR glasses, VR headsets, and other devices with communication functions. This embodiment uses a mobile phone as an example for illustration; other electronic devices can refer to this embodiment.

[0057] Please see Figure 2 The electronic device 1000 includes an antenna assembly 100.

[0058] Please see Figure 2Taking a mobile phone as an example, the working environment of the antenna assembly 100 is illustrated below. The electronic device 1000 includes a display screen 200, a mid-frame 300, and a back cover 400 arranged sequentially along its thickness. The mid-frame 300 includes a mid-plate 310 and a frame 320 surrounding the mid-plate 310. Of course, in other embodiments, the electronic device 1000 may not have a mid-plate 310. The display screen 200, mid-plate 310, and back cover 400 are stacked sequentially, forming receiving spaces between the display screen 200 and the mid-plate 310, and between the mid-plate 310 and the back cover 400, to accommodate components such as the motherboard, camera module, receiver module, battery, and various sensors. One side of the frame 320 surrounds the edge of the display screen 200, and the other side of the frame 320 surrounds the edge of the back cover 400, forming the complete external structure of the electronic device 1000. In this embodiment, the frame 320 and the middle plate 310 are an integral structure, while the frame 320 and the back cover 400 can be separate structures. The above describes the working environment of the antenna assembly 100 using a mobile phone as an example, but the antenna assembly 100 of this application is not limited to the above working environment.

[0059] Please see Figure 3 320mm border Figure 3 The frame (formed by dashed and solid lines) includes a top edge 321 and a bottom edge 322 arranged opposite to each other, and a first side edge 323 and a second side edge 324 connecting the top edge 321 and the bottom edge 322. The top edge 321 is the side away from the ground when the user holds and uses the electronic device 1000, and the bottom edge 322 is the side facing the ground when the user holds and uses the electronic device 1000.

[0060] Electronic device 1000 is used in many handheld scenarios and scenarios close to the human head. Based on this, detecting SAR hotspots and regulating the distribution of SAR hotspots have become technical problems that need to be solved.

[0061] Please see Figure 3 The electronic device 1000 includes a reference ground system 500 and an antenna assembly 100 disposed along the reference ground edge of the reference ground system 500. The reference ground system 500 is made of a conductive material and may be disposed in the middle plate 310 of the electronic device 1000. Optionally, the reference ground system 500 may include a metal alloy in the middle plate, a reference ground metal in the circuit board, etc. Taking a mobile phone as an example, the reference ground system 500 can be equivalently represented as a rectangular plate disposed within the frame.

[0062] Please see Figure 3 The antenna assembly 100 includes a radiator and a signal source 20.

[0063] Please see Figure 3The radiator also includes a first radiator 11 and a second radiator 12. The first radiator 11 includes a first grounding point 112, a feed point A, and a first free end 111, arranged sequentially. The feed point A is located between the first grounding point 112 and the first free end 111. The second radiator 12 includes a second free end 122 and a second grounding point 121, arranged sequentially. Both the first grounding point 112 and the second grounding point 121 are electrically connected to the reference ground system 500. The first free end 111 and the second free end 122 are coupled through a coupling gap.

[0064] The signal source 20 is mounted on the mainboard of the electronic device 1000. The signal source 20 is electrically connected to the feed point A. The signal source 20 is used to excite the first radiator 11 and the second radiator 12 to jointly form a first resonant mode and a second resonant mode.

[0065] The resonant frequency of the first resonant mode is lower than that of the second resonant mode. The resonant current intensity of the first resonant mode on the first radiator 11 is greater than the resonant current intensity of the first resonant mode on the second radiator 12. In other words, the resonant current of the first resonant mode on the first radiator 11 makes the main contribution to the radiated energy of the first resonant mode.

[0066] Please see Figure 4 The direction of the resonant current in the first resonant mode on the first radiator 11 is the same as the direction of the resonant current in the second radiator 12 of the first resonant mode.

[0067] The electrical length of the first radiator 11 determines the resonant frequency of the first resonant mode. Specifically, the first resonant mode forms a 1 / 4 wavelength mode corresponding to the first target frequency band on the first radiator 11. In other words, the electrical length of the first radiator 11 is close to 1 / 4 wavelength of the first target frequency band.

[0068] The electrical length described in this application can satisfy the following formula:

[0069]

[0070] Where L is the physical length, a is the transmission time of the electrical or electromagnetic signal in the medium, and b is the transmission time in the free scene.

[0071] When the antenna assembly 100 operates in the second resonant mode, the current intensity on the second radiator 12 is greater than the current intensity on the first radiator 11. In other words, the resonant current on the second radiator 12 in the second resonant mode makes the main contribution to the radiated energy of the second resonant mode.

[0072] Please see Figure 5The direction of the resonant current in the first radiator 11 in the second resonant mode is opposite to the direction of the resonant current in the second radiator 12 in the second resonant mode.

[0073] The electrical length of the second radiator 12 determines the resonant frequency of the second resonant mode. Specifically, the second resonant mode forms a 1 / 4 wavelength mode supporting the second target frequency band on the second radiator 12. In other words, the electrical length of the second radiator 12 is close to 1 / 4 wavelength of the second target frequency band. The difference between the resonant frequency of the first resonant mode and the resonant frequency of the second resonant mode is generally less than 1 GHz.

[0074] The antenna assembly 100 provided in this application can be referred to as an EE (electric field-electric field) antenna. The first resonant mode can be referred to as the radiation mode of the EE antenna, and the second resonant mode can be referred to as the balanced mode of the EE antenna. The first and second resonant modes form a dual-wave resonance, and the second resonant mode can improve the in-band efficiency of the first resonant mode.

[0075] Optional, please refer to Figure 4 and Figure 5 The antenna assembly 100 also includes a matching circuit M. The matching circuit M is electrically connected between the signal source 20 and the feed point A. The matching circuit M includes at least one of a capacitor and an inductor. Specifically, the matching circuit M may include, but is not limited to, a capacitor, an inductor, a series connection of a capacitor and an inductor, a parallel connection of a capacitor and an inductor, a series connection of the aforementioned components in parallel with a capacitor, a series connection of the aforementioned components in parallel with an inductor, two series connections in parallel, two parallel connections in series, and so on. The matching circuit M adjusts the impedance matching between the port of the signal source 20 and the port of the first radiator 11, facilitating the formation of a 1 / 4 wavelength mode corresponding to the first target frequency band under the excitation of the signal source 20, thereby tuning the resonant frequency of the first resonant mode.

[0076] Optionally, the preset frequency band F0 supported by the antenna assembly 100 may cover frequency bands that require reduced SAR values, including but not limited to B3 band, B1 band, B41 band, N78 band, GPS band, Wi-Fi 2.4G band, etc.

[0077] In this application, the first radiator 11 is the main branch, and the second radiator 12 is the parasitic branch. The first radiator 11 and the second radiator 12 form a dual-wave resonance. The second resonance mode of the second radiator 12 is used to improve the radiation efficiency of the first resonance mode of the first radiator 11. Therefore, the first resonance mode is often used as the main resonance, and the second resonance mode is used as a supplement. For example, the first resonance mode covers the B3 frequency band, and the second resonance mode is used to improve the efficiency of the B3 frequency band. Therefore, when analyzing the influence of the resonance point size on the SAR value of the antenna assembly 100, the analysis mainly focuses on the influence of the resonance point of the first resonance mode (hereinafter referred to as the first resonance frequency F1) on the SAR value of the antenna assembly 100. In the first resonance mode, the current is mainly in the main branch. Of course, when the second resonance mode mainly supports the preset frequency band F0, the influence of the resonance point of the second resonance mode (hereinafter referred to as the first resonance frequency F1) on the SAR value of the antenna assembly 100 can be analyzed.

[0078] Please see Figure 6 and Figure 7 The resonant frequency F1 of the first resonant mode is configured as a frequency point in the target frequency band Fa. The target frequency band Fa is a part of the effective frequency band Fb of the first resonant mode, and the target frequency band Fa falls within the preset frequency band F0 configured for the antenna assembly 100. The SAR value of the antenna assembly operating in the target frequency band Fa is less than or equal to the SAR value of the antenna assembly 100 operating in the preset frequency band F0 other than the target frequency band Fa.

[0079] The effective frequency band Fb of the first resonant mode can be reflected in the S-curve corresponding to the first resonant mode in a frequency band where the return loss is less than or equal to -4dB, -5dB, -6dB, -8dB, or -10dB.

[0080] Please see Figure 7 , Figure 7 A schematic diagram of the S-parameter curve waveform formed when the center frequency of the preset frequency band F0 does not coincide with the resonant frequency F1 of the first resonant mode. Figure 7 The frequency band with a return loss of -10dB corresponding to the S-curve of the dashed wave is the preset frequency band F0. The frequency band with a return loss of -10dB corresponding to the S-curve of the first solid wave following the dashed wave is the effective frequency band Fb. The common frequency band Fc between the preset frequency band F0 and the effective frequency band Fb can cover the B3 band, the B1 band, or other frequency bands. The second solid wave following the dashed wave is the S-parameter curve waveform of the second resonant mode.

[0081] Please see Figure 6 , Figure 6This diagram illustrates the S-parameter curve waveforms formed when the center frequency of the preset frequency band F0 coincides with the resonant frequency F1 of the first resonant mode. The first waveform represents the S-curve waveform of the first resonant mode, where the preset frequency band F0 coincides with the effective frequency band Fb. The second solid line wave following the dashed wave represents the S-parameter curve waveform of the second resonant mode.

[0082] This application takes the example of the antenna assembly 100 supporting a preset frequency band F0 covering the B3 frequency band, where the preset frequency band F0 is 1.7-1.95 GHz. In this case, the effective frequency band Fb of the first resonant mode also covers the B3 frequency band. Both the preset frequency band F0 and the effective frequency band Fb of the first resonant mode cover the frequency band configured for the antenna assembly 100, such as the B3 frequency band. The difference between the preset frequency band F0 and the effective frequency band Fb of the first resonant mode is that the resonant frequency F1 of the first resonant mode is located within the frequency range of the preset frequency band F0 where the SAR hotspot is lower. This application defines the frequency range of the preset frequency band F0 where the SAR hotspot is lower as the target frequency band Fa. If the frequency range of the preset frequency band F0 where the SAR hotspot is lower is located on the low-frequency side of the preset frequency band F0, then the resonant frequency F1 of the first resonant mode is located on the low-frequency side of the preset frequency band F0. If the frequency range of the preset frequency band F0 where the SAR hotspot is lower is located on the center frequency side of the preset frequency band F0, then the resonant frequency F1 of the first resonant mode is located on the center frequency side of the preset frequency band F0. If the frequency range with lower SAR hotspots in the preset frequency band F0 is located on the high-frequency side of the preset frequency band F0, then the resonant frequency F1 of the first resonant mode is located on the high-frequency side of the preset frequency band F0. In other words, the effective frequency band Fb of the first resonant mode overlaps with the preset frequency band, but the center frequencies may be set at intervals.

[0083] The target frequency band Fa is a part of the preset frequency band F0, and the target frequency band Fa is also a part of the effective frequency band Fb of the first resonant mode.

[0084] The resonant frequency F1 of the first resonant mode can be 1.7GHz, 1.75GHz, 1.8GHz, 1.85GHz, 1.9GHz, or 1.95GHz, so that the antenna assembly 100 can cover the B3 frequency band when operating in the first resonant mode.

[0085] In this embodiment, the target frequency band Fa is determined based on the SAR hotspot value in the preset frequency band F0, and the resonant frequency point F1 of the first resonant mode is determined in the target frequency band Fa. The frequency band with a return loss of -10dB in the S-curve corresponding to the resonant frequency point F1 of the first resonant mode is the effective frequency band Fb.

[0086] The electronic device 1000 provided in this application includes a first radiator 11, a second radiator 12, and a signal source 20 via an antenna assembly 100. The first radiator 11 includes a first ground point 112, a feed point A, and a first free end 111 arranged sequentially. The first ground point 112 is grounded. The second radiator 12 includes a second free end 122 and a second ground point 121 arranged sequentially. The second free end 122 is coupled to the first free end 111 through a coupling gap. The second ground point 121 is grounded. The signal source 20 is electrically connected to the feed point A. The signal source 20 is used to excite the first radiator 11 and the second radiator 12 to jointly form a first resonant mode and a second resonant mode. The resonant frequency F1 of the first resonant mode is greater than the resonant frequency of the second resonant mode. The current intensity of the first resonant mode on the first radiator 11 is greater than the current intensity on the second radiator 12. The resonant frequency F1 of the first resonant mode is configured as a frequency point in the target frequency band Fa. The target frequency band Fa belongs to a portion of the effective frequency band Fb of the first resonant mode, and the target frequency band Fa falls within the preset frequency band F0 configured for the antenna assembly 100. The SAR value of the antenna assembly operating in the target frequency band Fa is less than or equal to the SAR value of the antenna assembly 100 operating in the preset frequency band F0 other than the target frequency band Fa. This results in a smaller SAR value for the antenna assembly 100 operating in the target frequency band Fa, thereby reducing the SAR value of the antenna assembly 100 operating in the first resonant mode, and thus improving the SAR transmission pass rate or reducing unnecessary power back-off.

[0087] Of course, the frequency band configured for antenna assembly 100 can be switched. For example, the matching circuit M is equipped with an antenna switch to switch the frequency band configured for antenna assembly 100 to the B1 band. When antenna assembly 100 is configured to support the B1 band, the SAR of the B1 band can also be reduced in the manner described above.

[0088] Optionally, the difference between the maximum value and the minimum value of the target frequency band Fa is 0.1 GHz. In other words, the target frequency band Fa is the frequency band within the 0.1 GHz range corresponding to the minimum SAR value in the preset frequency band F0. The resonant frequency F1 of the first resonant mode is set within the 0.1 GHz range corresponding to the minimum SAR value to reduce the SAR value in the first resonant mode.

[0089] Optionally, the resonant frequency F1 of the first resonant mode is the center frequency of the target frequency band Fa. After determining the 0.1 GHz range corresponding to the minimum SAR value in the preset frequency band F0, the target resonant frequency position of the first resonant mode can be determined. A matching circuit M is designed so that when the first resonant mode is working, the resonant frequency F1 of the first resonant mode is at the center frequency of the 0.1 GHz range corresponding to the minimum SAR value, thereby making the working efficiency of the center frequency of the first resonant mode high while the SAR value low.

[0090] When the SAR value at the center frequency of the target frequency band Fa is the smallest, the efficiency of the center frequency of the first resonant mode is high and the SAR value is the lowest.

[0091] Of course, in other embodiments, the resonant frequency F1 of the first resonant mode may not be the center frequency of the target frequency band Fa.

[0092] Optionally, the radiator may be, but is not limited to, a metal frame 320, a metal frame embedded in a plastic frame 320, a metal radiator located within or on the surface of the frame 320, a flexible circuit board antenna formed on a flexible printed circuit board (FPC), a laser-directly formed antenna (LDS), a printed-directly formed antenna (PDS), or a conductive sheet antenna (e.g., a metal bracket antenna). In this embodiment, the radiator being part of a metal frame is used as an example for illustration.

[0093] Please see Figure 6 The preset frequency band F0 includes a first sub-band F01, a second sub-band F02, and a third sub-band F03 that are sequentially continuous and gradually increase in size. The center frequency of the second sub-band F02 is the center frequency of the preset frequency band F0. The center frequency of the target frequency band Fa is greater than the maximum value of the first sub-band. Optionally, the frequency band to be covered by the electronic device 1000 is divided into a first sub-band F01, a second sub-band F02, and a third sub-band F03. The second sub-band F02 is a frequency band near the center frequency of the preset frequency band F0. The first sub-band F01 is located on the low-frequency side of the preset frequency band F0. The third sub-band F03 is located on the high-frequency side of the preset frequency band F0. The center frequency of the target frequency band Fa is located in either the second sub-band F02 or the third sub-band F03. When the resonant frequency of the first resonant mode is the center frequency of the target frequency band Fa, the resonant frequency of the first resonant mode is located in either the second sub-band F02 or the third sub-band F03.

[0094] Taking the preset frequency band F0 covering the B3 frequency band as an example, the preset frequency band F0 is optionally 1.7GHz-1.95GHz. The first sub-frequency band F01 can be 1.7GHz-1.78GHz, the second sub-frequency band F02 can be 1.78GHz-1.86GHz, and the third sub-frequency band F03 can be 1.86GHz-1.95GHz.

[0095] The following embodiments of this application are illustrated using the resonant frequency F1 of the first resonant mode as the center frequency of the target frequency band Fa as an example.

[0096] In this embodiment, in one optional implementation, please refer to... Figure 6 The resonant frequency F1 of the first resonant mode is located in the second sub-band F02, and further located near the center frequency of the preset frequency band F0, so that the SAR value of the antenna assembly 100 when operating in the first resonant mode is lower than the SAR value of the antenna assembly 100 when operating in the first sub-band F01, thereby reducing the SAR value of the antenna assembly 100. This embodiment will be described in detail later.

[0097] In another alternative implementation, please refer to Figure 7 The resonant frequency F1 of the first resonant mode can be located in the third sub-band F03, and further located near the center frequency of the third sub-band F03, so that the SAR value of the antenna assembly 100 when operating in the first resonant mode is lower than the SAR value of the antenna assembly 100 when operating in the first sub-band F01, thereby reducing the SAR value of the antenna assembly 100. This embodiment will be described in detail later.

[0098] The reference ground system 500 forms a first characteristic mode and a second characteristic mode when the antenna assembly 100 operates in the first resonant mode.

[0099] Please see Figure 8 The first characteristic mode can be a half-wavelength mode in the first direction. The current intensity of the first characteristic mode in the first direction of the reference ground system 500 gradually increases from the two edges to the center. That is, the first characteristic mode forms a strong current region in the middle of the reference ground system 500 and two weak current regions at the two edges of the reference ground system 500. Therefore, the first characteristic mode causes the reference ground system 500 to form a strong SAR region N1 and two weak SAR regions N2 located on opposite sides of the strong SAR region N1 along the first direction. Optionally, the first direction can be the length direction of the electronic device 1000.

[0100] The second characteristic mode can be a half-wavelength mode in the second direction. The current intensity of the second characteristic mode in the second direction of the reference ground system 500 gradually increases from the two edges to the center. That is, the second characteristic mode forms a strong current region in the middle of the reference ground system 500 and two weak current regions at the two edges of the reference ground system 500, thereby forming a strong SAR region N1 and two weak SAR regions N2 located on opposite sides of the strong SAR region N1 along the second direction. The first direction is perpendicular to the second direction. The second direction can be the width direction of the electronic device 1000.

[0101] For ease of description, please refer to Figure 8The reference ground system 500 is defined as including a first reference edge 510, a second reference edge 520, a third reference edge 530, and a fourth reference edge 540 connected sequentially. The first reference edge 510 is opposite to the top edge 321, the second reference edge 520 is opposite to the first side edge 323, the third reference edge 530 is opposite to the bottom edge 322, and the fourth reference edge 540 is opposite to the second side edge 324. The second feature pattern divides the first reference edge 510 into a SAR weak region N2, a SAR strong region N1, and a SAR weak region N2 sequentially. The second feature pattern divides the third reference edge 530 into a SAR weak region N2, a SAR strong region N1, and a SAR weak region N2 sequentially. The first feature pattern divides the second reference edge 520 into a SAR weak region N2, a SAR strong region N1, and a SAR weak region N2 sequentially. The first feature pattern divides the fourth reference edge 540 into a SAR weak region N2, a SAR strong region N1, and a SAR weak region N2 sequentially.

[0102] The first radiator 11 and the second radiator 12 are disposed along either of the aforementioned reference edges. The first ground point 112 and the second ground point 121 of the antenna assembly 100 are electrically connected to the reference edge of the reference ground system 500. Therefore, the relationship between the position of the antenna assembly 100 and the SAR strong region N1 and SAR weak region N2 on the reference ground system 500 can be summarized as follows: First, the first grounding point 112 and the second grounding point 121 of the antenna assembly 100 are both electrically connected to the SAR weak region N2 of the reference ground system 500; Second, the first grounding point 112 of the antenna assembly 100 is electrically connected to the SAR strong region N1 of the reference ground system 500, and the second grounding point 121 of the antenna assembly 100 is electrically connected to the SAR weak region N2 of the reference ground system 500; Third, the first grounding point 112 of the antenna assembly 100 is electrically connected to the SAR weak region N2 of the reference ground system 500, and the second grounding point 121 of the antenna assembly 100 is electrically connected to the SAR strong region N1 of the reference ground system 500; Fourth, the first grounding point 112 and the second grounding point 121 of the antenna assembly 100 are both electrically connected to the SAR strong region N1 of the reference ground system 500.

[0103] The following implementation method illustrates the overall SAR values ​​based on different positions of the antenna assembly 100 on the reference ground system 500. The SAR measurement method employs the 5mm body SAR test method, where the surface under test is measured at a distance of 5mm from the mobile phone.

[0104] In one implementation, please refer to Figure 9The second grounding point 121 is electrically connected to the SAR strong region N1 of the reference ground system 500, and the SAR strong region N1 is used to form a SAR hotspot. The first grounding point 112 is electrically connected to the SAR weak region N2 of the reference ground system 500. The first radiator 11 and the second radiator 12 can be located at the top edge 321, the bottom edge 322, the first side edge 323, or the second side edge 324. In this embodiment, the first radiator 11 and the second radiator 12 are located at the bottom edge 322.

[0105] The following examples illustrate how the first resonant frequency F1 (the resonant frequency F1 of the first resonant mode) in this embodiment is located in the first sub-band F01, the second sub-band F02, and the third sub-band F03 of the preset frequency band F0.

[0106] Please see Figure 10 When the first resonant frequency F1 is located in the first sub-band F01 (low frequency side) of the preset frequency band F0, the main current distribution of the first resonant mode is a quarter wavelength mode from the first grounding point 112 to the coupling gap (first free end 111). The current from the feed point A to the coupling gap (first free end 111) is relatively weak. At this time, the current mainly flows to the ground from the first grounding point 112.

[0107] Please see Figure 11 The first grounding point 112 is the only location with strong current, generating a SAR hotspot. At the same time, the center of the reference ground edge of the reference ground system 500 will form a SAR hotspot on the reference ground system 500.

[0108] Please see Figure 12 The SAR hotspot on the reference ground system 500 and the SAR hotspot at the first ground point 112 are superimposed to form the overall SAR hotspot of the antenna assembly 100. The overall SAR hotspot is located between the first ground point 112 and the SAR hotspot on the reference ground system 500.

[0109] Please see Figure 13 When the first resonant frequency F1 is located in the second sub-band F02 (near the center resonant point) of the preset frequency band F0, the main current distribution of the first resonant mode is the IFA mode from the first grounding point 112 and the feed point A to the coupling gap (first free end 111), where the parasitic current on the second radiator 12 is relatively weak, and the current mainly flows to the ground from the feed point A and the first grounding point 112.

[0110] Please see Figure 14 Feed point A and first ground point 112 are two locations with strong current, generating two SAR hot spots. At the same time, the center of the reference ground edge of the reference ground system 500 will form a SAR hot spot on the reference ground system 500.

[0111] Please see Figure 15 The SAR hotspots on the reference ground system 500, feed point A, and the first ground point 112 are superimposed to form the overall SAR hotspot of the antenna assembly 100. This overall SAR hotspot is located between the feed point A and the SAR hotspot on the reference ground system 500. Compared to the overall SAR hotspot when the first resonant frequency F1 is located in the first sub-band F01 (low-frequency side) of the preset frequency band F0, the overall SAR hotspot in this embodiment shifts to the left because some of the SAR hotspots on the first radiator 11 are contributed by the ground current at feed point A. Furthermore, the overall SAR hotspot is a combination of three SAR hotspots. Compared to the overall SAR hotspot when the first resonant frequency F1 is located in the first sub-band F01 (low-frequency side) of the preset frequency band F0, the overall SAR distribution in this embodiment is more uniform, and the maximum SAR value is reduced. Because during SAR detection, power is backed up based on the maximum SAR value or whether the maximum SAR value exceeds the standard value to determine whether an over-detection has occurred, the reduction in the maximum SAR value in this embodiment can avoid unnecessary power back-up, improve the operating power of the antenna assembly 100, and increase the SAR test pass rate of the electronic device 1000.

[0112] Please see Figure 16 When the first resonant frequency F1 is located in the third sub-band F03 (high frequency side) of the preset frequency band F0, the main current distribution of the first resonant mode is still the IFA mode from the first grounding point 112 and the feed point A to the coupling gap (first free end 111). The parasitic current on the second radiator 12 is relatively weaker than the current on the first radiator 11, but due to the increase in frequency, the current on the second radiator 12 increases, so it is represented by two dashed lines. At this time, the current mainly flows to the ground from the feed point A and the first grounding point 112.

[0113] Please see Figure 17 The feed point A and the first grounding point 112 are two locations with strong currents, generating two SAR hot spots. Since the current intensity on the second radiator 12 is increased compared to when the first resonant frequency F1 is located in the first sub-band F01 and the second sub-band F02 of the preset frequency band F0, and the grounding position at the second grounding point 121 is closer to the strong SAR region N1 of the reference ground system 500, this embodiment will form a stronger SAR hot spot for the reference ground system 500 than when the first resonant frequency F1 is located in the first sub-band F01 and the second sub-band F02 of the preset frequency band F0.

[0114] Please see Figure 18The SAR hotspots on the reference ground system 500, the feed point A, and the first ground point 112 are superimposed to form the overall SAR hotspot of the antenna assembly 100. This overall SAR hotspot is located between the feed point A and the SAR hotspot on the reference ground system 500. At the same time, the SAR hotspot formed on the reference ground system 500 in this embodiment is stronger, so the overall SAR hotspot continues to shift to the left. However, the SAR of the reference ground system 500 is stronger at this time. Compared with the first resonant frequency F1 located in the second sub-band F02 of the preset frequency band F0, the SAR distribution is uneven. Therefore, the maximum SAR value of the antenna assembly 100 will also be higher than that of the first resonant frequency F1 located in the second sub-band F02 of the preset frequency band F0.

[0115] As can be seen from the above, as the resonant frequency F1 of the first resonant mode gradually increases within the preset frequency band F0, the overall SAR value of the antenna assembly 100 first decreases and then increases. Furthermore, when the resonant frequency F1 of the first resonant mode (the center frequency of the target frequency band Fa) is located in the second sub-band F02 of the preset frequency band F0, the overall SAR value distribution of the antenna assembly 100 becomes more uniform, and the maximum SAR value decreases. In other words, the center frequency of the target frequency band Fa falls into the second sub-band. When the resonant frequency of the first resonant mode is the center frequency of the target frequency band Fa, the resonant frequency of the first resonant mode falls into the second sub-band. Optionally, the resonant frequency of the first resonant mode can be the frequency with the smallest SAR value in the second sub-band. During SAR detection, power is backed up based on the maximum SAR value or whether the maximum SAR value exceeds the standard value to determine whether an over-detection has occurred. Therefore, in this embodiment, reducing the maximum SAR value can avoid unnecessary power back-up, improve the operating power of the antenna assembly 100, and increase the SAR detection pass rate of the electronic device 1000.

[0116] When the resonant frequency F1 (center frequency of target frequency band Fa) of the first resonant mode is located in the second sub-band F02 of the preset frequency band F0, the resonant current on the first radiator 11 in the first resonant mode is grounded through the feed point A and the first ground point 112. The resonant current at the feed point A and the resonant current at the first ground point 112 are both used to form SAR hotspots. Combined with the SAR hotspots near the center of the reference ground system 500, these three SAR hotspots are dispersed. The uniformity of the intensity of the SAR hotspots of the antenna assembly 100 and the SAR strong region N1 in the extension direction of the first radiator 11 and the second radiator 12 is greater than the uniformity of the intensity of the SAR hotspots when the center frequency of the target frequency band Fa falls into the first sub-band F01 or the third sub-band F03. This increases the uniformity of the intensity of the SAR hotspots of the antenna assembly 100 and the SAR strong region N1 in the extension direction of the first radiator 11 and the second radiator 12, making the overall SAR value distribution of the antenna assembly 100 more uniform and reducing the maximum SAR value.

[0117] Furthermore, the resonant frequency F1 of the first resonant mode is the center frequency of the preset frequency band F0. At this time, the current on the second radiator 12 is relatively weak, and the current intensity on the second radiator 12 ensures that the intensity of the SAR hotspot in the strong SAR region N1 on the reference ground system 500 is not too high. Moreover, the difference between the intensity of the SAR hotspot in the strong SAR region N1 on the reference ground system 500 and the intensity of the SAR hotspot formed by the first grounding point 112 and the feed point A is not too large, and they are relatively uniform, thereby reducing the maximum value of the overall SAR of the antenna assembly 100.

[0118] The following example uses the preset frequency band F0 that the antenna assembly 100 needs to support to cover the B3 frequency band. The normalized SAR value is used to verify the change of the SAR value of the antenna assembly 100 as the first resonant frequency F1 gradually increases when supporting the B3 frequency band.

[0119] Please refer to Table 1, which shows the normalized SAR simulation results of antenna assembly 100 when the first resonant frequency F1 is 1.7GHz, 1.75GHz, 1.8GHz, 1.85GHz, 1.9GHz, and 1.95GHz. Optionally, the preset frequency band F0 can be 1.7GHz-1.95GHz. Taking the antenna assembly 100 located at the bottom edge 322, the second grounding point 121 located near the reference ground system 500, and the first grounding point 112 located in the SAR weak region N2 as an example, the frequency value is gradually increased by adjusting the matching circuit M, successively to 1.7GHz, 1.75GHz, 1.8GHz, 1.85GHz, 1.9GHz, and 1.95GHz. SAR values ​​(including SAR hotspots on the reference ground system 500) are detected at a distance of 5mm from the bottom edge 322 at each frequency, and the SAR value when the power is normalized to 21dBm is obtained. The SAR results show that the overall SAR value of antenna assembly 100 first decreases and then increases with increasing frequency, and the overall SAR value of antenna assembly 100 is low at frequencies of 1.75 GHz, 1.8 GHz, and 1.85 GHz. It can be determined that the target frequency band Fa is 1.75-1.85 GHz. The second sub-band F02 of the preset frequency band F0 is 1.78-1.86 GHz, so the actual verification results also satisfy this, with the center frequency of the target frequency band Fa located in the second sub-band F02. The first resonant frequency F1 is located in the second sub-band F02 of the preset frequency band F0. All of these factors contribute to the low overall SAR value of antenna assembly 100.

[0120] Table 1

[0121]

[0122] Please see Figure 19 , Figure 19 This is a SAR hotspot simulation diagram when the antenna assembly 100 supports the B3 band, with the first resonant frequency F1 set to 1.75GHz, 1.85GHz, and 1.95GHz. From... Figure 19 It can be seen that the maximum SAR value is 2.08 W / kg when the first resonant frequency F1 is 1.75 GHz, 2.04 W / kg when the first resonant frequency F1 is 1.85 GHz, and 2.28 W / kg when the first resonant frequency F1 is 1.95 GHz. Furthermore, the SAR hotspot location gradually shifts to the left as the first resonant frequency F1 increases.

[0123] The following example uses the preset frequency band F0 that the antenna assembly 100 needs to support to cover the B1 frequency band. The normalized SAR value is used to verify the change of the SAR value of the antenna assembly 100 as the first resonant frequency F1 gradually increases when supporting the B1 frequency band.

[0124] Please refer to Table 2, which shows the normalized SAR simulation results of antenna assembly 100 when the first resonant frequency F1 is 1.85GHz, 1.9GHz, 1.95GHz, 2.0GHz, 2.05GHz, and 2.1GHz. Optionally, the preset frequency band F0 can be 1.85GHz-2.1GHz. Taking the antenna assembly 100 located at the bottom edge 322, the second grounding point 121 located near the reference ground system 500, and the first grounding point 112 located in the SAR weak region N2 as an example, the frequency value is gradually increased by adjusting the matching circuit M, successively to 1.85GHz, 1.9GHz, 1.95GHz, 2.0GHz, 2.05GHz, and 2.1GHz. SAR values ​​(including SAR hotspots on the reference ground system 500) are detected at a distance of 5mm from the bottom edge 322 at each frequency, and the SAR value when the power is normalized to 21dBm is obtained. The SAR results show that the overall SAR value of antenna assembly 100 first decreases and then increases with increasing frequency, and the overall SAR value of antenna assembly 100 is small at frequencies of 1.9 GHz, 1.95 GHz, and 2.0 GHz. Therefore, the target frequency band Fa is determined to be 1.9-2.0 GHz. The second sub-band F02 of the preset frequency band F0 is 1.93-2.01 GHz. The actual verification results also satisfy this, as the target frequency band Fa is located in the second sub-band F02. The center frequency of the target frequency band Fa is located in the second sub-band F02. The first resonant frequency F1 is located in the second sub-band F02 of the preset frequency band F0. All of these factors contribute to a lower overall SAR value of antenna assembly 100.

[0125] Table 2

[0126]

[0127] Please see Figure 20 , Figure 20 These are the S-parameter curves of the antenna assembly 100 provided in this application under free-field conditions and when a human body is near. Curve a represents the S-parameter curve of the antenna assembly 100 supporting the B1 band under free-field conditions. Curve b represents the S-parameter curve of the antenna assembly 100 supporting the B1 band under free-field conditions. Curve c represents the S-parameter curve of the antenna assembly 100 supporting the B3 band under free-field conditions. Curve d represents the S-parameter curve of the antenna assembly 100 supporting the B3 band under near-human-body conditions.

[0128] As can be seen, antenna component 100 exhibits dual-wave resonance in both the B3 and B1 bands. In the B3 and B1 bands, there is a certain frequency offset when a human body approaches (after adding the body).

[0129] As shown in Table 1, in the B3 band, as the first resonant frequency F1 increases, the overall SAR value of the antenna assembly 100 first decreases and then increases. When the first resonant frequency F1 is 1.7GHz-1.8GHz, the overall SAR value of the antenna assembly 100 is the smallest, which is consistent with the performance of the B3 band in free scene shown in curve c.

[0130] As shown in Table 2, in the B1 band, as the first resonant frequency F1 increases, the overall SAR value of antenna assembly 100 first decreases and then increases. The overall SAR value of antenna assembly 100 is minimum when the first resonant frequency F1 is between 1.9 GHz and 2.0 GHz. This matches the performance of the B1 band in free-field scenarios shown in curve a. In other words, the overall SAR value of antenna assembly 100 first decreases and then increases with the first resonant frequency F1, satisfying both free-field and near-human proximity conditions.

[0131] As can be seen, regardless of whether it is the B3 band or the B1 band, the lowest position of SAR is the deepest resonance position in the free scene, and the SAR will rise rapidly regardless of whether the frequency continues to shift lower or higher.

[0132] Please see Figure 21 , Figure 21 This is a SAR hotspot simulation diagram when the antenna assembly 100 supports the B1 band, with the first resonant frequency F1 set to 1.85GHz, 1.95GHz, and 2.05GHz. From... Figure 21 It can be seen that the maximum SAR value is 1.9 W / kg when the first resonant frequency F1 is 1.85 GHz, the maximum SAR value is 1.8 W / kg when the first resonant frequency F1 is 1.95 GHz, and the maximum SAR value is 2.0 W / kg when the first resonant frequency F1 is 2.05 GHz. Furthermore, the SAR hotspot location gradually shifts to the left as the first resonant frequency F1 increases.

[0133] In this embodiment, by setting the first resonant frequency F1 at the center frequency of the second sub-frequency band F02, the SAR value at the first resonant frequency F1 is minimized, and the overall SAR value of the antenna assembly 100 increases on both the low-frequency and high-frequency sides of the first resonant frequency F1.

[0134] The electronic device 1000 receives signals in frequency bands including a low-channel band, a mid-channel band, and a high-channel band, with frequencies increasing sequentially. The mid-channel band is located within the target frequency band Fa. That is, the first resonant frequency F1 is located within the mid-channel band. By locating the first resonant frequency F1 near the mid-channel band of the transmitting antenna, and consequently locating the high-channel and low-channel bands of the transmitting antenna near the first resonant frequency F1, a lower SAR value is achieved for the transmitting antenna.

[0135] In the second embodiment, please refer to Figure 22Both the first grounding point 112 and the second grounding point 121 are electrically connected to the same SAR weak region N2 of the reference ground system 500. In this embodiment, the antenna assembly 100 may be disposed on the upper or lower half of the first side 323 or the second side 324. In this embodiment, the SAR hotspots of the antenna assembly 100 may not consider the superposition of SAR hotspots on the reference ground system 500.

[0136] Please see Figure 22 When the first resonant frequency F1 is located in the first sub-band F01 (low-frequency side) of the preset frequency band F0, the main current distribution of the first resonant mode is a quarter-wavelength mode from the first grounding point 112 to the coupling gap (first free end 111). The current from the feed point A to the coupling gap (first free end 111) is relatively weak, and the current mainly flows to ground from the first grounding point 112. The first grounding point 112 is the only location with strong current, generating a SAR hotspot (within the dashed elliptical box in the figure). The SAR hotspot corresponds to the location of the first grounding point 112.

[0137] Please see Figure 23 When the first resonant frequency F1 is located in the second sub-band F02 of the preset frequency band F0 (near the center resonant point), the main current distribution of the first resonant mode is the IFA mode from the first grounding point 112 and the feed point A to the coupling gap (first free end 111). The parasitic current on the second radiator 12 is relatively weak, and the current mainly flows to the ground from the feed point A and the first grounding point 112. The feed point A and the first grounding point 112 are two locations with strong currents, generating two SAR hotspots (within the dashed elliptical box in the figure). The two SAR hotspots correspond to the locations of the feed point A and the first grounding point 112, respectively.

[0138] Compared to the SAR hotspots corresponding to the first grounding point 112 when the first resonant frequency F1 is located in the first sub-band F01 (low-frequency side) of the preset frequency band F0, the overall SAR hotspots in this embodiment shift to the left because a portion of the SAR hotspots on the first radiator 11 are contributed by the ground current at feed point A. Furthermore, the overall SAR hotspots are now a combination of two SAR hotspots. Compared to the SAR hotspots when the first resonant frequency F1 is located in the first sub-band F01 (low-frequency side) of the preset frequency band F0, the SAR intensity distribution in this embodiment is more uniform, and the maximum SAR value is reduced. From another perspective, in this embodiment, the current intensity distribution on the first radiator 11 is more uniform than when the first resonant frequency F1 is located in the first sub-band F01, resulting in a more uniform SAR intensity distribution and a reduced maximum SAR value.

[0139] Please see Figure 24When the first resonant frequency F1 is located in the third sub-band F03 (high-frequency side) of the preset frequency band F0, the main current distribution of the first resonant mode is still the IFA mode from the first grounding point 112 and the feed point A to the coupling gap (first free end 111). The parasitic current on the second radiator 12 is relatively weaker than the current on the first radiator 11, but due to the increased frequency, the proportion of current on the second radiator 12 increases, hence it is represented by two dashed lines. At this time, the current mainly flows to the ground from the feed point A and the first grounding point 112. The feed point A and the first grounding point 112 are two locations with strong currents, generating two SAR hotspots (within the dashed elliptical box in the figure). This contrasts with the SAR hotspot corresponding to the first grounding point 112 when the first resonant frequency F1 is located in the second sub-band F02. Since some of the SAR hotspots on the first radiator 11 are contributed by the ground current at feed point A, the current intensity on the second radiator 12 increases. In other words, in this embodiment, the uniformity of the current intensity on the first radiator 11 and the second radiator 12 is better than the uniformity of the current intensity on the first radiator 11 and the second radiator 12 when the first resonant frequency F1 is located in the second sub-frequency band F02. As a result, the SAR intensity distribution is more uniform, and the maximum SAR value will be further reduced.

[0140] Optionally, the resonant frequency F1 of the first resonant mode is greater than the center frequency of the preset frequency band F0, so that the first resonant frequency F1 is located on the high-frequency side of the preset frequency band F0. Further, the resonant frequency F1 of the first resonant mode (the center frequency of the target frequency band Fa) falls into the third sub-frequency band F03. Further, the resonant frequency F1 of the first resonant mode is the center frequency of the third sub-frequency band F03, making the SAR intensity distribution more uniform and further reducing the maximum SAR value.

[0141] When the first resonant frequency F1 is located in the third sub-band F03, in the first resonant mode, the resonant current on the first radiator 11 is grounded through the feed point A and the first ground point 112. The resonant current at the feed point A and the resonant current at the first ground point 112 are both used to form SAR hotspots, so that the current intensity on the first radiator 11 is relatively uniform. The resonant current intensity on the second radiator 12 in the first resonant mode is greater than the resonant current intensity on the second radiator 12 when the antenna assembly 100 resonates at a center frequency less than or equal to the center frequency of the target frequency band Fa, which is the center frequency of the preset frequency band F0. That is, the difference in current intensity between the second radiator 12 and the first radiator 11 in the first resonant mode is smaller, and the current intensity distribution on the first radiator 11 and the second radiator 12 is more uniform. The uniformity of the intensity of the SAR hotspots of the antenna assembly 100 and the SAR strong region N1 in the extension direction of the first radiator 11 and the second radiator 12 is greater than the uniformity of the intensity of the SAR hotspots when the center frequency of the target frequency band Fa falls into the first sub-frequency band F01 or the second sub-frequency band F02. This increases the uniformity of the intensity of the SAR hotspots on the antenna assembly 100 in the extension direction of the first radiator 11 and the second radiator 12, thereby reducing the maximum SAR value.

[0142] In the third embodiment, please refer to Figure 25 The first grounding point 112 is electrically connected to the SAR strong region N1 of the reference ground system 500, and the second grounding point 121 is electrically connected to the SAR weak region N2 of the reference ground system 500. In this embodiment, the antenna assembly 100 can be located at the middle of the first side 323 / or the second side 324. The overall SAR hotspot of the antenna assembly 100 in this embodiment needs to be superimposed on the SAR hotspot of the reference ground system 500 near the location of the first grounding point 112. Since the first radiator 11 is the main radiator and the first grounding point 112 itself is a high current point, the greater the current intensity on the second radiator 12, the smaller the difference in SAR intensity between the location of the first radiator 11 and the location of the second radiator 12. In embodiments where the first resonant frequency F1 is located in the first sub-band F01, the second sub-band F02, and the third sub-band F03, when the first resonant frequency F1 is located in the third sub-band F03, the current on the second radiator 12 is stronger, the SAR intensity difference between the location of the first radiator 11 and the location of the second radiator 12 is smaller, the intensity of the SAR hotspot is more uniform in the extension direction of the first radiator 11 and the second radiator 12, and the maximum SAR value is smaller. For a detailed analysis of the principle in this embodiment, please refer to the principle analysis in the first or second embodiment.

[0143] Optionally, the resonant frequency F1 of the first resonant mode is greater than the center frequency of the preset frequency band F0, so that the first resonant frequency F1 is located on the high-frequency side of the preset frequency band F0. In other words, the first resonant frequency F1 is located in the third sub-frequency band F03. Furthermore, the resonant frequency F1 of the first resonant mode is the center frequency of the third sub-frequency band F03, making the SAR intensity distribution more uniform and further reducing the maximum SAR value.

[0144] When the first resonant frequency F1 is located in the third sub-band F03, in the first resonant mode, the resonant current on the first radiator 11 is grounded through the feed point A and the first ground point 112. The resonant current at the feed point A and the resonant current at the first ground point 112 are both used to form SAR hotspots, making the current intensity on the first radiator 11 relatively uniform. The resonant current intensity on the second radiator 12 in the first resonant mode is greater than the resonant current intensity on the second radiator 12 when the antenna assembly 100 resonates at a center frequency less than or equal to the center frequency of the target frequency band Fa, which is the center frequency of the preset frequency band F0. That is, the difference in current intensity between the second radiator 12 and the first radiator 11 is smaller in the first resonant mode, and the current intensity distribution on the first radiator 11 and the second radiator 12 is more uniform, thereby increasing the uniformity of the intensity of the SAR hotspots on the antenna assembly 100 in the extension direction of the first radiator 11 and the second radiator 12, and thus reducing the maximum SAR value.

[0145] from Figure 20 It is known that the antenna assembly 100 will experience frequency offset in free-field scenarios and scenarios where a human is near. Since power back-off is required when SAR exceeds the limit, the impact of frequency offset needs to be considered. This application proposes that the power back-off value can be calculated by comparing the first SAR value corresponding to the sum of the resonant frequency point F1 of the first resonant mode and the second preset fluctuation value, and the second SAR value corresponding to the difference between the resonant frequency point F1 of the first resonant mode and the second preset fluctuation value. The maximum value between the first and second SAR values ​​is taken as the back-off SAR value, and maximum power back-off is performed, thus ensuring no SAR risk across the entire fluctuation frequency band.

[0146] For details, please refer to Figure 26The electronic device 1000 further includes a controller 30. The controller 30 is electrically connected to the antenna assembly 100. The controller 30 is used to compare the magnitude of a first SAR value corresponding to the sum of the resonant frequency F1 of the first resonant mode and a second preset fluctuation value, and a second SAR value corresponding to the difference between the resonant frequency F1 of the first resonant mode and the second preset fluctuation value. When the first SAR value is greater than the second SAR value, the controller 30 adjusts the power of the antenna assembly 100 to make the first SAR value less than the second preset SAR value. When the second SAR value is greater than the first SAR value, the controller 30 adjusts the power of the antenna assembly 100 to make the second SAR value less than the second preset SAR value.

[0147] This application does not specifically limit the magnitude of the second preset fluctuation value. The second preset fluctuation value can be obtained by detection, that is, by detecting the offset between the first resonant frequency F1 of the antenna assembly 100 in a free scene and the first resonant frequency F1 in a human approach scene, and determining this offset as the second preset fluctuation value. Optionally, the second preset fluctuation value is not limited to 50MHz, but is not limited to this data. The controller 30 compares the SAR value at the first resonant frequency F1±50MHz, takes the maximum value between the first SAR value and the second SAR value as the back-off SAR value, and performs maximum power back-off, thereby ensuring that there is no super SAR risk within the entire fluctuation frequency band.

[0148] Please see Figure 26 The antenna assembly 100 further includes at least one tuning circuit T. One end of the at least one tuning circuit T is electrically connected to the second grounding point 121 and / or the feed point A, and the other end of the at least one tuning circuit T is grounded. The controller 30 is electrically connected to the at least one tuning circuit T. The controller 30 is used to tune the impedance value of the tuning circuit T when the SAR transmission frequency of the electronic device 1000 is different from the resonant frequency F1 of the first resonant mode, so that the resonant frequency F1 of the first resonant mode is adjusted to the SAR transmission frequency, thereby reducing the SAR value of the antenna assembly 100 at the SAR transmission frequency.

[0149] Optionally, the tuning circuit T is an adjustable impedance circuit. Optionally, the tuning circuit T includes an antenna switch and / or an adjustable capacitor. In this embodiment, frequency tuning of the tuning circuit T refers to adjusting the electrical length of the first radiator 11 so that the electrical length of the first radiator 11 is close to 1 / 4 wavelength of the SAR measurement frequency.

[0150] Please see Figure 26Optionally, the tuning circuit T further includes a switching unit K and tuning branches T1. One end of each tuning branch T1 is electrically connected to one end of the switching unit K, and the other end of the switching unit K is electrically connected to a second grounding point 121 (or feed point A). That is, the switching unit K includes, but is not limited to, transistors, field-effect transistors, etc. The other end of each tuning branch T1 is grounded.

[0151] Each of the tuning branches T1 has a different impedance value. For example, the multiple tuning branches T1 are multiple capacitors with different capacitance values. Alternatively, the multiple tuning branches T1 are multiple inductors with different inductance values. Or, the tuning branch T1 includes multiple capacitors with different capacitance values ​​and multiple inductors with different inductance values. By adjusting the electrical connection of the switching unit K to different tuning branches T1, the impedance of the tuning circuit T is adjusted, thereby adjusting the electrical length of the second radiator 12 or the first radiator 11. Of course, in other embodiments, the tuning circuit T can also be an adjustable capacitor.

[0152] When the other end of the switching unit K is electrically connected to the second grounding point 121 and the tuning circuit T is electrically connected to the second grounding point 121, the tuning circuit T tunes the electrical length of the second radiator 12, thereby changing the current intensity on the second radiator 12, and thus making the SAR intensity distribution on the first radiator 11 and the second radiator 12 more uniform when the SAR measurement frequency is reached. For example, when the SAR transmission frequency of the electronic device 1000 is greater than the resonant frequency F1 of the first resonant mode, before the tuning circuit T is tuned, the SAR value at the SAR transmission frequency is originally less than the SAR value at the first resonant frequency F1. This is because the current distribution on the antenna assembly 100 and the reference ground system 500 at the SAR transmission frequency is more locally concentrated on the first radiator 11 compared to the current distribution on the antenna assembly 100 and the reference ground system 500 at the first resonant frequency F1. At this time, by switching the switching unit K of the tuning circuit T, the electrical length of the tuning circuit T can be increased, so that more current is distributed on the second radiator 12 at the SAR transmission frequency, reducing the current intensity difference near the first radiator 11, the second radiator 12, and the second grounding point 121, thereby making the SAR intensity distribution more uniform.

[0153] When the other end of the switching unit K is electrically connected to the second grounding point 121 and the tuning circuit T is electrically connected to the feed point A, the tuning circuit T tunes the electrical length of the first radiator 11, thereby changing the center frequency of the supported frequency band, so that the center frequency of the supported frequency band is the SAR measurement frequency, and thus achieves a more uniform SAR intensity distribution on the first radiator 11 and the second radiator 12 when the SAR measurement frequency (i.e., the first resonant frequency F1 is located at the SAR measurement frequency).

[0154] This application provides an antenna assembly 100, which includes an IFA antenna and a parasitic antenna. The IFA antenna and the parasitic antenna form a dual-resonance mode. In the dual resonance, the first resonant mode is the main operating mode. SAR values ​​will increase both below and above the first resonant frequency F1, regardless of the resonant frequency offset after a human body approaches. Therefore, in one practical application, to reduce SAR values, the main frequency bands, such as the frequencies corresponding to the low, medium, and high channels of the transmitting antenna, can be placed near the first resonant frequency F1. Furthermore, the medium channel frequency can be set to the first resonant frequency F1, and the low and high channels will be evenly distributed around the first resonant frequency F1 at frequencies close to it, thus obtaining the lowest SAR value. In another practical application, since the SAR measurement of the electronic device 1000 only tests a single frequency, such as the measurement frequency of the B3 band being 1.75GHz and B... The test frequency for band 1 is 1.95 GHz. The electrical length of the first radiator 11 can be changed by the tuning circuit T. When the second grounding point 121 is electrically connected to the strong SAR region N1 of the reference ground system 500 and the first grounding point 112 is electrically connected to the weak SAR region N2 of the reference ground system 500, the center frequency of the first resonant mode and the center frequency of the preset frequency band F0 are both set as the SAR test frequency. This allows the lowest SAR value to be measured at the SAR test frequency, reducing the difficulty of over-testing. In another practical application, when power back-off is performed when a human body approaches, the influence of frequency offset needs to be considered during back-off. Assuming that the frequency offset of the whole machine fluctuates within 50 MHz, the SAR value of the first resonant frequency point F1 ± 50 MHz needs to be calculated accordingly. The maximum value of the SAR values ​​measured at the two locations is taken as the back-off SAR value, and the maximum power back-off is performed to ensure that there is no risk of exceeding SAR within the entire fluctuating frequency band.

[0155] This application provides a method for reducing SAR (Self-Range Radiation) in its embodiments. Please refer to [link to relevant documentation]. Figures 1-4The method is applied to an electronic device 1000 having an antenna assembly 100. The antenna assembly 100 may refer to the antenna assembly 100 in any of the above embodiments. The antenna assembly 100 includes a first radiator 11, a second radiator 12, and a signal source 20. The first radiator 11 includes a first ground point 112, a feed point A, and a first free end 111 arranged sequentially. The first ground point 112 is grounded. The second radiator 12 includes a second free end 122 and a second ground point 121 arranged sequentially. The second free end 122 is coupled to the first free end 111 through a coupling gap (first free end 111), and the second ground point 121 is grounded. The signal source 20 is electrically connected to the feed point A. The signal source 20 is used to excite the first radiator 11 and the second radiator 12 to jointly form a first resonant mode and a second resonant mode. The resonant frequency F1 of the first resonant mode is less than the resonant frequency of the second resonant mode, the current intensity of the first resonant mode on the first radiator 11 is greater than the current intensity on the second radiator 12, and the first resonant mode forms a 1 / 4 wavelength mode corresponding to the first target frequency band on the first radiator 11.

[0156] Please see Figure 27 The method includes:

[0157] Step S100: Determine a target frequency band Fa within the preset frequency band F0 configured for the antenna assembly 100, wherein the target frequency band Fa falls within the preset frequency band F0 configured for the antenna assembly 100; the SAR value of the antenna assembly 100 operating in the target frequency band Fa is less than or equal to the SAR value of the antenna assembly 100 operating in the preset frequency band F0 other than the target frequency band Fa. The target frequency band Fa belongs to a portion of the effective frequency band of the first resonant mode. The effective frequency band can be referred to the foregoing description.

[0158] Step S200: Configure the resonant frequency F1 of the first resonant mode as a frequency point in the target frequency band Fa.

[0159] The SAR reduction method provided in this application determines a target frequency band Fa within a preset frequency band F0 configured for the antenna assembly 100, wherein the target frequency band Fa falls within the preset frequency band F0 configured for the antenna assembly 100; the SAR value of the antenna assembly 100 operating in the target frequency band Fa is less than or equal to the SAR value of the antenna assembly 100 operating in the preset frequency band F0 other than the target frequency band Fa; and the resonant frequency point F1 of the first resonant mode is configured as a frequency point in the target frequency band Fa, thereby reducing the SAR value of the antenna assembly 100 operating in the first resonant mode.

[0160] The electronic device 1000 is used to receive signals in frequency bands that include a low-channel band, a mid-channel band, and a high-channel band, with frequencies increasing sequentially. The mid-channel band of the received signals is set at the target frequency band Fa. That is, the first resonant frequency F1 is located in the mid-channel band. By placing the first resonant frequency F1 near the mid-channel band of the transmitting antenna, and consequently placing the high-channel and low-channel bands of the transmitting antenna near the first resonant frequency F1, a lower SAR value is achieved for the transmitting antenna.

[0161] In this embodiment, please refer to Figure 6 The preset frequency band F0 includes a first sub-frequency band F01, a second sub-frequency band F02, and a third sub-frequency band F03 that are sequentially continuous and gradually increase in size. The center frequency of the second sub-frequency band F02 is the center frequency of the preset frequency band F0.

[0162] Step S100: Determine a target frequency band Fa within the preset frequency band F0 where the antenna assembly 100 is configured, wherein the target frequency band Fa falls within the preset frequency band F0 where the antenna assembly 100 is configured; the SAR value of the antenna assembly 100 operating in the target frequency band Fa is less than or equal to the SAR value of the antenna assembly 100 operating in the preset frequency band F0 other than the target frequency band Fa, including:

[0163] Please see Figure 28 Step S110: Configure the difference between the maximum value and the minimum value of the target frequency band Fa to be 0.1 GHz, and the center frequency of the target frequency band Fa is greater than the maximum value of the first sub-frequency band F01.

[0164] Step S200: Configure the resonant frequency F1 of the first resonant mode as a frequency point in the target frequency band Fa, including:

[0165] Step S210: Configure the resonant frequency of the first resonant mode as the center frequency of the target frequency band.

[0166] In one optional implementation, the resonant frequency F1 of the first resonant mode may be located in the second sub-band F02, and further located near the center frequency of the preset frequency band F0, so that the SAR value of the antenna assembly 100 when operating in the first resonant mode is lower than the SAR value of the antenna assembly 100 when operating in the first sub-band F01, thereby reducing the SAR value of the antenna assembly 100.

[0167] In this embodiment, please refer to Figure 8The electronic device 1000 further includes a reference ground system 500. The resonant current of the antenna assembly 100 when operating in the first resonant mode flows to the reference ground system 500. A first characteristic mode and a second characteristic mode are formed on the reference ground system 500. The first characteristic mode causes the reference ground system 500 to form a strong SAR region N1 along a first direction and two weak SAR regions N2 located on opposite sides of the strong SAR region N1. The second characteristic mode causes the reference ground system 500 to form a strong SAR region N1 along a second direction and two weak SAR regions N2 located on opposite sides of the strong SAR region N1. The first direction is perpendicular to the second direction.

[0168] Please see Figure 22 and Figure 25 When both the first grounding point 112 and the second grounding point 121 are electrically connected to the same SAR weak region N2 of the reference ground system 500, or when the first grounding point 112 is electrically connected to the SAR strong region N1 of the reference ground system 500 and the second grounding point 121 is electrically connected to the SAR weak region N2 of the reference ground system 500, step S110: configuring the center frequency of the target frequency band Fa to be greater than the maximum value of the first sub-frequency band F01 includes:

[0169] Please see Figure 29 Step S111: Configure the center frequency of the target frequency band Fa to fall within the third sub-frequency band F03. That is, configure the resonant frequency F1 of the first resonant mode to be greater than the center frequency of the preset frequency band F0, so that the first resonant frequency F1 is located on the high-frequency side of the preset frequency band F0. In other words, the first resonant frequency F1 is located in the third sub-frequency band F03. Furthermore, the resonant frequency F1 of the first resonant mode is the center frequency of the third sub-frequency band F03, making the SAR intensity distribution more uniform and further reducing the maximum SAR value.

[0170] Please see Figure 9 When the second grounding point 121 is electrically connected to the SAR strong region N1 of the reference ground system 500, and the SAR strong region N1 is used to form a SAR hotspot, and the first grounding point 112 is electrically connected to the SAR weak region N2 of the reference ground system 500, step S110: the center frequency of the target frequency band Fa is greater than the maximum value of the first sub-frequency band F01, includes:

[0171] Please see Figure 30 Step S112: Configure the center frequency of the target frequency band Fa to fall into the second sub-frequency band F02.

[0172] As the resonant frequency F1 of the first resonant mode gradually increases within the preset frequency band F0, the overall SAR value of the antenna assembly 100 first decreases and then increases. Furthermore, when the resonant frequency F1 of the first resonant mode (the center frequency of the target frequency band Fa) is located in the second sub-band F02 of the preset frequency band F0, the overall SAR value distribution of the antenna assembly 100 becomes more uniform, and the maximum SAR value decreases. In other words, the center frequency of the target frequency band Fa (the resonant frequency F1 of the first resonant mode) is configured to fall within the second sub-band F02. During SAR detection, power is backed up based on the maximum SAR value or whether the maximum SAR value exceeds a standard value to determine if an over-detection has occurred. Therefore, in this embodiment, reducing the maximum SAR value can avoid unnecessary power back-up, increase the operating power of the antenna assembly 100, and improve the SAR test pass rate of the electronic device 1000.

[0173] Step S200: After configuring the resonant frequency of the first resonant mode as a frequency point in the target frequency band, the method further includes:

[0174] Please see Figure 31 Step S310: Compare the first SAR value corresponding to the sum of the resonant frequency F1 of the first resonant mode and the second preset fluctuation value, and compare the second SAR value corresponding to the difference between the resonant frequency F1 of the first resonant mode and the second preset fluctuation value.

[0175] Step S320: When the first SAR value is greater than the second SAR value, adjust the power of the antenna assembly 100 so that the first SAR value is less than or equal to the second preset SAR value; when the second SAR value is greater than the first SAR value, adjust the power of the antenna assembly 100 so that the second SAR value is less than or equal to the second preset SAR value.

[0176] Antenna assembly 100 experiences frequency offset in both free-field and near-human scenarios. Since power back-off is required when SAR exceeds limits, the impact of frequency offset needs to be considered. This application proposes that the power back-off value can be calculated by comparing the first SAR value corresponding to the sum of the resonant frequency F1 of the first resonant mode and a second preset fluctuation value, and the second SAR value corresponding to the difference between the resonant frequency F1 of the first resonant mode and the second preset fluctuation value. The maximum value between the first and second SAR values ​​is taken as the back-off SAR value, and maximum power back-off is performed, thus ensuring no SAR exceedance risk throughout the entire fluctuation frequency band.

[0177] Antenna assembly 100 further includes a matching circuit M. The matching circuit M is electrically connected between the signal source 20 and the feed point A. The method includes:

[0178] Adjust the impedance value of the matching circuit M to adjust the resonant frequency F1 of the first resonant mode.

[0179] The antenna assembly 100 further includes a tuning circuit T, one end of which is electrically connected to the second ground point 121 and / or the feed point A, and the other end of which is grounded. After step S200, the method further includes:

[0180] Please see Figure 32 Step S400: When the SAR transmission frequency of the electronic device 1000 is different from the resonant frequency F1 of the first resonant mode, the impedance value of the tuning circuit T is tuned so that the resonant frequency F1 of the first resonant mode is adjusted to the SAR transmission frequency, thereby reducing the SAR value of the antenna assembly 100 at the SAR transmission frequency.

[0181] When the other end of the switching unit K is electrically connected to the second grounding point 121 and the tuning circuit T is electrically connected to the second grounding point 121, the tuning circuit T tunes the electrical length of the second radiator 12, thereby changing the current intensity on the second radiator 12, and thus making the SAR intensity distribution on the first radiator 11 and the second radiator 12 more uniform when the SAR measurement frequency is reached. For example, when the SAR transmission frequency of the electronic device 1000 is greater than the resonant frequency F1 of the first resonant mode, before the tuning circuit T is tuned, the SAR value at the SAR transmission frequency is originally less than the SAR value at the first resonant frequency F1. This is because the current distribution on the antenna assembly 100 and the reference ground system 500 at the SAR transmission frequency is more locally concentrated on the first radiator 11 compared to the current distribution on the antenna assembly 100 and the reference ground system 500 at the first resonant frequency F1. At this time, by switching the switching unit K of the tuning circuit T, the electrical length of the tuning circuit T can be increased, so that more current is distributed on the second radiator 12 at the SAR transmission frequency, reducing the current intensity difference near the first radiator 11, the second radiator 12, and the second grounding point 121, thereby making the SAR intensity distribution more uniform.

[0182] When the other end of the switching unit K is electrically connected to the second grounding point 121 and the tuning circuit T is electrically connected to the feed point A, the tuning circuit T tunes the electrical length of the first radiator 11, thereby changing the center frequency of the supported frequency band, so that the center frequency of the supported frequency band is the SAR measurement frequency, and thus achieves a more uniform SAR intensity distribution on the first radiator 11 and the second radiator 12 when the SAR measurement frequency (i.e., the first resonant frequency F1 is located at the SAR measurement frequency).

[0183] Please see Figure 33This application also provides a SAR reduction device 600, which is applied to an electronic device 1000 having an antenna assembly 100. The antenna assembly 100 includes a first radiator 11, a second radiator 12, and a signal source 20. The first radiator 11 includes a first ground point 112, a feed point A, and a first free end 111 arranged sequentially, with the first ground point 112 grounded. The second radiator 12 includes a second free end 122 and a second ground point 121 arranged sequentially. The second free end 122 is coupled to the first free end 111 through a coupling gap (first free end 111), and the second ground point 121 is grounded. The signal source 20 is electrically connected to the feed point A. The signal source 20 is used to excite the first radiator 11 and the second radiator 12 to jointly form a first resonant mode and a second resonant mode. The resonant frequency F1 of the first resonant mode is less than the resonant frequency of the second resonant mode. The current intensity of the first resonant mode on the first radiator 11 is greater than the current intensity on the second radiator 12. The first resonant mode forms a 1 / 4 wavelength mode corresponding to the first target frequency band on the first radiator 11.

[0184] The device 600 includes a determining module 610 and a configuring module 620. The determining module 610 is used to determine a target frequency band Fa in a preset frequency band F0 in which the antenna assembly 100 is configured, wherein the target frequency band Fa falls within the preset frequency band F0 in which the antenna assembly 100 is configured; the SAR value of the antenna assembly 100 when operating in the target frequency band Fa is less than or equal to the SAR value of the antenna assembly 100 when operating in a frequency band other than the target frequency band Fa in the preset frequency band F0.

[0185] The configuration module 620 is used to configure the resonant frequency F1 of the first resonant mode as a frequency point in the target frequency band Fa.

[0186] For specific implementation details, please refer to step S100 above.

[0187] Please see Figure 34 This application also provides an electronic device 1000, including a memory 700 and a processor 800. The memory 700 is used to store computer programs, and the processor 800 is used to call and run any of the SAR hotspot distribution control methods described in the embodiments.

[0188] The memory 700 can be a separate device independent of the processor 800, or it can be integrated into the processor 800.

[0189] It should be understood that the processor 800 in this application embodiment may be an integrated circuit chip with signal processing capabilities. The processor 800 includes the controller 30 described above. In implementation, each step S of the above method embodiment can be completed by the integrated logic circuit of the hardware in the processor 800 or by instructions in the form of software. The processor 800 described above may be a general-purpose processor 800, a digital signal processor 800 (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. It can implement or execute the various methods, steps S, and logic block diagrams disclosed in the embodiments of this application. The general-purpose processor 800 may be a microprocessor 800 or any conventional processor 800, etc. Step S of the method disclosed in the embodiments of this application can be directly manifested as being executed by the hardware decoding processor 800, or being executed by a combination of hardware and software modules in the decoding processor 800. The software module can reside in a random access memory 700, flash memory, read-only memory 700, programmable read-only memory 700, electrically erasable programmable memory 700, registers, or other mature storage media in the art. This storage medium is located in memory 700, and the processor 800 reads information from memory 700 and, in conjunction with its hardware, completes the steps of the above method.

[0190] It is understood that the memory 700 in the embodiments of this application can be a volatile memory 700 or a non-volatile memory 700, or may include both volatile and non-volatile memory 700. The non-volatile memory 700 can be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or flash memory. The volatile memory 700 can be a random access memory (RAM) 700, which serves as an external cache. By way of example, but not limitation, many forms of RAM are available, such as Static Random Access Memory 700 (SRAM), Dynamic Random Access Memory 700 (DRAM), Synchronous Dynamic Random Access Memory 700 (SDRAM), Double Data Rate Synchronous Dynamic Random Access Memory 700 (DDRSDRAM), Enhanced Synchronous Dynamic Random Access Memory 700 (ESDRAM), Synchlink Dynamic Random Access Memory 700 (SLDRAM), and Direct Rambus RAM 700 (DRRAM). It should be noted that the memory 700 of the systems and methods described herein is intended to include, but is not limited to, these and any other suitable types of memory 700.

[0191] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application, and such improvements and refinements are also considered to be within the protection scope of this application.

Claims

1. An electronic device, comprising: The antenna assembly comprises: a first radiator comprising a first grounding point, a feeding point and a first free end arranged in sequence, the first grounding point being grounded; a second radiator comprising a second free end and a second grounding point arranged in sequence, the second free end being coupled to the first free end through a coupling gap, the second grounding point being grounded; and a signal source electrically connected to the feeding point, the signal source being configured to excite the first radiator and the second radiator to form a first resonance mode and a second resonance mode, the first resonance mode having a resonance frequency point smaller than that of the second resonance mode, and the first resonance mode having a current intensity on the first radiator greater than that on the second radiator. The resonance frequency point of the first resonance mode is configured as one of the frequency points in a target frequency band, the target frequency band falling within a preset frequency band configured for the antenna assembly, the SAR value of the antenna assembly when operating in the target frequency band being smaller than or equal to the SAR value of the frequency band when operating in the preset frequency band except for the target frequency band, and the difference between the maximum value of the target frequency band and the minimum value of the target frequency band being 0.1 GHz.

2. The electronic device of claim 1, wherein, The resonance frequency point of the first resonance mode is the center frequency point of the target frequency band.

3. The electronic device of claim 2, wherein, The preset frequency band comprises a first sub-frequency band, a second sub-frequency band and a third sub-frequency band arranged in sequence and gradually increasing, the center frequency of the second sub-frequency band being the center frequency of the preset frequency band, and the center frequency point of the target frequency band being greater than the maximum value of the first sub-frequency band.

4. The electronic device of claim 3, wherein, The electronic device further comprises a reference ground system, the reference ground system forming a first characteristic mode and a second characteristic mode when the antenna assembly operates in the first resonance mode, the first characteristic mode causing the reference ground system to form one SAR strong zone and two SAR weak zones located on opposite sides of the SAR strong zone along a first direction, and the second characteristic mode causing the reference ground system to form one SAR strong zone and two SAR weak zones located on opposite sides of the SAR strong zone along a second direction, the first direction being perpendicular to the second direction.

5. The electronic device of claim 4, wherein, The first grounding point and the second grounding point are both electrically connected to the same SAR weak zone of the reference ground system, and the center frequency of the target frequency band falls within the third sub-frequency band.

6. The electronic device of claim 4, wherein, The first grounding point is electrically connected to the SAR strong zone of the reference ground system, the second grounding point is electrically connected to the SAR weak zone of the reference ground system, and the center frequency of the target frequency band falls within the third sub-frequency band.

7. The electronic device of claim 5 or 6, wherein, In the first resonance mode, the resonant current on the first radiator is grounded through the feed point and the first ground point. The resonant current at the feed point and the resonant current at the first ground point are both used to form SAR hotspots. The intensity of the resonant current on the second radiator in the first resonance mode is greater than the intensity of the resonant current on the second radiator when the center frequency of the antenna assembly is less than or equal to the center frequency of the target frequency band, which is the center frequency of the preset frequency band. The uniformity of the intensity of the SAR hotspot on the antenna assembly in the extension direction of the first radiator and the second radiator is greater than the uniformity of the intensity of the SAR hotspot when the center frequency of the target frequency band falls into the first sub-frequency band or the second sub-frequency band.

8. The electronic device of claim 4, wherein, The second grounding point is electrically connected to the SAR strong region of the reference ground system, the SAR strong region is used to form SAR hotspots, the first grounding point is electrically connected to the SAR weak region of the reference ground system, and the center frequency of the target frequency band falls into the second sub-frequency band.

9. The electronic device of claim 8, wherein, In the first resonant mode, the resonant current on the first radiator is grounded through the feed point and the first ground point. The resonant current at the feed point and the resonant current at the first ground point are both used to form SAR hotspots. The uniformity of the intensity of the SAR hotspots in the antenna assembly and the SAR strong area in the extension direction of the first radiator and the second radiator is greater than the uniformity of the intensity of the SAR hotspots when the center frequency of the target frequency band falls into the first sub-frequency band or the third sub-frequency band.

10. The electronic device of any of claims 1-2, 4-6, 8, 9, wherein, The electronic device further includes a controller electrically connected to the antenna assembly; The controller is used to compare the magnitude of the first SAR value corresponding to the sum of the resonant frequency of the first resonant mode and the second preset fluctuation value, and the magnitude of the second SAR value corresponding to the difference between the resonant frequency of the first resonant mode and the second preset fluctuation value. When the first SAR value is greater than the second SAR value, the controller adjusts the power of the antenna assembly to make the first SAR value less than the second preset SAR value; When the second SAR value is greater than the first SAR value, the controller adjusts the power of the antenna assembly to make the second SAR value less than the second preset SAR value.

11. The electronic device of any of claims 1-2, 4-6, 8, 9, wherein, The antenna assembly further includes a controller and at least one tuning circuit. One end of the at least one tuning circuit is electrically connected to the second grounding point and / or the feed point, and the other end of the at least one tuning circuit is grounded. The controller is electrically connected to the at least one tuning circuit. The controller is used to tune the impedance value of the tuning circuit when the SAR transmission frequency of the electronic device is different from the resonant frequency of the first resonant mode, so that the resonant frequency of the first resonant mode is adjusted to the SAR transmission frequency, thereby reducing the SAR value of the antenna assembly at the SAR transmission frequency.

12. The electronic device of any of claims 1-2, 4-6, 8, 9, wherein, The electronic device is used to receive signals in frequency bands including low-channel band, mid-channel band and high-channel band, wherein the mid-channel band is located in the target frequency band.

13. A method of reducing SAR, characterized by, The method is applied to an electronic device with an antenna assembly, the antenna assembly including a first radiator, a second radiator, and a signal source. The first radiator includes a first grounding point, a feed point, and a first free end arranged sequentially, the first grounding point being grounded. The second radiator includes a second free end and a second grounding point arranged sequentially, the second free end being coupled to the first free end through a coupling gap, the second grounding point being grounded. The signal source is electrically connected to the feed point, the signal source being used to excite the first radiator and the second radiator to jointly form a first resonant mode and a second resonant mode, the resonant frequency of the first resonant mode being lower than the resonant frequency of the second resonant mode, and the current intensity of the first resonant mode on the first radiator being greater than the current intensity on the second radiator. The method includes: A target frequency band is determined within a preset frequency band in which the antenna assembly is configured, wherein the target frequency band falls within the preset frequency band in which the antenna assembly is configured; the SAR value of the antenna assembly when operating in the target frequency band is less than or equal to the SAR value of the frequency band in the preset frequency band other than the target frequency band; and the difference between the maximum value and the minimum value of the target frequency band is configured to be 0.1 GHz. Configure the resonant frequency of the first resonant mode as a frequency point in the target frequency band.

14. The method of claim 13, wherein, The preset frequency band includes a first sub-frequency band, a second sub-frequency band, and a third sub-frequency band that are sequentially continuous and gradually increase in size, wherein the center frequency point of the second sub-frequency band is the center frequency point of the preset frequency band; the step of determining a target frequency band within the preset frequency band in which the antenna assembly is configured, wherein the target frequency band falls within the preset frequency band in which the antenna assembly is configured; the SAR value of the antenna assembly operating in the target frequency band is less than or equal to the SAR value of the antenna assembly operating in a frequency band other than the target frequency band within the preset frequency band, including: The difference between the maximum value and the minimum value of the target frequency band is configured to be 0.1 GHz, and the center frequency of the target frequency band is greater than the maximum value of the first sub-frequency band; The resonant frequency point configured for the first resonant mode is a frequency point within the target frequency band, including: Configure the resonant frequency of the first resonant mode as the center frequency of the target frequency band.

15. The method of claim 14, wherein, The electronic device further includes a reference ground system. When the antenna assembly operates in the first resonant mode, the resonant current flows to the reference ground system. A first characteristic mode and a second characteristic mode are formed on the reference ground system. The first characteristic mode causes the reference ground system to form a strong SAR region and two weak SAR regions located on opposite sides of the strong SAR region along a first direction. The second characteristic mode causes the reference ground system to form a strong SAR region and two weak SAR regions located on opposite sides of the strong SAR region along a second direction. The first direction is perpendicular to the second direction. When both the first grounding point and the second grounding point are electrically connected to the same SAR weak region of the reference ground system, or when the first grounding point is electrically connected to the SAR strong region of the reference ground system and the second grounding point is electrically connected to the SAR weak region of the reference ground system, configuring the center frequency of the target frequency band to be greater than the maximum value of the first sub-frequency band includes: Configure the center frequency of the target frequency band to fall within the third sub-frequency band; When the second grounding point is electrically connected to the SAR strong region of the reference ground system, the SAR strong region is used to form a SAR hotspot, and the first grounding point is electrically connected to the SAR weak region of the reference ground system, configuring the center frequency of the target frequency band to be greater than the maximum value of the first sub-frequency band includes: Configure the center frequency of the target frequency band to fall into the second sub-frequency band.

16. The method of claim 13, wherein, After configuring the resonant frequency of the first resonant mode to be a frequency point in the target frequency band, the method further includes: The magnitudes of the first SAR value (the sum of the resonant frequency of the first resonant mode and the second preset fluctuation value) and the second SAR value (the difference between the resonant frequency of the first resonant mode and the second preset fluctuation value) are compared. When the first SAR value is greater than the second SAR value, the power of the antenna assembly is adjusted so that the first SAR value is less than or equal to the second preset SAR value. When the second SAR value is greater than the first SAR value, the power of the antenna assembly is adjusted so that the second SAR value is less than or equal to the second preset SAR value.

17. The method of claim 13, wherein, The antenna assembly further includes a tuning circuit, one end of which is electrically connected to the second ground point and / or the feed point, and the other end of which is grounded. The method further includes: When the SAR transmission frequency of the electronic device is different from the resonant frequency of the first resonant mode, the impedance value of the tuning circuit is tuned so that the resonant frequency of the first resonant mode is adjusted to the SAR transmission frequency, thereby reducing the SAR value of the antenna assembly at the SAR transmission frequency.

18. The method of claim 13, wherein, The method further includes: The electronic device is configured to use the middle channel frequency band of the received signal frequency band in the target frequency band.

19. An apparatus for reducing SAR, comprising: The device is applied to an electronic device with an antenna assembly. The antenna assembly includes a first radiator, a second radiator, and a signal source. The first radiator includes a first grounding point, a feed point, and a first free end arranged sequentially, with the first grounding point being grounded. The second radiator includes a second free end and a second grounding point arranged sequentially, with the second free end coupled to the first free end through a coupling gap, and the second grounding point being grounded. The signal source is electrically connected to the feed point. The signal source is used to excite the first radiator and the second radiator to jointly form a first resonant mode and a second resonant mode. The resonant frequency of the first resonant mode is lower than the resonant frequency of the second resonant mode, and the current intensity of the first resonant mode on the first radiator is greater than the current intensity on the second radiator. The device includes: A determining module is configured to determine a target frequency band within a preset frequency band in which the antenna assembly is configured, wherein the target frequency band falls within the preset frequency band in which the antenna assembly is configured; the SAR value of the antenna assembly operating in the target frequency band is less than or equal to the SAR value of the antenna assembly operating in a frequency band other than the target frequency band within the preset frequency band; and the difference between the maximum value and the minimum value of the target frequency band is 0.1 GHz. The configuration module is used to configure the resonant frequency of the first resonant mode as a frequency point in the target frequency band.

20. An electronic device, comprising: The device includes a memory and a processor, wherein the memory is used to store a computer program, and the processor is used to call and run the computer program stored in the memory to perform the method as described in any one of claims 13 to 18.

Images