WO2022267600A1 - 一种低sar天线及电子设备 - Google Patents

一种低sar天线及电子设备 Download PDF

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Publication number
WO2022267600A1
WO2022267600A1 PCT/CN2022/084112 CN2022084112W WO2022267600A1 WO 2022267600 A1 WO2022267600 A1 WO 2022267600A1 CN 2022084112 W CN2022084112 W CN 2022084112W WO 2022267600 A1 WO2022267600 A1 WO 2022267600A1
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Prior art keywords
radiator
antenna
frequency band
radiation
frequency
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PCT/CN2022/084112
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English (en)
French (fr)
Inventor
胡义武
张澳芳
魏鲲鹏
Original Assignee
荣耀终端有限公司
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Priority to US17/908,153 priority Critical patent/US20240128646A1/en
Priority to EP22757464.7A priority patent/EP4138219B1/en
Publication of WO2022267600A1 publication Critical patent/WO2022267600A1/zh

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/12—Supports; Mounting means
    • H01Q1/22—Supports; Mounting means by structural association with other equipment or articles
    • H01Q1/24—Supports; Mounting means by structural association with other equipment or articles with receiving set
    • H01Q1/241—Supports; Mounting means by structural association with other equipment or articles with receiving set used in mobile communications, e.g. GSM
    • H01Q1/242—Supports; Mounting means by structural association with other equipment or articles with receiving set used in mobile communications, e.g. GSM specially adapted for hand-held use
    • H01Q1/245—Supports; Mounting means by structural association with other equipment or articles with receiving set used in mobile communications, e.g. GSM specially adapted for hand-held use with means for shaping the antenna pattern, e.g. in order to protect user against rf exposure
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q9/00—Electrically-short antennas having dimensions not more than twice the operating wavelength and consisting of conductive active radiating elements
    • H01Q9/04—Resonant antennas
    • H01Q9/0407—Substantially flat resonant element parallel to ground plane, e.g. patch antenna
    • H01Q9/0421—Substantially flat resonant element parallel to ground plane, e.g. patch antenna with a shorting wall or a shorting pin at one end of the element
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/52—Means for reducing coupling between antennas; Means for reducing coupling between an antenna and another structure
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/002—Protection against seismic waves, thermal radiation or other disturbances, e.g. nuclear explosion; Arrangements for improving the power handling capability of an antenna
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/12—Supports; Mounting means
    • H01Q1/22—Supports; Mounting means by structural association with other equipment or articles
    • H01Q1/24—Supports; Mounting means by structural association with other equipment or articles with receiving set
    • H01Q1/241—Supports; Mounting means by structural association with other equipment or articles with receiving set used in mobile communications, e.g. GSM
    • H01Q1/242—Supports; Mounting means by structural association with other equipment or articles with receiving set used in mobile communications, e.g. GSM specially adapted for hand-held use
    • H01Q1/243—Supports; Mounting means by structural association with other equipment or articles with receiving set used in mobile communications, e.g. GSM specially adapted for hand-held use with built-in antennas
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/36—Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewith
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/48—Earthing means; Earth screens; Counterpoises
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/50—Structural association of antennas with earthing switches, lead-in devices or lightning protectors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q25/00—Antennas or antenna systems providing at least two radiating patterns
    • H01Q25/04—Multimode antennas
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q5/00—Arrangements for simultaneous operation of antennas on two or more different wavebands, e.g. dual-band or multi-band arrangements
    • H01Q5/10—Resonant antennas
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q5/00—Arrangements for simultaneous operation of antennas on two or more different wavebands, e.g. dual-band or multi-band arrangements
    • H01Q5/20—Arrangements for simultaneous operation of antennas on two or more different wavebands, e.g. dual-band or multi-band arrangements characterised by the operating wavebands
    • H01Q5/28—Arrangements for establishing polarisation or beam width over two or more different wavebands
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q5/00—Arrangements for simultaneous operation of antennas on two or more different wavebands, e.g. dual-band or multi-band arrangements
    • H01Q5/30—Arrangements for providing operation on different wavebands
    • H01Q5/307—Individual or coupled radiating elements, each element being fed in an unspecified way
    • H01Q5/314—Individual or coupled radiating elements, each element being fed in an unspecified way using frequency dependent circuits or components, e.g. trap circuits or capacitors
    • H01Q5/328—Individual or coupled radiating elements, each element being fed in an unspecified way using frequency dependent circuits or components, e.g. trap circuits or capacitors between a radiating element and ground
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q5/00—Arrangements for simultaneous operation of antennas on two or more different wavebands, e.g. dual-band or multi-band arrangements
    • H01Q5/30—Arrangements for providing operation on different wavebands
    • H01Q5/378—Combination of fed elements with parasitic elements
    • H01Q5/385—Two or more parasitic elements
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q5/00—Arrangements for simultaneous operation of antennas on two or more different wavebands, e.g. dual-band or multi-band arrangements
    • H01Q5/50—Feeding or matching arrangements for broad-band or multi-band operation
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q9/00—Electrically-short antennas having dimensions not more than twice the operating wavelength and consisting of conductive active radiating elements
    • H01Q9/04—Resonant antennas
    • H01Q9/30—Resonant antennas with feed to end of elongated active element, e.g. unipole
    • H01Q9/42—Resonant antennas with feed to end of elongated active element, e.g. unipole with folded element, the folded parts being spaced apart a small fraction of the operating wavelength

Definitions

  • the present application relates to the field of electronic equipment, in particular to a low SAR antenna and electronic equipment.
  • the electronic device can transmit and receive wireless signals through the antenna provided therein.
  • the radiation performance of the antenna is closely related to the environment of the antenna in the electronic equipment. For example, when the antenna is arranged at the lower part of the electronic device, the antenna will be covered by the electronic device held by the user, which will greatly affect the radiation performance of the antenna; thus affecting the communication experience when the user holds the electronic device.
  • the antenna can be arranged on the upper part of the electronic device, so as to avoid the influence on the radiation performance of the antenna by holding the electronic device.
  • Embodiments of the present application provide a low-SAR antenna and electronic equipment, which can provide better mid-to-high frequency radiation performance while having a lower SAR value.
  • a low SAR antenna which is applied to an electronic device, and the antenna includes: a first radiating structure and a second radiating structure.
  • the first radiating structure includes a first radiating body
  • the second radiating structure includes a second radiating body
  • the first radiating body is not connected to the second radiating body.
  • the first end of the first radiator is opposite to the first end of the second radiator, and the first end of the first radiator and the first end of the second radiator form a first slot.
  • the second end of the first radiator is suspended, and the second end of the second radiator is grounded.
  • the feed point of the antenna is coupled to the first radiator, and the feed point is used as a boundary to divide the first radiator into a first part and a second part, the length of the first part is shorter than the length of the second part .
  • a grounding point is provided on the second part between the second end of the first radiator and the feeding point.
  • the antenna may have two radiation areas, such as a first radiation structure and a second radiation structure.
  • each radiating structure may include a corresponding radiator and related grounding and/or feeding structures.
  • the first radiating structure can be used as the object of direct feeding, that is, the feeding signal can be directly fed into the first radiator through the feeding point, so as to stimulate the operation of the first radiator.
  • the working frequency band of the first radiator may include low frequency.
  • low frequency coverage can be achieved by exciting 1/4 wavelength on the first radiator.
  • the first radiator can also cover medium and high frequencies by exciting high-order modes.
  • the second radiating structure may act as a parasitic arrangement of the first radiating structure.
  • the parasitic may be arranged near the short stub of the first radiator.
  • the short branches of the first radiator (such as the first part of the first radiator) can be jointly excited with the second radiator to cover medium and high frequencies. Since the mode covering the mid-high frequency is not a high-order mode (such as the high-order mode of the IFA antenna), it has a lower SAR value in the mid-high frequency band.
  • the low-frequency and medium-high frequency combination design of the solution in this example does not introduce additional insertion loss caused by the low-frequency and medium-high frequency split.
  • the first part of the first radiator and the second radiator work together in the first frequency band and the second frequency band, and the frequency of the first frequency band is lower than that of the second frequency of the band.
  • the direction of the current on the first part is the same as the direction of the current on the second radiator.
  • the direction of the current on the first part is opposite to the direction of the current on the second radiator at the first slit. So that the SAR values of the antenna in the first frequency band and the second frequency band are lower than the SAR values of the first radiation structure working independently in the first frequency band and the second frequency band.
  • the first radiator and the second radiator can jointly excite the CM mode and the DM mode, thereby replacing the high-order mode of the IFA antenna to cover the medium and high frequencies, thereby providing better radiation performance while avoiding the interference caused by the high-order mode.
  • the first radiation structure is an IFA antenna.
  • the first radiation structure may have a radiation form of an IFA antenna. That is to say, the first radiation structure may include a first radiator, a feed point, and a ground point near the feed point.
  • the first radiation structure may further include a matching circuit between the feeding point and the radio frequency module.
  • the matching circuit can reduce the antenna port insertion loss by connecting capacitors or inductors in series and/or in parallel.
  • a small capacitor (such as less than 2pF) may be connected in series in the matching circuit of the IFA antenna to excite the left-handed mode on the IFA antenna to cover the low frequency end.
  • the ground point of the IFA antenna may be in the form that the first radiator is grounded through a switch circuit. In this way, low-frequency resonant switching can be realized by switching the inductance and/or capacitance of the switch circuit.
  • the second radiating structure constitutes a parasitic structure of the first radiating body, and when the antenna is working, the second radiating structure passes through the first slit and interacts with the first radiating structure of the first radiating structure.
  • the electric field coupling is performed on the second radiating body to excite the current on the second radiating body.
  • the second radiating structure may be a parasitic of the first radiating structure.
  • the second radiating structure may be disposed near short branches of the first radiating body. Therefore, the parasitic effect of the second radiating structure can play a role in broadening the resonance frequency band corresponding to the short branches of the first radiating body.
  • there may be no feeding point in the second radiating structure thereby ensuring a single-feed structure of the antenna.
  • the current on the second radiating structure can be excited through electric field coupling with the first radiating structure.
  • the first frequency band is covered by exciting the common mode slot CM mode of the slot antenna on the first part of the first radiator and the second radiator, and through the first radiation
  • the first part of the body and the differential mode slot DM mode of the excitation slot antenna on the second radiator cover the second frequency band.
  • the excitation of the CM mode and the DM mode can be obtained through the joint action of the first part of the first radiator (such as a short branch) and the second radiator, so as to obtain at least two resonance coverages in the middle and high frequencies. Therefore, while providing enough bandwidth to cover the middle and high frequencies to ensure its radiation performance, a lower SAR value can be obtained.
  • the feeding point coupled to the first radiator is located at a bend of the first radiator.
  • the feed point coupled to the first radiator may be located at the upper right corner of the back view of the electronic device.
  • a specific schematic position of the feeding point of the first radiator is provided.
  • the feeding point of the first radiator is also the feeding point of the antenna.
  • the long branches (such as the second part) of the first radiator may be arranged along the side of the mobile phone, and the short branches (such as the first part) may be arranged along the top of the mobile phone.
  • the working frequency band of the second part of the first radiator covers a third frequency band, and the frequency of the third frequency band is lower than that of the second frequency band.
  • a codirectional current is distributed on the first radiator, and the first radiator covers the third frequency band by exciting the left-handed mode.
  • the first radiator can achieve low-frequency coverage through long branches (such as the second part). Wherein, in this design, the first coverage can be realized by exciting the left-right mode of the co-directional current on the first radiator.
  • a small capacitor (such as less than 2pF) can be connected in series in the matching circuit to realize the excitation of the left-handed mode.
  • the low frequency coverage may also be implemented by stimulating the low frequency 1/4 IFA mode.
  • the 1/4IFA mode can be achieved by exciting a co-directional current on the second part.
  • the antenna further includes a third radiating structure, the third radiating structure includes a third radiator, and the third radiator is not connected to the first radiator or the second radiator respectively, The first end of the third radiator is opposite to the second end of the first radiator. A second gap is formed between the first end of the third radiator and the second end of the first radiator, and a grounding point is arranged on the third radiator.
  • a third radiating structure may also be provided at the end of a short branch (such as the second part) of the first radiating structure.
  • the third radiating structure can realize the excitation between the intermediate frequency and the high frequency, thereby further increasing the radiation performance of the antenna at the medium and high frequency. In particular, it can significantly improve the radiation performance of the mid-frequency and high-frequency transition bands.
  • the third radiating structure when the antenna is working, the third radiating structure constitutes a parasitic structure of the first radiating body, and the third radiating body is used to pass through the second slit to conduct an electric field with the first radiating body. coupled to excite the current on the third radiator.
  • the third radiating structure may constitute a parasitic structure.
  • the size of the third radiator of the third radiating structure may correspond to 1/4 wavelength of the frequency band where the mid-high frequency resonance needs to be covered.
  • the third radiating structure can be coupled with the electric field through the second slit, thereby exciting the parasitic current on the third radiating body, thereby realizing the excitation of 1/4 wavelength. This improves the mid-to-high frequency performance.
  • the working frequency band of the third radiator covers a fourth frequency band, and the frequency of the fourth frequency band is between the frequencies of the first frequency band and the second frequency band.
  • the third radiation structure is provided.
  • the CM mode and the DM mode are incompatible, radiation performance may deteriorate near a frequency band where the CM mode and the DM mode intersect.
  • the above-mentioned performance degradation can be compensated by tuning the coverage resonance between the CM mode and the DM mode, so that the antenna has better mid-high frequency radiation performance.
  • the fourth frequency band may include a frequency band for switching between the CM mode and the DM mode within the range of 2300-2700 MHz.
  • the fourth frequency band may cover a frequency band around 2.5 GHz.
  • an electronic device is provided, and the electronic device is provided with at least one processor, a radio frequency module, and the low SAR antenna described in the first aspect and any possible design thereof.
  • the electronic device transmits or receives signals, it transmits or receives signals through the radio frequency module and the low SAR antenna.
  • FIG. 1 is a schematic diagram of an antenna setting area
  • Fig. 2 is a schematic diagram of a distributed antenna
  • FIG. 3 is a schematic diagram of a typical IFA antenna
  • Figure 4 is a schematic diagram of the comparison between different modes and the current distribution of the floor
  • Fig. 5 is the schematic diagram of the S parameter of different mode excitation
  • FIG. 6 is a schematic diagram of the composition of an electronic device provided by an embodiment of the present application.
  • FIG. 7 is a schematic composition diagram of an electronic device provided in an embodiment of the present application.
  • FIG. 8 is a schematic diagram of the composition of an antenna provided by an embodiment of the present application.
  • FIG. 9 is a schematic diagram of the composition of an antenna provided in an embodiment of the present application.
  • FIG. 10 is a schematic diagram of S parameters of the antenna provided by the embodiment of the present application.
  • FIG. 11 is a schematic diagram of current flow provided by the embodiment of the present application.
  • FIG. 12 is a schematic diagram of S parameters of an antenna provided by an embodiment of the present application.
  • Fig. 13A is a schematic diagram of current flow provided by the embodiment of the present application.
  • Fig. 13B is a schematic diagram of the simulation results provided by the embodiment of the present application.
  • FIG. 14 is a schematic diagram of S parameters of an antenna provided in an embodiment of the present application.
  • Fig. 15 is a schematic diagram of the current distribution provided by the embodiment of the present application.
  • FIG. 16 is a schematic diagram of the composition of an antenna provided by an embodiment of the present application.
  • FIG. 17 is a schematic diagram of the composition of an antenna provided by an embodiment of the present application.
  • FIG. 18 is a schematic diagram of the composition of an antenna provided by an embodiment of the present application.
  • FIG. 19 is a schematic diagram of the composition of an antenna provided in an embodiment of the present application.
  • FIG. 20 is a schematic diagram of S parameters of an antenna provided by an embodiment of the present application.
  • Figure 21 is a schematic diagram of the current distribution provided by the embodiment of the present application.
  • FIG. 22 is a schematic diagram of the composition of an antenna provided by an embodiment of the present application.
  • Figure 23 is a schematic diagram of body SAR hotspot distribution provided by the embodiment of the present application.
  • Figure 24 is a schematic diagram of body SAR hotspot distribution provided by the embodiment of the present application.
  • Fig. 25 is a schematic diagram of the distribution of Head SAR hotspots provided by the embodiment of the present application.
  • multiple antennas may be provided in an electronic device for performing wireless communications in different frequency bands.
  • an antenna (such as called a main antenna) used for communication at a main frequency (covering a frequency of 700 MHz-3 GHz) may be included.
  • a main antenna used for communication at a main frequency (covering a frequency of 700 MHz-3 GHz)
  • the electronic device Take the electronic device as a mobile phone as an example.
  • the main antenna is arranged at the lower part of the mobile phone, the antenna will be covered by the user's hand holding the mobile phone, which will lead to deterioration of the performance of the antenna.
  • the main antenna can be arranged on the upper part of the electronic device, so as to avoid the influence on the radiation performance of the antenna when the user holds the electronic device.
  • FIG. 1 it is a schematic diagram of an antenna arrangement of an electronic device.
  • the electronic device is a mobile phone as an example.
  • Figure 1 is a back view of the mobile phone.
  • the main antenna can be set in the upper antenna area. In this way, when the user uses the mobile phone, the hand holding the mobile phone will not cover the main antenna, so that the radiation performance of the main antenna will not be significantly affected.
  • the main antenna in the upper antenna area are shown.
  • the main antenna may consist of Antenna 1 and Antenna 2 .
  • the antenna 1 can be used to realize low frequency (low frequency band, LB) radiation.
  • LB can cover the 700MHz-960MHz frequency band.
  • antenna 1 may be an IFA antenna.
  • the feed point can be coupled to one end of the radiator, and a ground point can be set at a position close to the feed point to be coupled to the radiator, so as to realize the radiation form of the IFA antenna.
  • the length of the radiator of the IFA antenna can be close to 1/4 wavelength of LB, so that the radiation in the LB frequency band can be excited through the feeding point.
  • the antenna 1 is made to work in the LB frequency band.
  • the antenna 2 may have a loop antenna (loop antenna) plus a parasitic structure, so as to realize middle/high frequency (middle/high frequency band, MHB) radiation.
  • the frequency bands covered by medium and high frequencies may include 1710MHz-2690MHz.
  • the loop antenna may have a feed point-radiator-ground structure.
  • One end of the parasitic radiator can be close to the loop antenna, and the other end can be grounded. Therefore, the parasitic radiator can obtain energy from the loop antenna through spatial coupling, thereby realizing the radiation function of the antenna 2 together with the loop antenna.
  • low-frequency excitation can be performed on the antenna 1 (that is, a low-frequency signal is input at the feeding point of the antenna 1 ) to realize low-frequency radiation.
  • the antenna 1 can also receive low-frequency electromagnetic waves in space, and convert them into currents that are transmitted from the feeding point to the radio frequency/hardware module (not shown in FIG. 2 ).
  • the antenna 2 can also achieve medium and high frequency radiation. In this way, the radiation performance covering the main frequency is realized.
  • the antenna scheme shown in Figure 2 adopts the split form of low frequency and medium and high frequency.
  • additional components need to be introduced in the RF front-end compared to the undivided form.
  • all components on the communication link will introduce loss to the signal (that is, insertion loss). Therefore, the solution shown in Figure 2 will introduce at least one level of switch insertion loss in the RF front-end, so that the full-band RF
  • the conduction loss is about 0.5dB-1dB, which means that the energy obtained by the antenna during radiation is lost (for example, the loss is 0.5dB-1dB), which also reduces the radiation performance of the antenna.
  • the antenna radiator after splitting the low frequency and mid-high frequency, the antenna radiator also needs to be set separately. This will inevitably make the space in the already crowded upper antenna area more tense, thereby limiting the size of the mid-high frequency (or low-frequency) radiator, which will lead to a decrease in high-frequency (or low-frequency) bandwidth and reduced radiation capability.
  • FIG. 3 shows an antenna scheme that does not separate low-frequency and mid-high frequency. Since there is no need to separate the low frequency and mid-high frequency at the RF front end, there is no additional insertion loss, thus improving the performance of the antenna on the conductive side.
  • the radiation of the main antenna can be realized in the form of an IFA in the upper antenna area.
  • the low frequency can be covered by the 1/4 wavelength mode of the IFA antenna
  • the intermediate frequency can be covered by the 1/2 wavelength mode of the IFA antenna
  • the high frequency can be covered by the 3/4 wavelength or 1 times wavelength mode of the IFA antenna.
  • the antenna with the composition shown in Figure 3 can simultaneously cover low frequency and mid-high frequency, so it can avoid the decline of antenna radiation performance due to mid-high frequency splitting.
  • the radiation situation of the antenna radiation to the human body may be identified by a specific absorption rate (Specific Absorption Rate, SAR) of the antenna.
  • SAR Specific Absorption Rate
  • the SAR detection may include head SAR, which is used to identify the radiation situation of the antenna to the user's head during the radiation process.
  • the SAR detection may also include body (body) SAR, which is used to identify the radiation situation of the antenna to the user's torso during the radiation process.
  • the radiation of medium and high frequencies is the high-order mode of the antenna. This will make the current of the medium and high frequency mostly concentrated near the antenna radiator during the radiation process, which will cause the SAR to exceed the standard.
  • the radiation conditions of the fundamental mode (such as 1/4 wavelength) and the higher order mode (such as 3/4 wavelength) shown in FIG. 3 will be described below with reference to FIG. 4 and FIG. 5 .
  • FIG. 4 shows the distribution of current on the floor when different modes radiate.
  • the size of the antenna A may be 1/4 wavelength of the working frequency band, and the antenna A may be arranged on the top of the electronic device.
  • the size of the antenna B can be 1/4 wavelength of the working frequency band, and the antenna B can be arranged on the side of the electronic device near the top.
  • the size of the antenna C may be 3/4 wavelength of the working frequency band, and the antenna C may be arranged on the side of the electronic device near the top.
  • Figure 5 shows the radiation performance of antenna A, antenna B and antenna C.
  • the return loss (S11) can be used to identify the single-port radiation capability of the antenna.
  • the smaller S11 is it indicates that the return loss at this frequency point is greater during the single-port test, that is, the antenna at this frequency point can have better efficiency.
  • the bandwidth and S11 of antenna A and antenna B are better than that of antenna C. That is, the radiation performance of the fundamental mode is better than that of the higher-order modes.
  • Fig. 5 also shows the system efficiency comparison of antenna A, antenna B and antenna C. It can be seen that, similar to S11, antenna A and antenna B have better system efficiency (for example, larger bandwidth and higher efficiency). In contrast, the system efficiency of the high-order mode (that is, antenna C) shows a narrower bandwidth and lower efficiency.
  • Body SAR Antenna A Antenna B Antenna C 2.5GHz 0.61 0.63 2.59 2.55GHz 0.62 0.63 2.33 2.6GHz 0.63 0.64 2.31
  • the SAR of antenna A is 0.61
  • the SAR of antenna B is 0.63
  • the SAR of antenna C is 2.59.
  • the SAR of antenna A is 0.62
  • the SAR of antenna B is 0.63
  • the SAR of antenna C is 2.33.
  • the SAR of antenna A is 0.63
  • the SAR of antenna B is 0.64
  • the SAR of antenna C is 2.31.
  • the IFA antenna can achieve the coverage of the main frequency in the upper antenna area, since the high frequencies are high-order mode radiation, compared with the fundamental mode radiation, if the same or similar radiation is to be achieved Performance has higher requirements for space. And this is obviously not suitable for the small environmental constraints of the upper antenna area.
  • the SAR will be significantly improved, making it difficult to control the amount of radiation to the human body.
  • the electronic device is taken as an example of a mobile phone.
  • Table 1 above shows the comparison of different modes in the body SAR test.
  • the SAR value of the high-order mode is also higher than that of the fundamental mode.
  • the IFA antenna is arranged on the upper antenna area, therefore, when the user holds the mobile phone close to the human ear (such as making a call), the radiation of the antenna to the user's head is relatively high.
  • the SAR of the high-order mode radiation of the IFA antenna is relatively high, which will make it difficult to control the head SAR when the main antenna is set in the upper antenna area.
  • the embodiment of the present application provides a low SAR antenna solution, which can avoid the problem of too high SAR value when the main antenna is arranged in the upper antenna area, and can ensure the radiation performance of the antenna at the same time.
  • the low SAR antenna solution provided in the embodiment of the present application may be applied to a user's electronic device.
  • the electronic device may be provided with an antenna, and the antenna may be used to support the electronic device to realize a wireless communication function.
  • the electronic device may be a portable mobile device such as a mobile phone, a tablet computer, a personal digital assistant (personal digital assistant, PDA), an augmented reality (augmented reality, AR)/virtual reality (virtual reality, VR) device, a media player, etc.
  • PDA personal digital assistant
  • AR augmented reality
  • VR virtual reality
  • the electronic device may also be a wearable electronic device such as a smart watch.
  • the embodiment of the present application does not specifically limit the specific form of the device.
  • FIG. 6 is a schematic structural diagram of an electronic device 600 provided in an embodiment of the present application.
  • the electronic device 600 may include a processor 610, an external memory interface 620, an internal memory 621, a universal serial bus (universal serial bus, USB) interface 630, a charging management module 640, a power management module 641, a battery 642, antenna 1, antenna 2, mobile communication module 650, wireless communication module 660, audio module 670, speaker 670A, receiver 670B, microphone 670C, earphone jack 670D, sensor module 680, button 690, motor 691, indicator 692, camera 693, a display screen 694, and a subscriber identification module (subscriber identification module, SIM) card interface 695, etc.
  • SIM subscriber identification module
  • the sensor module 680 may include a pressure sensor, a gyroscope sensor, an air pressure sensor, a magnetic sensor, an acceleration sensor, a distance sensor, a proximity light sensor, a fingerprint sensor, a temperature sensor, a touch sensor, an ambient light sensor, a bone conduction sensor, and the like.
  • the structure shown in this embodiment does not constitute a specific limitation on the electronic device 600 .
  • the electronic device 600 may include more or fewer components than shown, or combine certain components, or separate certain components, or arrange different components.
  • the illustrated components can be realized in hardware, software or a combination of software and hardware.
  • the processor 610 may include one or more processing units, for example: the processor 610 may include an application processor (application processor, AP), a modem processor, a graphics processing unit (graphics processing unit, GPU), an image signal processor (image signal processor, ISP), controller, memory, video codec, digital signal processor (digital signal processor, DSP), baseband processor, and/or neural network processor (neural-network processing unit, NPU) Wait. Wherein, different processing units may be independent devices, or may be integrated in one or more processors 610 .
  • application processor application processor, AP
  • modem processor graphics processing unit
  • graphics processing unit graphics processing unit
  • ISP image signal processor
  • controller memory
  • video codec digital signal processor
  • DSP digital signal processor
  • baseband processor baseband processor
  • neural network processor neural-network processing unit, NPU
  • the ISP can process the image, such as the processing can include automatic exposure (Automatic Exposure), automatic focus (Automatic Focus), automatic white balance (Automatic White Balance), denoising, backlight compensation , color enhancement and other processing.
  • the processing of automatic exposure, automatic focus, and automatic white balance can also be called 3A processing.
  • the ISP can obtain the corresponding photos. This process may also be referred to as the slice operation of the ISP.
  • processor 610 may include one or more interfaces.
  • the interface may include an integrated circuit (inter-integrated circuit, I2C) interface, an integrated circuit built-in audio (inter-integrated circuit sound, I2S) interface, a pulse code modulation (pulse code modulation, PCM) interface, a universal asynchronous transmitter (universal asynchronous receiver/transmitter, UART) interface, mobile industry processor interface (mobile industry processor interface, MIPI), general-purpose input and output (general-purpose input/output, GPIO) interface, subscriber identity module (subscriber identity module, SIM) interface, and /or universal serial bus (universal serial bus, USB) interface, etc.
  • I2C integrated circuit
  • I2S integrated circuit built-in audio
  • PCM pulse code modulation
  • PCM pulse code modulation
  • UART universal asynchronous transmitter
  • MIPI mobile industry processor interface
  • GPIO general-purpose input and output
  • subscriber identity module subscriber identity module
  • SIM subscriber identity module
  • USB universal serial bus
  • the electronic device 600 can realize the shooting function through the ISP, the camera 693 , the video codec, the GPU, the display screen 694 and the application processor.
  • the ISP is used for processing the data fed back by the camera 693 .
  • the light is transmitted to the photosensitive element of the camera 693 through the lens, and the light signal is converted into an electrical signal, and the photosensitive element of the camera 693 transmits the electrical signal to the ISP for processing, and converts it into an image visible to the naked eye.
  • ISP can also perform algorithm optimization on image noise, brightness, and skin color. ISP can also optimize the exposure, color temperature and other parameters of the shooting scene.
  • the ISP may be located in the camera 693 .
  • Camera 693 is used to capture still images or video.
  • the object generates an optical image through the lens and projects it to the photosensitive element.
  • the photosensitive element may be a charge coupled device (CCD) or a complementary metal-oxide-semiconductor (CMOS) phototransistor.
  • CMOS complementary metal-oxide-semiconductor
  • the photosensitive element converts the light signal into an electrical signal, and then transmits the electrical signal to the ISP to convert it into a digital image signal.
  • the ISP outputs the digital image signal to the DSP for processing.
  • DSP converts digital image signals into standard RGB, YUV and other image signals.
  • the electronic device 600 may include 1 or N cameras 693, where N is a positive integer greater than 1.
  • Digital signal processors are used to process digital signals. In addition to digital image signals, they can also process other digital signals. For example, when the electronic device 600 selects a frequency point, the digital signal processor is used to perform Fourier transform on the energy of the frequency point.
  • Video codecs are used to compress or decompress digital video.
  • the electronic device 600 may support one or more video codecs.
  • the electronic device 600 can play or record videos in various encoding formats, for example: moving picture experts group (moving picture experts group, MPEG) 1, MPEG2, MPEG3, MPEG4 and so on.
  • MPEG moving picture experts group
  • the NPU is a neural-network (NN) computing processor.
  • NN neural-network
  • Applications such as intelligent cognition of the electronic device 600 can be realized through the NPU, such as image recognition, face recognition, speech recognition, text understanding, and the like.
  • the charging management module 640 is configured to receive charging input from the charger.
  • the charger may be a wireless charger or a wired charger.
  • the charging management module 640 can receive charging input from the wired charger through the USB interface 630 .
  • the charging management module 640 may receive wireless charging input through a wireless charging coil of the electronic device 600 . While the charging management module 640 is charging the battery 642 , it can also supply power to the electronic device 600 through the power management module 641 .
  • the power management module 641 is used for connecting the battery 642 , the charging management module 640 and the processor 610 .
  • the power management module 641 receives the input of the battery 642 and/or the charging management module 640, and supplies power for the processor 610, the internal memory 621, the external memory, the display screen 694, the camera 693, and the wireless communication module 660, etc.
  • the power management module 641 can also be used to monitor parameters such as the capacity of the battery 642 , the number of cycles of the battery 642 , and the state of health of the battery 642 (leakage, impedance).
  • the power management module 641 may also be set in the processor 610 .
  • the power management module 641 and the charging management module 640 can also be set in the same device.
  • the wireless communication function of the electronic device 600 can be realized by the antenna 1 , the antenna 2 , the mobile communication module 650 , the wireless communication module 660 , the modem processor 610 and the baseband processor 610 .
  • Antenna 1 and Antenna 2 are used to transmit and receive electromagnetic wave signals.
  • Each antenna in electronic device 600 may be used to cover single or multiple communication frequency bands. Different antennas can also be multiplexed to improve the utilization of the antennas.
  • Antenna 1 can be multiplexed as a diversity antenna of a wireless local area network.
  • the antenna may be used in conjunction with a tuning switch.
  • the mobile communication module 650 can provide wireless communication solutions including 2G/3G/4G/5G applied on the electronic device 600 .
  • the mobile communication module 650 may include at least one filter, switch, power amplifier, low noise amplifier (low noise amplifier, LNA) and the like.
  • the mobile communication module 650 can receive electromagnetic waves through the antenna 1, filter and amplify the received electromagnetic waves, and send them to the modem processor for demodulation.
  • the mobile communication module 650 can also amplify the signal modulated by the modem processor, convert it into electromagnetic wave and radiate it through the antenna 1 .
  • at least part of the functional modules of the mobile communication module 650 may be set in the processor 610 .
  • at least part of the functional modules of the mobile communication module 650 and at least part of the modules of the processor 610 may be set in the same device.
  • a modem processor may include a modulator and a demodulator.
  • the modulator is used for modulating the low-frequency baseband signal to be transmitted into a medium-high frequency signal.
  • the demodulator is used to demodulate the received electromagnetic wave signal into a low frequency baseband signal. Then the demodulator sends the demodulated low-frequency baseband signal to the baseband processor for processing.
  • the low-frequency baseband signal is passed to the application processor after being processed by the baseband processor.
  • the application processor outputs sound signals through audio equipment (not limited to speaker 670A, receiver 670B, etc.), or displays images or videos through display screen 694 .
  • the modem processor may be a stand-alone device.
  • the modem processor may be independent of the processor 610, and be set in the same device as the mobile communication module 650 or other functional modules.
  • the wireless communication module 660 can provide wireless local area network (wireless local area networks, WLAN) (such as wireless fidelity (wireless fidelity, Wi-Fi) network), bluetooth (bluetooth, BT), global navigation satellite System (global navigation satellite system, GNSS), frequency modulation (frequency modulation, FM), near field communication technology (near field communication, NFC), infrared technology (infrared, IR) and other wireless communication solutions.
  • the wireless communication module 660 may be one or more devices integrating at least one communication processing module.
  • the wireless communication module 660 receives electromagnetic waves via the antenna 2 , frequency-modulates and filters the electromagnetic wave signals, and sends the processed signals to the processor 610 .
  • the wireless communication module 660 can also receive the signal to be sent from the processor 610, frequency-modulate it, amplify it, and convert it into electromagnetic waves through the antenna 2 to radiate out.
  • the antenna 1 of the electronic device 600 is coupled to the mobile communication module 650, and the antenna 2 is coupled to the wireless communication module 660, so that the electronic device 600 can communicate with the network and other devices through wireless communication technology.
  • the wireless communication technology may include global system for mobile communications (GSM), general packet radio service (general packet radio service, GPRS), code division multiple access (code division multiple access, CDMA), broadband Code division multiple access (wideband code division multiple access, WCDMA), time division code division multiple access (time-division code division multiple access, TD-SCDMA), long term evolution (long term evolution, LTE), BT, GNSS, WLAN, NFC , FM, and/or IR techniques, etc.
  • GSM global system for mobile communications
  • GPRS general packet radio service
  • code division multiple access code division multiple access
  • CDMA broadband Code division multiple access
  • WCDMA wideband code division multiple access
  • time division code division multiple access time-division code division multiple access
  • TD-SCDMA time-division code division multiple access
  • the GNSS may include a global positioning system (global positioning system, GPS), a global navigation satellite system (global navigation satellite system, GLONASS), a Beidou navigation satellite system (beidou navigation satellite system, BDS), a quasi-zenith satellite system (quasi -zenith satellite system (QZSS) and/or satellite based augmentation systems (SBAS).
  • GPS global positioning system
  • GLONASS global navigation satellite system
  • Beidou navigation satellite system beidou navigation satellite system
  • BDS Beidou navigation satellite system
  • QZSS quasi-zenith satellite system
  • SBAS satellite based augmentation systems
  • the electronic device 600 implements a display function through a GPU, a display screen 694 , and an application processor 610 .
  • the GPU is a microprocessor for image processing, connected to the display screen 694 and the application processor. GPUs are used to perform mathematical and geometric calculations for graphics rendering.
  • Processor 610 may include one or more GPUs that execute program instructions to generate or alter display information.
  • the display screen 694 is used to display images, videos and the like.
  • Display 694 includes a display panel.
  • the display panel can be a liquid crystal display (LCD), an organic light-emitting diode (OLED), an active-matrix organic light-emitting diode or an active-matrix organic light-emitting diode (active-matrix organic light emitting diode, AMOLED), flexible light-emitting diode (flex light-emitting diode, FLED), Miniled, MicroLed, Micro-oLed, quantum dot light emitting diodes (quantum dot light emitting diodes, QLED), etc.
  • the electronic device 600 may include 1 or N display screens 694, where N is a positive integer greater than 1.
  • the external memory interface 620 can be used to connect an external memory card, such as a Micro SD card, to expand the storage capacity of the electronic device 600.
  • the external memory card communicates with the processor 610 through the external memory interface 620 to implement a data storage function. Such as saving music, video and other files in the external memory card.
  • the internal memory 621 may be used to store computer-executable program code, which includes instructions.
  • the processor 610 executes various functional applications and data processing of the electronic device 600 by executing instructions stored in the internal memory 621 .
  • the internal memory 621 may include an area for storing programs and an area for storing data.
  • the stored program area can store an operating system, at least one application program required by a function (such as a sound playing function, an image playing function, etc.) and the like.
  • the storage data area can store data (such as audio data, phone book, etc.) created during the use of the electronic device 600 .
  • the internal memory 621 may include a high-speed random access memory, and may also include a non-volatile memory, such as at least one magnetic disk storage device, flash memory device, universal flash storage (universal flash storage, UFS) and the like.
  • the electronic device 600 may implement an audio function through an audio module 670 , a speaker 670A, a receiver 670B, a microphone 670C, an earphone interface 670D, and an application processor 610 . Such as music playback, recording, etc.
  • the audio module 670 is used to convert digital audio information into analog audio signal output, and is also used to convert analog audio input into digital audio signal.
  • the audio module 670 may also be used to encode and decode audio signals.
  • the audio module 670 may be set in the processor 610 , or some functional modules of the audio module 670 may be set in the processor 610 .
  • Loudspeaker 670A also called “horn” is used to convert audio electrical signals into sound signals.
  • Electronic device 600 can listen to music through speaker 670A, or listen to hands-free calls.
  • Receiver 670B also called “earpiece”, is used to convert audio electrical signals into audio signals.
  • the receiver 670B When the electronic device 600 receives a call or a voice message, the receiver 670B can be placed close to the human ear to receive the voice.
  • the microphone 670C also called “microphone” or “microphone”, is used to convert sound signals into electrical signals.
  • the user When making a call or sending a voice message, or when the electronic device 600 needs to be triggered to perform certain functions through the voice assistant, the user can make a sound by approaching the microphone 670C with a human mouth, and input the sound signal into the microphone 670C.
  • the electronic device 600 may be provided with at least one microphone 670C. In some other embodiments, the electronic device 600 may be provided with two microphones 670C, which may also implement a noise reduction function in addition to collecting sound signals.
  • the electronic device 600 can also be provided with three, four or more microphones 670C to collect sound signals, reduce noise, identify sound sources, and realize directional recording functions, etc.
  • the earphone interface 670D is used to connect wired earphones.
  • the earphone interface 670D may be a USB interface 630, or a 3.5mm open mobile terminal platform (open mobile terminal platform, OMTP) standard interface, or a cellular telecommunications industry association of the USA (CTIA) standard interface. .
  • Touch sensor also known as "touch panel”.
  • the touch sensor can be arranged on the display screen 694, and the touch sensor and the display screen 694 form a touch screen, also called “touch screen”.
  • the touch sensor is used to detect a touch operation on or near it.
  • the touch sensor can pass the detected touch operation to the application processor to determine the type of touch event.
  • visual output related to touch operations can be provided through the display screen 694 .
  • the touch sensor may also be disposed on the surface of the electronic device 600 , which is different from the position of the display screen 694 .
  • the pressure sensor is used to sense the pressure signal and convert the pressure signal into an electrical signal.
  • a pressure sensor may be located on the display screen 694 .
  • pressure sensors such as resistive pressure sensors, inductive pressure sensors, and capacitive pressure sensors.
  • a capacitive pressure sensor may be comprised of at least two parallel plates with conductive material. When a force is applied to the pressure sensor, the capacitance between the electrodes changes.
  • the electronic device 600 determines the intensity of pressure according to the change in capacitance.
  • the electronic device 600 detects the intensity of the touch operation according to the pressure sensor.
  • the electronic device 600 may also calculate the touched position according to the detection signal of the pressure sensor.
  • touch operations acting on the same touch position but with different touch operation intensities may correspond to different operation instructions. For example: when a touch operation with a touch operation intensity less than the first pressure threshold acts on the short message application icon, an instruction to view short messages is executed. When a touch operation with a touch operation intensity greater than or equal to the first pressure threshold acts on the short message application icon, the instruction of creating a new short message is executed.
  • the gyro sensor can be used to determine the motion posture of the electronic device 600 .
  • the acceleration sensor can detect the acceleration of the electronic device 600 in various directions (generally three axes). Distance sensor for measuring distance.
  • the electronic device 600 can measure the distance by infrared or laser.
  • the electronic device 600 can use the proximity light sensor to detect that the user holds the electronic device 600 close to the ear to make a call, so as to automatically turn off the screen to save power.
  • the ambient light sensor is used to sense the ambient light brightness.
  • the fingerprint sensor is used to collect fingerprints.
  • a temperature sensor is used to detect temperature. In some embodiments, the electronic device 600 uses the temperature detected by the temperature sensor to implement a temperature processing strategy.
  • the audio module 670 can analyze the voice signal based on the vibration signal of the vibrating bone mass of the vocal part acquired by the bone conduction sensor, so as to realize the voice function.
  • the application processor can analyze the heart rate information based on the blood pressure beating signal acquired by the bone conduction sensor, so as to realize the heart rate detection function.
  • the keys 690 include a power key, a volume key and the like.
  • the motor 691 can generate a vibrating reminder.
  • the indicator 692 can be an indicator light, and can be used to indicate charging status, power change, and can also be used to indicate messages, missed calls, notifications, and the like.
  • the SIM card interface 695 is used for connecting a SIM card.
  • the electronic device 600 may support 1 or N SIM card interfaces 695, where N is a positive integer greater than 1.
  • SIM card interface 695 can support Nano SIM card, Micro SIM card, SIM card etc. Multiple cards can be inserted into the same SIM card interface 695 at the same time.
  • the SIM card interface 695 is also compatible with different types of SIM cards.
  • the SIM card interface 695 is also compatible with external memory cards.
  • the electronic device 600 interacts with the network through the SIM card to implement functions such as calling and data communication.
  • the electronic device 600 adopts an eSIM, that is, an embedded SIM card.
  • the eSIM card can be embedded in the electronic device 600 and cannot be separated from the electronic device 600 .
  • All the low SAR antenna solutions provided in the embodiments of the present application can be applied to electronic devices with the composition shown in FIG. 6 .
  • the solution provided by the embodiment of the present application can be applied to the antenna 1 to realize radiation with low SAR and high efficiency.
  • the composition of the electronic device shown in FIG. 6 is only an example. It does not constitute a limitation on the application environment of the solutions provided by the embodiments of the present application.
  • the electronic device may also have other components.
  • the electronic device 600 may be provided with a communication module for realizing the wireless communication function of the electronic device 600 .
  • the communication module may include an antenna, a radio frequency module coupled to the antenna, and a processor.
  • the antenna may be an antenna covering a main frequency band.
  • the radio frequency module may include components such as a filter, a power amplifier, and a radio frequency switch, and is used for processing the sending and receiving signals in the radio frequency domain.
  • the processor may include a baseband processor, and the processor may be coupled with the radio frequency module, and is used to process the sending and receiving signals in the digital domain.
  • the antenna solution provided in the embodiment of the present application can also be applied to the antenna shown in FIG. 7 .
  • FIG. 8 shows a schematic diagram of a low SAR antenna provided by an embodiment of the present application.
  • the antenna may be disposed on the upper antenna area of the electronic device. In this way, the impact on the antenna caused by the electronic device held by the user is avoided. It should be noted that, for ease of description, in the following examples, the electronic device is taken as an example for description. Wherein, the schematic diagrams of the position of the antenna on the mobile phone are the rear views of the mobile phone.
  • the low SAR antenna provided in the embodiment of the present application may include at least two radiation structures.
  • the first radiation structure is used to realize low-frequency radiation
  • the second radiation structure is used to realize medium-high frequency radiation.
  • the first radiating structure is radiating structure 1 and the second radiating structure is radiating structure 2 .
  • the two radiation structures in this example will be described separately below.
  • the radiation structure 1 can realize its low-frequency radiation function through the IFA antenna.
  • the radiation structure 1 may include at least one radiator, one feeding point, and one switching module (such as SW1 ).
  • the radiator in the radiation structure 1 may be located at the upper right of the mobile phone.
  • the radiator in the radiation structure 1 is realized by any one or more of the following forms: flexible circuit board (Flexible Printed Circuit, FPC) antenna, stamping (stamping) metal antenna, laser direct forming (Laser-Direct-structuring, LDS) antenna.
  • the radiator in the radiation structure 1 can also reuse metal structural parts in the mobile phone. For example, when the mobile phone has a metal frame design, the metal frame can be used at the position corresponding to the radiation structure 1 as shown in FIG. 8 to realize the radiation function of the radiator.
  • the feed point may be a position where the radio frequency module is coupled with the antenna.
  • metal shrapnel, thimble and other components can be used at the feeding point to realize the coupling between the circuit and the antenna radiator.
  • a radio frequency module is disposed on a printed circuit board (printed circuit board, PCB) as an example.
  • the radio frequency signal can be transmitted to the electrical connection parts at the feed point (such as the above-mentioned metal shrapnel, thimble, etc.) through the radio frequency line on the PCB, through the rigid connection of the electrical connection parts or through the electronic circuit on the FPC Welding of conductive materials such as so that the radio frequency signal can be transmitted to the antenna radiator.
  • the antenna radiator can transmit radio frequency signals (analog signals) in the form of electromagnetic waves in the corresponding working frequency band of the antenna.
  • the radiator of the radiation structure 1 can work in the low frequency band, then after receiving the radio frequency signal from the feeding point, the radiator of the radiation structure 1 can transmit the radio frequency signal in the form of electromagnetic waves at a low frequency.
  • the radiator of radiation structure 1 can receive low-frequency electromagnetic wave signals (that is, low-frequency electromagnetic waves), convert the low-frequency electromagnetic waves into analog signals, and feed them back to the radio frequency module through the feed point, thereby realizing low-frequency signal take over.
  • the feeding point may be set at the upper right corner of the top of the mobile phone.
  • the current strength point that excites the floor and the current strength point of the eigenmode of the floor are separated, thereby more effectively dispersing the floor current, and achieving the effect of reducing the SAR value.
  • the horizontal and vertical currents of the floor can be better stimulated, and the antenna efficiency and bandwidth can be improved.
  • a matching circuit may also be provided between the feeding point and the radio frequency module.
  • the matching circuit can be used to tune the working frequency band of the antenna. By switching or adjusting, the impedance of the antenna is adjusted to match the RF module (such as tuning to 75 ohms or 50 ohms), thereby reducing the signal reflection at the antenna port , to improve signal transmission or reception efficiency.
  • the switching module SW1 can be used to switch the radiation structure 1 to work in different low frequency states, so that the radiation structure 1 can cover the whole low frequency band.
  • one end of SW1 may be coupled to the radiator of the radiation structure 1 , and the other end of SW2 may be grounded.
  • the antenna shown in FIG. 8 works at a low frequency
  • the antenna can work in the 1/4 mode of the IFA, that is, work in the fundamental mode. Therefore, better radiation performance and lower SAR value can be provided.
  • a radiation structure 2 may also be included.
  • the radiation structure 2 can cooperate with the radiation structure 1 to realize medium and high frequency radiation.
  • the radiation structure 2 may include at least one radiator.
  • One end of the radiator of the radiating structure 2 can be close to the radiator of the radiating structure 1 , so as to achieve the effect of electric field coupling with the radiator of the radiating structure 1 .
  • the other end of the radiator of the radiation structure 2 may be coupled to SW2.
  • the radiators of radiation structure 1 and radiation structure 2 can be coupled through the gap, and the top radiator is excited to obtain the slot common mode (slot common mode, Slot CM)/slot antenna difference Mode (slot differential mode, Slot DM) two modes.
  • slot common mode slot common mode
  • Slot CM slot common mode
  • slot DM slot differential mode
  • the Slot CM mode is referred to as the CM mode
  • the Slot DM mode is referred to as the DM mode for short.
  • the switching module (such as SW2) in the radiation structure 2 can be loaded with a capacitor or the capacitor can tune the resonance of the top branch to 1710MHz-2690MHz, so as to achieve medium and high frequency coverage. .
  • the medium and high frequencies are covered by CM mode and DM mode, which replaces the high-order mode of the traditional IFA antenna covering the medium and high frequencies, so the radiation of the antenna in the medium and high frequencies can be significantly improved While improving the performance, reduce the SAR value of medium and high frequencies.
  • FIG. 9 shows a specific composition of an antenna solution having a logical composition as shown in FIG. 8 .
  • a specific implementation of SW1 and SW2 is given.
  • SW1 and SW2 can be realized by Single Pole N Throw (SPNT) switches.
  • SPNT Single Pole N Throw
  • SW1 and SW2 can use single-pole three-throw to realize their switching functions.
  • the number of switching states of the single-pole multi-throw switch may also be other numbers, such as switching of at least three states (such as 1-pass, 2-pass, and all-off) through a single-pole double-throw (SPDT) switch.
  • SW1 and SW2 may also implement their functions through other components with switching functions.
  • SW1 and/or SW2 can realize their switching function through an adjustable/variable device.
  • SW1 and/or SW2 can realize its switching function through multiple poles and multiple throws.
  • SW1 and SW2 can switch between at least 4 states (such as 01, 10, 00, 11) through 2*SPST.
  • different paths of SW1 may be loaded with inductors for low-frequency switching.
  • the radiator of the radiation structure 1 can be grounded, thereby forming a radiation form of the IFA.
  • a small capacitance (such as a capacitance less than 2pF) may be connected in series between the radiator of the radiating structure 1 and the feed source of the radio frequency circuit, so that the radiating structure 1 can The excitation acquires the left-handed mode, thereby realizing low-frequency excitation in a small space.
  • a current without a reverse point can be formed on the entire radiator of the radiation structure 1 . This current distribution is also the current distribution of the left-handed mode. It should be understood that the excitation of the left-handed mode can successfully excite low frequency radiation in a small space.
  • the radiator In the case of exciting the left-handed mode, by switching different paths on SW1, the radiator returns to the ground through inductances of different sizes, which can play the role of switching low-frequency resonance, so that the low-frequency resonance in different states can cooperate to cover the entire LB band.
  • FIG. 9 The working mechanism of the antenna solution shown in FIG. 9 will be described in detail in FIGS. 10-15 below.
  • the working conditions of the radiation structure 1 are firstly described below.
  • FIG. 10 it is a schematic diagram of the radiation situation of the antenna when the radiation structure 1 works alone.
  • (a) in FIG. 10 shows S11 when the radiation structure 1 works alone. It can be seen that when the radiation structure 1 works alone, the deepest part of the low-frequency resonance has exceeded -16dB, which is ideal.
  • -16dB the deepest part of the low-frequency resonance
  • the resonances corresponding to the higher-order modes are obtained near 2 GHz and 2.5 GHz.
  • the radiation efficiency (radiation efficiency) can be used to identify the difference between the energy input from the port and the energy fed back to the port through radiation and loss in the case of single-port excitation in the current antenna system.
  • the higher the radiation efficiency the smaller the energy fed back to the port, and the stronger the radiation capability provided by the current antenna system.
  • the system efficiency can be used to identify the difference between the energy input from the port and the energy fed back to the port through radiation in the case of single-port excitation of the current antenna system.
  • the higher the system efficiency the more energy the antenna radiates out, that is, the higher the radiation performance of the antenna. That is to say, ideally, the system efficiency of the current antenna system can reach the level of radiation efficiency, and the radiation efficiency can be the maximum radiation capability that the current antenna system can provide.
  • FIG. 11 shows a schematic diagram of current flow when the radiation structure 1 works alone.
  • 0.74GHz ie low frequency
  • 1.94GHz ie intermediate frequency
  • 2.54GHz ie high frequency
  • the mid-high frequency resonance as shown in (a) in FIG. 10 is the radiation generated by the high-order mode of the IFA antenna.
  • the antenna may further include a radiation structure 2 in addition to the radiation structure 1 .
  • the radiating structure 2 can be excited by the CM mode and DM mode with the top structure of the radiating structure 1 through the form of electric field coupling, thereby adjusting the excitation mode of the medium and high frequency, while obtaining better system efficiency or radiation efficiency, avoiding The SAR value is too high.
  • FIG. 12 shows a schematic diagram of S11 when the antenna having the composition shown in FIG. 9 is in operation. That is to say, as shown in FIG. 12 , it is the result of the radiation structure 1 and the radiation structure 2 working together.
  • FIG. 12 a schematic diagram of S11 when only the radiation structure 1 is working is also shown for comparison.
  • CM mode and DM mode coverage are obtained under medium and high frequency excitation. In this way, the problem that the SAR value of the high-order mode of the IFA antenna is too high can be avoided.
  • FIG. 13A shows a schematic diagram of medium and high frequency currents when the radiation structure 1 and the radiation structure 2 work simultaneously.
  • (a) in FIG. 13A shows the current flow at a frequency point around 2.5 GHz. It can be seen that current distribution in the same direction can be generated in the top radiator (including the top part of the radiator of the radiation structure 1 and the radiator of the radiation structure 2 ). Since there is no electrical connection between the top portion of the radiator of the radiation structure 1 and the radiator of the radiation structure 2 , that is, there is a gap, the current distribution can constitute CM mode radiation. Combining with S11 shown in Figure 12, it can be seen that the CM mode can cover the intermediate frequency for radiation.
  • FIG. 13A shows the current flow at a frequency point around 2.7 GHz. It can be seen that the current in the top radiator (including the top portion of the radiator of the radiation structure 1 and the radiator of the radiation structure 2 ) can generate a reverse current distribution. Since there is no electrical connection between the top portion of the radiator of the radiation structure 1 and the radiator of the radiation structure 2 , that is, there is a gap, the current distribution can constitute radiation in the DM mode. Combined with S11 shown in Figure 12, it can be seen that the DM mode can cover high frequencies for radiation.
  • Fig. 13B shows the actual model simulated current distributions for CM mode and DM mode. It can be seen that at medium and high frequencies, as shown in (a) in Figure 13B, the CM mode can excite the top radiator to obtain a current in the same direction (across the gap), and at the same time, the current on the long branch on the side of the mobile phone is small. As shown in (b) in FIG. 13B , the DM mode can separately stimulate the radiators on both sides of the slot to obtain reverse currents, and at the same time, the current on the long branches on the side of the mobile phone is relatively small. It can thus be proved that by adding the radiation structure 2 , the effect of exciting and acquiring the CM mode and DM mode at the top can be achieved.
  • FIG. 14 shows the radiation efficiency of the entire antenna system and the change of the system efficiency after the radiation structure 2 is added.
  • the radiation efficiency between 2.3 GHz and 2.7 GHz is significantly increased. From this, it can be determined that after adding the radiation structure 2 to introduce the DM mode and the CM mode, the radiation performance that the entire antenna system can provide is optimized.
  • the system efficiency in the entire mid- and high-frequency bands is improved. Therefore, after adding the radiation structure 2 to introduce the DM mode and the CM mode, the actual radiation performance provided by the entire antenna system is also optimized. Therefore, when the radiating structure 1 and the radiating structure 2 work simultaneously, they can provide better radiation performance than typical IFA antennas.
  • FIG. 15 shows a floor current diagram of a typical IFA antenna when only the radiating structure 1 works at medium and high frequencies (as shown in FIG. 15 ( (a) ), and the floor current at medium and high frequencies when the radiating structure 1 and the radiating structure 2 work simultaneously (as shown in (b) in FIG. 15 ).
  • the distribution area of the current on the floor is larger.
  • the distribution area of the current on the floor is relatively small. Therefore, when the radiating structure 1 and the radiating structure 2 work at the same time, the medium and high frequency currents are more dispersed, so that the SAR value of the antenna system at the medium and high frequencies is also smaller.
  • the SW2 on the radiating structure 2 is set at the end far away from the radiating structure 1 as an example. In some other embodiments of the present application, the SW2 on the radiating structure 2 can also be set at other positions to achieve the effect of switching between the CM mode and the DM mode covering frequency bands through different states of the SW2.
  • FIG. 16 shows yet another configuration of SW2.
  • SW2 may be disposed in the radiation structure 2 , close to one end of the radiation structure 1 .
  • the radiator of the radiating structure 2 can be grounded at an end away from the radiating structure 1, so as to effectively excite the CM mode and/or the DM mode.
  • FIG. 17 shows a specific diagram of an antenna having the topology shown in FIG. 16 .
  • different paths of SW2 can be loaded with inductors to adjust the frequency bands covered by the CM mode and/or the DM mode. For example, when channel 1 of SW2 is turned on, the CM mode and/or DM mode can be adjusted to frequency band 1. When channel 2 of SW2 is turned on, CM mode and/or DM mode can be adjusted to band 2. Wherein, when the inductance values of path 1 and path 2 are different, frequency band 1 and frequency band 2 are different.
  • the medium and high frequency can be covered by the CM mode and the DM mode, so as to improve the medium and high frequency radiation performance and reduce the SAR value.
  • the antenna may further include a radiation structure 3 .
  • the radiation structure 3 can further optimize the radiation performance of medium and high frequencies.
  • the CM mode can be used to generate a resonance around 2.6 GHz, which can be identified on S11 as a notch for the resonance.
  • the DM mode can be used to resonate around 2.9GHz, which can also be marked as a resonant notch on the S11.
  • 2.9GHz can also be marked as a resonant notch on the S11.
  • S11 bump due to mode incompatibility.
  • efficiency there will be a reduction in efficiency around the 2.75 GHz, which can be expressed as a depression on the efficiency curve.
  • the antenna may further include a third radiation structure (such as the radiation structure 3 ).
  • the radiation structure 3 can be used to excite a new resonance between the mid-high frequency CM mode and the DM mode, thereby improving the overall mid-high frequency radiation performance.
  • the radiation structure 3 may include at least one radiator.
  • One end of the radiator of the radiating structure 3 may be close to the radiator of the radiating structure 1 , but the radiator of the radiating structure 3 is not connected to the radiator of the radiating structure 1 .
  • a gap may be formed between the radiator of the radiation structure 3 and the radiator of the radiation structure 1 .
  • a changing current occurs at the radiator of the radiation structure 1 .
  • energy can be coupled to the radiation structure 3 , thereby exciting the radiator of the radiation structure 3 to generate an alternating current.
  • the radiator of the radiating structure 3 may be grounded at the end far away from the radiating structure 1 , so that the radiating structure 3 forms a parasitic antenna to work.
  • the size of the radiator of the radiating structure 3 can correspond to 1/4 of the wavelength of the frequency band where the efficiency of the CM mode and the DM mode is notched, so that the radiating structure 3 can generate new energy in the frequency band where the efficiency of the CM mode and the DM mode is notched by parasitic effects. resonance. In some implementations, as shown in FIG.
  • a switching module SW3 may be provided at the end of the radiation structure 3 close to the radiation structure 1, and the SW3 may be used to switch different paths so that the radiator of the radiation structure 3 exhibits different
  • the electrical length allows the radiation structure 3 to adjust the resonance position corresponding to the parasitic according to the needs of different scenarios, and more effectively compensate for the efficiency sag in the middle and high frequencies.
  • the SW3 may not be provided in the radiation structure 3 , so as to achieve the effects of compensating for medium and high frequency radiation performance and reducing device cost and layout space.
  • FIG. 19 shows a specific implementation of the antenna with the topology shown in FIG. 18 .
  • FIG. 19 shows a specific implementation of the antenna with the topology shown in FIG. 18 .
  • the composition of the radiator of the radiation structure 3 is similar to that of the radiators of the radiation structure 1 and the radiation structure 2 above, which can be realized by FPC, LDS, stamping, or the metal structure of the mobile phone itself.
  • the SW3 can realize its switching function through the SPNT in the above example or a plurality of switching switches, or other components with a switching function.
  • SW3 can implement its switching function through SP3T.
  • inductance can be loaded separately, so as to achieve the effect of adjusting the electrical length of parasitic branches by switching different paths.
  • the resonance generated by the radiation structure 3 may be located in the frequency band A.
  • the path B of SW3 is turned on, the resonance generated by the radiation structure 3 can be located in the frequency band B.
  • the inductance values loaded on path A and path B are different, frequency band A and frequency band B are different.
  • the frequency band (that is, frequency band A) where the resonance generated by the radiation structure 3 can be shifted from a lower frequency band to The higher frequency band where Band B is located moves.
  • the mid-high frequency resonance can be significantly improved, and the mid-high frequency efficiency pit caused by the introduction of the CM mode and the DM mode can be weakened.
  • the radiation performance of the antenna after adding the radiation structure 2 and the radiation structure 3 will be described in detail below in combination with the simulation results.
  • FIG. 20 is a schematic diagram showing the distribution of S parameters of the antenna having the composition shown in FIG. 19 provided by the embodiment of the present application.
  • (a) of FIG. 20 after adding the radiation structure 2 and the radiation structure 3, a spurious resonance appears between the CM mode and the DM mode on S11.
  • S11 after only adding the radiation structure 2 shown in Figure 12, after adding the radiation structure 3 again, due to the appearance of spurious resonance, the bulge between the resonances of the CM mode and the DM mode is compensated, and the highest point is shown in Figure 12 Shown around -11dB, down to around -13dB as shown in Figure 12.
  • the radiation efficiency of the antenna at medium and high frequencies is significantly improved.
  • the actual efficiency of the antenna at medium and high frequencies is also significantly improved. Therefore, it can be shown that after adding the radiation structure 2 and the radiation structure 3 , compared with a typical IFA antenna, it can provide better radiation performance at medium and high frequencies. Comparing the efficiency diagram after adding the radiating structure 2 as shown in FIG. 14 , it can be seen that after the radiating structure 3 is added again, the effect of compensating the medium and high frequency performance can be achieved.
  • FIG. 21 shows the distribution of the floor current when only the radiation structure 1 is working.
  • the distribution of the floor current when the radiation structure 2 and the radiation structure 3 are working at the same time it can be clearly seen that after the radiation structure 2 and the radiation structure 3 are added , the floor current distribution is extended.
  • the energy distribution of the antenna with the composition shown in FIG. 19 is more dispersed when radiating, so that it can have a lower SAR value than a typical IFA.
  • Fig. 18 and Fig. 19 are only examples of the radiation structure 3 provided by the embodiment of the present application.
  • the radiation structure 3 may also have other components, so as to achieve the effect of compensating the CM mode and the DM mode through parasitic effects.
  • the radiator of the radiation structure 3 may not be grounded (eg suspended) at the end far away from the radiation structure 1 .
  • each path of SW3 can be loaded with capacitance, so that when SW3 is switched to a different path, the capacitance on the different path can be loaded on the radiator of the radiation structure 3, thereby stimulating the parasitic resonance of the radiation structure 3 At the same time, the resonance position is adjusted through the capacitance on different paths.
  • the SW3 is set at the end of the radiation structure 3 close to the radiation structure 1 as an example.
  • the SW3 can also be arranged at other positions in the radiation structure 3 , which can also have the effect of adjusting the corresponding frequency band of the parasitic resonance of the radiation structure 3 .
  • the embodiment of the present application does not limit the specific position of SW3 in the radiation structure 3 .
  • the antenna solution provided by the embodiment of the present application has better radiation performance than a typical IFA antenna, and can avoid the problem of excessive high-frequency SAR value caused by the IFA high-order mode.
  • FIG. 23 is a schematic diagram of the distribution of hot spots during the measurement process of a typical IFA antenna and the antenna with the composition shown in FIG. 19 .
  • (a) in FIG. 23 is the hotspot distribution of a typical IFA antenna
  • (b) in FIG. 23 is the hotspot distribution of the antenna provided by the present application. It is obvious that the distribution of hot spots shown in (b) in Fig. 23 is more scattered, so the SAR value should be lower.
  • Table 2 below shows the actual SAR measurement results of the two antennas.
  • the SAR value of the antenna provided by the embodiment of the present application with the composition shown in FIG. 19 is smaller than that of a typical IFA antenna in the entire frequency band of 2 GHz-2.6 GHz.
  • FIG. 24 is a schematic diagram of the distribution of hot spots during the measurement process of a typical IFA antenna and the antenna with the composition shown in FIG. 19 .
  • (a) in FIG. 24 is the hotspot distribution of a typical IFA antenna
  • (b) in FIG. 24 is the hotspot distribution of the antenna provided by the present application. It is obvious that the distribution of hot spots shown in (b) in Fig. 24 is more scattered, so the SAR value should be lower.
  • Table 3 below shows the actual SAR measurement results of the two antennas.
  • the SAR value of the antenna provided by the embodiment of the present application with the composition shown in FIG. 19 is smaller than that of a typical IFA antenna in the entire frequency band of 2 GHz-2.6 GHz.
  • FIG. 25 shows a typical IFA antenna and an antenna with the composition shown in FIG. 19 showing the distribution of hot spots during the measurement process.
  • (a) in FIG. 25 is the hotspot distribution of a typical IFA antenna
  • (b) in FIG. 25 is the hotspot distribution of the antenna provided by the present application. It is obvious that the distribution of hot spots shown in (b) in Fig. 25 is more dispersed, so the SAR value should be lower.
  • Table 4 below shows the actual SAR measurement results of the two antennas.
  • the SAR value of the antenna provided by the embodiment of the present application with the composition shown in FIG. 19 is smaller than that of a typical IFA antenna in the entire frequency band of 2 GHz-2.6 GHz.
  • the functions or actions or operations or steps in the above-mentioned embodiments may be fully or partially implemented by software, hardware, firmware or any combination thereof.
  • a software program When implemented using a software program, it may be implemented in whole or in part in the form of a computer program product.
  • the computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on the computer, the processes or functions according to the embodiments of the present application will be generated in whole or in part.
  • the computer can be a general purpose computer, a special purpose computer, a computer network, or other programmable devices.
  • the computer instructions may be stored in or transmitted from one computer-readable storage medium to another computer-readable storage medium, for example, the computer instructions may be transmitted from a website, computer, server, or data center Transmission to another website site, computer, server or data center by wired (such as coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (such as infrared, wireless, microwave, etc.).
  • the computer-readable storage medium may be any available medium that can be accessed by a computer, or may include one or more data storage devices such as servers and data centers that can be integrated with the medium.
  • the available medium may be a magnetic medium (such as a floppy disk, a hard disk, or a magnetic tape), an optical medium (such as a DVD), or a semiconductor medium (such as a solid state disk (solid state disk, SSD)), etc.

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Abstract

本申请实施例公开了一种低SAR天线及电子设备，涉及电子设备领域，可以提供较好的中高频辐射性能，同时具有较低的SAR值。具体方案为：第一辐射结构包括第一辐射体，第二辐射结构包括第二辐射体。第一辐射体的第一端与第二辐射体的第一端构成第一缝隙。第一辐射体的第二端悬空，第二辐射体的第二端接地。天线的馈电点与第一辐射体耦接，以馈电点为分界，将第一辐射体划分为第一部分和第二部分。在天线工作时，第一辐射体的第一部分与第二辐射体共同工作在第一频段和第二频段，第一频段的频率低于第二频段的频率。

Description

一种低SAR天线及电子设备
本申请要求于2021年6月25日提交国家知识产权局、申请号为202110711505.9、发明名称为“一种低SAR天线及电子设备”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请涉及电子设备领域，尤其涉及一种低SAR天线及电子设备。
背景技术
电子设备可以通过其中设置的天线进行无线信号的收发。天线的辐射性能与天线在电子设备中的环境关系紧密。比如，当天线设置在电子设备的下部时，由于用户手握电子设备会覆盖天线，从而对天线的辐射性能造成较大影响；进而影响用户手持电子设备时的通信体验。
目前，可以将天线设置在电子设备的上部，从而避免手握电子设备对天线辐射性能的影响。
可以理解的是，电子设备在工作时，在为用户提供畅通的无线通信体验之外，还需要将对人体的辐射控制在合理范围内，从而避免电磁辐射对人体的伤害。而当天线设置在电子设备的上部时，在用户使用电子设备的一些场景下(如用户使用手机进行通话时)，天线距离用户头部的距离较近。而具有较好辐射性能的天线所产生或接收的电磁波的功率一般较大，由此也就会对用户的头部产生较大的辐射。
因此，如何保证电子设备的辐射能力的同时，将对人体的辐射控制在合理范围内成为保证电子设备的无线通信性能的关键。
发明内容
本申请实施例提供一种低SAR天线及电子设备，可以提供较好的中高频辐射性能，同时具有较低的SAR值。
为了达到上述目的，本申请实施例采用如下技术方案：
第一方面，提供一种低SAR天线，应用于电子设备，该天线包括：第一辐射结构和第二辐射结构。该第一辐射结构包括第一辐射体，该第二辐射结构包括第二辐射体，该第一辐射体与该第二辐射体不导通。该第一辐射体的第一端与该第二辐射体的第一端相对设置，该第一辐射体的第一端与该第二辐射体的第一端构成第一缝隙。该第一辐射体的第二端悬空，该第二辐射体的第二端接地。该天线的馈电点与该第一辐射体耦接，以该馈电点为分界，将该第一辐射体划分为第一部分和第二部分，该第一部分的长度小于该第二部分的长度。该第二部分上在该第一辐射体的第二端和该馈电点之间设置有接地点。
基于该方案，提供了一种具体的具有低SAR高性能天线的方案示例。在本示例中，该天线可以具有两个辐射区域，如第一辐射结构和第二辐射结构。其中，每个辐射结 构都可以包括对应的辐射体以及相关的接地和/或馈电结构。在本示例提供的方案中，第一辐射结构可以作为直接馈电的对象，即馈电信号可以直接通过馈电点馈入第一辐射体，从而激励第一辐射体的工作。比如，第一辐射体的工作频段可以包括低频。在一些实现中，可以通过在第一辐射体上激励1/4波长实现低频覆盖。在另一些实现中，第一辐射体还可以通过激励高次模覆盖中高频。第二辐射结构可以作为第一辐射结构的寄生设置。在本示例中，该寄生可以设置在第一辐射体的短枝节附近。需要说明的是，在本示例的方案中，第一辐射体的短枝节(如第一辐射体的第一部分)可以与第二辐射体共同激励覆盖中高频。而由于该覆盖中高频的模式并非高次模(如IFA天线的高次模)，因此具有较低的中高频段的SAR值。另外，本示例中的方案的低频和中高频合路设计，因此不会引入低频和中高频分路导致的额外插损。
在一种可能的设计中，在该天线工作时，该第一辐射体的第一部分与该第二辐射体共同工作在第一频段和第二频段，该第一频段的频率低于该第二频段的频率。工作在该第一频段时，该第一部分上的电流方向与该第二辐射体上的电流方向相同。工作在该第二频段时，该第一部分上的电流方向与该第二辐射体上的电流方向在该第一缝隙处反向。以使得该天线在该第一频段和该第二频段的SAR值低于该第一辐射结构单独工作在该第一频段和该第二频段时的SAR值。基于该方案，提供了本示例提供的天线方案在工作时的具体机制。比如，第一辐射体和第二辐射体可以共同激励CM模式以及DM模式，从而代替IFA天线的高次模覆盖中高频，由此在提供较好的辐射性能的同时，避免高次模引入的SAR过高的问题。
在一种可能的设计中，该第一辐射结构为IFA天线。基于该方案，提供了一种具体的第一辐射结构的实现。比如，在该示例中，该第一辐射结构可以具有IFA天线的辐射形式。也就是说，该第一辐射结构中，可以包括第一辐射体，还可以包括馈电点，以及馈电点附近的接地点。在一些实现中，第一辐射结构中还可以包括馈电点与射频模块之间的匹配电路。该匹配电路可以通过串联和/或并联电容或电感器件，减少天线端口插损。在本示例中，IFA天线的匹配电路中可以串联有小电容(如小于2pF)，用于在IFA天线上激励左手模式覆盖低频端。在一些实现中，该IFA天线的接地点可以是第一辐射体通过开关电路接地的形式。这样，可以通过切换开关电路的电感和/或电容值，实现低频谐振切换。
在一种可能的设计中，该第二辐射结构构成该第一辐射体的寄生结构，在该天线工作时，该第二辐射结构通过该第一缝隙，与该第一辐射结构的第一辐射体进行电场耦合，以激励该第二辐射体上的电流。基于该方案，提供了一种具体的第二辐射结构的示例。在本示例中，第二辐射结构可以为第一辐射结构的寄生。在一些实现中，该第二辐射结构可以设置在第一辐射体的短枝节附近。因此第二辐射结构的寄生作用可以起到对第一辐射体的短枝节对应的谐振的频段展宽的作用。在本示例中，第二辐射结构可以不存在馈电点，由此保证天线的单馈结构。在天线工作时，第二辐射结构上的电流可以通过与第一辐射结构进行电场耦合激励。
在一种可能的设计中，该天线工作时，通过在该第一辐射体的第一部分和该第二辐射体上激励槽天线共模slot CM模式覆盖该第一频段，通过在该第一辐射体的第一部分和该第二辐射体上激励槽天线差模slot DM模式覆盖该第二频段。基于该方案， 提供了一种具体的本申请实施例提供的天线覆盖中高频的示例。在本示例中，可以通过第一辐射体的第一部分(如短枝节)和第二辐射体的共同作用，获取CM模式和DM模式的激励，从而在中高频获取至少2个谐振覆盖。由此在提供足够带宽覆盖中高频以保证其辐射性能的同时，可以获取较低的SAR值。
在一种可能的设计中，耦接所述第一辐射体的馈电点位于所述第一辐射体的弯折处。示例性的，耦接该第一辐射体的馈电点可以位于该电子设备背视图的右上角。基于该方案，提供了一种具体的第一辐射体的馈电点的位置示意。该第一辐射体的馈电点也就是天线的馈电点。通过将馈电点设置在电子设备(如手机)的右上角，能够更加有效地激励地板电流，从而达到展宽天线带宽提升辐射性能的效果。在本示例的一些实现中，第一辐射体的长枝节(如第二部分)可以是沿手机侧边设置的，短枝节(如第一部分)可以是沿手机顶部设置的。
在一种可能的设计中，该第一辐射体的第二部分的工作频段覆盖第三频段，该第三频段的频率小于该第二频段。在该天线工作在该第三频段的情况下，该第一辐射体上分布有同向电流，该第一辐射体通过激励左手模式覆盖该第三频段。基于该方案，提供了一种本申请实施例提供的天线覆盖低频的方案示例。在本示例中，第一辐射体可以通过长枝节(如第二部分)实现低频覆盖。其中，在本设计中，第一覆盖可以通过激励第一辐射体上同向电流的左右模式实现。作为一种可能的实现，可以在匹配电路中串联小电容(如小于2pF)实现左手模式的激励。需要说明的是，在本申请的另一些实现中，还可以通过激励低频的1/4IFA模式实现低频覆盖。在该实现中，该1/4IFA模式可以通过在第二部分上激励同向电流实现。
在一种可能的设计中，该天线还包括第三辐射结构，该第三辐射结构包括第三辐射体，该第三辐射体分别与该第一辐射体或该第二辐射体不导通，该第三辐射体的第一端与该第一辐射体的第二端相对设置。第三辐射体的第一端与该第一辐射体的第二端之间构成第二缝隙，该第三辐射体上设置有接地点。基于该方案，提供了又一种低SAR天线的组成示例。在本示例中，在第一辐射结构的短枝节(如第二部分)末端还可以设置第三辐射结构。该第三辐射结构可以实现在中频和高频之间的激励，从而进一步增加该天线中高频的辐射性能。尤其是能够显著提升中频和高频过度频段的辐射性能。
在一种可能的设计中，在该天线工作时，该第三辐射结构构成该第一辐射体的寄生结构，该第三辐射体用于通过该第二缝隙，与该第一辐射体进行电场耦合，以激励该第三辐射体上的电流。基于该方案，提供了一种第三辐射结构的具体实现示例。在本示例中，第三辐射结构可以构成寄生结构。在一些实现中，该第三辐射结构的第三辐射体的尺寸可以与需要覆盖的中高频的谐振所在频段的1/4波长对应。由此，通过寄生作用，可以使得第三辐射结构可以通过第二缝隙进行电场耦合，由此激励第三辐射体上的寄生电流，从而实现1/4波长的激励。进而提升中高频性能。
在一种可能的设计中，该第三辐射体的工作频段覆盖第四频段，该第四频段的频率位于该第一频段和该第二频段的频率之间。基于该方案，提供了一种第三辐射结构的具体设计示例。在一些实现中，CM模式和DM模式由于模式不相容，因此在CM模式和DM模式相交的频段附近，会出现辐射性能恶化的情况。通过本示例所示的寄生结构， 可以通过将覆盖谐振调谐到CM模式和DM模式之间，从而补偿上述性能恶化，以使得天线具有更好的中高频辐射性能。示例性的，第四频段可以包括2300-2700MHz范围内，CM模式和DM模式切换的频段。比如，在一些实现中，第四频段可以覆盖2.5GHz附近频段。
第二方面，提供一种电子设备，该电子设备设置有至少一个处理器，射频模块，以及如第一方面及其任一种可能的设计中所述的低SAR天线。该电子设备在进行信号发射或接收时，通过该射频模块和该低SAR天线进行信号的发射或接收。
应当理解的是，上述第二方面提供的技术方案，其技术特征均可对应到第一方面及其可能的设计中提供的低SAR天线，因此能够达到的有益效果类似，此处不再赘述。
附图说明
图1为一种天线设置区域的示意图；
图2为一种分布式天线的示意图；
图3为一种典型IFA天线的示意图；
图4为不同模式与地板的电流分布的对比示意图；
图5为不同模式激励的S参数示意图；
图6为本申请实施例提供的一种电子设备的组成示意图；
图7为本申请实施例提供的一种电子设备的组成示意图；
图8为本申请实施例提供的一种天线的组成示意图；
图9为本申请实施例提供的一种天线的组成示意图；
图10为本申请实施例提供的天线的S参数示意图；
图11为本申请实施例提供的电流流向示意图；
图12为本申请实施例提供的一种天线的S参数示意图；
图13A为本申请实施例提供的一种电流流向示意图；
图13B为本申请实施例提供的仿真结果的示意图；
图14为本申请实施例提供的一种天线的S参数示意图；
图15为本申请实施例提供的电流分布示意图；
图16为本申请实施例提供的一种天线的组成示意图；
图17为本申请实施例提供的一种天线的组成示意图；
图18为本申请实施例提供的一种天线的组成示意图；
图19为本申请实施例提供的一种天线的组成示意图；
图20为本申请实施例提供的一种天线的S参数示意图；
图21为本申请实施例提供的电流分布示意图；
图22为本申请实施例提供的一种天线的组成示意图；
图23为本申请实施例提供的body SAR热点分布示意图；
图24为本申请实施例提供的body SAR热点分布示意图；
图25为本申请实施例提供的Head SAR热点分布示意图。
具体实施方式
一般而言，电子设备中可以设置有多个天线，用于进行不同频段的无线通信。
示例性的，在电子设备的多个天线中，可以包括用于进行主频(频率覆盖 700MHz-3GHz)通信的天线(如称为主天线)。以电子设备为手机为例。在主天线设置在手机的下部时，天线会被用户持握手机的手覆盖，由此会导致天线性能的恶化。
在一些设计中，可以将主天线设置在电子设备的上部，从而避免用户手握电子设备时，对天线辐射性能的影响。
示例性的，结合图1，为一种电子设备的天线设置的示意图。其中，以电子设备为手机为例。该图1为手机的背部视图。如图1所示，可以将主天线设置在上天线区域。这样，在用户使用手机时，持握手机的手就不会覆盖主天线，从而不会对主天线的辐射性能产生显著的影响。
结合图2和图3，示出了一些上天线区域中主天线的示例。在图2的示例中，主天线可以由天线1和天线2组成。其中，天线1可以用于实现低频(low frequency band，LB)辐射。LB可以覆盖700MHz-960MHz频段。在如图2的示例中，天线1可以为IFA天线。比如，馈电点可以与辐射体的一端耦接，在靠近馈电点的位置，可以设置接地点与辐射体耦接，从而实现IFA天线的辐射形式。在一些实现中，该IFA天线的辐射体的长度可以接近LB的1/4波长，从而使得通过馈电点能够激励LB频段的辐射。进而使得天线1工作在LB频段。
在如图2所示的示例中，天线2可以具有环天线(loop天线)加寄生的结构，从而实现中高频(middle/high frequency band，MHB)的辐射。其中，中高频覆盖的频段可以包括1710MHz-2690MHz。环天线可以具有馈电点-辐射体-接地点的结构。寄生的辐射体的一端可以接近环天线，另一端可以接地。从而使得寄生的辐射体能够通过空间耦合从环天线获取能量，由此与环天线一同实现天线2的辐射功能。
可以看到，在如图2所示的天线方案中，可以对天线1进行低频激励(即在天线1的馈电点输入低频信号)，实现低频辐射。在接收场景下，天线1也可以接收空间中的低频电磁波，并转换为电流从馈电点传输给射频/硬件模块(图2中未示出)。类似的，天线2也可以实现中高频的辐射。由此就实现了覆盖主频的辐射性能。
然而，如图2所示的天线方案，采用了低频和中高频拆分的形式。这样，相比于未拆分的形式，在射频前端需要引入额外的部件。可以理解的是，通信链路上的所有部件都会引入对信号的损耗(即插损)，因此，如图2所示的方案会在射频前端引入至少一级开关插损，从而使得全频段射频传导损失0.5dB-1dB左右，也就使得天线在进行辐射时获取的能量的损失(如损失0.5dB-1dB)，也就使得天线的辐射性能被降低。另外，在拆分低频和中高频之后，天线辐射体也需要分别设置。由此就必然会使得本就拥挤的上天线区域的空间更加紧张，从而限制中高频(或者低频)辐射体的尺寸，这就会导致高频(或者低频)的带宽的下降，辐射能力降低。
相比于图2所示的低频和中高频分离方案，图3示出了一种不分离低频和中高频的天线方案。由于不需要在射频前端分离低频和中高频，由此就不会产生额外的插损，因此能够在传导侧提升天线性能。
在如图3所示的方案中，在上天线区域可以通过IFA形式实现主天线的辐射。其中，低频可以通过IFA天线的1/4波长模式覆盖，中频可以通过IFA天线的1/2波长模式覆盖，高频采用IFA天线3/4波长或1倍波长模式覆盖。
具有如图3所示的组成的天线，能够同时覆盖低频和中高频，因此能够避免由于 中高频拆分导致的天线辐射性能的下降。
需要说明的是，在电子设备的使用过程中，还需要避免由于天线辐射对人体的伤害。在一些实现中，天线辐射对人体的辐射情况可以通过天线的比吸收率(Specific Absorption Rate，SAR)进行标识。同一个天线，由于不同频段的辐射性能不同，因此不同频段的SAR也不同。SAR的检测可以包括头SAR，用于标识天线在辐射过程中对用户头部的辐射情况。SAR的检测还可以包括身体(body)SAR，用于标识天线在辐射过程中对用户躯干的辐射情况。目前，不同的运营商或者市场监管部门都对SAR提出了强制要求，以控制电子设备在使用过程中对用户的辐射。比如，美国联邦通信委员会(Federal Communications Commission，FCC)要求相关频段(主要为中高频段)的SAR不能超过1.6W/Kg(1g值)。
具有如图3所示的天线方案，中高频的辐射均为天线的高次模。这会使得中高频的在辐射过程中电流大多集中在天线辐射体附近，从而导致SAR的超标。
以下结合图4和图5对如图3所示的基模(如1/4波长)和高次模(如3/4波长)的辐射情况进行说明。
示例性的，图4示出了不同的模式在进行辐射时电流在地板上的分布情况。其中，图4中的(a)，图4中的(b)以及图4中的(c)均工作在相同的频段。如图4中的(a)所示，天线A的尺寸可以为工作频段的1/4波长，该天线A可以设置在电子设备的顶部。如图4中的(b)所示，天线B的尺寸可以为工作频段的1/4波长，该天线B可以设置在电子设备的侧边靠近顶部的位置。如图4中的(c)所示，天线C的尺寸可以为工作频段的3/4波长，该天线C可以设置在电子设备的侧边靠近顶部的位置。
对比图4中的(a)，图4中的(b)以及图4中的(c)，可以看到，天线A和天线B在工作时，地板上的电流分布相较于天线C工作时地板上的电流分布更加均匀。即天线A和天线B工作时，地板上电流较小的区域较小，而天线C工作时，地板上电流较小的区域较大。也就是说，3/4波长的高次模模式在辐射时，相较于基模(如1/4波长)辐射时的电流分布更加集中；即SAR更高。
图5示出了天线A，天线B和天线C的辐射性能情况。其中，回波损耗(S11)可以用于标识天线的单端口辐射能力。一般而言，S11越小，则表明单端口测试过程中该频点的回波损耗越大，即在该频点天线可以具有较好的效率。可以看到，天线A和天线B的带宽以及S11均要优于天线C。即，基模的辐射性能优于高次模的辐射性能。
图5同时还示出了天线A，天线B和天线C的系统效率对比。可以看到，与S11类似的，天线A和天线B具有较好的系统效率(如带宽更大，效率也更高)。相比之下，高次模(即天线C)的系统效率则表现的带宽较窄，效率也较低。
可以理解的是，通过如图4和图5的实验，可以看到，基模的辐射性能优于高次模的辐射性能。同时，从地板电流的分布分析可以看到，基模的SAR也会低于高次模的SAR。例如，表1示出了天线A，天线B和天线C在相同频点(如2.5GHz，2.55GHz，2.6GHz)，相同测试环境(如back面，CE 5mm，10g，输入功率24dBm，body SAR)的SAR测试结果对比。
表1
Body SAR 天线A 天线B 天线C
2.5GHz 0.61 0.63 2.59
2.55GHz 0.62 0.63 2.33
2.6GHz 0.63 0.64 2.31
由表1所示，在2.5GHz下，同样的测试环境中，天线A的SAR为0.61，天线B的SAR为0.63，天线C的SAR为2.59。在2.55GHz下，同样的测试环境中，天线A的SAR为0.62，天线B的SAR为0.63，天线C的SAR为2.33。在2.6GHz下，同样的测试环境中，天线A的SAR为0.63，天线B的SAR为0.64，天线C的SAR为2.31。
由此即可说明高次模的SAR要显著地高于基模的SAR。
然而，结合图3的说明，IFA天线虽然在上天线区域能够实现主频的覆盖，但是由于其中高频均为高次模辐射，因此相比于基模辐射，如果要达到相同或相近的辐射性能，对空间就有更高的要求。而这显然是不适合上天线区域本就较小的环境限制的。另外，当高次模的辐射性能得到提升之后，就会使得SAR显著提升，使得对人体的辐射量难以控制。
应当理解的是，以电子设备为手机为例。上述表1中示出了body SAR测试中，不同模式的对比。与之类似的，在头(head)SAR的测试过程中，高次模的SAR值也高于基模。而由于IFA天线设置在上天线区域，因此，在用户手持手机靠近人耳(如进行通话)时，天线对用户的头部辐射本就较高。加上IFA天线高次模辐射的SAR偏高，就会使得主天线设置在上天线区域时，头SAR的难以控制。
为了解决上述问题，本申请实施例提供一种低SAR天线方案，能够避免主天线设置在上天线区域时，SAR值过高的问题，同时能够保证天线的辐射性能。
以下结合附图对本申请实施例提供的方案进行详细说明。
需要说明的是，本申请实施例提供的低SAR天线方案，可以应用在用户的电子设备中。该电子设备可以设置有天线，该天线可以用于支持电子设备实现无线通信功能。比如，该电子设备可以是手机、平板电脑、个人数字助理(personal digital assistant，PDA)、增强现实(augmented reality，AR)\虚拟现实(virtual reality，VR)设备、媒体播放器等便携式移动设备，该电子设备也可以是智能手表等可穿戴电子设备。本申请实施例对该设备的具体形态不作特殊限制。
请参考图6，为本申请实施例提供的一种电子设备600的结构示意图。
如图6所示，该电子设备600可以包括处理器610，外部存储器接口620，内部存储器621，通用串行总线(universal serial bus，USB)接口630，充电管理模块640，电源管理模块641，电池642，天线1，天线2，移动通信模块650，无线通信模块660，音频模块670，扬声器670A，受话器670B，麦克风670C，耳机接口670D，传感器模块680，按键690，马达691，指示器692，摄像头693，显示屏694，以及用户标识模块(subscriber identification module，SIM)卡接口695等。其中，传感器模块680可以包括压力传感器，陀螺仪传感器，气压传感器，磁传感器，加速度传感器，距离传感器，接近光传感器，指纹传感器，温度传感器，触摸传感器，环境光传感器，骨传导传感器等。
可以理解的是，本实施例示意的结构并不构成对电子设备600的具体限定。在另一些实施例中，电子设备600可以包括比图示更多或更少的部件，或者组合某些部件，或者拆分某些部件，或者不同的部件布置。图示的部件可以以硬件，软件或软件和硬件的组合实现。
处理器610可以包括一个或多个处理单元，例如：处理器610可以包括应用处理器(application processor，AP)，调制解调处理器，图形处理器(graphics processing unit，GPU)，图像信号处理器(image signal processor，ISP)，控制器，存储器，视频编解码器，数字信号处理器(digital signal processor，DSP)，基带处理器，和/或神经网络处理器(neural-network processing unit，NPU)等。其中，不同的处理单元可以是独立的器件，也可以集成在一个或多个处理器610中。作为一种示例，在本申请中，ISP可以对图像进行处理，如该处理可以包括自动曝光(Automatic Exposure)、自动对焦(Automatic Focus)、自动白平衡(Automatic White Balance)、去噪、背光补偿、色彩增强等处理。其中，自动曝光，自动对焦，以及自动白平衡的处理也可以称为3A处理。经过处理后，ISP就可以进行获取对应的照片。该过程也可称为ISP的成片操作。
在一些实施例中，处理器610可以包括一个或多个接口。接口可以包括集成电路(inter-integrated circuit，I2C)接口，集成电路内置音频(inter-integrated circuit sound，I2S)接口，脉冲编码调制(pulse code modulation，PCM)接口，通用异步收发传输器(universal asynchronous receiver/transmitter，UART)接口，移动产业处理器接口(mobile industry processor interface，MIPI)，通用输入输出(general-purpose input/output，GPIO)接口，用户标识模块(subscriber identity module，SIM)接口，和/或通用串行总线(universal serial bus，USB)接口等。
电子设备600可以通过ISP，摄像头693，视频编解码器，GPU，显示屏694以及应用处理器等实现拍摄功能。
ISP用于处理摄像头693反馈的数据。例如，拍照时，打开快门，光线通过镜头被传递到摄像头693感光元件上，光信号转换为电信号，摄像头693感光元件将所述电信号传递给ISP处理，转化为肉眼可见的图像。ISP还可以对图像的噪点，亮度，肤色进行算法优化。ISP还可以对拍摄场景的曝光，色温等参数优化。在一些实施例中，ISP可以设置在摄像头693中。
摄像头693用于捕获静态图像或视频。物体通过镜头生成光学图像投射到感光元件。感光元件可以是电荷耦合器件(charge coupled device，CCD)或互补金属氧化物半导体(complementary metal-oxide-semiconductor，CMOS)光电晶体管。感光元件把光信号转换成电信号，之后将电信号传递给ISP转换成数字图像信号。ISP将数字图像信号输出到DSP加工处理。DSP将数字图像信号转换成标准的RGB，YUV等格式的图像信号。在一些实施例中，电子设备600可以包括1个或N个摄像头693，N为大于1的正整数。
数字信号处理器用于处理数字信号，除了可以处理数字图像信号，还可以处理其他数字信号。例如，当电子设备600在频点选择时，数字信号处理器用于对频点能量进行傅里叶变换等。
视频编解码器用于对数字视频压缩或解压缩。电子设备600可以支持一种或多种视频编解码器。这样，电子设备600可以播放或录制多种编码格式的视频，例如：动态图像专家组(moving picture experts group，MPEG)1，MPEG2，MPEG3，MPEG4等。
NPU为神经网络(neural-network，NN)计算处理器，通过借鉴生物神经网络结构，例如借鉴人脑神经元之间传递模式，对输入信息快速处理，还可以不断的自学习。通过NPU可以实现电子设备600的智能认知等应用，例如：图像识别，人脸识别，语音识别，文本理解等。
充电管理模块640用于从充电器接收充电输入。其中，充电器可以是无线充电器，也可以是有线充电器。在一些有线充电的实施例中，充电管理模块640可以通过USB接口630接收有线充电器的充电输入。在一些无线充电的实施例中，充电管理模块640可以通过电子设备600的无线充电线圈接收无线充电输入。充电管理模块640为电池642充电的同时，还可以通过电源管理模块641为电子设备600供电。
电源管理模块641用于连接电池642，充电管理模块640与处理器610。电源管理模块641接收电池642和/或充电管理模块640的输入，为处理器610，内部存储器621，外部存储器，显示屏694，摄像头693，和无线通信模块660等供电。电源管理模块641还可以用于监测电池642容量，电池642循环次数，电池642健康状态(漏电，阻抗)等参数。在其他一些实施例中，电源管理模块641也可以设置于处理器610中。在另一些实施例中，电源管理模块641和充电管理模块640也可以设置于同一个器件中。
电子设备600的无线通信功能可以通过天线1，天线2，移动通信模块650，无线通信模块660，调制解调处理器610以及基带处理器610等实现。
天线1和天线2用于发射和接收电磁波信号。电子设备600中的每个天线可用于覆盖单个或多个通信频带。不同的天线还可以复用，以提高天线的利用率。例如：可以将天线1复用为无线局域网的分集天线。在另外一些实施例中，天线可以和调谐开关结合使用。
移动通信模块650可以提供应用在电子设备600上的包括2G/3G/4G/5G等无线通信的解决方案。移动通信模块650可以包括至少一个滤波器，开关，功率放大器，低噪声放大器(low noise amplifier，LNA)等。移动通信模块650可以由天线1接收电磁波，并对接收的电磁波进行滤波，放大等处理，传送至调制解调处理器进行解调。移动通信模块650还可以对经调制解调处理器调制后的信号放大，经天线1转为电磁波辐射出去。在一些实施例中，移动通信模块650的至少部分功能模块可以被设置于处理器610中。在一些实施例中，移动通信模块650的至少部分功能模块可以与处理器610的至少部分模块被设置在同一个器件中。
调制解调处理器可以包括调制器和解调器。其中，调制器用于将待发送的低频基带信号调制成中高频信号。解调器用于将接收的电磁波信号解调为低频基带信号。随后解调器将解调得到的低频基带信号传送至基带处理器处理。低频基带信号经基带处理器处理后，被传递给应用处理器。应用处理器通过音频设备(不限于扬声器670A，受话器670B等)输出声音信号，或通过显示屏694显示图像或视频。在一些实施例中，调制解调处理器可以是独立的器件。在另一些实施例中，调制解调处理器可以独立于 处理器610，与移动通信模块650或其他功能模块设置在同一个器件中。
无线通信模块660可以提供应用在电子设备600上的包括无线局域网(wireless local area networks，WLAN)(如无线保真(wireless fidelity，Wi-Fi)网络)，蓝牙(bluetooth，BT)，全球导航卫星系统(global navigation satellite system，GNSS)，调频(frequency modulation，FM)，近距离无线通信技术(near field communication，NFC)，红外技术(infrared，IR)等无线通信的解决方案。无线通信模块660可以是集成至少一个通信处理模块的一个或多个器件。无线通信模块660经由天线2接收电磁波，将电磁波信号调频以及滤波处理，将处理后的信号发送到处理器610。无线通信模块660还可以从处理器610接收待发送的信号，对其进行调频，放大，经天线2转为电磁波辐射出去。
在一些实施例中，电子设备600的天线1和移动通信模块650耦合，天线2和无线通信模块660耦合，使得电子设备600可以通过无线通信技术与网络以及其他设备通信。所述无线通信技术可以包括全球移动通讯系统(global system for mobile communications，GSM)，通用分组无线服务(general packet radio service，GPRS)，码分多址接入(code division multiple access，CDMA)，宽带码分多址(wideband code division multiple access，WCDMA)，时分码分多址(time-division code division multiple access，TD-SCDMA)，长期演进(long term evolution，LTE)，BT，GNSS，WLAN，NFC，FM，和/或IR技术等。所述GNSS可以包括全球卫星定位系统(global positioning system，GPS)，全球导航卫星系统(global navigation satellite system，GLONASS)，北斗卫星导航系统(beidou navigation satellite system，BDS)，准天顶卫星系统(quasi-zenith satellite system，QZSS)和/或星基增强系统(satellite based augmentation systems，SBAS)。
电子设备600通过GPU，显示屏694，以及应用处理器610等实现显示功能。GPU为图像处理的微处理器，连接显示屏694和应用处理器。GPU用于执行数学和几何计算，用于图形渲染。处理器610可包括一个或多个GPU，其执行程序指令以生成或改变显示信息。
显示屏694用于显示图像，视频等。显示屏694包括显示面板。显示面板可以采用液晶显示屏694(liquid crystal display，LCD)，有机发光二极管(organic light-emitting diode，OLED)，有源矩阵有机发光二极体或主动矩阵有机发光二极体(active-matrix organic light emitting diode，AMOLED)，柔性发光二极管(flex light-emitting diode，FLED)，Miniled，MicroLed，Micro-oLed，量子点发光二极管(quantum dot light emitting diodes，QLED)等。在一些实施例中，电子设备600可以包括1个或N个显示屏694，N为大于1的正整数。
外部存储器接口620可以用于连接外部存储卡，例如Micro SD卡，实现扩展电子设备600的存储能力。外部存储卡通过外部存储器接口620与处理器610通信，实现数据存储功能。例如将音乐，视频等文件保存在外部存储卡中。
内部存储器621可以用于存储计算机可执行程序代码，所述可执行程序代码包括指令。处理器610通过运行存储在内部存储器621的指令，从而执行电子设备600的各种功能应用以及数据处理。内部存储器621可以包括存储程序区和存储数据区。其 中，存储程序区可存储操作系统，至少一个功能所需的应用程序(比如声音播放功能，图像播放功能等)等。存储数据区可存储电子设备600使用过程中所创建的数据(比如音频数据，电话本等)等。此外，内部存储器621可以包括高速随机存取存储器，还可以包括非易失性存储器，例如至少一个磁盘存储器件，闪存器件，通用闪存存储器(universal flash storage，UFS)等。
电子设备600可以通过音频模块670，扬声器670A，受话器670B，麦克风670C，耳机接口670D，以及应用处理器610等实现音频功能。例如音乐播放，录音等。
音频模块670用于将数字音频信息转换成模拟音频信号输出，也用于将模拟音频输入转换为数字音频信号。音频模块670还可以用于对音频信号编码和解码。在一些实施例中，音频模块670可以设置于处理器610中，或将音频模块670的部分功能模块设置于处理器610中。扬声器670A，也称“喇叭”，用于将音频电信号转换为声音信号。电子设备600可以通过扬声器670A收听音乐，或收听免提通话。受话器670B，也称“听筒”，用于将音频电信号转换成声音信号。当电子设备600接听电话或语音信息时，可以通过将受话器670B靠近人耳接听语音。麦克风670C，也称“话筒”，“传声器”，用于将声音信号转换为电信号。当拨打电话或发送语音信息或需要通过语音助手触发电子设备600执行某些功能时，用户可以通过人嘴靠近麦克风670C发声，将声音信号输入到麦克风670C。电子设备600可以设置至少一个麦克风670C。在另一些实施例中，电子设备600可以设置两个麦克风670C，除了采集声音信号，还可以实现降噪功能。在另一些实施例中，电子设备600还可以设置三个，四个或更多麦克风670C，实现采集声音信号，降噪，还可以识别声音来源，实现定向录音功能等。耳机接口670D用于连接有线耳机。耳机接口670D可以是USB接口630，也可以是3.5mm的开放移动电子设备600平台(open mobile terminal platform，OMTP)标准接口，美国蜂窝电信工业协会(cellular telecommunications industry association of the USA，CTIA)标准接口。
触摸传感器，也称“触控面板”。触摸传感器可以设置于显示屏694，由触摸传感器与显示屏694组成触摸屏，也称“触控屏”。触摸传感器用于检测作用于其上或附近的触摸操作。触摸传感器可以将检测到的触摸操作传递给应用处理器，以确定触摸事件类型。在一些实施例中，可以通过显示屏694提供与触摸操作相关的视觉输出。在另一些实施例中，触摸传感器也可以设置于电子设备600的表面，与显示屏694所处的位置不同。
压力传感器用于感受压力信号，可以将压力信号转换成电信号。在一些实施例中，压力传感器可以设置于显示屏694。压力传感器的种类很多，如电阻式压力传感器，电感式压力传感器，电容式压力传感器等。电容式压力传感器可以是包括至少两个具有导电材料的平行板。当有力作用于压力传感器，电极之间的电容改变。电子设备600根据电容的变化确定压力的强度。当有触摸操作作用于显示屏694，电子设备600根据压力传感器检测所述触摸操作强度。电子设备600也可以根据压力传感器的检测信号计算触摸的位置。在一些实施例中，作用于相同触摸位置，但不同触摸操作强度的触摸操作，可以对应不同的操作指令。例如：当有触摸操作强度小于第一压力阈值的触摸操作作用于短消息应用图标时，执行查看短消息的指令。当有触摸操作强度大于 或等于第一压力阈值的触摸操作作用于短消息应用图标时，执行新建短消息的指令。陀螺仪传感器可以用于确定电子设备600的运动姿态。加速度传感器可检测电子设备600在各个方向上(一般为三轴)加速度的大小。距离传感器，用于测量距离。电子设备600可以通过红外或激光测量距离。电子设备600可以利用接近光传感器检测用户手持电子设备600贴近耳朵通话，以便自动熄灭屏幕达到省电的目的。环境光传感器用于感知环境光亮度。指纹传感器用于采集指纹。温度传感器用于检测温度。在一些实施例中，电子设备600利用温度传感器检测的温度，执行温度处理策略。音频模块670可以基于所述骨传导传感器获取的声部振动骨块的振动信号，解析出语音信号，实现语音功能。应用处理器可以基于所述骨传导传感器获取的血压跳动信号解析心率信息，实现心率检测功能。
按键690包括开机键，音量键等。马达691可以产生振动提示。指示器692可以是指示灯，可以用于指示充电状态，电量变化，也可以用于指示消息，未接来电，通知等。SIM卡接口695用于连接SIM卡。电子设备600可以支持1个或N个SIM卡接口695，N为大于1的正整数。SIM卡接口695可以支持Nano SIM卡，Micro SIM卡，SIM卡等。同一个SIM卡接口695可以同时插入多张卡。SIM卡接口695也可以兼容不同类型的SIM卡。SIM卡接口695也可以兼容外部存储卡。电子设备600通过SIM卡和网络交互，实现通话以及数据通信等功能。在一些实施例中，电子设备600采用eSIM，即：嵌入式SIM卡。eSIM卡可以嵌在电子设备600中，不能和电子设备600分离。
本申请实施例提供的低SAR天线方案均能够应用于具有如图6所示的组成的电子设备中。示例性的，本申请实施例提供的方案能够应用于天线1中，实现低SAR高效率的辐射。
需要说明的是图6所示的电子设备的组成仅为一种示例。并不构成对本申请实施例提供的方案的应用环境的限制。比如，在一些实施例中，电子设备还可以具有其他组成。示例性的，结合图7，电子设备600中可以设置有通信模块，用于实现电子设备600的无线通信功能。
在如图7所示的示例中，通信模块可以包括天线，与天线耦接的射频模块，以及处理器。在该通信模块用于实现主频辐射时，天线可以是覆盖主频频段的天线。射频模块可以包括滤波器，功率放大器，射频开关等部件，用于对收发信号进行射频域的处理。处理器可以包括基带处理器，该处理器可以与射频模块耦接，用于对收发信号进行数字域的处理。
本申请实施例提供的天线方案，还能够应用于如图7所示的天线中。
示例性的，图8示出了本申请实施例提供的一种低SAR天线的示意图。
在本示例中，该天线可以设置于电子设备的上天线区域。从而避免用户手握电子设备对天线造成的影响。需要说明的是，为了便于说明，以下示例中，以电子设备为手机为例进行说明。其中，天线在手机的位置示意图均为手机的背面视图。
本申请实施例提供的低SAR天线可以包括至少两个辐射结构。比如，第一辐射结构用于实现低频辐射，第二辐射结构用于实现中高频辐射。
参考图8，以第一辐射结构为辐射结构1，第二辐射结构为辐射结构2为例。以下对本示例中的连个辐射结构分别进行说明。
在本示例中，辐射结构1可以通过IFA天线实现其低频辐射功能。
示例性的，如图8所示，辐射结构1可以包括至少1个辐射体，一个馈电点，以及一个切换模块(如SW1)。其中，辐射结构1中的辐射体可以位于手机的右上方。该辐射结构1中的辐射体采用如下形式中的任一种或多种实现：柔性电路板(Flexible Printed Circuit，FPC)天线，冲压(stamping)金属天线，激光直接成型(Laser-Direct-structuring，LDS)天线。在一些实现中，辐射结构1中的辐射体还可以复用手机中的金属结构件。比如，在手机具有金属边框设计时，在如图8所示的辐射结构1对应的位置可以使用金属边框实现辐射体的辐射功能。
馈电点可以是射频模块与天线耦接的位置。为了实现馈电的功能，在馈电点处可以使用金属弹片，顶针等部件，实现电路与天线辐射体之间的耦接。示例性的，以射频模块设置在印制线路板(printed circuit board，PCB)上为例。在发射场景下，射频信号可以通过PCB上的射频线路，传输给馈电点位置的电连接部件(如上述金属弹片，顶针等)，通过电连接部件的刚性连接或者通过如FPC上的电子线路等导电材质的焊接，使得射频信号可以被传输到天线辐射体上。由此天线辐射体就可以以天线对应的工作频段，将射频信号(模拟信号)以电磁波的形式传输出去。比如，辐射结构1的辐射体可以工作在低频段，那么在接收到来自馈电点的射频信号之后，辐射结构1的辐射体就可以以低频将射频信号以电磁波的形式传输出去。对应的，在接收场景下，辐射结构1的辐射体可以接收低频的电磁波信号(即低频电磁波)，并将该低频电磁波转换成模拟信号，通过馈电点反馈给射频模块，从而实现低频信号的接收。
需要说明的是，在本申请实施例中，馈电点可以设置在手机顶部右上角的位置。由此使得激励地板的电流强点与地板本征模的电流强点拉开间距，进而更有效的分散地板电流，达到降低SAR值的效果。此外，通过将馈电点设置在手机顶部右上角，可以更好的激励地板的横纵向电流，提升天线效率及带宽。
在一些实施例中，在馈电点和射频模块之间还可以设置有匹配电路(图8中未示出)。该匹配电路可以用于调谐天线的工作频段，通过切换或者调整的方式，将天线的阻抗调整到与射频模块匹配的状态(如调谐到75欧姆或者50欧姆)，从而减少天线端口处的信号反射，提升信号发射或者接收效率。
在如图8所示的辐射结构1中，切换模块SW1可以用于切换辐射结构1工作在不同的低频状态，从而使得辐射结构1能够覆盖低频全频段。在一些实现中，SW1的一端可以与辐射结构1的辐射体耦接，SW2的另一端可以接地。
可以理解的是，结合前述说明，在图8所示的天线工作在低频时，那么天线可以工作在IFA的1/4模式，即工作在基模。因此能够提供较好的辐射性能以及较低的SAR值。
接续参考图8，在本示例提供的天线方案中，还可以包括辐射结构2。
该辐射结构2可以配合辐射结构1，实现中高频辐射。
在本示例中，辐射结构2可以包括至少1个辐射体。该辐射结构2的辐射体的一端可以与辐射结构1的辐射体接近，从而达到与辐射结构1的辐射体进行电场耦合的效果。该辐射结构2的辐射体的另一端可以与SW2耦接。
如图8所示的天线工作在中高频时，辐射结构1和辐射结构2的辐射体能够通过 缝隙耦合，在顶部辐射体激励获取槽天线共模(slot common mode，Slot CM)/槽天线差模(slot differential mode，Slot DM)两种模式。为了便于描述，以下将Slot CM模式简称为CM模式，将Slot DM模式简称为DM模式。通过激励CM模式和DM模式，能够产生中高频段的辐射，从而实现天线的中高频覆盖。
在一些实施例中，辐射结构2中的切换模块(如SW2)可以通过加载电容或电容可以将顶部枝节谐振调谐到1710MHz-2690MHz，从而实现中高频的覆盖。.
可以理解的是，在本示例提供的天线方案中，中高频通过CM模式以及DM模式覆盖，取代了传统IFA天线的高次模覆盖中高频的方案，因此能够显著地提升天线在中高频的辐射性能的同时，降低中高频SAR值。
作为一种具体的实现，图9示出了具有如图8所示的逻辑组成的天线方案的具体组成。在该示例中，给出了一种SW1以及SW2的具体实施方案。
如图9所示，在本示例中，SW1以及SW2可以通过单刀多掷(Single Pole N Throw，SPNT)开关实现。比如，如图9所示，SW1和SW2可以采用单刀三掷实现其切换功能。在另一些实现中，单刀多掷开关的切换状态数量，还可以是其他数量，比如通过单刀双掷(SPDT)开关实现至少3个状态(如1通，2通，全断)的切换。需要说明的是，在本申请的另一些实现中，SW1以及SW2还可以通过其他具有切换功能的部件实现其功能。示例性的，作为一种可能的设计，SW1和/或SW2可以通过可调/可变器件实现其切换功能。在另一些设计中，SW1和/或SW2可以通过多刀多掷实现其切换功能。比如，SW1和SW2可以通过2*SPST实现至少4个状态的切换(如01,10,00,11)。
在本申请的一些实施例中，SW1的不同通路上可以加载有电感，用于实现低频切换。在如图9所示的示例中，SW1导通其中一路时，可以使得辐射结构1的辐射体接地，从而形成IFA的辐射形式。
需要说明的是，在本申请的一些实施例中，在辐射结构1的辐射体以及射频电路的馈源之间，可以串联有小电容(如小于2pF的电容)，以便能够在辐射结构1上激励获取左手模式，从而实现小空间下的低频激励。示例性的，在辐射结构1的辐射体以及射频电路之间串联小电容之后，可以在辐射结构1的整个辐射体上形成没有反向点的电流。该电流的分布也就是左手模式的电流分布。应当理解的是，左手模式的激励能够在较小空间中，成功激励低频辐射。在激励左手模式的情况下，通过切换SW1上不同通路，实现辐射体通过不同大小的电感回地，就能够起到切换低频谐振的作用，由此使得不同状态下的低频谐振能够配合覆盖LB全频段。
以下图10-图15将对具有如图9所示的天线方案的工作机制进行详细说明。为了能够清楚地对本申请实施例提供的天线方案的工作机制进行说明，以下首先对辐射结构1的工作情况进行说明。
如图10所示，为辐射结构1单独工作时的天线辐射情况示意。其中，图10中的(a)示出了辐射结构1单独工作时的S11。可以看到辐射结构1单独工作时，低频谐振最深处已经超过-16dB，较为理想。而对于中高频而言，作为典型的IFA天线，在辐射体上激励了高次模进行中高频的辐射。如图10中的(a)所示，在2GHz附近以及2.5GHz附近均获取了高次模对应的谐振。
图10中的(b)示出了辐射结构1单独工作时的系统效率以及辐射效率的示意图。 其中，辐射效率(radiation efficiency)可以用于标识当前天线系统在单端口激励情况下，从端口输入能量与经过辐射和损耗反馈到端口的能量的差异。辐射效率越高，表明反馈到端口的能量越小，那么则表明当前天线系统能够提供的辐射能力越强。对应的，系统效率(system efficiency)可以用于标识当前天线系统在单端口激励情况下，从端口输入能量与经过辐射反馈到端口的能量的差异。系统效率越高，表明天线将更多的能量辐射出去，即天线的辐射性能越高。也就是说，在理想情况下，当前天线系统的系统效率能够达到辐射效率的水平，而辐射效率就可以是当前天线系统能够提供的最大的辐射能力。
如图10中的(b)所示，在辐射结构1单独工作时，在中高频(1.7GHz-3GHz)的系统效率均在-4dB以上，因此表明该辐射结构1能够提供较强中高频的效率。
图11示出了辐射结构1单独工作时的电流流向示意图。如图11中的(a)所示，0.74GHz(即低频)可以工作在1/4波长模式。如图11中的(b)所示，1.94GHz(即中频)可以工作在1/2波长模式。如图11中的(c)所示，2.54GHz(即高频)可以工作在1倍波长模式。
通过图11的电流示意说明，也能够进一步说明如图10中的(a)所示的中高频谐振为IFA天线的高次模产生的辐射。
结合前述图3-图5的说明，可以理解的是，在辐射结构1单独工作时，由于中高频的辐射均为IFA高次模提供的，因此即使能够产生较好的系统效率或者辐射效率，也会产生SAR值过高的问题。
在本申请实施例中，继续参考图9，在辐射结构1之外，天线还可以包括辐射结构2。该辐射结构2能够通过电场耦合的形式，与辐射结构1的顶部结构体行程CM模式以及DM模式的激励，从而调整中高频的激励模式，在获得较好的系统效率或者辐射效率的同时，避免SAR值过高的问题。
示例性的，参考图12，示出了具有如图9所示组成的天线在工作时的S11的示意。也就是说，在如图12的示意中，是辐射结构1和辐射结构2共同工作的结果。
为了便于说明，在如图12的示例中，同时示出了仅辐射结构1工作时的S11的示意作为对比。
如图12所示，在增加了辐射结构2之后，在中高频激励获取了CM模式以及DM模式覆盖。由此即可避免IFA天线的高次模的SAR值过高的问题发生。
作为一种示例，图13A示出了辐射结构1和辐射结构2同时工作时，中高频的电流就像示意图。示例性的，图13A中的(a)示出了2.5GHz附近频点的电流流向。可以看到，电流在顶部辐射体(包括辐射结构1的辐射体的顶部部分以及辐射结构2的辐射体)可以产生同向的电流分布。由于辐射结构1的辐射体的顶部部分以及辐射结构2的辐射体之间并未电连接，即存在缝隙，因此该电流分布就可以构成CM模式的辐射。结合图12所示的S11，可以看到CM模式能够覆盖中频进行辐射。
图13A中的(b)示出了2.7GHz附近频点的电流流向。可以看到，电流在顶部辐射体(包括辐射结构1的辐射体的顶部部分以及辐射结构2的辐射体)可以产生反向的电流分布。由于辐射结构1的辐射体的顶部部分以及辐射结构2的辐射体之间并未电连接，即存在缝隙，因此该电流分布就可以构成DM模式的辐射。结合图12所示的 S11，可以看到DM模式能够覆盖高频进行辐射。
图13B示出了CM模式和DM模式的实际模型仿真电流分布情况。可以看到在中高频，如图13B中的(a)所示，CM模式可以在顶部辐射体激励获取同向电流(横跨缝隙)，同时，手机侧边长枝节上的电流较小。如图13B中的(b)所示，DM模式可以在缝隙两侧的辐射体上分别激励获取反向电流，同时，手机侧边长枝节上的电流较小。由此即可证明通过增加辐射结构2，能够达到激励获取位于顶部的CM模式和DM模式的效果。
图14示出了增加辐射结构2之后，整个天线系统的辐射效率以及系统效率的变化情况示意。如图14中的(a)所示，增加辐射结构2之后，在2.3GHz到2.7GHz之间的辐射效率显著增加。由此即可确定在增加辐射结构2引入DM模式和CM模式之后，整个天线系统能够提供的辐射性能得到优化。如图14中的(b)所示，增加辐射结构2之后，在中高频全频段的系统效率都有所提升。因此，在增加辐射结构2引入DM模式和CM模式之后，整个天线系统实际提供的辐射性能也得到了优化。因此，在辐射结构1和辐射结构2同时工作时，相比于典型的IFA天线，能够提供更好的辐射性能。
为了说明本申请实施例提供的天线方案同时起到优化SAR值的效果，图15示出了仅辐射结构1工作时的典型IFA天线工作在中高频时的地板电流示意(如图15中的(a)所示)，以及辐射结构1和辐射结构2同时工作时在中高频的地板电流示意(如图15中的(b)所示)。显而易见的，在如图15中的(b)所示的示意中，电流在地板上的分布区域更大。对应的，在如图15中的(a)的示意中，电流在地板上的分布区域相对较小。因此，辐射结构1和辐射结构2同时工作时，中高频的电流更加分散，由此使得天线系统在中高频的SAR值也会更小。
结合前述对图8-图15的说明，可以看到，具有如图8或图9所示结构的天线方案，相较于常规的IFA天线，能够在不拆分低频和中高频的情况下，在上天线区域获取更好的辐射性能以及更低的SAR值。
需要说明的是，在如图8-图15的说明中，是以辐射结构2上的SW2设置在远离辐射结构1的一端为例进行说明的。在本申请的另一些实施例中，辐射结构2上的SW2还可以设置在其他位置，达到通过SW2的不同状态切换CM模式和DM模式覆盖频段的效果。
作为一种示例，图16示出了又一种SW2的设置示意。在如图16的示意中，SW2可以设置在辐射结构2中，靠近辐射结构1的一端。在本示例中，辐射结构2的辐射体可以在远离辐射结构1的一端回地，以便于有效激励CM模式和/或DM模式。与图16对应的，图17示出了一种具有如图16所示的拓扑结构的天线的具体示意。在如图17所示的示意中，SW2的不同通路上可以通过加载电感实现对CM模式和/或DM模式覆盖频段的调整。比如，在SW2的通路1导通时，可以将CM模式和/或DM模式调整到频段1。在SW2的通路2导通时，可以将CM模式和/或DM模式调整到频段2。其中，在通路1和通路2的电感值不同时，频段1和频段2不同。
基于上述包括辐射结构1和辐射结构2的天线的说明，即可实现通过CM模式和DM模式覆盖中高频，达到提升中高频辐射性能以及降低SAR值的效果。
在本申请的另一些实施例中，结合图7所示的逻辑组成，天线还可以包括辐射结 构3。该辐射结构3能够进一步优化中高频的辐射性能。
可以理解的是，结合图12以及图14，可以看到具有如图8或图9所示的组成的天线，工作在中高频时，在CM模式和DM模式中间会出现由于两个模式不相兼容导致的凹坑。在S11上可以表现为CM模式对应的谐振和DM模式对应的谐振之间出现凸起，在效率(包括系统效率以及辐射效率)上可以表现为CM模式对应的谐振和DM模式对应的谐振之间出现的效率凹陷。比如，以图12为例。在如图12所示的示例中，CM模式可以用于在2.6GHz附近产生谐振，在S11上可以标识为谐振的凹陷。DM模式可以用于在2.9GHz附近产生谐振，在S11上同样可以标识为谐振的凹陷。在CM模式和DM模式的谐振之间，在2.75GHz附近，则产生了由于模式不兼容导致的S11凸起。那么对应的在该2.75GHz附近就会出现效率的降低，即可以表现为在效率曲线上的凹陷。
那么，在本示例中，通过在辐射结构1以及辐射结构2的基础上，增加辐射结构3，在CM模式以及DM模式之间激励新的谐振，以补偿CM模式以及DM模式之间的效率凹陷，提升中高频辐射性能。
示例性的，结合图18，为本申请实施例提供的又一种天线的拓扑示意图。对比图8所示的天线，该如图18的示例中，在天线中还可以包括第三辐射结构(如辐射结构3)。
该辐射结构3可以用于在中高频的CM模式以及DM模式之间激励新的谐振，从而提升中高频整体的辐射性能。在本示例中，辐射结构3可以包括至少1个辐射体。该辐射结构3的辐射体的一端可以接近辐射结构1的辐射体，但该辐射结构3的辐射体不与辐射结构1的辐射体连接。在辐射结构3的辐射体以及辐射结构1的辐射体之间可以形成缝隙。在辐射结构1工作时，辐射结构1的辐射体上出现变化的电流。通过在辐射结构3的辐射体以及辐射结构1的辐射体之间的缝隙，能量可以通过耦合到辐射结构3上，从而激励辐射结构3的辐射体上出现交变电流。
在一些实施例中，辐射结构3的辐射体在远离辐射结构1的一端可以做接地处理，由此使得辐射结构3形成寄生天线进行工作。该辐射结构3的辐射体的尺寸可以与CM模式和DM模式的效率凹陷所在频段波长的1/4对应，从而使得辐射结构3可以通过寄生效果在CM模式和DM模式的效率凹陷所在频段产生新的谐振。在一些实现中，如图18所示，在辐射结构3靠近辐射结构1的一端，可以设置有切换模块SW3，该SW3可以用于通过切换不同的通路，使得辐射结构3的辐射体呈现出不同的电长度，从而使得辐射结构3能够根据不同场景的需要，调整寄生对应的谐振位置，更加有效地补偿中高频的效率凹陷。当然，在一些实施例中，在辐射结构3中也可不设置该SW3，由此达到补偿中高频辐射性能的同时，精简器件成本和布局空间的效果。
为了能够对如图18所示的天线进行更加清楚的说明，图19示出了具有如图18所示的拓扑结构的天线的具体实现。其中，辐射结构1和辐射结构2的示意可以参考图9中的说明，此处不再赘述。
在如图19所示的示例中，辐射结构3的辐射体的组成，类似与上述辐射结构1和辐射结构2的辐射体，可以通过FPC，LDS，stamping，或者手机自身的金属结构件实现其辐射功能。在辐射结构3中，SW3可以通过上述示例中的SPNT或者多个切换开关，或者其他具有切换功能的部件实现其切换功能。比如，在如图19所示的示例中， SW3可以通过SP3T实现其切换功能。在SP3T的不同通路上，可以分别加载电感，以便于通过切换不同的通路，实现调整寄生枝节的电长度的效果。
例如，在SW3的通路A导通时，则辐射结构3产生的谐振可以位于频段A。在SW3的通路B导通时，则辐射结构3产生的谐振可以位于频段B。当通路A和通路B上加载的电感数值不同时，则频段A和频段B不同。作为一种示例，当通路A的电感A大于通路B的电感B时，则当SW3由通路A切换到通路B上时辐射结构3产生的谐振所在频段(即频段A)可以从较低频段向频段B所在的较高频段移动。
在本申请实施例中，增加了辐射结构3之后，能够显著地提升中高频的谐振，弱化由于引入CM模式和DM模式产生的中高频的效率凹坑。以下结合仿真结果对增加辐射结构2和辐射结构3之后的天线辐射性能进行详细说明。
为了便于说明，在附图中同时示出了仅辐射结构1工作时的典型IFA模式的S参数的分布情况。
请参考图20，为本申请实施例提供的具有如图19所示组成的天线的S参数的分布情况示意。如图20中的(a)所示，增加了辐射结构2和辐射结构3之后，在S11上的CM模式和DM模式之间出现了寄生谐振。结合图12所示的仅增加辐射结构2之后的S11，再次增加辐射结构3之后，由于寄生谐振的出现，使得CM模式和DM模式的谐振之间的凸起得到补偿，最高点由如图12所示的-11dB左右，下降到如图12所示的-13dB左右。
继续参考图20中的(b)，增加辐射结构3之后，显著地提升了天线在中高频的辐射效率。此外，如图20中的(c)所示，增加辐射结构3之后，天线实际在中高频的效率也得到了明显的提升。由此，可以说明在增加辐射结构2和辐射结构3之后，相较于典型的IFA天线能够在中高频提供更好的辐射性能。对比如图14所示的增加辐射结构2之后的效率示意，可以看到再次层架辐射结构3之后，能够达到补偿中高频性能的效果。
以下通过增加辐射结构2和辐射结构3之后，电流在地板上的分布对比，说明具有如图19所示组成的天线的SAR值可以更低。
图21中的(a)为仅辐射结构1工作时，地板电流的分布情况。相比于图21中的(b)所示的辐射结构1，辐射结构2以及辐射结构3同时工作时，地板电流的分布情况，可以明显看到，在增加了辐射结构2和辐射结构3之后，地板电流分布被扩展。由此使得具有如图19所示的组成的天线在进行辐射时，其能量分布更加分散，从而可以具有比典型IFA更低的SAR值。
需要说明的是，图18和图19仅为一种本申请实施例提供的辐射结构3的示例。在本申请的另一些实施例中，该辐射结构3还可以具有其他组成，从而实现通过寄生作用补偿CM模式和DM模式的效果。示例性的，在一些实施例中，结合图22，辐射结构3的辐射体在远离辐射结构1的一端也可以不作接地处理(如悬空)。对应的，SW3的各个通路上可以加载电容，从而使得在SW3切换到不同的通路上时，不同通路上的电容可以加载到辐射结构3的辐射体上，由此在激励辐射结构3的寄生谐振的同时，通过不同通路上的电容进行谐振位置的调整。
在上述如图18-图22的说明中，是以SW3设置在辐射结构3中靠近辐射结构1一 端为例进行说明的。在本申请的另一些实施例中，SW3还可以设置在辐射结构3中其他位置，也能够起到调整辐射结构3的寄生谐振对应频段的效果。本申请实施例对于SW3在辐射结构3中的具体位置不作限定。
通过上述说明，应当理解的是，本申请实施例提供的天线方案，具有相较于典型的IFA天线更好的辐射性能，同时能够避免IFA高次模导致的中高频SAR值过高的问题。
示例性的，以下通过对典型IFA天线以及具有如图19所示的组成的天线进行SAR实测的结果，说明上述效果。
1、不同天线在中高频的CE 5mm 10g body SAR测量结果对比。
请参考图23，为典型IFA天线以及具有如图19所示的组成的天线在测量过程中的热点分布示意。其中如图23中的(a)为典型IFA天线的热点分布，图23中的(b)为本申请提供的天线的热点分布。显而易见的，图23中的(b)所示的热点分布更加分散，因此SAR值应当较低。
如下表2示出了两种天线的SAR实测结果。
表2
Figure PCTCN2022084112-appb-000001
可以看到，本申请实施例提供的具有如图19所示组成的天线在2GHz-2.6GHz全频段的SAR值均小于典型的IFA天线。
2、不同天线在中高频的CE 0mm 10g body SAR测量结果对比。
请参考图24，为典型IFA天线以及具有如图19所示的组成的天线在测量过程中的热点分布示意。其中如图24中的(a)为典型IFA天线的热点分布，图24中的(b)为本申请提供的天线的热点分布。显而易见的，图24中的(b)所示的热点分布更加分散，因此SAR值应当较低。
如下表3示出了两种天线的SAR实测结果。
表3
Figure PCTCN2022084112-appb-000002
可以看到，本申请实施例提供的具有如图19所示组成的天线在2GHz-2.6GHz全频段的SAR值均小于典型的IFA天线。
3、不同天线在中高频的Head SAR测量结果对比。
请参考图25，为典型IFA天线以及具有如图19所示的组成的天线在测量过程中的热点分布示意。其中如图25中的(a)为典型IFA天线的热点分布，图25中的(b)为本申请提供的天线的热点分布。显而易见的，图25中的(b)所示的热点分布更加分散，因此SAR值应当较低。
如下表4示出了两种天线的SAR实测结果。
表4
Figure PCTCN2022084112-appb-000003
可以看到，本申请实施例提供的具有如图19所示组成的天线在2GHz-2.6GHz全频段的SAR值均小于典型的IFA天线。
在上述实施例中的功能或动作或操作或步骤等，可以全部或部分地通过软件、硬件、固件或者其任意组合来实现。当使用软件程序实现时，可以全部或部分地以计算机程序产品的形式来实现。该计算机程序产品包括一个或多个计算机指令。在计算机上加载和执行计算机程序指令时，全部或部分地产生按照本申请实施例所述的流程或功能。所述计算机可以是通用计算机、专用计算机、计算机网络、或者其他可编程装置。所述计算机指令可以存储在计算机可读存储介质中，或者从一个计算机可读存储 介质向另一个计算机可读存储介质传输，例如，所述计算机指令可以从一个网站站点、计算机、服务器或者数据中心通过有线(例如同轴电缆、光纤、数字用户线(digital subscriber line，DSL))或无线(例如红外、无线、微波等)方式向另一个网站站点、计算机、服务器或数据中心进行传输。所述计算机可读存储介质可以是计算机能够存取的任何可用介质或者是包括一个或多个可以用介质集成的服务器、数据中心等数据存储设备。所述可用介质可以是磁性介质(例如，软盘、硬盘、磁带)，光介质(例如，DVD)、或者半导体介质(例如固态硬盘(solid state disk，SSD))等。
尽管结合具体特征及其实施例对本申请进行了描述，显而易见的，在不脱离本申请的精神和范围的情况下，可对其进行各种修改和组合。相应地，本说明书和附图仅仅是所附权利要求所界定的本申请的示例性说明，且视为已覆盖本申请范围内的任意和所有修改、变化、组合或等同物。显然，本领域的技术人员可以对本申请进行各种改动和变型而不脱离本申请的精神和范围。这样，倘若本申请的这些修改和变型属于本申请权利要求及其等同技术的范围之内，则本申请也意图包括这些改动和变型在内。

Claims (12)

  1. 一种低SAR天线，其特征在于，应用于电子设备，所述天线包括：第一辐射结构和第二辐射结构；
    所述第一辐射结构包括第一辐射体，所述第二辐射结构包括第二辐射体，所述第一辐射体与所述第二辐射体不导通；
    所述第一辐射体的第一端与所述第二辐射体的第一端相对设置，所述第一辐射体的第一端与所述第二辐射体的第一端构成第一缝隙；所述第一辐射体的第二端悬空，所述第二辐射体的第二端接地；
    所述天线的馈电点与所述第一辐射体耦接，以所述馈电点为分界，将所述第一辐射体划分为第一部分和第二部分，所述第一部分的长度小于所述第二部分的长度；所述第二部分上在所述第一辐射体的第二端和所述馈电点之间设置有接地点。
  2. 根据权利要求1所述的天线，其特征在于，
    在所述天线工作时，所述第一辐射体的第一部分与所述第二辐射体共同工作在第一频段和第二频段，所述第一频段的频率低于所述第二频段的频率；
    工作在所述第一频段时，所述第一部分上的电流方向与所述第二辐射体上的电流方向相同；工作在所述第二频段时，所述第一部分上的电流方向与所述第二辐射体上的电流方向在所述第一缝隙处反向；以使得所述天线在所述第一频段和所述第二频段的SAR值低于所述第一辐射结构单独工作在所述第一频段和所述第二频段时的SAR值。
  3. 根据权利要求1或2所述的天线，其特征在于，所述第一辐射结构为IFA天线。
  4. 根据权利要求1-3中任一项所述的天线，其特征在于，所述第二辐射结构构成所述第一辐射体的寄生结构，
    在所述天线工作时，所述第二辐射结构通过所述第一缝隙，与所述第一辐射结构的第一辐射体进行电场耦合，以激励所述第二辐射体上的电流。
  5. 根据权利要求1-4中任一项所述的天线，其特征在于，所述天线工作时，通过在所述第一辐射体的第一部分和所述第二辐射体上激励槽天线共模slot CM模式覆盖所述第一频段，通过在所述第一辐射体的第一部分和所述第二辐射体上激励槽天线差模slot DM模式覆盖所述第二频段。
  6. 根据权利要求1-5中任一项所述的天线，其特征在于，耦接所述第一辐射体的馈电点位于所述第一辐射体的弯折处。
  7. 根据权利要求1-6中任一项所述的天线，其特征在于，所述第一辐射体的第二部分的工作频段覆盖第三频段，所述第三频段的频率小于所述第二频段；
    在所述天线工作在所述第三频段的情况下，所述第一辐射体上分布有同向电流，所述第一辐射体通过激励左手模式覆盖所述第三频段。
  8. 根据权利要求1-7中任一项所述的天线，其特征在于，所述天线还包括第三辐射结构，所述第三辐射结构包括第三辐射体，所述第三辐射体分别与所述第一辐射体或所述第二辐射体不导通，所述第三辐射体的第一端与所述第一辐射体的第二端相对设置；第三辐射体的第一端与所述第一辐射体的第二端之间构成第二缝隙，所述第三辐射体上设置有接地点。
  9. 根据权利要求8所述的天线，其特征在于，在所述天线工作时，所述第三辐射 结构构成所述第一辐射体的寄生结构，
    所述第三辐射体用于通过所述第二缝隙，与所述第一辐射体进行电场耦合，以激励所述第三辐射体上的电流。
  10. 根据权利要求8或9所述的天线，其特征在于，所述第三辐射体的工作频段覆盖第四频段，所述第四频段的频率位于所述第一频段和所述第二频段的频率之间。
  11. 根据权利要求8-10中任一项所述的天线，其特征在于，所述第一频段包括[2300，2500]MHz，所述第二频段包括[2500，2700]MHz，所述第三频段包括[700,960]MHz。
  12. 一种电子设备，其特征在于，所述电子设备设置有至少一个处理器，射频模块，以及如权利要求1-11中任一项所述的低SAR天线；
    所述电子设备在进行信号发射或接收时，通过所述射频模块和所述低SAR天线进行信号的发射或接收。
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