Antenna assembly and electronic device

Abstract

The application provides an antenna assembly and an electronic device. The antenna assembly comprises a signal source, a reference ground, an antenna radiator and a first tuning circuit. The antenna radiator comprises a first free end, a first ground end, a feeding point and a first connecting point arranged between the feeding point and the first free end. The first ground end is electrically connected to the reference ground. The feeding point is electrically connected to the signal source. The first connecting point is electrically connected to the reference ground through the first tuning circuit. The antenna radiator between the first ground end and the first free end generates a first resonant mode supporting a first target frequency band under the excitation of the signal source, and the first resonant mode is a 1 / 4 wavelength mode. The antenna radiator between the first ground end and the first connecting point and the first tuning circuit generate a second resonant mode supporting the first target frequency band under the excitation of the signal source, and the second resonant mode is a 1 / 2 wavelength mode. The antenna assembly and the electronic device provided by the application can balance the communication performance and the SAR value.

Description

Technical Field

[0001] This application relates to the field of wireless communication technology, specifically to an antenna assembly and an electronic device. Background Technology

[0002] With the release of the new domestic standard for specific absorption rate (SAR) of electromagnetic radiation, how to further reduce the SAR value while ensuring communication performance has become a technical problem that needs to be solved. Summary of the Invention

[0003] This application provides an antenna assembly and electronic device that can further reduce SAR values ​​while ensuring communication performance.

[0004] On the one hand, this application provides an antenna assembly, including

[0005] Signal source;

[0006] Reference location; and

[0007] An antenna unit includes an antenna radiator and a first tuning circuit. The antenna radiator includes a first free end, a first ground end, a feed point located between the first free end and the first ground end, and a first connection point located between the feed point and the first free end. The first ground end is electrically connected to a reference ground, the feed point is electrically connected to a signal source, and the first connection point is electrically connected to the reference ground through the first tuning circuit. Under the excitation of the signal source, the antenna radiator between the first ground end and the first free end generates a first resonant mode supporting a first target frequency band. The first resonant mode is a 1 / 4 wavelength mode. Under the excitation of the signal source, the antenna radiator between the first ground end and the first connection point and the first tuning circuit generate a second resonant mode supporting the first target frequency band. The second resonant mode is a 1 / 2 wavelength mode.

[0008] On the other hand, this application also provides an electronic device, including a frame, a circuit board and the antenna assembly, wherein the frame encloses a receiving space, the circuit board is disposed within the receiving space, the signal source, the reference ground and the first tuning circuit are disposed on the circuit board, and the antenna radiator is disposed on the frame.

[0009] The antenna assembly provided in this application includes a signal source, a reference ground, and an antenna element. The antenna element includes an antenna radiator and a first tuning circuit. Since the first connection point in the antenna radiator, located between the feed point and the first free end, is electrically connected to the reference ground through the first tuning circuit, a first resonant mode supporting the first target frequency band can be generated between the first ground end and the first free end of the antenna radiator under the excitation of the signal source. A second resonant mode supporting the first target frequency band can be generated between the first ground end and the first connection point of the antenna radiator, and the first tuning circuit can also be generated under the excitation of the signal source. Therefore, the antenna radiator of this application has multiple strong current points formed by the first and second resonant modes. The first resonant mode is a 1 / 4 wavelength mode, and the second resonant mode is a 1 / 2 wavelength mode. Thus, the multiple strong current points are distributed at different locations on the antenna radiator, achieving the effect of current shunting at the strong current points on the antenna radiator, thereby reducing the SAR value. Furthermore, the first and second resonant modes simultaneously support the first target frequency band, so the communication performance is not reduced, meaning that the SAR value can be further reduced while ensuring communication performance. Attached Figure Description

[0010] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly described below.

[0011] Figure 1 A schematic diagram of the structure of an electronic device provided in an embodiment of this application;

[0012] Figure 2 A schematic diagram of an antenna assembly provided for an embodiment of this application;

[0013] Figure 3 for Figure 2 The diagram shows the structure of the antenna radiator in the antenna assembly, which includes a first radiating segment and a second radiating segment.

[0014] Figure 4 for Figure 2 The diagram shows a structural schematic of the antenna radiator having a first resonant current corresponding to the first resonant mode in the antenna assembly shown.

[0015] Figure 5 for Figure 2 The diagram shows a structural schematic of the second resonant current corresponding to the second resonant mode on the antenna radiator of the antenna assembly shown.

[0016] Figure 6 for Figure 2 The diagram shows a schematic of the structure of the first tuning circuit in the antenna assembly, which includes an inductor.

[0017] Figure 7 for Figure 6 The antenna assembly shown also includes a structural diagram of the matching circuit;

[0018] Figure 8 for Figure 7 The antenna assembly shown is a structural diagram illustrating the length of the antenna radiator between the first connection point and the first free end, the length of the antenna radiator between the first free end and the first ground end, and the length of the antenna radiator between the feed point and the first ground end.

[0019] Figure 9 for Figure 7 The diagram shows the structure of the antenna assembly where the second resonant mode forms a second current weakness at the target point.

[0020] Figure 10 A schematic diagram showing the current intensity changes in the first and second resonant modes of the antenna assembly provided in this application embodiment;

[0021] Figure 11 Schematic diagrams of the structures of three antenna assemblies provided in the embodiments of this application;

[0022] Figure 12 for Figure 11 The return loss curves for the three antenna components are shown below.

[0023] Figure 13 for Figure 11 Simulation diagrams of current distribution for some of the three types of antenna components shown;

[0024] Figure 14 for Figure 7 The antenna assembly shown also includes a parasitic element, which includes a parasitic stub and a schematic diagram of the second tuning circuit.

[0025] Figure 15 for Figure 14 The diagram shows a structure with a third resonant current corresponding to the third resonant mode on a parasitic stub in the antenna assembly shown.

[0026] Figure 16 for Figure 14 The diagram shows a structure in the antenna assembly with a fourth resonant current corresponding to the fourth resonant mode on a parasitic stub.

[0027] Figure 17 for Figure 14 The diagram shows a schematic of the second tuning circuit in the antenna assembly, which includes an inductor.

[0028] Figure 18 for Figure 17 The diagram shows the structure of the antenna assembly, illustrating the length of the parasitic stub between the second connection point and the second free end, and the length of the parasitic stub between the second free end and the second ground end. Detailed Implementation

[0029] The technical solution of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the embodiments described in this application are only a portion of the embodiments, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments provided in this application without creative effort are within the protection scope of this application.

[0030] In this application, the term "implementation" means that a specific feature, structure, or characteristic described in connection with an implementation may be included in at least one implementation of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same implementation, nor is it a mutually exclusive, independent, or alternative implementation. Those skilled in the art will understand, explicitly and implicitly, that the implementations described in this application can be combined with other implementations.

[0031] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, an assembly or device comprising one or more components is not limited to the one or more components listed, but may optionally also include one or more components not listed but inherent to the exemplified product, or one or more components that it should have based on the described function.

[0032] The terms “end” and “point” in the specification, claims, and accompanying drawings of this application may refer to a small segment of the body relative to the whole of the corresponding body, or to a corresponding port. That is, “end” should not be narrowly interpreted as the end point, and “point” should not be narrowly interpreted as a single point.

[0033] Please refer to Figure 1 and Figure 2 , Figure 1 A schematic diagram of the structure of the electronic device 1000 provided in the embodiments of this application. Figure 2 This is a schematic diagram of an antenna assembly 100 provided in an embodiment of this application. The electronic device 1000 can be a mobile phone, tablet, watch, or other device with wireless communication capabilities. In this embodiment, a mobile phone is used as an example. The electronic device 1000 includes a frame 300, a circuit board 200, and an antenna assembly 100. The antenna assembly 100 includes a signal source 10, a reference ground 11, and an antenna element 12.

[0034] The frame 300 may be made of one or more of the following materials: metal, alloy, plastic, ceramic, and glass. The frame 300 encloses and forms a receiving space 34. In one possible embodiment, the frame 300 includes a first sub-frame 30, a second sub-frame 31, a third sub-frame 32, and a fourth sub-frame 33 connected end-to-end. The first sub-frame 30 and the third sub-frame 32 are positioned opposite each other. The second sub-frame 31 and the fourth sub-frame 33 are positioned opposite each other. This application does not specifically limit the bending connection method between the first sub-frame 30 and the second sub-frame 31, between the second sub-frame 31 and the third sub-frame 32, between the third sub-frame 32 and the fourth sub-frame 33, and between the fourth sub-frame 33 and the first sub-frame 30. For example, the first sub-frame 30 and the second sub-frame 31, the second sub-frame 31 and the third sub-frame 32, the third sub-frame 32 and the fourth sub-frame 33, and the fourth sub-frame 33 and the first sub-frame 30 can be bent at right angles; or, the first sub-frame 30 and the second sub-frame 31, the second sub-frame 31 and the third sub-frame 32, the third sub-frame 32 and the fourth sub-frame 33, and the fourth sub-frame 33 and the first sub-frame 30 can be bent in an arc shape. A receiving space 34 is formed between the first sub-frame 30, the second sub-frame 31, the third sub-frame 32, and the fourth sub-frame 33. The receiving space 34 can accommodate the circuit board 200, the antenna assembly 100, etc.

[0035] Circuit board 200 may include the main circuit board and / or sub-circuit board of electronic device 1000. Circuit board 200 is disposed within receiving space 34. When classified by the number of structural layers, circuit board 200 may be a single-sided circuit board, a double-sided circuit board, or a multilayer circuit board. When classified by bending characteristics, circuit board 200 may be a flexible circuit board, a rigid circuit board, or a rigid-flex board. When classified by molding process, circuit board 200 may be a printed circuit board (PCB), a flexible printed circuit board (FPC), a laser direct structuralizing (LDS), etc. Circuit board 200 includes a ground plane.

[0036] Signal source 10 provides excitation signals to antenna element 12. Signal source 10 may include a transceiver, or it may include a transceiver and an RF front-end module. The transceiver includes a transmitter and a receiver. The transceiver is capable of transmitting and receiving RF signals. The RF front-end module is electrically connected between the transceiver and antenna element 12, and is capable of amplifying the power of the RF signals transmitted between the transceiver and antenna element 12, filtering out spurious signals, etc. Signal source 10 is located on circuit board 200.

[0037] The reference potential of reference ground 11 is zero. Specifically, reference ground 11 refers to the conductive ground portion of electronic device 1000 that is not affected by any grounding configuration. The potential of reference ground 11 is conventionally zero. For example, reference ground 11 may include the ground plane of the main circuit board, the ground plane of the sub-circuit board, the metal parts of the middle frame, and conductive parts electrically connected to one or more of the ground planes of the main circuit board, the sub-circuit board, and the metal parts of the middle frame in electronic device 1000. In the following embodiment, reference ground 11 is taken as the ground plane of circuit board 200. In other words, reference ground 11 is provided on circuit board 200.

[0038] Antenna unit 12 includes an antenna radiator 120 and a first tuning circuit 121. The antenna radiator 120 is disposed on the frame 300. Optionally, the antenna radiator 120 may be disposed on the inner surface of the frame 300, or the antenna radiator 120 may be integrated on the frame 300, or the antenna radiator 120 may be disposed on the outer surface of the frame 300. In other words, the antenna radiator 120 may be a built-in antenna radiator, or the antenna radiator 120 may be a metal frame antenna radiator, or the antenna radiator 120 may be an external antenna radiator. In the following embodiments, unless otherwise specified, the antenna radiator 120 is exemplified by a metal frame antenna radiator. The material of the antenna radiator 120 may include at least one conductive material such as metal, alloy, or carbon fiber. The first tuning circuit 121 may include capacitors and / or inductors. This application does not specifically limit the number of capacitors or inductors included in the first tuning circuit 121. When the first tuning circuit 121 includes multiple capacitors, the multiple capacitors may be connected in series or in parallel. When the first tuning circuit 121 includes multiple inductors, the inductors can be connected in series or in parallel. When the first tuning circuit 121 includes one or more capacitors and one or more inductors, the inductors and capacitors can be connected in series or in parallel. The first tuning circuit 121 can be matched to be inductive or capacitive depending on the frequency band supported by the antenna radiator 120. The first tuning circuit 121 is disposed on the circuit board 200.

[0039] The antenna radiator 120 includes a first free end A, a first ground end B, a feed point C located between the first free end A and the first ground end B, and a first connection point D located between the feed point C and the first free end A. The first free end A can be understood as the end of the antenna radiator 120 that is not electrically connected to a conductive element or has a gap between it and a conductive element. The first ground end B can be understood as the end or port of the antenna radiator 120 electrically connected to reference ground 11. The feed point C can be understood as the port of the antenna radiator 120 that receives the excitation signal. The first connection point D can be understood as the port of the antenna radiator 120 that is electrically connected to the first tuning circuit 121.

[0040] In one possible implementation, such as Figure 2As shown, the antenna radiator 120 is linear, with one end forming the first free end A and the other end forming the first ground end B. The feed point C is located between the first free end A and the first ground end B, spaced apart from both. The first connection point D can be located between the feed point C and the first free end A, spaced apart from both; alternatively, the first connection point D can be located at the first free end A.

[0041] In this embodiment, the antenna radiator 120 can be disposed in one of the first sub-frame 30, the second sub-frame 31, the third sub-frame 32, and the fourth sub-frame 33.

[0042] Of course, in other possible implementations, such as Figure 3 As shown, the antenna radiator 120 may include a first radiating segment 1201 and a second radiating segment 1202 that are bent and connected. The end of the first radiating segment 1201 away from the second radiating segment 1202 may form the first free end A, and the end of the second radiating segment 1202 away from the first radiating segment 1201 may form the first grounding end B. The feed point C may be located in either the first radiating segment 1201 or the second radiating segment 1202. When the feed point C is located in the first radiating segment 1201, the first connection point D is located in the first radiating segment 1201; when the feed point C is located in the second radiating segment 1202, the first connection point D may be located in either the first radiating segment 1201 or the second radiating segment 1202.

[0043] In this embodiment, the antenna radiator 120 can be disposed on two adjacent sub-frames 30, 31, 32, and 33. For example, one of the first radiating segment 1201 and the second radiating segment 1202 is disposed on the first sub-frame 30, and the other is disposed on the second sub-frame 31 or the fourth sub-frame 33; or, one of the first radiating segment 1201 and the second radiating segment 1202 is disposed on the third sub-frame 32, and the other is disposed on the second sub-frame 31 or the fourth sub-frame 33.

[0044] The power supply point C is electrically connected to the signal source 10. The power supply point C and the signal source 10 can be directly or indirectly connected. For example, the power supply point C and the signal source 10 can be directly soldered, or they can be electrically connected through electrical connectors such as coaxial cables, microstrip lines, conductive springs, and conductive adhesives.

[0045] The first grounding terminal B is electrically connected to the reference ground 11. The first grounding terminal B and the reference ground 11 can be directly electrically connected or indirectly electrically connected. For example, the first grounding terminal B and the reference ground 11 can be directly soldered, or electrically connected through electrical connectors such as conductive wires, conductive springs, and conductive adhesive.

[0046] The first connection point D is electrically connected to the reference ground 11 through the first tuning circuit 121. In other words, the first tuning circuit 121 is electrically connected between the first connection point D and the reference ground 11. The first tuning circuit 121 and the first connection point D can be directly or indirectly connected. For example, the first tuning circuit 121 and the first connection point D can be directly soldered, or electrically connected through electrical connectors such as conductive wires, conductive springs, or conductive adhesive. The first tuning circuit 121 and the reference ground 11 can be directly or indirectly connected. For example, the first tuning circuit 121 and the reference ground 11 can be directly soldered, or electrically connected through electrical connectors such as conductive wires, conductive springs, or conductive adhesive.

[0047] like Figure 4 As shown, the antenna radiator 120 between the first ground terminal B and the first free terminal A is used to generate a first resonant mode supporting the first target frequency band under the excitation of the signal source 10. The first resonant mode is a 1 / 4 wavelength mode. It can be understood that the first resonant current corresponding to the first resonant mode is distributed between the first ground terminal B and the first free terminal A of the antenna radiator 120. The first resonant current corresponding to the first resonant mode can be referred to in the appendix. Figure 4 The dashed line indicates I1. It should be noted that since the first resonant current is alternating current, its direction changes periodically. Therefore, the direction shown for I1 in the attached diagram is only one possible flow direction of the first resonant current. In the first resonant mode, the antenna radiator 120 can receive and / or transmit electromagnetic wave signals in the first target frequency band.

[0048] This application does not specifically limit the first target frequency band. For example, the first target frequency band can be located in a low-frequency (less than or equal to 1 GHz) band; or, the first target frequency band can be located in a mid-high frequency (greater than 1 GHz and less than or equal to 3 GHz) band; or, the first target frequency band can be located in an ultra-high frequency (greater than 3 GHz) band. The first target frequency band can be a 4G LTE band or a 5G NR band. In the following embodiments, unless otherwise specified, the first target frequency band includes LTE B3 and LTE B1. Compared with frequency bands such as N41 and N78, which have a relatively small uplink airspace ratio in actual networks, LTE B3 and LTE B1 (4G, 1.7 GHz to 1.9 GHz) have a relatively large uplink airspace ratio in actual networks, requiring consideration of power backoff. Therefore, the technical problem to be solved by this application is more significant for LTE B3 and LTE B1.

[0049] In one possible implementation, when the antenna radiator 120 between the first ground terminal B and the first free terminal A generates a resonant current that gradually weakens under the excitation of the signal source 10, and the resonant current generated at the first ground terminal B is relatively strong while the resonant current generated at the first free terminal A is relatively weak, it can be considered that the antenna radiator 120 between the first ground terminal B and the first free terminal A generates a first resonant mode under the excitation of the signal source 10. The first resonant mode is a 1 / 4 wavelength mode. In other words, the first resonant mode forms a first current strong point at the first ground terminal B and a first current weak point at the first free terminal A, and the current intensity between the first ground terminal B and the first free terminal A gradually decreases.

[0050] In another possible implementation, when the electrical length of the antenna radiator 120 between the first ground terminal B and the first free terminal A is equal to or close to 1 / 4 wavelength of the first target frequency band, it can be considered that the antenna radiator 120 between the first ground terminal B and the first free terminal A can generate a first resonant mode under the excitation of the signal source 10. The first resonant mode is a 1 / 4 wavelength mode. Here, the electrical length of the antenna radiator 120 between the first ground terminal B and the first free terminal A is equal to k1*PL1. k1 is the ratio of the transmission time of the electrical or electromagnetic wave signal in the first target frequency band in the medium to its transmission time in free space; PL1 is the physical length of the antenna radiator 120 between the first ground terminal B and the first free terminal A. Taking the first target frequency band including LTE B3 and LTE B1 as an example, the 1 / 4 wavelength of the first target frequency band can be 35mm to 55mm. That is, when the electrical length of the antenna radiator 120 between the first ground terminal B and the first free terminal A is between 35mm and 55mm, it can be considered that the antenna radiator 120 between the first ground terminal B and the first free terminal A can generate a first resonant mode under the excitation of the signal source 10. The first resonant mode is a 1 / 4 wavelength mode.

[0051] like Figure 5 As shown, the antenna radiator 120 and the first tuning circuit 121 between the first ground terminal B and the first connection point D are used to generate a second resonant mode supporting the first target frequency band under the excitation of the signal source 10. The second resonant mode is a 1 / 2 wavelength mode. It can be understood that the second resonant current corresponding to the second resonant mode is distributed from the first ground terminal B of the antenna radiator 120 to the first connection point D and the first tuning circuit 121. The second resonant current corresponding to the second resonant mode can be referred to in the appendix. Figure 5 The dashed line indicates I2. It should be noted that because the second resonant current is alternating current, its direction changes periodically. Therefore, the direction shown for I2 in the attached diagram is only one possible flow direction of the second resonant current. In the second resonant mode, the antenna radiator 120 can receive and / or transmit electromagnetic wave signals in the first target frequency band.

[0052] In this configuration, the second resonant mode and the first resonant mode coexist. In other words, the first resonant current corresponding to the first resonant mode and the second resonant current corresponding to the second resonant mode are simultaneously distributed in the antenna radiator 120. Since the second resonant mode and the first resonant mode are different wavelength modes, the current intensity points of the second resonant mode and the first resonant mode are different, thereby dispersing the current intensity points of the antenna radiator 120 and achieving the effect of reducing SAR.

[0053] In one possible implementation, when the antenna radiator 120 between the first ground terminal B and the first connection point D generates a resonant current that gradually weakens and then strengthens under the excitation of the signal source 10, and the resonant current generated at the first ground terminal B and the first connection point D is relatively strong, and there is a current weakness between the first ground terminal B and the first connection point D, it can be considered that the antenna radiator 120 and the first tuning circuit 121 between the first ground terminal B and the first connection point D generate a second resonant mode under the excitation of the signal source 10. The second resonant mode is a 1 / 2 wavelength mode. In other words, the second resonant mode forms a second strong current point at the first ground terminal B and a third strong current point at the first connection point D. The current intensity between the first ground terminal B and the first connection point D first gradually decreases and then gradually increases.

[0054] In another possible implementation, when the sum of the electrical length of the antenna radiator 120 between the first grounding terminal B and the first connection point D, and the equivalent electrical length of the first tuning circuit 121, is equal to or close to half the wavelength of the first target frequency band, it can be considered that the antenna radiator 120 between the first grounding terminal B and the first connection point D, and the first tuning circuit 121, can generate a second resonant mode under the excitation of the signal source 10. The second resonant mode is a half-wavelength mode. Here, the electrical length of the antenna radiator 120 between the first grounding terminal B and the first connection point D is equal to k1*PL2. k1 is the ratio of the transmission time of the electrical or electromagnetic wave signal in the medium to its transmission time in free space in the first target frequency band; PL2 is the physical length of the antenna radiator 120 between the first grounding terminal B and the first connection point D. Taking the first target frequency band including LTE B3 and LTE B1 as an example, the half wavelength of the first target frequency band can be 70mm to 110mm. That is, when the sum of the electrical length of the antenna radiator 120 between the first ground terminal B and the first connection point D and the equivalent electrical length of the first tuning circuit 121 is between 70mm and 110mm, it can be considered that the antenna radiator 120 between the first ground terminal B and the first connection point D and the first tuning circuit 121 can generate a second resonant mode under the excitation of the signal source 10. The second resonant mode is a half wavelength mode.

[0055] The antenna assembly 100 provided in this application includes a signal source 10, a reference ground 11, and an antenna element 12. The antenna element 12 includes an antenna radiator 120 and a first tuning circuit 121. Since the first connection point D in the antenna radiator 120, located between the feed point C and the first free end A, is electrically connected to the reference ground 11 through the first tuning circuit 121, the first ground end B and the first free end A of the antenna radiator 120 can generate a first resonant mode supporting the first target frequency band under the excitation of the signal source 10. The first ground end B and the first connection point D of the antenna radiator 120, and the first tuning circuit 121, can generate a second resonant mode supporting the first target frequency band under the excitation of the signal source 10. Therefore, there are multiple strong current points formed by the first resonant mode and the second resonant mode on the antenna radiator 120 of this application. The first resonant mode is a 1 / 4 wavelength mode, and the second resonant mode is a 1 / 2 wavelength mode. Therefore, the multiple strong current points are distributed at different positions on the antenna radiator 120, thereby achieving the effect of current shunting on the strong current points on the antenna radiator 120 and reducing the SAR value. Furthermore, both the first and second resonant modes support the first target frequency band, so the communication performance of the first target frequency band is not reduced, meaning that the SAR value can be further reduced while ensuring communication performance.

[0056] like Figure 6 As shown, the first tuning circuit 121 is inductive. Optionally, the first tuning circuit 121 includes an inductor; or, the first tuning circuit 121 includes multiple inductors connected in series; or, the first tuning circuit 121 includes at least one inductor and at least one capacitor, wherein the effect of the inductor is greater than the effect of the capacitor. In one possible embodiment, the first tuning circuit 121 includes an inductor. The first tuning circuit 121 is connected in series between the reference ground 11 and the first connection point D of the antenna radiator 120.

[0057] The first tuning circuit 121 is inductive, which can correspondingly extend the electrical length of the antenna radiator 120. This is more conducive to the antenna radiator 120 and the first tuning circuit 121 between the first ground terminal B and the first connection point D generating a second resonant mode that supports low-frequency bands or mid-to-high-frequency bands under the excitation of the signal source 10. This helps to solve the technical problem that the uplink space ratio of actual networks such as LTE B3 and LTE B1 is relatively large, and the frequency bands that need to consider power back-off cannot take into account both communication performance and SAR value.

[0058] like Figure 7As shown, antenna element 12 also includes a matching circuit 122 electrically connected between feed point C and signal source 10. The matching circuit 122 and feed point C can be directly or indirectly connected. For example, feed point C and signal source 10 can be directly soldered or electrically connected via conductive wires, conductive springs, conductive adhesive, or other electrical connectors. The matching circuit 122 can also include capacitors and / or inductors. This application does not specifically limit the number of capacitors or inductors included in the matching circuit 122. When the matching circuit 122 includes multiple capacitors, the multiple capacitors can be connected in series or parallel. When the matching circuit 122 includes multiple inductors, the multiple inductors can be connected in series or parallel. When the matching circuit 122 includes one or more capacitors and one or more inductors, the inductors and capacitors can be connected in series or in parallel. The matching circuit 122 is located on the circuit board 200.

[0059] Optionally, the matching circuit 122 may include a capacitor and an inductor connected in series; or, the matching circuit 122 may also include a capacitor and an inductor connected in parallel; or, the matching circuit 122 may also include an inductor, a first capacitor, and a second capacitor, with the inductor connected in parallel with the first capacitor and then in series with the second capacitor; or, the matching circuit 122 may also include a first inductor, a second inductor, and a capacitor, with the first inductor connected in parallel with the capacitor and then in series with the second inductor; or, the matching circuit 122 may also include an inductor, a first capacitor, and a second capacitor, with the inductor connected in series with the first capacitor and then in parallel with the second capacitor. Alternatively, the matching circuit 122 may include a first inductor, a second inductor, and a capacitor, with the first inductor and capacitor connected in series and then connected in parallel with the second inductor; or, the matching circuit 122 may include a first matching branch formed by the first inductor and the first capacitor connected in parallel, and a second matching branch formed by the second inductor and the second capacitor connected in parallel, with the first matching branch and the second matching branch connected in series; or, the matching circuit 122 may include a third matching branch formed by the first inductor and the first capacitor connected in series, and a fourth matching branch formed by the second inductor and the second capacitor connected in series, with the third matching branch and the fourth matching branch connected in parallel.

[0060] Matching circuit 122 is used to achieve impedance matching for the first resonant mode and / or the second resonant mode. It can be understood that matching circuit 122 is used to achieve impedance matching for the first resonant mode; or, matching circuit 122 is used to achieve impedance matching for the second resonant mode; or, matching circuit 122 is used to achieve impedance matching for both the first and second resonant modes. Impedance matching refers to a working state where the load impedance and the internal impedance of the signal source 10 are mutually matched to obtain maximum power output. Matching circuit 122 achieving impedance matching for the first resonant mode can be understood as follows: in the first resonant mode, matching circuit 122 can ensure that the internal resistance of the signal source 10 is equal in magnitude and phase to the load impedance. At this time, the load impedance is the impedance of the antenna radiator 120 between the first ground terminal B and the first free terminal A. The matching circuit 122 is used to achieve impedance matching in the second resonant mode. This can be understood as follows: in the second resonant mode, the matching circuit 122 can achieve that the internal resistance of the signal source 10 is equal in magnitude and phase to the load impedance. At this time, the load impedance is the sum of the impedance of the antenna radiator 120 between the first ground terminal B and the first connection point D and the impedance of the first tuning circuit 121.

[0061] By including a matching circuit 122 electrically connected between the feed point C and the signal source 10 in the antenna element 12, the matching circuit 122 is used to achieve impedance matching of the first resonant mode and / or the second resonant mode, which can reduce the reflected signal of the antenna radiator 120 and improve the efficiency of the antenna assembly 100.

[0062] like Figure 8 As shown, the length of the antenna radiator 120 between the first connection point D and the first free end A is less than or equal to 1 / 4 of the length of the antenna radiator 120 between the first free end A and the first ground end B. It can be understood that the first connection point D is located at the midpoint of the antenna radiator 120 on the side opposite to the first ground end B, and relatively close to the first free end A. In this embodiment, the first free end A is one end of the antenna radiator 120, and the first ground end B is the other end of the antenna radiator 120. The length of the antenna radiator 120 between the first free end A and the first ground end B can be understood as the overall length of the antenna radiator 120. The length of the antenna radiator 120 between the first connection point D and the first free end A can be referred to in the appendix. Figure 8 As shown in L1, the length of the antenna radiator 120 between the first free end A and the first ground end B can be referenced in the appendix. Figure 8 As shown in L2. In one possible embodiment, the first target frequency band includes LTE B3 and LTE B1, the length of the antenna radiator 120 between the first free end A and the first ground end B can be 35mm to 55mm, and the length of the antenna radiator 120 between the first connection point D and the first free end A can be less than or equal to 10mm.

[0063] By making the length of the antenna radiator 120 between the first connection point D and the first free end A less than or equal to 1 / 4 of the length of the antenna radiator 120 between the first free end A and the first ground end B, it is beneficial to achieve excitation of the second resonant mode on the antenna radiator 120 between the first ground end B and the first connection point D, and the length of the antenna radiator 120 itself can be utilized more, reducing the design difficulty of the first tuning circuit 121.

[0064] like Figure 8 As shown, the length of the antenna radiator 120 between the feed point C and the first ground terminal B is less than or equal to 1 / 4 of the length of the antenna radiator 120 between the first free end A and the first ground terminal B. It can be understood that the feed point C is located at the midpoint of the antenna radiator 120, away from the first free end A, and relatively close to the first ground terminal B. The length of the antenna radiator 120 between the feed point C and the first ground terminal B can be referred to the attached figure. Figure 8 As shown in L3. In one possible embodiment, the first target frequency band includes LTE B3 and LTE B1, and the length of the antenna radiator 120 between the feed point C and the first ground terminal B can be less than or equal to 15 mm.

[0065] By making the length of the antenna radiator 120 between the feed point C and the first grounding terminal B less than or equal to 1 / 4 of the length of the antenna radiator 120 between the first free end A and the first grounding terminal B, it is beneficial to achieve excitation of the first resonant mode on the antenna radiator 120 between the first grounding terminal B and the first free end A, and it can reduce other modes that are excited on the antenna radiator 120.

[0066] In the first resonant mode, a first strong current point is formed at the first grounding terminal B, and a first weak current point is formed at the first free terminal A. The current intensity between the first grounding terminal B and the first free terminal A gradually decreases. In the second resonant mode, a second strong current point is formed at the first grounding terminal B, and a third strong current point is formed at the first connection point D. The current intensity between the first grounding terminal B and the first connection point D first gradually decreases and then gradually increases.

[0067] Understandably, the antenna radiator 120 has a first current strong point, a second current strong point, and a third current strong point. The first current strong point and the second current strong point are both formed at the first ground terminal B. However, since the first current strong point and the second current strong point are the current strong points of the first resonant mode and the second resonant mode, respectively, and the second resonant mode not only has the second current strong point but also has the third current strong point formed at the first connection point D, the current strong points of the antenna radiator 120 can be dispersed compared to the antenna radiator 120 that only generates one resonant mode. This can further reduce the SAR value while ensuring communication performance.

[0068] In one possible implementation, such as Figure 9 As shown, the second resonant mode forms a second current weakness at target point E. It can be understood that the second resonant mode forms a second current strength at the first grounding terminal B, a third current strength at the first connection point D, and a second current weakness at target point E. The current intensity gradually decreases from the first connection point D to target point E, and gradually increases from target point E to the first grounding terminal B. Target point E is located between the first connection point D and the feed point C. Optionally, target point E is relatively closer to the first connection point D and relatively farther from the feed point C; or, target point E is relatively closer to the feed point C and relatively farther from the first connection point D; or, target point E is located at the midpoint between the first connection point D and the feed point C.

[0069] Since the feed point C is close to the first grounding terminal B, which is conducive to exciting the first resonant mode, and the first connection point D is close to the first free end A, which is conducive to exciting the second resonant mode, by making the second resonant mode form a second current weakness at the target point E, which is located between the first connection point D and the feed point C, the antenna radiator 120 between the feed point C and the first grounding terminal B can have a strong resonant current in the first resonant mode, and the antenna radiator 120 between the feed point C and the first grounding terminal B can have a strong resonant current in the second resonant mode. This ensures the resonant current intensity of the first and second resonant modes, and ensures that the antenna assembly 100 has good communication performance to support the first target frequency band.

[0070] like Figure 10 As shown, this scheme moves the feed point C to a position close to the first grounding terminal B of the antenna radiator 120, and only connects an inductor to the first free end A near the antenna radiator 120 to reduce the SAR value, without increasing the area and length of the antenna radiator 120. The specific principle is as follows... Figure 10 As shown, after an inductor is connected to the end of the antenna radiator 120, the antenna boundary conditions change. Therefore, the antenna assembly 100 contains components of two resonant modes: the quarter-wavelength mode of the inverted-F antenna and the half-wavelength mode of the loop antenna introduced by the inductor. According to the radiation principle of the inverted-F antenna and the loop antenna, the quarter-wavelength mode of the inverted-F antenna generates a strong current point Imax1 at the first grounding terminal B. The half-wavelength mode of the loop antenna generates strong current points Imax2 and Imax3 at both the first grounding terminal B and the first connection point D. Thus, the strong current point Imax on the antenna radiator 120 is equal to the sum of Imax1 and Imax2, achieving the effect of current shunting at the strong points on the antenna radiator 120 and meeting the requirement of reducing the SAR value of the LTE B3 / B1 band.

[0071] Please refer to Figure 11 and Figure 12 , Figure 11Figure (a) is a partial structural schematic diagram of the electronic device 1000 provided in the embodiments of this application; Figure 11 Figure (b) is a schematic diagram of the structure of the antenna assembly 100 in the electronic device 1000 in Figure (a) when the first tuning circuit 121 is removed; Figure 11 Figure (c) is a schematic diagram of the structure of the antenna assembly 100 in Figure (a) with the first tuning circuit 121 removed and the length of the antenna radiator 120 increased. Figure 12 The middle curve (d) is Figure 11 The return loss curve corresponding to the antenna assembly 100 in the electronic device 1000 in Figure (a); Figure 12 The middle curve (e) is Figure 11 The return loss curve corresponding to the electronic device in Figure (b); Figure 12 The middle curve (f) is Figure 11 The return loss curve corresponding to the electronic device in Figure (c). From Figure 12 Curves (d), (e), and (f) show that all three electronic devices support the LTE B3 / B1 bands. As shown in Table 1... Figure 11 The table shows the measured SAR values ​​of the antenna components in Figures (a), (b), and (c). As can be seen from Table 1, the antenna component 100 in the electronic device 1000 of scheme (a) and the electronic device in scheme (c) both achieve a SAR value reduction of approximately 30% compared to the electronic device in scheme (b), demonstrating significant effectiveness. Furthermore, the antenna component 100 in the electronic device 1000 of scheme (a) provided in this embodiment does not require an increase in the area and length of the antenna radiator 120 compared to scheme (c), thus occupying less space and facilitating the layout of the antenna component 100 in the electronic device 1000.

[0072] Table 1:

[0073]

[0074] Please refer to Figure 11 and Figure 13 , Figure 13 The middle (g) diagram is Figure 11 Figure (a) shows the simulation diagram of the current distribution corresponding to the antenna component 100 in the electronic device 1000; Figure 13 The middle (h) diagram is Figure 11 Figure (b) shows a simulation diagram of the current distribution corresponding to the antenna component in the electronic device. Figure 13 As can be seen from Figures (g) and (h) of the present application, the antenna assembly 100 in Figure (a) has two obvious hot spots, which are located at the first connection point D and the first grounding terminal B of the antenna radiator 120, respectively. In contrast, the antenna assembly in Figure (b) has only one hot spot at the grounding terminal, which confirms the technical effect of the aforementioned dual-resonance mode.

[0075] Furthermore, such as Figure 14 As shown, the antenna assembly 100 also includes a parasitic unit 13. The parasitic unit 13 includes a parasitic stub 130 and a second tuning circuit 131. The parasitic stub 130 is disposed on the frame 300. Optionally, the parasitic stub 130 can be disposed on the inner surface of the frame 300, or the parasitic stub 130 can be integrated onto the frame 300, or the parasitic stub 130 can be disposed on the outer surface of the frame 300. In other words, the parasitic stub 130 can be a built-in parasitic stub, or the parasitic stub 130 can be a metal frame parasitic stub, or the parasitic stub 130 can be an external parasitic stub. In the following embodiments, unless otherwise specified, the parasitic stub 130 is exemplified as a metal frame parasitic stub. The material of the parasitic stub 130 can include at least one conductive material such as metal, alloy, or carbon fiber. The second tuning circuit 131 can include capacitors and / or inductors, etc. This application does not specifically limit the number of capacitors or inductors included in the second tuning circuit 131. When the second tuning circuit 131 includes multiple capacitors, the multiple capacitors can be connected in series or in parallel. When the second tuning circuit 131 includes multiple inductors, the multiple inductors can be connected in series or in parallel. When the second tuning circuit 131 includes one or more capacitors and one or more inductors, the inductors and capacitors can be connected in series or in parallel. Depending on the frequency band supported by the parasitic stub 130, the second tuning circuit 131 can be matched to be either inductive or capacitive. The second tuning circuit 131 is disposed on the circuit board 200.

[0076] The parasitic stub 130 includes a second free end F, a second ground end G, and a second connection point H located between the second free end F and the second ground end G. The second free end F can be understood as the end or port of the parasitic stub 130 that couples with the antenna radiator 120. The second ground end G can be understood as the end or port of the parasitic stub 130 that is electrically connected to the reference ground 11. The second connection point H can be understood as the port of the parasitic stub 130 that is electrically connected to the second tuning circuit 131.

[0077] In one possible implementation, the parasitic branch 130 is straight, with one end forming the second free end F and the other end forming the second grounding end G. A second connection point H is located between the second free end F and the second grounding end G, and is spaced apart from both ends. In this embodiment, the parasitic branch 130 can be located on one of the first sub-frame 30, the second sub-frame 31, the third sub-frame 32, and the fourth sub-frame 33.

[0078] Of course, in other possible implementations, the parasitic branch 130 may include a first parasitic segment and a second parasitic segment that are bent and connected together. The end of the first parasitic segment away from the second parasitic segment forms the second free end F, and the end of the second parasitic segment away from the first parasitic segment forms the second grounding end G. The second connection point H may be located on either the first parasitic segment or the second parasitic segment. In this embodiment, the parasitic branch 130 may be located on two adjacent sub-frames 30, 31, 32, and 33. For example, one of the first parasitic segment and the second parasitic segment may be located on the first sub-frame 30, and the other on the second sub-frame 31 or the fourth sub-frame 33; or, one of the first parasitic segment and the second parasitic segment may be located on the third sub-frame 32, and the other on the second sub-frame 31 or the fourth sub-frame 33.

[0079] A coupling gap is formed between the second free end F and the first free end A. In other words, the parasitic stub 130 and the antenna radiator 120 are coupled through the coupling gap, meaning that the parasitic stub 130 and the antenna radiator 120 can transmit radiated energy through the coupling gap. The size of the coupling gap can be 0.5 mm to 2 mm.

[0080] The second grounding terminal G is electrically connected to the reference ground 11. The second grounding terminal G and the reference ground 11 can be directly electrically connected or indirectly electrically connected. For example, the second grounding terminal G and the reference ground 11 can be directly soldered, or electrically connected through electrical connectors such as conductive wires, conductive springs, and conductive adhesive.

[0081] The second connection point H is electrically connected to the reference ground 11 through the second tuning circuit 131. In other words, the second tuning circuit 131 is electrically connected between the second connection point H and the reference ground 11. The second tuning circuit 131 and the second connection point H can be directly or indirectly connected. For example, the second tuning circuit 131 and the second connection point H can be directly soldered, or electrically connected through electrical connectors such as conductive wires, conductive springs, or conductive adhesive. The second tuning circuit 131 and the reference ground 11 can be directly or indirectly connected. For example, the second tuning circuit 131 and the reference ground 11 can be directly soldered, or electrically connected through electrical connectors such as conductive wires, conductive springs, or conductive adhesive.

[0082] like Figure 15 As shown, the parasitic stub 130 between the second ground terminal G and the second free terminal F is used to generate a third resonant mode supporting the second target frequency band under the excitation of the signal source 10. The third resonant mode is a 1 / 4 wavelength mode. It can be understood that the third resonant current corresponding to the third resonant mode is distributed between the second ground terminal G and the second free terminal F of the parasitic stub 130. The third resonant current corresponding to the third resonant mode can be referred to in the appendix. Figure 15The diagram shows I3. It should be noted that because the third resonant current is alternating current, its direction changes periodically. Therefore, the direction shown for I3 in the attached diagram is only one possible flow direction of the third resonant current. In the third resonant mode, the parasitic stub 130 can receive and / or transmit electromagnetic wave signals in the second target frequency band.

[0083] This application does not specifically limit the second target frequency band. For example, the second target frequency band may be located in a low-frequency (less than or equal to 1 GHz) band; or, the second target frequency band may be located in a mid-high frequency (greater than 1 GHz and less than or equal to 3 GHz) band; or, the second target frequency band may be located in an ultra-high frequency (greater than 3 GHz) band. The second target frequency band may be different from the first target frequency band. In one possible implementation, the center frequency of the second target frequency band may be higher than the center frequency of the first target frequency band.

[0084] In one possible implementation, when the parasitic stub 130 between the second ground terminal G and the second free terminal F generates a resonant current that decreases in strength under the excitation of the signal source 10, and the resonant current generated at the second ground terminal G is relatively strong while the resonant current generated at the second free terminal F is relatively weak, it can be considered that the parasitic stub 130 between the second ground terminal G and the second free terminal F generates a third resonant mode under the excitation of the signal source 10. The third resonant mode is a 1 / 4 wavelength mode. In other words, the third resonant mode forms a strong current point at the second ground terminal G and a weak current point at the second free terminal F, and the current intensity between the second ground terminal G and the second free terminal F gradually decreases.

[0085] In another possible implementation, when the electrical length of the parasitic stub 130 between the second ground terminal G and the second free terminal F is equal to or close to 1 / 4 wavelength of the second target frequency band, the parasitic stub 130 between the second ground terminal G and the second free terminal F can be considered as being used to generate a third resonant mode under the excitation of the signal source 10. The third resonant mode is a 1 / 4 wavelength mode. Here, the electrical length of the parasitic stub 130 between the second ground terminal G and the second free terminal F is equal to k2*PL3. k2 is the ratio of the propagation time of the electrical or electromagnetic wave signal in the second target frequency band in the medium to its propagation time in free space; PL3 is the physical length of the parasitic stub 130 between the second ground terminal G and the second free terminal F.

[0086] like Figure 16As shown, the parasitic stub 130 between the second ground terminal G and the second connection point H, and the second tuning circuit 131, are used to generate a fourth resonant mode supporting the second target frequency band under the excitation of the signal source 10. The fourth resonant mode is a 1 / 2 wavelength mode. It can be understood that the fourth resonant current corresponding to the fourth resonant mode is distributed from the second ground terminal G of the parasitic stub 130 to the second connection point H and the second tuning circuit 131. The fourth resonant current corresponding to the fourth resonant mode can be referred to in the appendix. Figure 16 The diagram shows I4. It should be noted that because the second parasitic current is alternating current, the direction of the fourth resonant current changes periodically. Therefore, the direction shown for I4 in the attached diagram is only one possible flow direction of the fourth resonant current. In the fourth resonant mode, the parasitic stub 130 can receive and / or transmit electromagnetic wave signals in the second target frequency band.

[0087] In one possible implementation, when the parasitic stub 130 between the second ground terminal G and the second connection point H generates a resonant current that changes from strong to weak and then back to strong under the excitation of the signal source 10, and the resonant current generated at the second ground terminal G and the second connection point H is relatively strong, while there is a current weakness between the second ground terminal G and the second connection point H, it can be considered that the parasitic stub 130 between the second ground terminal G and the second connection point H and the second tuning circuit 131 generate a fourth resonant mode under the excitation of the signal source 10. The fourth resonant mode is a 1 / 2 wavelength mode. In other words, the fourth resonant mode forms a strong current point at the second ground terminal G and a strong current point at the second connection point H, and the current intensity between the second ground terminal G and the second connection point H first gradually decreases and then gradually increases.

[0088] In another possible implementation, when the sum of the electrical length of the parasitic stub 130 between the second grounding terminal G and the second connection point H, and the equivalent electrical length of the second tuning circuit 131, is equal to or close to half the wavelength of the second target frequency band, it can be considered that the parasitic stub 130 between the second grounding terminal G and the second connection point H, and the second tuning circuit 131, are used to generate a fourth resonant mode under the excitation of the signal source 10. The fourth resonant mode is a half-wavelength mode. Wherein, the electrical length of the parasitic stub 130 between the second grounding terminal G and the second connection point H is equal to k2*PL4. k2 is the ratio of the transmission time of the electrical or electromagnetic wave signal in the medium to its transmission time in free space in the second target frequency band; PL4 is the physical length of the parasitic stub 130 between the second grounding terminal G and the second connection point H.

[0089] In this embodiment, the parasitic stub 130 contains multiple strong current points formed by the third and fourth resonant modes. The third resonant mode is a quarter-wavelength mode, and the fourth resonant mode is a half-wavelength mode. Therefore, these multiple strong current points are distributed at different locations on the parasitic stub 130, achieving the effect of current diversion on the strong current points on the parasitic stub 130 and reducing the SAR value. Furthermore, both the third and fourth resonant modes simultaneously support the second target frequency band; therefore, the communication performance of the second target frequency band is not reduced, meaning that the SAR value can be further reduced while ensuring communication performance.

[0090] like Figure 17 As shown, the second tuning circuit 131 is inductive. Optionally, the second tuning circuit 131 includes an inductor; or, the second tuning circuit 131 includes multiple inductors connected in series; or, the second tuning circuit 131 includes at least one inductor and at least one capacitor, wherein the effect of the inductor is greater than the effect of the capacitor. In one possible embodiment, the second tuning circuit 131 includes an inductor. The second tuning circuit 131 is connected in series between reference ground 11 and the second connection point H of the parasitic stub 130.

[0091] The second tuning circuit 131 is inductive, which can correspondingly extend the electrical length of the parasitic stub 130. This is more conducive to the parasitic stub 130 between the second ground terminal G and the second connection point H. Under the excitation of the signal source 10, the second tuning circuit 131 generates a fourth resonant mode that supports the low-frequency band or the mid-to-high-frequency band. This makes it easier to solve the technical problem that the frequency bands in the low-frequency band or the mid-to-high-frequency band that need to consider power back-off cannot take into account both communication performance and SAR value.

[0092] like Figure 18 As shown, the length of the parasitic branch 130 between the second connection point H and the second free end F is less than or equal to 1 / 4 of the length of the parasitic branch 130 between the second free end F and the second grounding end G. It can be understood that the second connection point H is located on the side of the parasitic branch 130 away from the second grounding end G at its midpoint, and relatively close to the second free end F. In this embodiment, the second free end F is one end of the parasitic branch 130, and the second grounding end G is the other end of the parasitic branch 130. The length of the parasitic branch 130 between the second free end F and the second grounding end G can be understood as the overall length of the parasitic branch 130. The length of the parasitic branch 130 between the second connection point H and the second free end F can be referred to the appendix. Figure 18 As shown in L4. The length of the parasitic branch 130 between the second free end F and the second grounded end G can be referred to in Appendix. Figure 18 As shown in L5.

[0093] In one possible embodiment, the center frequency of the second target frequency band may be higher than the center frequency of the first target frequency band, the length of the parasitic stub 130 between the second free end F and the second ground end G may be less than the length of the antenna radiator 120 between the first free end A and the first ground end B, and the length of the parasitic stub 130 between the second connection point H and the second free end F may be less than the length of the antenna radiator 120 between the first connection point D and the first free end A.

[0094] By making the length of the parasitic stub 130 between the second connection point H and the second free end F less than or equal to 1 / 4 of the length of the parasitic stub 130 between the second free end F and the second ground end G, it is beneficial to realize the excitation of the fourth resonant mode on the parasitic stub 130 between the second ground end G and the second connection point H, and the length of the parasitic stub 130 itself can be utilized more, reducing the design difficulty of the second tuning circuit 131.

[0095] The features mentioned above in the specification, claims, and drawings can be combined in any way as long as they are meaningful within the scope of this application. The advantages and features described with respect to the antenna are applied accordingly to the electronic device 1000.

[0096] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application, and such improvements and refinements are also considered to be within the protection scope of this application.

Claims

1. An antenna assembly, characterized in that, include: Signal source; Reference location; and An antenna unit includes an antenna radiator and a first tuning circuit. The antenna radiator includes a first free end, a first ground end, a feed point located between the first free end and the first ground end, and a first connection point located between the feed point and the first free end. The first ground end is electrically connected to a reference ground, the feed point is electrically connected to a signal source, and the first connection point is electrically connected to the reference ground through the first tuning circuit. Under the excitation of the signal source, the antenna radiator between the first ground end and the first free end generates a first resonant mode supporting a first target frequency band. The first resonant mode is a 1 / 4 wavelength mode. Under the excitation of the signal source, the antenna radiator between the first ground end and the first connection point and the first tuning circuit generate a second resonant mode supporting the first target frequency band. The second resonant mode is a 1 / 2 wavelength mode. The second resonant mode and the first resonant mode coexist. Both the first resonant mode and the second resonant mode support the first target frequency band.

2. The antenna assembly according to claim 1, characterized in that, The first tuning circuit is inductive; the antenna unit further includes a matching circuit electrically connected between the feed point and the signal source, the matching circuit being used to achieve impedance matching of the first resonant mode and / or impedance matching of the second resonant mode.

3. The antenna assembly according to claim 1, characterized in that, The length of the antenna radiator between the first connection point and the first free end is less than or equal to 1 / 4 of the length of the antenna radiator between the first free end and the first ground end.

4. The antenna assembly according to claim 1, characterized in that, The length of the antenna radiator between the feed point and the first grounding terminal is less than or equal to 1 / 4 of the length of the antenna radiator between the first free end and the first grounding terminal.

5. The antenna assembly according to any one of claims 1 to 4, characterized in that, The first resonant mode forms a first strong current point at the first grounding terminal and a first weak current point at the first free terminal, with the current intensity gradually decreasing between the first grounding terminal and the first free terminal; the second resonant mode forms a second strong current point at the first grounding terminal and a third strong current point at the first connection point, with the current intensity gradually decreasing and then gradually increasing between the first grounding terminal and the first connection point.

6. The antenna assembly according to claim 5, characterized in that, The second resonant mode creates a second current weakness at the target point, which is located between the first connection point and the feed point.

7. The antenna assembly according to any one of claims 1 to 4, characterized in that, The antenna assembly further includes a parasitic unit, which includes a parasitic stub and a second tuning circuit. The parasitic stub includes a second free end, a second ground end, and a second connection point located between the second free end and the second ground end. A coupling gap is formed between the second free end and the first free end. The second ground end is electrically connected to the reference ground, and the second connection point is electrically connected to the reference ground through the second tuning circuit. Under the excitation of the signal source, the parasitic stub between the second ground end and the second free end generates a third resonant mode supporting the second target frequency band. The third resonant mode is a 1 / 4 wavelength mode. Under the excitation of the signal source, the parasitic stub between the second ground end and the second connection point and the second tuning circuit generate a fourth resonant mode supporting the second target frequency band. The fourth resonant mode is a 1 / 2 wavelength mode.

8. The antenna assembly according to claim 7, characterized in that, The second tuning circuit is inductive.

9. The antenna assembly according to claim 7, characterized in that, The length of the parasitic branch between the second connection point and the second free end is less than or equal to 1 / 4 of the length of the parasitic branch between the second free end and the second grounding end.

10. An electronic device, characterized in that, The device includes a frame, a circuit board, and an antenna assembly as described in any one of claims 1 to 9. The frame encloses a receiving space, the circuit board is disposed within the receiving space, the signal source, the reference ground, and the first tuning circuit are disposed on the circuit board, and the antenna radiator is disposed on the frame.

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