Method and device for reducing SAR (Synthetic Aperture Radar) and electronic equipment

Abstract

The invention discloses a method, device and electronic equipment, a first radiator comprises a first grounding point, a feeding point and a first free end which are arranged in sequence, a second radiator comprises a second free end and a second grounding point which are arranged in sequence, the second free end and the first free end are coupled through a coupling gap, and a signal source is electrically connected with the feeding point. The signal source is used for exciting to form a first resonant mode and a second resonant mode, the resonant frequency point of the first resonant mode is smaller than that of the second resonant mode, the current intensity of the first resonant mode on the first radiator is larger than that of the second radiator, and the resonant frequency point of the first resonant mode belongs to a target frequency band; the target frequency band falls into the configured preset frequency band of the antenna assembly, and the SAR value of the antenna assembly working in the target frequency band is smaller than or equal to the SAR value of the frequency band, except the target frequency band, in the preset frequency band. According to the invention, the SAR value can be reduced.

Description

Technical Field

[0001] The present application relates to the field of communication technology, and in particular to a method, device and electronic device for reducing SAR. Background Art

[0002] As the communication requirements on electronic devices such as mobile phones increase, the number of antennas required on electronic devices also increases. How to reduce the overall distribution of the specific absorption rate (SAR) of the antenna components on electronic devices, improve the SAR test pass rate or reduce unnecessary power back-off has become a technical problem that needs to be solved. Summary of the invention

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

[0004] In a first aspect, the present application provides an electronic device, including an antenna assembly, wherein the antenna assembly includes:

[0005] The first radiator comprises a first grounding point, a feeding point and a first free end which are arranged in sequence, wherein the first grounding point is grounded;

[0006] A second radiator includes a second free end and a second grounding point which are arranged in sequence, the second free end is coupled to the first free end via a coupling gap, and the second grounding point is grounded; and

[0007] A signal source, the signal source is electrically connected to the feeding 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 less 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 in a target frequency band, the target frequency falls within a preset frequency band configured for the antenna assembly, and 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 when the antenna assembly operates in the preset frequency band except the target frequency band.

[0008] In a second aspect, the present application provides a method for reducing SAR, the method being applied to an electronic device having an antenna assembly, the antenna assembly comprising a first radiator, a second radiator and a signal source, the first radiator comprising a first grounding point, a feeding point and a first free end arranged in sequence, the first grounding point being grounded; the 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, and the second grounding point being grounded; the signal source being electrically connected to the feeding 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 less 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 comprising:

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

[0010] The resonant frequency point of the first resonant mode is configured to be a frequency point in the target frequency band.

[0011] In a third aspect, the present 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 comprising a first radiator, a second radiator and a signal source, the first radiator comprising a first grounding point, a feeding point and a first free end arranged in sequence, the first grounding point being grounded; the 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, and the second grounding point being grounded; the signal source is electrically connected to the feeding 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 less 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 comprises:

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

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

[0014] In a fourth aspect, the present application provides an electronic device, comprising 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 execute the method for reducing SAR.

[0015] The method, device and electronic device for reducing SAR provided by the present application include a first radiator, a second radiator and a signal source through an antenna assembly. The first radiator includes a first grounding point, a feeding point and a first free end arranged in sequence, the first grounding point is grounded, the second radiator includes a second free end and a second grounding point arranged in sequence, the second free end is coupled to the first free end through a coupling gap, the second grounding point is grounded, the signal source is electrically connected to the feeding 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 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 to be a frequency in a target frequency band, the target frequency falls within the preset frequency band configured by the antenna assembly, 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 when the antenna assembly operates in the preset frequency band except the target frequency band, so as to reduce the SAR value of the antenna assembly when operating in the first resonant mode. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments are briefly introduced below.

[0017] Figure 1 It is a structural schematic diagram of an electronic device provided in an embodiment of the present application;

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

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

[0020] Figure 4 is a current distribution diagram of a first resonant mode of an antenna assembly provided in an embodiment of the present application;

[0021] Figure 5 is a current distribution diagram of the second resonant mode of the antenna assembly provided in an embodiment of the present application;

[0022] Figure 6 This is a schematic diagram of a first position distribution of the central frequency point of the first resonant mode of the antenna assembly provided in an embodiment of the present application;

[0023] Figure 7 This is a schematic diagram of a second position distribution of the center frequency point of the first resonant mode of the antenna assembly provided in an embodiment of the present application;

[0024] Figure 8 is a SAR intensity distribution diagram on a reference ground system provided in an embodiment of the present application;

[0025] Fig. 9 This is a first position layout diagram of an antenna assembly provided in an embodiment of the present application arranged on a reference ground system;

[0026] Fig.10 is a current distribution diagram of the antenna assembly provided in an embodiment of the present application at a first resonant frequency point in a first sub-band of a preset frequency band;

[0027] Fig.11 It is a SAR distribution of the antenna assembly provided in an embodiment of the present application at a first resonant frequency point in a first sub-band of a preset frequency band and a SAR distribution diagram on a reference ground system;

[0028] Fig.12 The overall SAR distribution diagram is formed by the SAR distribution of the antenna assembly provided in the embodiment of the present application 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;

[0029] Fig.13 is a current distribution diagram of the antenna assembly provided in an embodiment of the present application when the first resonant frequency point is located in the second sub-frequency band of the preset frequency band;

[0030] Fig.14 It is a SAR distribution of the antenna assembly provided in an embodiment of the present application at a first resonant frequency point in a second sub-band of a preset frequency band and a SAR distribution diagram on a reference ground system;

[0031] Fig.15 The overall SAR distribution diagram is formed by the SAR distribution of the antenna assembly provided in the embodiment of the present application 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;

[0032] Fig.16 is a current distribution diagram of the antenna assembly provided in an embodiment of the present application, in which the first resonant frequency point is located in the third sub-frequency band of the preset frequency band;

[0033] Fig.17 It is a SAR distribution of the antenna assembly provided in an embodiment of the present application at a first resonant frequency point in a third sub-band of a preset frequency band and a SAR distribution diagram on a reference ground system;

[0034] Fig.18 It is an overall SAR distribution diagram formed by the SAR distribution of the antenna assembly provided in an embodiment of the present application 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;

[0035] Fig.19 It is a SAR hot spot simulation diagram when the antenna assembly provided in an embodiment of the present application supports the B3 frequency band and the first resonant frequency is 1.75 GHz, 1.85 GHz, and 1.95 GHz;

[0036] Fig. 20 is an S parameter curve of the antenna assembly provided in an embodiment of the present application in a free scene and when close to a human body;

[0037] Fig.21 It is a SAR hot spot simulation diagram when the antenna assembly provided in an embodiment of the present application supports the B1 frequency band and the first resonant frequency is 1.85 GHz, 1.95 GHz, and 2.05 GHz;

[0038] Fig. 22 The second position layout of the antenna assembly provided in the embodiment of the present application on the reference ground system and the current distribution and SAR heat map of the first resonant frequency point in the first sub-band of the preset frequency band;

[0039] Fig.23 The second position layout of the antenna assembly provided in the embodiment of the present application on the reference ground system and the current distribution and SAR heat map of the second sub-band of the preset frequency band with the first resonant frequency point;

[0040] Fig.24 The second position layout of the antenna assembly provided in the embodiment of the present application on the reference ground system and the current distribution and SAR heat map of the first resonant frequency point in the third sub-band of the preset frequency band;

[0041] Fig.25 This is a third position layout diagram of an antenna assembly provided in an embodiment of the present application disposed on a reference ground system;

[0042] Fig.26 It is a schematic diagram of the structure of the electrical connection between the controller and the tuning circuit and matching circuit of the antenna assembly provided in an embodiment of the present application;

[0043] Fig. 27 is a schematic diagram of a method for reducing SAR provided in an embodiment of the present application;

[0044] Fig.28 yes Fig. 27 Schematic diagram of the detailed steps in the provided method;

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

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

[0047] Fig.31 is a schematic diagram of an embodiment after step S200 provided in an embodiment of the present application;

[0048] Fig.32 is a schematic diagram of another embodiment after step S200 provided in an embodiment of the present application;

[0049] Fig.33 is a schematic diagram of a device for reducing SAR provided in an embodiment of the present application;

[0050] Fig.34 It is a schematic diagram of an electronic device provided in an embodiment of the present application including a processor and a memory.

[0051] Description of Figure 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; feeding 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-band F01; second sub-band F02; third sub-band F03; SAR strong area N1; SAR weak area N2; tuning circuit T; switch unit K; tuning branch T1; determination module 610; configuration module 620; memory 700; processor 800. DETAILED DESCRIPTION

[0053] The technical solution of the present application will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the embodiments described in the present application are only a part of the embodiments, not all of the embodiments. Based on the embodiments provided in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0054] Reference to "embodiments" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it mutually exclusive, independent, or alternative to other embodiments. It can 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 and claims of this application and the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example: a component or device including one or more parts is not limited to the one or more parts listed, but optionally includes one or more parts that are not listed but inherent to the exemplified product, or one or more parts that it should have based on the described function.

[0056] See also Figure 1 , Figure 1 The following is a schematic diagram of the structure of an electronic device 1000 provided in an embodiment of the present application. The electronic device 1000 includes but is not limited to a mobile phone, a wearable device, a virtual reality (VR) controller, a VR goggles, a VR helmet, and other devices with communication functions. The present embodiment of the present application is described by taking a mobile phone as an example, and other electronic devices can refer to this embodiment.

[0057] See also Figure 2 , the electronic device 1000 includes an antenna assembly 100.

[0058] See also Figure 2, taking the electronic device 1000 as a mobile phone as an example, the working environment of the antenna assembly 100 is illustrated. The electronic device 1000 includes a display screen 200, a middle frame 300 and a back cover 400 arranged in sequence along the thickness direction. Among them, the middle frame 300 includes a middle plate 310 and a frame 320 surrounding the side of the middle plate 310. Of course, in other embodiments, the electronic device 1000 may not have a middle plate 310. The display screen 200, the middle plate 310 and the back cover 400 are stacked in sequence, and a receiving space is formed between the display screen 200 and the middle plate 310, and between the middle plate 310 and the back cover 400 to accommodate components such as a main board, a camera module, a receiver module, a battery, and various sensors. One side of the frame 320 is surrounded by the edge of the display screen 200, and the other side of the frame 320 is surrounded by the edge of the back cover 400 to form a complete appearance structure of the electronic device 1000. In this embodiment, the frame 320 and the middle plate 310 are an integral structure, and the frame 320 and the back cover 400 may be separate structures. The above is the working environment of the antenna assembly 100 taking a mobile phone as an example, but the antenna assembly 100 of the present application is not limited to the above working environment.

[0059] See also Figure 3 , border 320( Figure 3 The frame formed by the dashed line and the solid line includes a top edge 321 and a bottom edge 322 that are arranged opposite to each other, and a first side edge 323 and a second side edge 324 that are connected to the top edge 321 and the bottom edge 322. The top edge 321 is the side away from the ground when the user holds the electronic device 1000, and the bottom edge 322 is the side facing the ground when the user holds the electronic device 1000.

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

[0061] See also Figure 3 , the electronic device 1000 includes a reference ground system 500 and an antenna assembly 100 arranged along the reference ground edge of the reference ground system 500. The reference ground system 500 is made of conductive material and can be arranged in the middle plate 310 of the electronic device 1000. Optionally, the reference ground system 500 includes a metal alloy in the middle plate, a reference ground metal in the circuit board, etc. Taking the electronic device as a mobile phone as an example, the reference ground system 500 can be equivalent to a rectangular plate arranged in the frame.

[0062] See also Figure 3 , the antenna assembly 100 includes a radiator and a signal source 20.

[0063] See also Figure 3The radiator further includes a first radiator 11 and a second radiator 12. The first radiator 11 includes a first grounding point 112, a feeding point A and a first free end 111 arranged in sequence. The feeding 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 in sequence. The first grounding point 112 and the second grounding point 121 are both electrically connected to the reference ground system 500. The first free end 111 and the second free end 122 are coupled via a coupling gap.

[0064] The signal source 20 is disposed on a main board of the electronic device 1000. The signal source 20 is electrically connected to the feeding 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 the resonant frequency 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 radiation energy of the first resonant mode.

[0066] See also Figure 4 , the direction of the resonant current of the first resonant mode on the first radiator 11 is the same as the direction of the resonant current of the first resonant mode on the second radiator 12.

[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 a 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 a major contribution to the radiation energy of the second resonant mode.

[0072] See also Figure 5, the direction of the resonant current in the second resonant mode on the first radiator 11 is opposite to the direction of the resonant current in the second resonant mode on the second radiator 12.

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

[0075] Optional, see 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 feeding point A. The matching circuit M includes at least one of a capacitor and an inductor. Specifically, the matching circuit M includes but is not limited to a capacitor, or an inductor, or a series device of a capacitor and an inductor, or a parallel device of a capacitor and an inductor, or the above-mentioned series device in parallel with a capacitor, or the above-mentioned series device in parallel with an inductor, or two of the above-mentioned series devices in parallel, or two of the above-mentioned parallel devices 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, so that the first radiator 11 with an electrical length close to 1 / 4 wavelength of the first target frequency band forms a 1 / 4 wavelength mode corresponding to the first target frequency band under the excitation of the signal source 20, so as to tune the resonant frequency of the first resonant mode.

[0076] Optionally, the preset frequency band F0 that the antenna assembly 100 needs to support covers the frequency bands that need to reduce the SAR value, including but not limited to B3 band, B1 band, B41 band, N78 band, GPS band, Wi-Fi 2.4G band, etc.

[0077] The first radiator 11 in the present application is a main branch, and the second radiator 12 is a parasitic branch. The first radiator 11 and the second radiator 12 form a double-wave resonance, wherein 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 the influence of the resonance point size on the SAR value of the antenna component 100 is subsequently analyzed, the influence of the resonance point of the first resonance mode (hereinafter referred to as the first resonance frequency point F1) on the SAR value of the antenna component 100 is mainly analyzed. In the first resonance mode, the current is mainly on 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 point F1) on the SAR value of the antenna component 100 can be analyzed.

[0078] See also Figure 6 and Figure 7 , the resonant frequency point 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 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 by the antenna assembly 100. The SAR value of the antenna assembly when operating in the target frequency band Fa is less than or equal to the SAR value of the frequency band when the antenna assembly 100 operates in the preset frequency band F0 except the target frequency band Fa.

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

[0080] See also Figure 7 , Figure 7 It is a schematic diagram of the waveform of the S parameter curve formed when the center frequency of the preset frequency band F0 does not coincide with the resonant frequency point F1 of the first resonant mode. Figure 7 The frequency band in which the return loss is -10dB in the S curve corresponding to the dotted wave is the preset frequency band F0, and the frequency band in which the return loss is -10dB in the S curve corresponding to the first solid wave after the dotted 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 frequency band, or the B1 frequency band or other frequency bands. The second solid wave after the dotted wave is the S parameter curve waveform of the second resonance mode.

[0081] See also Figure 6 , Figure 6Schematic diagram of the S parameter curve waveform formed when the center frequency of the preset frequency band F0 coincides with the resonant frequency point F1 of the first resonant mode. Among them, the first waveform diagram is the S curve waveform of the first resonant mode. Among them, the preset frequency band F0 coincides with the effective frequency band Fb. The second solid line wave after the dotted line wave is the S parameter curve waveform of the second resonant mode.

[0082] This application takes the preset frequency band F0 required to be supported by the antenna assembly 100 covering the B3 frequency band as an example, and the preset frequency band F0 is 1.7-1.95GHz. At this time, the effective frequency band Fb of the first resonance mode also covers the B3 frequency band. Among them, the preset frequency band F0 and the effective frequency band Fb of the first resonance mode both cover the frequency band configured by 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 resonance mode is that the resonant frequency point F1 of the first resonance mode is located in the frequency band range with lower SAR hotspots in the preset frequency band F0. This application defines the frequency band range with lower SAR hotspots in the preset frequency band F0 as the target frequency band Fa. If the frequency band range with lower SAR hotspots in the preset frequency band F0 is located on the low frequency side of the preset frequency band F0, then the resonant frequency point F1 of the first resonance mode is located on the low frequency side of the preset frequency band F0. If the frequency band range with lower SAR hotspots in the preset frequency band F0 is located on the center frequency side of the preset frequency band F0, then the resonant frequency point F1 of the first resonance mode is located on the center frequency side of the preset frequency band F0. If the frequency range with a lower SAR hotspot in the preset frequency band F0 is located on the high frequency side of the preset frequency band F0, then the resonant frequency point 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 resonance mode.

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

[0085] In the embodiment of the present application, the target frequency band Fa is determined according to the SAR hotspot value in the preset frequency band F0, and the resonant frequency F1 of the first resonant mode is determined in the target frequency band Fa. When the resonant frequency of the first resonant mode is F1, the frequency band corresponding to the return loss of -10dB in the S curve corresponding to the resonant frequency of the first resonant mode is the effective frequency band Fb.

[0086] The electronic device 1000 provided in the present application includes a first radiator 11, a second radiator 12 and a signal source 20 through an antenna assembly 100. The first radiator 11 includes a first grounding point 112, a feeding point A and a first free end 111 arranged in sequence, the first grounding point 112 is grounded, the second radiator 12 includes a second free end 122 and a second grounding point 121 arranged in sequence, the second free end 122 is coupled with the first free end 111 through a coupling gap, the second grounding point 121 is grounded, the signal source 20 is electrically connected to the feeding 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, and 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 part of the effective frequency band Fb of the first resonance mode, and the target frequency band Fa falls within the preset frequency band F0 configured by the antenna assembly 100. The SAR value of the antenna assembly when operating in the target frequency band Fa is less than or equal to the SAR value of the frequency band when the antenna assembly 100 operates in the preset frequency band F0 except the target frequency band Fa, so that the SAR value of the antenna assembly 100 when operating in the target frequency band Fa is smaller, thereby reducing the SAR value of the antenna assembly 100 operating in the first resonance mode, thereby improving the SAR test pass rate or reducing unnecessary power back-off.

[0087] Of course, the frequency band configured by the antenna assembly 100 can be switched. For example, an antenna switch is provided in the matching circuit M to switch the frequency band configured by the antenna assembly 100 to the B1 frequency band. When the antenna assembly 100 is configured to support the B1 frequency band, the B1 frequency band can also reduce SAR in the above manner.

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

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

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

[0092] Optionally, the radiator may be in the form of a metal frame 320, a metal frame embedded in a plastic frame 320, a metal radiator located in or on the frame 320, a flexible printed circuit board antenna formed on a flexible printed circuit board (FPC), a laser direct structured antenna formed by laser direct structure (LDS), a printed direct structured antenna formed by printing direct structure (PDS), a conductive sheet antenna (e.g., a metal bracket antenna), etc. In this embodiment, the radiator is taken as a part of a metal frame for illustration.

[0093] See also Figure 6 , the preset frequency band F0 includes a first sub-band F01, a second sub-band F02 and a third sub-band F03 which are continuous and gradually increase in sequence, and 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 required 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. Among them, 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 the second sub-band F02 or the third sub-band F03. When the resonant frequency of the first resonance mode is the center frequency of the target frequency band Fa, the resonant frequency of the first resonance mode is located in 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, optionally, the preset frequency band F0 is 1.7 GHz-1.95 GHz, the first sub-frequency band F01 can be 1.7 GHz-1.78 GHz, the second sub-frequency band F02 can be 1.78 GHz-1.86 GHz, and the third sub-frequency band F03 can be 1.86 GHz-1.95 GHz.

[0095] The following embodiments of the present application are described by taking the resonant frequency point F1 of the first resonant mode as the center frequency of the target frequency band Fa as an example.

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

[0097] In another alternative embodiment, see Figure 7 The resonant frequency point F1 of the first resonant mode may be located in the third sub-frequency band F03, and further located near the center frequency point of the third sub-frequency 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-frequency band F01, so as to reduce the SAR value of the antenna assembly 100. This implementation 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 resonance mode.

[0099] See also Figure 8 , the first characteristic mode may be a 1 / 2 wavelength mode in the first direction, and the current intensity of the first characteristic mode in the first direction of the reference ground system 500 gradually increases from the edges to the center of both sides, that is, the first characteristic mode forms a strong current area in the middle of the reference ground system 500, and forms two weak current areas at the two edges of the reference ground system 500, and then the first characteristic mode causes the reference ground system 500 to form a SAR strong area N1 and two SAR weak areas N2 located on opposite sides of the SAR strong area N1 along the first direction. Optionally, the first direction may be the length direction of the electronic device 1000.

[0100] The second characteristic mode may be a 1 / 2 wavelength mode in the second direction, and the current intensity of the second characteristic mode in the second direction of the reference ground system 500 gradually increases from the edges to the center of the two sides, that is, the second characteristic mode forms a strong current area in the middle of the reference ground system 500, and forms two weak current areas at the two edges of the reference ground system 500, thereby forming a SAR strong area N1 and two SAR weak areas N2 located on opposite sides of the SAR strong area N1 in the reference ground system 500 along the second direction. The first direction is perpendicular to the second direction. The second direction may be the width direction of the electronic device 1000.

[0101] For ease of description, see Figure 8, the reference ground system 500 is defined to include a first reference edge 510, a second reference edge 520, a third reference edge 530 and a fourth reference edge 540 connected in sequence, 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 characteristic pattern divides the first reference edge 510 into a SAR weak area N2, a SAR strong area N1 and a SAR weak area N2 in sequence. The second characteristic pattern divides the third reference edge 530 into a SAR weak area N2, a SAR strong area N1 and a SAR weak area N2 in sequence. The first characteristic pattern divides the second reference edge 520 into a SAR weak area N2, a SAR strong area N1 and a SAR weak area N2 in sequence. The first characteristic pattern divides the fourth reference edge 540 into a SAR weak area N2, a SAR strong area N1 and a SAR weak area N2 in sequence.

[0102] The first radiator 11 and the second radiator 12 are disposed along any one of the 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 area N1 and the SAR weak area N2 on the reference ground system 500 can be summarized as the following several situations: the first situation is that the first grounding point 112 and the second grounding point 121 of the antenna assembly 100 are both electrically connected to the SAR weak area N2 of the reference ground system 500; the second situation is that the first grounding point 112 of the antenna assembly 100 is electrically connected to the SAR strong area 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 area N2 of the reference ground system 500; the third situation is that the first grounding point 112 of the antenna assembly 100 is electrically connected to the SAR weak area 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 area N1 of the reference ground system 500; the fourth situation is that the first grounding point 112 and the second grounding point 121 of the antenna assembly 100 are both electrically connected to the SAR strong area N1 of the reference ground system 500.

[0103] The following embodiments are described by way of example based on the overall SAR values ​​when the antenna assembly 100 is disposed at different positions on the reference ground system 500. The SAR is measured by using a 5mm body SAR test method, that is, the surface to be tested is located 5mm away from the mobile phone for measurement.

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

[0105] In the following, an example is given in which the first resonance frequency point F1 (the resonance frequency point F1 of the first resonance mode) of the present embodiment is respectively 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] See also Fig.10 When the first resonant frequency point 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 slot (first free end 111), wherein the current from the feeding point A to the coupling slot (first free end 111) is relatively weak, and at this time the current mainly flows to the ground from the first grounding point 112.

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

[0108] See also Fig.12 The SAR hotspot on the reference ground system 500 is superimposed with the SAR hotspot at the first grounding point 112 to form an overall SAR hotspot of the antenna assembly 100, and the overall SAR hotspot is located between the first grounding point 112 and the SAR hotspot on the reference ground system 500.

[0109] See also Fig.13 When the first resonant frequency point F1 is located in the second sub-band F02 (near the central 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 feeding point A to the coupling gap (the first free end 111), wherein the parasitic current on the second radiator 12 is relatively weak, and at this time the current mainly flows to the ground from the feeding point A and the first grounding point 112.

[0110] See also Fig.14 The feeding point A and the first grounding point 112 are two strong current locations, generating two SAR hotspots. Meanwhile, the center position of the reference ground edge of the reference ground system 500 will form a SAR hotspot on the reference ground system 500.

[0111] See also Fig.15 , the SAR hotspot on the reference ground system 500, the SAR hotspot at the feed point A and the first ground point 112 are superimposed to form the overall SAR hotspot of the antenna assembly 100, and the overall SAR hotspot is located between the feed point A and the SAR hotspot on the reference ground system 500. Compared with the overall SAR hotspot when the first resonant frequency point F1 is located in the first sub-band F01 (low-frequency side) of the preset frequency band F0, since a part of the SAR hotspots on the first radiator 11 are contributed by the ground current of the feed point A, the overall SAR hotspot in this embodiment is shifted to the left, and the overall SAR hotspot is a combination of three SAR hotspots at this time. Compared with the overall SAR hotspot when the first resonant frequency point 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 SAR maximum value will be reduced. Because when performing SAR detection, the power is backed off according to the maximum value of the SAR value or whether the maximum value of the SAR value exceeds the standard value to determine whether it has been inspected, the reduction of the maximum value of SAR in this embodiment can avoid unnecessary power backoff, improve the working power of the antenna assembly 100 and improve the pass rate of the SAR test of the electronic device 1000.

[0112] See also Fig.16 When the first resonant frequency point 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 feeding point A to the coupling gap (the first free end 111), wherein 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 proportion on the second radiator 12 increases, and is therefore represented by two dotted lines. At this time, the current mainly flows down from the feeding point A and the first grounding point 112.

[0113] See also Fig.17 , the feeding point A and the first grounding point 112 are two strong current positions, generating two SAR hot spots. Since the current intensity on the second radiator 12 is increased compared to when the first resonant frequency point F1 is located in the first sub-band F01 and the second sub-band F02 of the preset frequency band F0, and the SAR strong area N1 of the reference ground system 500 is closer to the ground position at the second grounding point 121, the present embodiment will form a stronger SAR hot spot of the reference ground system 500 than when the first resonant frequency point F1 is located in the first sub-band F01 and the second sub-band F02 of the preset frequency band F0.

[0114] See also Fig.18The SAR hotspot on the reference ground system 500, the SAR hotspot at the feed point A and the first grounding point 112 are superimposed to form an overall SAR hotspot of the antenna assembly 100, and the 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 of the reference ground system 500 formed in this embodiment is stronger, so the overall SAR hotspot continues to move left, but at this time the SAR of the reference ground system 500 is stronger, and the SAR distribution is uneven compared to when the first resonant frequency point F1 is located in the second sub-band F02 of the preset frequency band F0. Therefore, the maximum SAR value of the antenna assembly 100 will also increase compared to when the first resonant frequency point F1 is 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 in the preset frequency band F0, the overall SAR value of the antenna assembly 100 first decreases and then increases, and 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 is more uniform, and the SAR maximum value is reduced. 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 may be the frequency with the smallest SAR value in the second sub-band. When performing SAR detection, the power is backed off according to the maximum value of the SAR value or it is determined whether the inspection is passed according to whether the maximum value of the SAR value exceeds the standard value. Therefore, the reduction of the maximum value of SAR in this embodiment can avoid unnecessary power backoff, improve the working power of the antenna assembly 100, and improve the pass rate of the SAR test of the electronic device 1000.

[0116] When the resonant frequency point F1 of the first resonant mode (the center frequency point of the target frequency band Fa) 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 feeding point A and the first grounding point 112. The resonant current at the feeding point A and the resonant current at the first grounding point 112 are both used to form a SAR hotspot, and a SAR hotspot is also formed near the center position of the reference ground system 500. The three SAR hotspots are dispersedly distributed, and the uniformity of the intensity of the SAR hotspot of the antenna assembly 100 and the SAR strong area 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 hotspot when the center frequency of the target frequency band Fa falls into the first sub-band F01 or the third sub-band F03, so as to increase the uniformity of the intensity of the SAR hotspot of the antenna assembly 100 and the SAR strong area N1 in the extension direction of the first radiator 11 and the second radiator 12, and the overall SAR value distribution of the antenna assembly 100 is more uniform, and the SAR maximum value is reduced.

[0117] Further, the resonant frequency F1 of the first resonant mode is the central 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 makes the intensity of the SAR hotspot of the SAR strong area N1 on the reference ground system 500 not too high, and the difference between the intensity of the SAR hotspot of the SAR strong area N1 on the reference ground system 500 and the intensity of the SAR hotspot formed by the first grounding point 112 and the feeding point A is not too large, and is relatively uniform, thereby achieving a reduction in the maximum value of the overall SAR of the antenna assembly 100.

[0118] Taking the preset frequency band F0 that the antenna assembly 100 needs to support covering the B3 frequency band as an example, the SAR value of the antenna assembly 100 is verified by normalizing the SAR value as the first resonant frequency point F1 gradually increases when supporting the B3 frequency band.

[0119] Please refer to Table 1, which shows the normalized SAR simulation results of the antenna assembly 100 when the first resonant frequency F1 is 1.7 GHz, 1.75 GHz, 1.8 GHz, 1.85 GHz, 1.9 GHz, and 1.95 GHz. Optionally, the preset frequency band F0 may be 1.7 GHz-1.95 GHz. Take the case where the antenna assembly 100 is located at the bottom edge 322, the second grounding point 121 is located near the reference ground system 500, and the first grounding point 112 is located in the SAR weak area N2. By adjusting the matching circuit M, the frequency value is gradually increased to 1.7 GHz, 1.75 GHz, 1.8 GHz, 1.85 GHz, 1.9 GHz, and 1.95 GHz, respectively. At each frequency, the SAR value (including the SAR hotspot on the reference ground system 500) is detected at a distance of 5 mm from the bottom edge 322 to obtain the SAR value when the power is normalized to 21 dBm. From the SAR value results, it can be seen that as the frequency increases, the overall SAR value of the antenna assembly 100 first decreases and then increases, and when the frequencies are 1.75 GHz, 1.8 GHz, and 1.85 GHz, the overall SAR value of the antenna assembly 100 is small. 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 meet the requirements that the center frequency of 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 point F1 is located in the second sub-band F02 of the preset frequency band F0. The above makes the overall SAR value of the antenna assembly 100 lower.

[0120] Table 1

[0121]

[0122] See also Fig.19 , Fig.19 SAR hot spot simulation diagram when the antenna assembly 100 supports the B3 frequency band and the first resonant frequency F1 is 1.75 GHz, 1.85 GHz, and 1.95 GHz. Fig.19 It can be seen that the maximum SAR value is 2.08W / kg when the first resonant frequency F1 is 1.75GHz, the maximum SAR value is 2.04W / kg when the first resonant frequency F1 is 1.85GHz, and the maximum SAR value is 2.28W / kg when the first resonant frequency F1 is 1.95GHz. And the SAR hotspot position gradually shifts to the left with the increase of the first resonant frequency F1.

[0123] Taking the preset frequency band F0 that the antenna assembly 100 needs to support covering the B1 frequency band as an example, the SAR value of the antenna assembly 100 is verified by normalizing the SAR value as the first resonant frequency point F1 gradually increases when supporting the B1 frequency band.

[0124] Please refer to Table 2, which shows the normalized SAR simulation results of the antenna assembly 100 when the first resonant frequency F1 is 1.85 GHz, 1.9 GHz, 1.95 GHz, 2.0 GHz, 2.05 GHz, and 2.1 GHz. Optionally, the preset frequency band F0 may be 1.85 GHz-2.1 GHz. Take the case where the antenna assembly 100 is located at the bottom edge 322, the second grounding point 121 is located near the reference ground system 500, and the first grounding point 112 is located in the SAR weak area N2. By adjusting the matching circuit M, the frequency value is gradually increased to 1.85 GHz, 1.9 GHz, 1.95 GHz, 2.0 GHz, 2.05 GHz, and 2.1 GHz, respectively. At each frequency, the SAR value (including the SAR hotspot on the reference ground system 500) is detected at a distance of 5 mm from the bottom edge 322 to obtain the SAR value when the power is normalized to 21 dBm. From the SAR value results, it can be seen that as the frequency increases, the overall SAR value of the antenna assembly 100 first decreases and then increases, and when the frequencies are 1.9 GHz, 1.95 GHz, and 2.0 GHz, the overall SAR value of the antenna assembly 100 is small. It can be determined that the target frequency band Fa is 1.9-2.0 GHz. The second sub-band F02 of the preset frequency band F0 is 1.93-2.01 GHz. Therefore, the actual verification results also meet the requirement that 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 point F1 is located in the second sub-band F02 of the preset frequency band F0. The above makes the overall SAR value of the antenna assembly 100 lower.

[0125] Table 2

[0126]

[0127] See also Fig. 20 , Fig. 20 It is the S parameter curve of the antenna assembly 100 provided by the present application in a free scene and when the human body is close. Among them, curve a is the S parameter curve of the antenna assembly 100 supporting the B1 frequency band and in a free scene. Curve b is the S parameter curve of the antenna assembly 100 supporting the B1 frequency band and when the human body is close. Curve c is the S parameter curve of the antenna assembly 100 supporting the B3 frequency band and in a free scene. Curve d is the S parameter curve of the antenna assembly 100 supporting the B3 frequency band and when the human body is close.

[0128] It can be seen that the antenna assembly 100 is double-wave resonant in both the B3 and B1 frequency bands. In the B3 and B1 frequency bands, there is a certain frequency deviation when a human body approaches (after adding a body).

[0129] It can be seen from Table 1 that in the B3 frequency 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 1.7 GHz-1.8 GHz, the overall SAR value of the antenna assembly 100 is the smallest, which is consistent with the performance of the B3 frequency band in curve c in a free scene.

[0130] As can be seen from Table 2, in the B1 frequency band, as the first resonant frequency F1 increases, the overall SAR value of the antenna assembly 100 first decreases and then increases, and when the first resonant frequency F1 is 1.9 GHz-2.0 GHz, the overall SAR value of the antenna assembly 100 is the smallest, which is consistent with the performance of the B1 frequency band in the free scene in curve a. In other words, the overall SAR value of the antenna assembly 100 first decreases and then increases as the first resonant frequency F1 increases, which is satisfied in both the free scene and the human body approaching state.

[0131] It can be seen that no matter in the B3 band or the B1 band, the lowest SAR position is the deepest resonance position in the free scene, and no matter whether the frequency continues to deviate to a lower or higher level, the SAR will rise rapidly.

[0132] See also Fig.21 , Fig.21 SAR hot spot simulation diagram when the antenna assembly 100 supports the B1 frequency band and the first resonant frequency F1 is 1.85 GHz, 1.95 GHz, and 2.05 GHz. Fig.21 It can be seen that the maximum SAR value is 1.9W / kg when the first resonant frequency F1 is 1.85GHz, 1.8W / kg when the first resonant frequency F1 is 1.95GHz, and 2.0W / kg when the first resonant frequency F1 is 2.05GHz. And the SAR hotspot position gradually shifts to the left as the first resonant frequency F1 increases.

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

[0134] The signal frequency bands received by the electronic device 1000 include a low channel frequency band, a middle channel frequency band and a high channel frequency band with increasing frequencies. The middle channel frequency band is located in the target frequency band Fa. That is, the first resonant frequency point F1 is located in the middle channel frequency band. By locating the first resonant frequency point F1 near the middle channel frequency band of the transmitting antenna, and then locating the high channel frequency band and the low channel frequency band of the transmitting antenna near the first resonant frequency point F1, the transmitting antenna can have a lower SAR value.

[0135] In the second embodiment, see Fig. 22, the first grounding point 112 and the second grounding point 121 are both electrically connected to the same SAR weak zone N2 of the reference ground system 500. In this embodiment, the antenna assembly 100 may be disposed at the upper half or the lower half of the first side 323 and / or the second side 324. The SAR hotspot of the antenna assembly 100 in this embodiment may not consider the SAR hotspot superposition on the reference ground system 500.

[0136] See also Fig. 22 When the first resonant frequency point 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 slot (first free end 111), wherein the current from the feeding point A to the coupling slot (first free end 111) is relatively weak, and at this time the current mainly flows to the ground from the first grounding point 112. The first grounding point 112 is the only strong current position, generating a SAR hotspot (as shown in the dotted ellipse in the figure). The SAR hotspot corresponds to the position of the first grounding point 112.

[0137] See also Fig.23 , when the first resonant frequency point F1 is located in the second sub-band F02 (near the central 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 feeding point A to the coupling gap (the first free end 111), wherein the parasitic current on the second radiator 12 is relatively weak, and at this time the current mainly flows to the ground from the feeding point A and the first grounding point 112. The feeding point A and the first grounding point 112 are two strong current positions, generating two SAR hot spots (as shown in the dotted ellipse in the figure). The two SAR hot spots correspond to the positions of the feeding point A and the first grounding point 112, respectively.

[0138] Compared with the SAR hotspot corresponding to the first grounding point 112 when the first resonant frequency point F1 is located in the first sub-band F01 (low-frequency side) of the preset frequency band F0. Since a part of the SAR hotspots on the first radiator 11 comes from the contribution of the ground current of the feeding point A, the overall SAR hotspot in this embodiment shifts to the left, and at this time the overall SAR hotspot is a combination of two SAR hotspots, compared with the SAR hotspot when the first resonant frequency point 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 SAR maximum value will be reduced. From another perspective, in the embodiment of the present application, the current intensity distribution on the first radiator 11 is more uniform than the current intensity distribution on the first radiator 11 when the first resonant frequency point F1 is located in the first sub-band F01, and thus the SAR intensity distribution is more uniform, and the SAR maximum value will be reduced.

[0139] See also Fig.24, when the first resonant frequency point 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 feeding point A to the coupling gap (the first free end 111), wherein 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 accounts for an increased proportion, and is therefore represented by two dotted lines. At this time, the current mainly flows from the feeding point A and the first grounding point 112 to the ground, and the feeding point A and the first grounding point 112 are two strong current positions, generating two SAR hotspots (as shown in the dotted ellipse in the figure). Compared with the SAR hotspot corresponding to the first grounding point 112 when the first resonant frequency point F1 is located in the second sub-band F02. Since a part of the SAR hot spots on the first radiator 11 come from the contribution of the underground current at the feeding 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 point F1 is located in the second sub-band F02, so that the SAR intensity distribution is more uniform, and the SAR maximum 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, and further, the resonant frequency F1 of the first resonant mode is the center frequency of the third sub-frequency band F03, so that the SAR intensity distribution is more uniform, and the SAR maximum value is further reduced.

[0141] When the first resonant frequency point F1 is located in the third sub-frequency band F03, in the first resonant mode, the resonant current on the first radiator 11 is grounded through the feeding point A and the first grounding point 112, and the resonant current at the feeding point A and the resonant current at the first grounding point 112 are both used to form a SAR hotspot, 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 target frequency band Fa, which is the center frequency of the preset frequency band F0, that is, the current intensity difference 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 hotspot of the antenna assembly 100 and the SAR strong area 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 hotspot when the center frequency of the target frequency band Fa falls into the first sub-band F01 or the second sub-band F02, so as to increase the uniformity of the intensity of the SAR hotspot on the antenna assembly 100 in the extension direction of the first radiator 11 and the second radiator 12, thereby reducing the SAR maximum value.

[0142] In the third embodiment, see Fig.25 , the first grounding point 112 is electrically connected to the SAR strong area N1 of the reference ground system 500, and the second grounding point 121 is electrically connected to the SAR weak area N2 of the reference ground system 500. In this embodiment, the antenna assembly 100 can be arranged in 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 on 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 current strong 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 the implementation manner where the first resonant frequency point F1 is respectively located in the first sub-band F01, the second sub-band F02 and the third sub-band F03, when the first resonant frequency point F1 is located in the third sub-band F03, the current on the second radiator 12 is stronger, the difference in SAR intensity between the first radiator 11 and 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 SAR maximum value is smaller. The specific principle analysis in this implementation manner can refer to the principle analysis in the first implementation manner or the second implementation manner.

[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 at 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, and further, the resonant frequency F1 of the first resonant mode is the center frequency of the third sub-frequency band F03, so that the SAR intensity distribution is more uniform, and the SAR maximum value is further reduced.

[0144] When the first resonant frequency point F1 is located in the third sub-frequency band F03, in the first resonant mode, the resonant current on the first radiator 11 is grounded through the feeding point A and the first grounding point 112, and the resonant current at the feeding point A and the resonant current at the first grounding point 112 are both used to form a SAR hotspot, 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 target frequency band Fa, which is the center frequency of the preset frequency band F0, that is, the difference in current intensity on 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, so as to increase the uniformity of the intensity of the SAR hotspot on the antenna assembly 100 in the extension direction of the first radiator 11 and the second radiator 12, thereby reducing the SAR maximum value.

[0145] from Fig. 20 It can be known that the antenna assembly 100 will have frequency deviation in free scenes and human body approach scenes. When the SAR exceeds the required power backoff, the frequency offset effect needs to be considered. The embodiment of the present application proposes that when performing the power backoff value, 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 can be compared. The maximum value between the first SAR value and the second SAR value is taken as the backoff SAR value, and the maximum power backoff is performed, which can ensure that there is no risk of exceeding SAR in the entire fluctuation frequency band.

[0146] For details, please refer to Fig.26, the electronic device 1000 also includes a controller 30. The controller 30 is electrically connected to the antenna assembly 100. The controller 30 is used to 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 the 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 so that the first SAR value is 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 so that the second SAR value is less than the second preset SAR value.

[0147] The present application does not make any specific limitation on the size of the second preset fluctuation value. The second preset fluctuation value can be obtained by detection, that is, detecting the offset between the first resonant frequency point F1 of the antenna assembly 100 in a free scene and the first resonant frequency point F1 in a human body approaching scene, and determining the offset as the second preset fluctuation value. Optionally, the second preset fluctuation value includes but is not limited to 50MHz, and is not limited to this data. The controller 30 compares the SAR values ​​at the first resonant frequency point 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 to ensure that there is no risk of over-SAR in the entire fluctuation frequency band.

[0148] See also Fig.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 feeding 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, so that the SAR value of the antenna assembly 100 at the SAR transmission frequency is reduced.

[0149] Optionally, the tuning circuit T is a circuit with adjustable impedance. Optionally, the tuning circuit T includes an antenna switch and / or an adjustable capacitor. In this embodiment, the frequency modulation 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 transmission frequency.

[0150] See also Fig.26Optionally, the tuning circuit T further includes a switch unit K and a tuning branch T1. One end of each of the multiple tuning branches T1 is electrically connected to one end of the switch unit K, and the other end of the switch unit K is electrically connected to the second grounding point 121 (or the feeding point A). That is, the switch unit K includes but is not limited to a transistor, a field effect transistor, etc. The other end of each of the multiple tuning branches T1 is grounded.

[0151] The impedance value of each tuning branch T1 is different. For example, the multiple tuning branches T1 are multiple capacitors with different capacitance values. Or, 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 switch unit K to be electrically connected to different tuning branches T1, the impedance of the tuning circuit T is adjusted, and then the electrical length of the second radiator 12 or the first radiator 11 is adjusted. Of course, in other embodiments, the tuning circuit T can also be an adjustable capacitor.

[0152] When the other end of the switch 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, thereby achieving a more uniform SAR intensity distribution on the first radiator 11 and the second radiator 12 at the SAR transmission frequency. 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 originally at the SAR transmission frequency is smaller than the SAR value at the first resonant frequency F1. This is because the current distribution on the antenna component 100 and the reference ground system 500 at the SAR transmission frequency is more locally concentrated on the first radiator 11 than the current distribution on the antenna component 100 and the reference ground system 500 at the first resonant frequency F1. At this time, the switch unit K of the tuning circuit T can be switched to increase the electrical length of the tuning circuit T, so that more current at the SAR transmission frequency is distributed on the second radiator 12, thereby reducing the difference in current intensity 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 switch unit K is electrically connected to the second grounding point 121 and the tuning circuit T is electrically connected to the feeding 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 transmission frequency, and then the SAR intensity distribution on the first radiator 11 and the second radiator 12 is more uniform when the SAR transmission frequency (that is, the first resonant frequency point F1 is located at the SAR transmission frequency).

[0154] The embodiment of the present application provides an antenna assembly 100, which includes an IFA antenna + a parasitic antenna. The IFA antenna + the parasitic antenna form a dual resonance mode. The first resonance mode in the dual resonance is the main working mode. The SAR value will increase both below the first resonance frequency F1 and above the first resonance frequency F1. This has nothing to do with the resonance frequency deviation after the human body approaches. Therefore, in an actual application, in order to reduce the SAR value, the main frequency band, such as the frequencies corresponding to the low, medium and high channels of the transmitting antenna, can be placed near the first resonance frequency F1. Further, the medium channel frequency can be set to the first resonance frequency F1, and the low and high channels will be evenly distributed at frequencies close to the first resonance frequency F1. At this time, the lowest SAR value will be obtained; in another actual application, since the SAR transmission test of the electronic device 1000 only tests a single-point frequency, such as the transmission frequency of the B3 frequency band is 1.75GHz and B The test frequency of band 1 is 1.95 GHz, and 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 SAR strong area N1 of the reference ground system 500 and the first grounding point 112 is electrically connected to the SAR weak area N2 of the reference ground system 500, the center frequency of the first resonant mode and the center frequency band of the preset frequency band F0 are both set as the SAR test frequency, so as to measure the lowest SAR value at the SAR test frequency, thereby reducing the difficulty of over-testing. In another practical application, when the human body is close to perform power back-off, the frequency offset effect needs to be considered during back-off. Assuming that the frequency offset fluctuation of the whole machine is 50 MHz, the SAR value of the first resonant frequency point F1±50 MHz needs to be calculated accordingly, and the maximum value of the SAR values ​​measured at the two positions is taken as the back-off SAR value, and the maximum power back-off is performed, so as to ensure that there is no risk of exceeding SAR in the entire fluctuation frequency band.

[0155] A method for reducing SAR provided in the embodiment of the present application is shown in Figure 1-Figure 4, the method is applied to an electronic device 1000 having an antenna component 100. The antenna component 100 can refer to the antenna component 100 in any of the above-mentioned embodiments. The antenna component 100 includes a first radiator 11, a second radiator 12 and a signal source 20. The first radiator 11 includes a first grounding point 112, a feeding point A and a first free end 111 arranged in sequence. The first grounding point 112 is grounded. The second radiator 12 includes a second free end 122 and a second grounding point 121 arranged in sequence. The second free end 122 is coupled to the first free end 111 through a coupling gap (first free end 111), and the second grounding point 121 is grounded. The signal source 20 is electrically connected to the feeding point A. The signal source 20 is used to excite the first radiator 11 and the second radiator 12 to form a first resonant mode and a second resonant mode together. The resonant frequency F1 of the first resonant mode is lower than the resonant frequency F1 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.

[0156] See also Fig. 27 , the method comprising:

[0157] Step S100: Determine a target frequency band Fa in 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 when operating in the target frequency band Fa is less than or equal to the SAR value of the frequency band other than the target frequency band Fa when the antenna assembly 100 operates in the preset frequency band F0. The target frequency band Fa belongs to a part of the effective frequency band of the first resonant mode. The effective frequency band can refer to the above description.

[0158] Step S200: configuring the resonance frequency point F1 of the first resonance mode to be a frequency point in the target frequency band Fa.

[0159] The method for reducing SAR provided in the present application is by determining a target frequency band Fa in 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 when operating in the target frequency band Fa is less than or equal to the SAR value of the frequency band when the antenna assembly 100 operates in the preset frequency band F0 except 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, so as to reduce the SAR value of the antenna assembly 100 operating in the first resonant mode.

[0160] The signal frequency bands received by the electronic device 1000 include a low channel frequency band, a middle channel frequency band and a high channel frequency band with increasing frequencies in sequence. The middle channel frequency band of the signal frequency band received by the electronic device 1000 is set in the target frequency band Fa. That is, the first resonant frequency point F1 is located in the middle channel frequency band. By locating the first resonant frequency point F1 near the middle channel frequency band of the transmitting antenna, and then locating the high channel frequency band and the low channel frequency band of the transmitting antenna near the first resonant frequency point F1, the transmitting antenna can have a lower SAR value.

[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 which are continuous and gradually increase in sequence, and the center frequency point of the second sub-frequency band F02 is the center frequency point of the preset frequency band F0.

[0162] Step S100: determining a target frequency band Fa in 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; a SAR value of the antenna assembly 100 when operating in the target frequency band Fa is less than or equal to a SAR value of a frequency band other than the target frequency band Fa in the preset frequency band F0 when the antenna assembly 100 operates, including:

[0163] See also Fig.28 , step S110: configure the difference between the maximum value of the target frequency band Fa and the minimum value of the target frequency band Fa to be 0.1 GHz, and the center frequency point of the target frequency band Fa is greater than the maximum value of the first sub-frequency band F01.

[0164] Step S200: configuring the resonance frequency point F1 of the first resonance mode to be a frequency point in the target frequency band Fa, including:

[0165] Step S210: configuring the resonant frequency of the first resonant mode to be the center frequency of the target frequency band.

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

[0167] In this embodiment, please refer to Figure 8, the electronic device 1000 also 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 SAR strong area N1 and two SAR weak areas N2 located on opposite sides of the SAR strong area N1 along a first direction. The second characteristic mode causes the reference ground system 500 to form a SAR strong area N1 and two SAR weak areas N2 located on opposite sides of the SAR strong area N1 along a second direction. The first direction is perpendicular to the second direction.

[0168] See also Fig. 22 and Fig.25 , when the first grounding point 112 and the second grounding point 121 are both electrically connected to the same SAR weak zone N2 of the reference ground system 500 or the first grounding point 112 is electrically connected to the SAR strong zone N1 of the reference ground system 500 and the second grounding point 121 is electrically connected to the SAR weak zone 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] See also Fig.29 , step S111: configure the center frequency of the target frequency band Fa to fall into the third sub-frequency band F03. That is, configure the resonant frequency point F1 of the first resonant mode to be greater than the center frequency point of the preset frequency band F0, so that the first resonant frequency point F1 is located on the high frequency side of the preset frequency band F0. In other words, the first resonant frequency point F1 is located in the third sub-frequency band F03, and further, the resonant frequency point F1 of the first resonant mode is the center frequency point of the third sub-frequency band F03, so that the SAR intensity distribution is more uniform, and the SAR maximum value is further reduced.

[0170] See also Fig. 9 , when the second grounding point 121 is electrically connected to the SAR strong area N1 of the reference ground system 500, the SAR strong area N1 is used to form a SAR hotspot, and the first grounding point 112 is electrically connected to the SAR weak area 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, including:

[0171] See also Fig.30 , step S112: configuring 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 in the preset frequency band F0, the overall SAR value of the antenna assembly 100 first decreases and then increases, and 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 is more uniform, and the SAR maximum value is reduced. 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 into the second sub-band F02. When performing SAR detection, the power is backed off according to the maximum value of the SAR value or it is determined whether the test is passed according to whether the maximum value of the SAR value exceeds the standard value. Therefore, the reduction of the maximum value of SAR in this embodiment can avoid unnecessary power backoff, increase the working power of the antenna assembly 100, and improve the pass rate of the SAR test of the electronic device 1000.

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

[0174] See also Fig.31 Step S310: 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 comparing 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;

[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 a 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 a second preset SAR value.

[0176] The antenna assembly 100 will have frequency deviation in free scenes and human body approach scenes. When the SAR exceeds the required power backoff, the frequency offset effect needs to be considered. The embodiment of the present application proposes that when performing the power backoff value, 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 can be compared. The maximum value between the first SAR value and the second SAR value is taken as the backoff SAR value, and the maximum power backoff is performed, which can ensure that there is no risk of exceeding SAR in the entire fluctuation frequency band.

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

[0178] The impedance value of the matching circuit M is adjusted to adjust the resonant frequency point F1 of the first resonant mode.

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

[0180] See also Fig.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 to adjust the resonant frequency F1 of the first resonant mode to the SAR transmission frequency, so that the SAR value of the antenna assembly 100 at the SAR transmission frequency is reduced.

[0181] When the other end of the switch 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, thereby achieving a more uniform SAR intensity distribution on the first radiator 11 and the second radiator 12 at the SAR transmission frequency. 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 originally at the SAR transmission frequency is smaller than the SAR value at the first resonant frequency F1. This is because the current distribution on the antenna component 100 and the reference ground system 500 at the SAR transmission frequency is more locally concentrated on the first radiator 11 than the current distribution on the antenna component 100 and the reference ground system 500 at the first resonant frequency F1. At this time, the switch unit K of the tuning circuit T can be switched to increase the electrical length of the tuning circuit T, so that more current at the SAR transmission frequency is distributed on the second radiator 12, thereby reducing the difference in current intensity 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 switch unit K is electrically connected to the second grounding point 121 and the tuning circuit T is electrically connected to the feeding 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 transmission frequency, and then the SAR intensity distribution on the first radiator 11 and the second radiator 12 is more uniform when the SAR transmission frequency (that is, the first resonant frequency point F1 is located at the SAR transmission frequency).

[0183] See also Fig.33, the embodiment of the present application also provides a device 600 for reducing SAR, and the device 600 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 grounding point 112, a feeding point A and a first free end 111 arranged in sequence, and the first grounding point 112 is grounded. The second radiator 12 includes a second free end 122 and a second grounding point 121 arranged in sequence. The second free end 122 is coupled to the first free end 111 through a coupling gap (first free end 111), and the second grounding point 121 is grounded. The signal source 20 is electrically connected to the feeding 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 resonance 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 determination module 610 and a configuration module 620. The determination module 610 is used to determine a target frequency band Fa in 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; and 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 frequency band in the preset frequency band F0 except the target frequency band Fa when the antenna assembly 100 operates.

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

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

[0187] See also Fig.34 The present application also provides an electronic device 1000, including a memory 700 and a processor 800, wherein the memory 700 is used to store computer programs, and the processor 800 is used to call and run any one of the methods for controlling the SAR hotspot distribution described in the implementation examples.

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

[0189] It should be understood that the processor 800 of the embodiment of the present application may be an integrated circuit chip with signal processing capabilities. The processor 800 includes the above-mentioned controller 30. In the implementation process, each step S of the above-mentioned method embodiment can be completed by the hardware integrated logic circuit or software instructions in the processor 800. The above-mentioned processor 800 can be a general processor 800, a digital signal processor 800 (Digital Signal Processor, DSP), an application-specific integrated circuit (Application Specific Integrated Circuit, ASIC), a field programmable gate array (Field Programmable Gate Array, FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components. The disclosed methods, steps S and logic block diagrams in the embodiments of the present application can be implemented or executed. The general processor 800 can be a microprocessor 800 or the processor 800 can also be any conventional processor 800, etc. The step S of the method disclosed in the embodiment of the present application can be directly embodied as a hardware decoding processor 800 to be executed, or it can be executed by a combination of hardware and software modules in the decoding processor 800. The software module may be located in a storage medium mature in the art such as a random access memory 700, a flash memory, a read-only memory 700, a programmable read-only memory 700 or an electrically erasable programmable memory 700, a register, etc. The storage medium is located in the memory 700, and the processor 800 reads the information in the memory 700 and completes the steps of the above method in combination with its hardware.

[0190] It can be understood that the memory 700 in the embodiment of the present application can be a volatile memory 700 or a non-volatile memory 700, or can include both volatile and non-volatile memories 700. Among them, the non-volatile memory 700 can be a read-only memory 700 (Read-Only Memory, ROM), a programmable read-only memory 700 (Programmable ROM, PROM), an erasable programmable read-only memory 700 (Erasable PROM, EPROM), an electrically erasable programmable read-only memory 700 (Electrically EPROM, EEPROM) or a flash memory. The volatile memory 700 can be a random access memory 700 (Random Access Memory, RAM), which is used as an external cache. By way of example and not limitation, many forms of RAM are available, such as static RAM 700 (SRAM), dynamic RAM 700 (DRAM), synchronous DRAM 700 (SDRAM), double data rate synchronous DRAM 700 (DDR SDRAM), enhanced SDRAM 700 (ESDRAM), synchronous link DRAM 700 (SLDRAM), and direct RAM bus 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 the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in the field can change, modify, replace and modify the above embodiments within the scope of the present application, and these improvements and modifications are also regarded as the scope of protection of the present application.

Claims

1. An electronic device, characterized in that: An antenna assembly is included, the antenna assembly comprising: The first radiator comprises a first grounding point, a feeding point and a first free end which are arranged in sequence, wherein the first grounding point is grounded; A second radiator includes a second free end and a second grounding point which are arranged in sequence, the second free end is coupled to the first free end via a coupling gap, and the second grounding point is grounded; and A signal source, the signal source is electrically connected to the feeding 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 higher than the current intensity on the second radiator; The resonant frequency point 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 configured for the antenna assembly, and a SAR value of the antenna assembly when operating in the target frequency band is less than or equal to a SAR value of a frequency band in the preset frequency band except the target frequency band.

2. The electronic device according to claim 1, wherein: The difference between the maximum value of the target frequency band and the minimum value of the target frequency band is 0.1 GHz.

3. The electronic device according to claim 2, characterized in that: The resonant frequency point of the first resonant mode is the central frequency point of the target frequency band.

4. The electronic device according to claim 2 or 3, characterized in that: The preset frequency band includes a first sub-frequency band, a second sub-frequency band and a third sub-frequency band which are continuous and gradually increase in sequence, the center frequency of the second sub-frequency band is the center frequency of the preset frequency band, and the center frequency point of the target frequency band is greater than the maximum value of the first sub-frequency band.

5. The electronic device according to claim 4, characterized in that: The electronic device also includes a reference ground system, which forms a first characteristic mode and a second characteristic mode when the antenna assembly operates in the first resonant mode. The first characteristic mode enables the reference ground system to form a SAR strong area and two SAR weak areas located on opposite sides of the SAR strong area along a first direction. The second characteristic mode enables the reference ground system to form a SAR strong area and two SAR weak areas located on opposite sides of the SAR strong area along a second direction. The first direction is perpendicular to the second direction.

6. The electronic device according to claim 5, characterized in that: The first grounding point and the second grounding point are both electrically connected to the same SAR weak area 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 according to claim 5, characterized in that: The first grounding point is electrically connected to the SAR strong area of ​​the reference ground system, the second grounding point is electrically connected to the SAR weak area of ​​the reference ground system, and the center frequency of the target frequency band falls into the third sub-frequency band.

8. The electronic device according to claim 6 or 7, characterized in that: In the first resonance mode, the resonant current on the first radiator goes to the ground through the feeding point and the first grounding point, and the resonant current at the feeding point and the resonant current at the first grounding point are both used to form a SAR hotspot. 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 antenna component resonates at a center frequency less than or equal to 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 component 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.

9. The electronic device according to claim 5, characterized in that: The second grounding point is electrically connected to the SAR strong area of ​​the reference ground system, the SAR strong area is used to form a SAR hotspot, the first grounding point is electrically connected to the SAR weak area of ​​the reference ground system, and the center frequency of the target frequency band falls into the second sub-frequency band.

10. The electronic device according to claim 9, characterized in that: In the first resonance mode, the resonant current on the first radiator goes to the ground through the feeding point and the first grounding point, the resonant current at the feeding point and the resonant current at the first grounding point are both used to form a SAR hotspot, and the intensity uniformity of the SAR hotspot of the antenna component and the SAR strong area in the extension direction of the first radiator and the second radiator is greater than the intensity uniformity of the SAR hotspot when the center frequency of the target frequency band falls into the first sub-frequency band or the third sub-frequency band.

11. The electronic device according to any one of claims 1-3, 5-7, 9 and 10, characterized in that: The electronic device further comprises a controller, wherein the controller is electrically connected to the antenna assembly; The controller is used to compare a first SAR value corresponding to the sum of the resonant frequency of the first resonant mode and the second preset fluctuation value and a 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 so that the first SAR value is less than a 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 a second preset SAR value.

12. The electronic device according to any one of claims 1-3, 5-7, 9, and 10, characterized in that: The antenna assembly also 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 feeding point, the other end of the at least one tuning circuit is grounded, the controller is electrically connected to the at least one tuning circuit, and 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, so that the SAR value of the antenna assembly at the SAR transmission frequency is reduced.

13. The electronic device according to any one of claims 1-3, 5-7, 9 and 10, characterized in that: The signal frequency bands received by the electronic device include a low channel frequency band, a middle channel frequency band and a high channel frequency band, and the middle channel frequency band is located in the target frequency band.

14. A method for reducing SAR, characterized in that: The method is applied to an electronic device having an antenna assembly, wherein the antenna assembly comprises a first radiator, a second radiator and a signal source, wherein the first radiator comprises a first grounding point, a feeding point and a first free end which are arranged in sequence, and the first grounding point is grounded; the second radiator comprises a second free end and a second grounding point which are arranged in sequence, the second free end is coupled to the first free end via a coupling gap, and the second grounding point is grounded; the signal source is electrically connected to the feeding point, and 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, wherein 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 higher than the current intensity on the second radiator; the method comprises: Determining a target frequency band in the preset frequency band configured for the antenna assembly, wherein the target frequency band falls within the preset frequency band configured for the antenna assembly; a SAR value of the antenna assembly when operating in the target frequency band is less than or equal to a SAR value of a frequency band other than the target frequency band in the preset frequency band when the antenna assembly operates; The resonant frequency point of the first resonant mode is configured to be a frequency point in the target frequency band.

15. The method according to claim 14, characterized in that The preset frequency band includes a first sub-frequency band, a second sub-frequency band and a third sub-frequency band which are continuous and gradually increase in sequence, and the center frequency point of the second sub-frequency band is the center frequency point of the preset frequency band; the target frequency band is determined in the preset frequency band configured by the antenna assembly, wherein the target frequency band falls within the preset frequency band configured by the antenna assembly; 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 when the antenna assembly operates in the preset frequency band except the target frequency band, including: The difference between the maximum value of the target frequency band 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 configuring the resonant frequency point of the first resonant mode to be a frequency point in the target frequency band includes: The resonant frequency point of the first resonant mode is configured as the center frequency point of the target frequency band.

16. The method according to claim 15, characterized in that The electronic device further comprises a reference ground system, a resonant current of the antenna assembly when operating in the first resonant mode flows toward the reference ground system, a first characteristic mode and a second characteristic mode are formed on the reference ground system, the first characteristic mode enables the reference ground system to form a SAR strong area and two SAR weak areas located on opposite sides of the SAR strong area along a first direction, the second characteristic mode enables the reference ground system to form a SAR strong area and two SAR weak areas located on opposite sides of the SAR strong area along a second direction, and the first direction is perpendicular to the second direction; When the first grounding point and the second grounding point are both electrically connected to the same SAR weak area of ​​the reference ground system or the first grounding point is electrically connected to the SAR strong area of ​​the reference ground system and the second grounding point is electrically connected to the SAR weak area of ​​the reference ground system, the configuring a center frequency point of the target frequency band is greater than a maximum value of the first sub-frequency band, including: Configuring the center frequency of the target frequency band to fall into the third sub-frequency band; When the second grounding point is electrically connected to the SAR strong area of ​​the reference ground system, the SAR strong area is used to form a SAR hotspot, and the first grounding point is electrically connected to the SAR weak area of ​​the reference ground system, the central frequency point of the target frequency band is configured to be greater than the maximum value of the first sub-frequency band, including: The center frequency of the target frequency band is configured to fall within the second sub-frequency band.

17. The method according to claim 14, characterized in that After configuring the resonant frequency point of the first resonant mode to be a frequency point in the target frequency band, the method further includes: Comparing the first SAR value corresponding to the sum of the resonant frequency of the first resonant mode and the second preset fluctuation value, and comparing 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, adjusting the power of the antenna assembly so that the first SAR value is less than or equal to a second preset SAR value; When the second SAR value is greater than the first SAR value, the power of the antenna assembly is adjusted to make the second SAR value less than or equal to a second preset SAR value.

18. The method of claim 14, wherein: The antenna assembly further includes a tuning circuit, one end of the tuning circuit is electrically connected to the second ground point and / or the feeding point, and the other end of the tuning circuit is grounded, and 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.

19. The method of claim 14, wherein: The method further comprises: The mid-channel frequency band in the signal frequency band received by the electronic device is set in the target frequency band.

20. A device for reducing SAR, characterized in that: The device is applied to an electronic device with an antenna assembly, wherein the antenna assembly comprises a first radiator, a second radiator and a signal source, wherein the first radiator comprises a first grounding point, a feeding point and a first free end which are arranged in sequence, and the first grounding point is grounded; the second radiator comprises a second free end and a second grounding point which are arranged in sequence, the second free end is coupled to the first free end through a coupling gap, and the second grounding point is grounded; the signal source is electrically connected to the feeding point, and 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, wherein 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 higher than the current intensity on the second radiator; the device comprises: A determination module, configured to determine a target frequency band in the preset frequency band configured for the antenna assembly, wherein the target frequency band falls within the preset frequency band configured for the antenna assembly; and a SAR value of the antenna assembly when operating in the target frequency band is less than or equal to a SAR value of a frequency band other than the target frequency band in the preset frequency band when the antenna assembly operates; A configuration module is used to configure the resonant frequency point of the first resonant mode to be a frequency point in the target frequency band.

21. An electronic device, characterized in that: It comprises 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 as claimed in any one of claims 14 to 19.

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