An antenna system and electronic device

Abstract

The present application provides an antenna system and an electronic device, wherein the antenna system includes a first antenna and a ground. The first antenna includes: a first feeding circuit, an electrical device, a first branch, and a second branch. The second branch is coupled to the first branch at a first connection point, and the first branch is coupled to the ground to form a return ground for the first antenna. The second branch includes a first sub-branch and a second sub-branch, and the first sub-branch and the second sub-branch are located on both sides of the first connection point. The first sub-branch is coupled to the first feeding circuit for feeding the first antenna. In addition, the length of the second sub-branch is different from the length of the first sub-branch, and the second sub-branch is coupled to the ground through an electrical device.

Description

[0001] This application claims priority to the Chinese patent application filed with the Intellectual Property Office of the People's Republic of China on August 23, 2022, with application number 202211014485.0 and invention name "An Antenna and Electronic Device", all contents of which are incorporated by reference in this application. Technical Field

[0002] The present application relates to the field of communication technology, and in particular to an antenna system and electronic equipment. Background Art

[0003] As people's requirements for data transmission rate continue to increase, the development of Multi-Input Multi-Output (MIMO) antenna technology has been accelerated. MIMO antennas can improve the spectrum efficiency of transmitted signals, increase channel capacity and signal transmission rate, and can also improve the reliability of received signals in wireless communication systems. Therefore, MIMO antennas have become one of the key development technologies for wireless communication equipment.

[0004] However, when several adjacent antennas working in adjacent frequency bands are placed in a limited space of a terminal device, the antennas are too close to each other and the coupling is strong, which will cause poor isolation between antennas in the same and adjacent frequency bands, resulting in mutual coupling interference, reduced antenna efficiency, and drastic changes in radiation patterns. Therefore, it is imperative to implement a compact high-isolation antenna design solution. Summary of the invention

[0005] The present application provides an antenna system and an electronic device to improve the efficiency of the antenna system.

[0006] In a first aspect, the present application provides an antenna system. The antenna system includes a first antenna and a ground. The first antenna includes: a first feeding circuit, an electrical device, a first branch, and a second branch. The second branch is coupled to the first branch at a first connection point, and the first branch is coupled to the ground to form a return ground for the first antenna. The second branch includes a first sub-branch and a second sub-branch, and the first sub-branch and the second sub-branch are located on both sides of the first connection point. The first sub-branch is coupled to the first feeding circuit for feeding the first antenna. In addition, the length of the second sub-branch is different from the length of the first sub-branch, and the second sub-branch is coupled to the ground through an electrical device. By setting the electrical device so that the equivalent electrical length of the second sub-branch is close to or slightly larger than the equivalent electrical length of the first sub-branch, the antenna efficiency of the first antenna can be improved, and the structure is relatively simple and occupies less space.

[0007] When the second branch is specifically set, the first sub-branch and the second sub-branch extend on the same straight line.

[0008] In one technical solution, the length of the second sub-branch is less than that of the first sub-branch, and the electrical device is a capacitor, and the equivalent capacitance of the capacitor is in the range of 0.2pf to 6pf. The capacitance value in this range can meet the antenna efficiency increase requirement.

[0009] Specifically, when the electrical device includes one or more capacitors, the capacitance value of each capacitor can be within the range of 0.2 pf to 6 pf.

[0010] In addition, the electrical device includes an adjustable capacitor, which can be switched between capacitors with fixed capacitances by switches, or one or more switch branches can be turned on to form series and / or parallel capacitors, or a steplessly adjustable capacitor.

[0011] When the length of the second sub-branch is less than that of the first sub-branch, the length of the second sub-branch is 30% to 95% of the length of the first sub-branch. Within this range, the equivalent electrical length of the second sub-branch can be adjusted by setting the electrical device to improve the efficiency of the antenna.

[0012] When the first antenna is working, the first antenna generates a first resonance and a second resonance, wherein the center frequency of the first resonance is higher than the center frequency of the second resonance, wherein the first resonance is used to cover the working frequency band of the first antenna, and the second resonance is used to improve the system efficiency of the first resonance, that is, to improve the system efficiency of the working frequency band of the first antenna.

[0013] The frequency difference between the center frequency of the first resonance and the center frequency of the second resonance is less than or equal to 15% of the lower center frequency. Specifically, the frequency difference between the center frequency of the first resonance and the center frequency of the second resonance is less than or equal to 100 MHz, for example, it can be 50 MHz. The smaller the frequency difference between the center frequency of the first resonance and the center frequency of the second resonance, the better the system efficiency improvement for the working frequency band of the first antenna.

[0014] When the first resonance and the second resonance are specifically formed, the first sub-branch and the second sub-branch and the electrical device are used to generate the first resonance, and the current corresponding to the first resonance is the same-direction current on the first sub-branch and the second sub-branch.

[0015] The second sub-branch and the electrical device are used to generate a second resonance, and the current corresponding to the second resonance is the same-direction current on the second sub-branch.

[0016] When the above-mentioned second branch is specifically set, the above-mentioned second branch includes a first open end and a second open end, the first open end is located at an end of the first sub-branch away from the second sub-branch, and the second open end is located at an end of the second sub-branch away from the first sub-branch.

[0017] The distance between the coupling position of the above-mentioned electrical device and the second sub-branch and the second open end is within 40% of the total length of the second sub-branch. The closer the distance between the coupling position of the above-mentioned electrical device and the second sub-branch and the second open end is, the more fully the physical length of the second sub-branch can be utilized. Specifically, the distance between the coupling connection position of the capacitor and the second sub-branch and the second open end can be within 10 mm, for example, 5 mm or shorter, which can be specifically set in combination with the preparation process and structural layout.

[0018] In another technical solution, the antenna system further includes a second antenna, which includes a second feed circuit, a third branch and a fourth branch. The first end of the fourth branch is coupled to the third branch, the third branch is coupled to the ground, the fourth branch is coupled to the second feed circuit, the second end of the fourth branch is arranged relative to the second sub-branch, and there is a gap between the second end of the fourth branch and the second sub-branch. The first antenna and the second antenna can share the above-mentioned gap, that is, the fourth branch and the second sub-branch are both formed as open ends through the gap, thereby, the first antenna and the second antenna are arranged more compactly and occupy less space. In this solution, the second sub-branch is connected to an electrical device, and the loading of the electrical device can make the equivalent electrical length of the second sub-branch slightly larger than or close to the equivalent electrical length of the fourth branch and the equivalent electrical length of the first sub-branch, so that the electrical characteristics of the components can be symmetrical, the working mode of the first antenna and the second antenna can be adjusted, and the isolation between the first antenna and the second antenna can be improved.

[0019] When the antenna system is specifically formed, the fourth branch and the second branch are located in the same structural component, and the structural component has the gap. This solution facilitates the preparation and formation of the fourth branch and the second sub-branch.

[0020] The fourth branch includes a third open end, and the third open end is the second end of the fourth branch. In other words, the second end of the fourth branch is the third open end.

[0021] The width of the gap between the second end of the fourth branch and the second sub-branch is 0.5 mm to 2 mm. In other words, the width of the gap between the third open end of the fourth branch and the second sub-branch is 0.5 mm to 2 mm.

[0022] When the branches of the antenna system are specifically set, the physical length L4 of the fourth branch and the physical length L11 of the first sub-branch satisfy: L4 = L11*(100±30)%. The physical length of the fourth branch differs from the physical length of the first sub-branch by less than 30% of the physical length of the first sub-branch.

[0023] In the antenna system, the second antenna generates a third resonance and a fourth resonance, and the center frequency of the third resonance is higher than the center frequency of the fourth resonance. The third resonance is used to cover the operating frequency band of the second antenna, and the fourth resonance is used to improve the isolation between the first resonance and the third resonance.

[0024] The frequency difference between the center frequency of the third resonance and the center frequency of the fourth resonance is less than or equal to 15% of the lower center frequency. Specifically, the frequency difference between the center frequency of the third resonance and the center frequency of the fourth resonance is less than or equal to 100 MHz, for example, it can be 50 MHz, 40 MHz, 30 MHz or 20 MHz. The larger the frequency difference between the center frequency of the third resonance and the center frequency of the fourth resonance, the more conducive it is to improve the isolation between the first antenna and the second antenna.

[0025] Specifically, when the third resonance is formed, the fourth branch, the second sub-branch and the electrical device are used to generate the third resonance, and the current corresponding to the third resonance is the reverse current on the fourth branch and the second sub-branch.

[0026] Specifically, when the fourth resonance is formed, the second sub-branch and the electrical device are used to generate the fourth resonance, and the current corresponding to the fourth resonance is the same-direction current on the second sub-branch.

[0027] The working frequency band of the first antenna includes the first frequency band; the working frequency band of the second antenna includes the second frequency band, and the frequency difference between the center frequency of the first frequency band and the center frequency of the second frequency band is less than or equal to 15% of the lower center frequency. In a specific embodiment, the first frequency band and the second frequency band at least partially overlap, or are the same working frequency band. The first antenna and the second antenna in the antenna system can work together in the same working frequency band or adjacent working frequency bands.

[0028] In a second aspect, the present application further provides an electronic device, which includes a housing and the antenna system provided in the first aspect, wherein a portion of the structure of the housing forms a second branch and a fourth branch to fully utilize the structure of the electronic device itself, which is beneficial to reducing the volume of the antenna. Alternatively, the antenna system can also be prepared independently, and then the antenna system is arranged in the housing. The antenna system of the electronic device has high efficiency, and the isolation between different antennas is also high. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A schematic diagram of the structure of an electronic device in an embodiment of the present application;

[0030] Figure 2 A schematic diagram of the structure of an antenna system in an embodiment of the present application;

[0031] Figure 3 This is an S parameter curve diagram of the first antenna in the embodiment of the present application;

[0032] Figure 4 This is a current diagram of the antenna system in an embodiment of the present application;

[0033] Figure 5 is a current diagram of an antenna system without the above-mentioned electrical components;

[0034] Figure 6 This is an efficiency curve diagram of the first antenna in the embodiment of the present application;

[0035] Figure 7 Another structural schematic diagram of the antenna system in the embodiment of the present application;

[0036] Figure 8 This is an S parameter curve diagram of the second antenna in the embodiment of the present application;

[0037] Fig. 9 This is a current diagram of the antenna system in an embodiment of the present application;

[0038] Fig.10 is an S parameter curve diagram of the first antenna and the second antenna in the embodiment of the present application;

[0039] Fig.11 is an S parameter curve diagram of the first antenna and the second antenna when the second sub-branch is directly coupled to the ground;

[0040] Fig.12a This is a current distribution diagram of the first antenna in the embodiment of the present application;

[0041] Figure 12b This is a current distribution diagram of the second antenna in the embodiment of the present application;

[0042] Fig.13 This is a working structure diagram of the first antenna and the second antenna in the embodiment of the present application;

[0043] Fig.14 Another structural schematic diagram of the antenna system in the embodiment of the present application;

[0044] Fig.15 Another structural schematic diagram of the antenna system in the embodiment of the present application;

[0045] Fig.16 Another structural schematic diagram of the antenna system in an embodiment of the present application.

[0046] Reference numerals:

[0047] 1- housing; 2- antenna system;

[0048] 3- first antenna; 31- first branch;

[0049] 32-second branch; 321-first sub-branch;

[0050] 322-second sub-branch; 33-first connection point;

[0051] 34-electrical device; 4-second antenna;

[0052] 41-third branch; 42-fourth branch;

[0053] 5- Third antenna. DETAILED DESCRIPTION

[0054] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings.

[0055] The terms used in the following embodiments are only for the purpose of describing specific embodiments and are not intended to be limiting of the present application. As used in the specification and appended claims of the present application, the singular expressions "a", "an", "said", "above", "the" and "this" are intended to also include expressions such as "one or more", unless there is a clear contrary indication in the context.

[0056] References to "one embodiment" or "a specific embodiment" in this specification mean that one or more embodiments of the present application include a particular feature, structure or characteristic described in conjunction with the embodiment. The terms "include", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized.

[0057] In order to facilitate the understanding of the antenna system and electronic device provided in the embodiments of the present application, the application scenarios are first introduced below. The antenna provided in the embodiments of the present application is suitable for electronic devices that adopt one or more of the following communication technologies: Bluetooth (blue-tooth, BT) communication technology, global positioning system (global positioning system, GPS) communication technology, wireless fidelity (wireless fidelity, WiFi) communication technology, global system for mobile communications (global system for mobile communications, GSM) communication technology, wideband code division multiple access (wideband code division multiple access, WCDMA) communication technology, long term evolution (long term evolution, LTE) communication technology, 5G communication technology and other future communication technologies. The electronic device in the embodiments of the present application can be a mobile phone, a tablet computer, a laptop computer, a smart home product, a smart bracelet, a smart watch, a smart helmet, smart glasses, a vehicle's intelligent navigation device, a security intelligent sensing device, and a drone. Unmanned transport vehicles, robots or medical sensing products, etc. The electronic device may also be a handheld device with wireless communication function, a computing device or other processing device connected to a wireless modem, a vehicle-mounted device, an electronic device in a 5G network, or an electronic device in a future-evolved public land mobile communication network (public land mobile network, PLMN), etc., and the embodiments of the present application are not limited to this.

[0058] Any of the above-mentioned electronic devices may include the antenna system in the embodiments of the present application to realize the communication or detection function of the electronic device. In a specific embodiment, the antenna system in the above-mentioned electronic device may be directly installed in the electronic device and electrically connected to the processor in the electronic device to realize the communication function and / or detection function of the electronic device. Alternatively, the antenna system may be integrated into a sensor or a sensing module, and then the above-mentioned sensor or sensing module may be installed in the electronic device, and the processor of the electronic device may be electrically connected to the sensor or sensing module to realize the communication function and / or detection function of the electronic device. The above-mentioned processor may specifically refer to a chip, and the present application does not impose any restrictions on this as long as it can process data and realize at least part of the functions of the electronic device.

[0059] To facilitate understanding of the embodiments of the present application, the following briefly introduces the terms that appear in the embodiments of the present application.

[0060] Connected / connected: can refer to a mechanical connection relationship or a physical connection relationship, that is, A and B are connected or A and B are connected, which can mean that there is a fastening component (such as screws, bolts, rivets, etc.) between A and B, or A and B are in contact with each other and A and B are difficult to separate.

[0061] Coupling: can be understood as direct coupling and / or indirect coupling, and "coupled connection" can be understood as direct coupling connection and / or indirect coupling connection. Direct coupling can also be called "electrical connection", which is understood as the physical contact and electrical conduction between components; it can also be understood as the connection between different components in the circuit structure through physical lines such as printed circuit board (PCB) copper foil or wires that can transmit electrical signals; "indirect coupling" can be understood as two conductors being electrically conductive in an airless / non-contact manner. In one embodiment, indirect coupling can also be called capacitive coupling, for example, signal transmission is achieved by coupling between the gaps between two conductive parts to form an equivalent capacitor.

[0062] Relative or opposite arrangement: A and B being oppositely arranged may mean that A and B are arranged face to face (opposite to, or face to face). For example, when two radiators are arranged opposite to each other, the two radiators are arranged to overlap at least partially in a certain direction. In one embodiment, the two oppositely arranged radiators are arranged adjacent to each other and no other radiators are arranged between them, and no conductive body other than the antenna structure is arranged between them.

[0063] Lumped component: refers to the collective name for all components when the size of the component is much smaller than the wavelength relative to the circuit operating frequency. For the signal, regardless of any time, the component characteristics always remain fixed and are independent of frequency.

[0064] Distributed components: Unlike lumped components, if the size of the component is similar to or larger than the wavelength relative to the circuit operating frequency, then when the signal passes through the component, the characteristics of each point of the component itself will vary due to changes in the signal. At this time, the component as a whole cannot be regarded as a single entity with fixed characteristics, but should be called a distributed component.

[0065] It should be understood that a component can also be called a device, a component, an electrical device, etc.

[0066] Capacitance: It can be understood as lumped capacitance and / or distributed capacitance. Lumped capacitance refers to capacitive components, such as capacitors; distributed capacitance (or distributed capacitance) refers to the equivalent capacitance formed by two conductive parts separated by a certain gap.

[0067] Inductance: It can be understood as lumped inductance and / or distributed inductance. Lumped inductance refers to inductive components, such as inductors; distributed inductance (or distributed inductance) refers to the equivalent inductance formed by a certain length of conductive parts.

[0068] Main radiator: It is a device in the antenna used to receive / send electromagnetic wave radiation. Specifically, the main radiator converts the waveguide energy from the transmitter into radio waves, or converts radio waves into waveguide energy, which is used to radiate and receive radio waves. The modulated high-frequency current energy (or waveguide energy) generated by the transmitter is transmitted to the main radiator for transmission (corresponding to the main radiator of the transmitting antenna), which converts it into a certain polarized electromagnetic wave energy through the main radiator and radiates it in the desired direction. The main radiator for reception (corresponding to the main radiator of the receiving antenna) converts a certain polarized electromagnetic wave energy from a specific direction in space into modulated high-frequency current energy and transmits it to the input end of the receiver.

[0069] The main radiator can be a conductor with a specific shape and size, such as a linear or sheet shape, etc. The present application does not limit the specific shape. In one embodiment, the linear radiator can be simply referred to as a linear antenna. In one embodiment, the linear radiator can be implemented by a conductive frame, which can also be called a frame antenna. In one embodiment, the linear radiator can be implemented by a bracket conductor, which can also be called a bracket antenna. In one embodiment, the linear radiator, or the radiator of the linear antenna, has a wire diameter (for example, including thickness and width) much smaller than the wavelength (for example, the dielectric wavelength) (for example, less than 1 / 16 of the wavelength), and the length can be compared with the wavelength (for example, the dielectric wavelength) (for example, the length is about 1 / 8 of the wavelength, or 1 / 8 to 1 / 4, or 1 / 4 to 1 / 2, or longer). The main forms of linear antennas are dipole antennas, half-wave dipole antennas, monopole antennas, loop antennas, inverted F antennas (also known as IFA, Inverted F Antenna), and planar inverted F antennas (also known as PIFA, Planar Inverted F Antenna). For example, for a dipole antenna, each dipole antenna generally includes two radiating branches, and each branch is fed by a feeding unit from the feeding end of the radiating branch. For example, an inverted-F antenna (IFA) can be regarded as a monopole antenna with a ground path added. The IFA antenna has a feeding point and a grounding point, and is called an inverted-F antenna because its side view is an inverted F shape. In one embodiment, the sheet radiator may include a microstrip antenna, or a patch antenna. In one embodiment, the sheet radiator may be implemented by a planar conductor (such as a conductive sheet or a conductive coating, etc.). In one embodiment, the sheet radiator may include a conductive sheet, such as a copper sheet, etc. In one embodiment, the sheet radiator may include a conductive coating, such as a silver paste, etc. The shape of the sheet radiator includes a circle, a rectangle, a ring, etc., and the present application does not limit the specific shape. The structure of the microstrip antenna is generally composed of a dielectric substrate, a radiator and a floor, wherein the dielectric substrate is arranged between the radiator and the floor.

[0070] The radiator may also include a slot or a slit formed on the conductor, for example, a closed or semi-closed slot or slit formed on a grounded conductor surface. In one embodiment, a slotted or slitted radiator may be referred to as a slot antenna or a slit antenna. In one embodiment, a radiator with a closed slot or slit may be referred to as a closed slot antenna. In one embodiment, a radiator with a semi-closed slot or slit (for example, an opening is added to a closed slot or slit) may be referred to as an open slot antenna. In some embodiments, the slot is in the shape of an elongated strip. In some embodiments, the length of the slot is approximately half a wavelength (for example, a dielectric wavelength). In some embodiments, the length of the slot is approximately an integer multiple of the wavelength (for example, one dielectric wavelength). In some embodiments, the slot may be fed with a transmission line spanning one or both sides thereof, whereby a radio frequency electromagnetic field is excited on the slot and electromagnetic waves are radiated into space. In one embodiment, the radiator of the slot antenna or slot antenna can be implemented by a conductive frame with both ends grounded, which can also be called a frame antenna; in this embodiment, it can be regarded as that the slot antenna or slot antenna includes a linear radiator, which is spaced apart from the floor and grounded at both ends of the radiator, thereby forming a closed or semi-closed slot or slot. In one embodiment, the radiator of the slot antenna or slot antenna can be implemented by a bracket conductor with both ends grounded, which can also be called a bracket antenna.

[0071] In an embodiment of the present application, the main radiator specifically includes a branch structure. In an embodiment, the branch structure is a linear conductor.

[0072] Resonance frequency: The resonance frequency is also called the resonant frequency. The resonance frequency can have a frequency range, that is, the frequency range in which resonance occurs. The resonance frequency can be a frequency range in which the return loss characteristic is less than -6dB. The frequency corresponding to the strongest resonance point is the center frequency - point frequency. The return loss characteristic of the center frequency can be less than -20dB.

[0073] Resonant frequency band: The range of the resonant frequency is the resonant frequency band. The return loss characteristic of any frequency point in the resonant frequency band can be less than -6dB or -5dB.

[0074] Communication frequency band / working frequency band: Regardless of the type of antenna, it always works within a certain frequency range (band width). For example, an antenna that supports the B40 frequency band has a working frequency band that includes frequencies in the range of 2300MHz to 2400MHz, or in other words, the working frequency band of the antenna includes the B40 frequency band. The frequency range that meets the index requirements can be regarded as the working frequency band of the antenna. The width of the working frequency band is called the working bandwidth. The working bandwidth of an omnidirectional antenna may reach 3-5% of the center frequency. The working bandwidth of a directional antenna may reach 5-10% of the center frequency. The bandwidth can be considered as a frequency range on both sides of the center frequency (for example, the resonant frequency of a dipole), where the antenna characteristics are within the acceptable value range of the center frequency.

[0075] The resonant frequency band and the operating frequency band may be the same or different, or their frequency ranges may partially overlap. In one embodiment, the resonant frequency band of the antenna may cover multiple operating frequency bands of the antenna.

[0076] Ground / floor: can refer to at least a part of any grounding layer, grounding plate, or grounding metal layer, etc. in an electronic device (such as a mobile phone), or at least a part of any combination of any of the above grounding layers, grounding plates, or grounding components, etc., and "floor" can be used for grounding components in electronic devices. In one embodiment, the "floor" may include any one or more of the following: the grounding layer of the circuit board of the electronic device, the grounding plate formed by the middle frame of the electronic device, the grounding metal layer formed by the metal film under the screen, the conductive grounding layer of the battery, and the conductive parts or metal parts electrically connected to the above grounding layer / grounding plate / metal layer. In one embodiment, the circuit board can be a printed circuit board (PCB), such as an 8-layer, 10-layer or 12 to 14-layer board having 8, 10, 12, 13 or 14 layers of conductive material, or an element separated and electrically insulated by a dielectric layer or insulating layer such as glass fiber, polymer, etc.

[0077] Any of the above-mentioned grounding layers, grounding plates, or grounding metal layers are made of conductive materials. In one embodiment, the conductive material can be any of the following materials: copper, aluminum, stainless steel, brass and their alloys, copper foil on an insulating substrate, aluminum foil on an insulating substrate, gold foil on an insulating substrate, silver-plated copper, silver-plated copper foil on an insulating substrate, silver foil and tin-plated copper on an insulating substrate, cloth impregnated with graphite powder, graphite-coated substrates, copper-plated substrates, brass-plated substrates, and aluminum-plated substrates. It will be appreciated by those skilled in the art that the grounding layer / grounding plate / grounding metal layer can also be made of other conductive materials.

[0078] Grounding: refers to coupling with the above-mentioned ground / floor in any way. In one embodiment, grounding can be achieved through physical grounding, such as physical grounding (or physical ground) at a specific position on the frame through some structural parts of the middle frame. In one embodiment, grounding can be achieved through device grounding, such as grounding through devices such as capacitors / inductors / resistors connected in series or in parallel (or device ground).

[0079] End / point: The "end / point" in the first end / second end / feeding end / grounding end / feeding point / grounding point / connection point of the antenna radiator cannot be narrowly understood as a point, but can also be considered as a section of the radiator including the first end point on the antenna radiator; nor can it be narrowly understood as an end point or end that is disconnected from other radiators, but can also be considered as a point or a section on a continuous radiator. In one embodiment, the "end / point" may include the end point of the antenna radiator at the first gap, for example, the first end of the antenna radiator can be considered as a section of the radiator within 5mm (for example, 2mm) from the gap on the radiator. In one embodiment, the "end / point" may include a connection / coupling area on the antenna radiator that is coupled to other conductive structures, for example, the feeding end / feeding point may be a coupling area on the antenna radiator that is coupled to a feeding structure or a feeding circuit (for example, an area facing a part of the feeding circuit), and for another example, the grounding end / grounding point may be a connection / coupling area on the antenna radiator that is coupled to a grounding structure or a grounding circuit.

[0080] Open end, closed end: In some embodiments, the open end / closed end is, for example, relative to whether it is grounded. The closed end is grounded, and the open end is not grounded. In some embodiments, the open end / closed end is, for example, relative to other conductors. The closed end is electrically connected to other conductors, and the open end is not electrically connected to other conductors. In one embodiment, the open end can also be called an open end or an open circuit end. In one embodiment, the closed end can also be called a grounded end or a short circuit end.

[0081] The current unidirectional / reverse distribution mentioned in the embodiments of the present application should be understood as the direction of the main current on the conductor on the same side being unidirectional / reverse. For example, when stimulating a unidirectional distributed current on a bent or annular conductor (for example, the current path is also bent or annular), it should be understood that, for example, the main current stimulating on the conductors on both sides of the annular conductor (for example, a conductor surrounding a gap, on the conductors on both sides of the gap) is reversed in direction, but it still belongs to the definition of unidirectional distributed current in the present application. In one embodiment, the unidirectional current on a conductor may refer to the current on the conductor having no reverse point. In one embodiment, the reverse current on a conductor may refer to the current on the conductor having at least one reverse point. In one embodiment, the unidirectional current on two conductors may refer to the current on both conductors having no reverse point and flowing in the same direction. In one embodiment, the reverse current on two conductors may refer to the current on both conductors having no reverse point and flowing in opposite directions. The unidirectional / reverse current on multiple conductors can be understood accordingly.

[0082] The same operating frequency band (also referred to as same frequency) mentioned in the embodiments of the present application can be understood as any one of the following two situations:

[0083] 1) The working frequency band of the first antenna and the working frequency band of the second antenna include the same communication frequency band. In one embodiment, the first antenna and the second antenna are both used as sub-units in the MIMO antenna system. For example, the working frequency band of the first antenna and the working frequency band of the second antenna both include the sub6G frequency band in 5G.

[0084] 2) The operating frequency band of the first antenna and the operating frequency band of the second antenna partially overlap. For example, the operating frequency band of the first antenna includes B35 (1.85-1.91 GHz) in LTE, and the operating frequency band of the second antenna includes B39 (1.88-1.92 GHz) in LTE.

[0085] The adjacent working frequency bands mentioned in this application can be understood as:

[0086] In the working frequency band of the first antenna and the working frequency band of the second antenna, the distance between the starting frequency point of the higher frequency band and the ending frequency point of the lower frequency band is less than 10% of the center frequency of the higher frequency band. For example, the working frequency band of the first antenna includes B3 (1.71-1.785 GHz) in LTE, and the working frequency band of the second antenna includes L1 (1578.42±1.023 MHz) in GPS, where the frequency band B3 (1.71-1.785 GHz) and the frequency band L1 (1578.42±1.023 MHz) are adjacent frequency bands, and it can be considered that the working frequency bands of the first antenna and the second antenna are adjacent. Or for example, the operating frequency band of the first antenna includes B40 (2.3-2.4GHz) in LTE, and the operating frequency band of the second antenna includes the Bluetooth (also known as BT) band (2.4-2.485GHz), where B40 (2.3-2.4GHz) and the BT band (2.4-2.485GHz) are adjacent frequency bands, then it can be considered that the operating frequency bands of the first antenna and the second antenna are adjacent.

[0087] System efficiency: refers to the ratio of the power radiated by the antenna into space (i.e. the power of the electromagnetic wave part that is effectively converted) to the input power of the antenna. System efficiency is the actual efficiency after considering the matching of the antenna port, that is, the system efficiency of the antenna is the actual efficiency (i.e. efficiency) of the antenna.

[0088] Radiation efficiency: refers to the ratio of the power radiated by the antenna into space (i.e. the power of the electromagnetic wave part that is effectively converted) to the active power input to the antenna. Among them, the active power input to the antenna = the input power of the antenna - the loss power; the loss power mainly includes the return loss power and the ohmic loss power of the metal and / or the dielectric loss power. Metal loss and dielectric loss are both factors that affect radiation efficiency.

[0089] Those skilled in the art can understand that efficiency is generally expressed as a percentage, and there is a corresponding conversion relationship between efficiency and dB. The closer the efficiency is to 0 dB, the better the efficiency of the antenna.

[0090] dB: decibel, a logarithmic concept with ten as the base. Decibel is only used to evaluate the proportional relationship between one physical quantity and another physical quantity, and it itself has no physical dimension. For every 10-fold increase in the ratio between two quantities, their difference can be expressed as 10 decibels. For example: A = "100", B = "10", C = "5", D = "1", then, A / D = 20dB; B / D = 10dB; C / D = 7dB; B / C = 3dB. In other words, a difference of 10 decibels between two quantities is a difference of 10 times, a difference of 20 decibels is a difference of 100 times, and so on. A difference of 3dB is a difference of 2 times between the two quantities.

[0091] dBi: Usually mentioned together with dBd. dBi and dBd are units of power gain, both are relative values, but with different reference standards. The reference standard for dBi is the omnidirectional antenna; the reference standard for dBd is the dipole. It is generally believed that dBi and dBd represent the same gain, and the value expressed in dBi is 2.15dBi larger than that expressed in dBd. For example: for an antenna with a gain of 16dBd, when its gain is converted into units of dBi, it is 18.15dBi. Generally, the decimal places are ignored and it is 18dBi.

[0092] Antenna return loss: It can be understood as the ratio of the signal power reflected back to the antenna port through the antenna circuit to the transmit power of the antenna port. The smaller the reflected signal, the larger the signal radiated into space through the antenna, and the greater the radiation efficiency of the antenna. The larger the reflected signal, the smaller the signal radiated into space through the antenna, and the lower the radiation efficiency of the antenna.

[0093] Antenna return loss can be expressed by the S11 parameter, which is one of the S parameters. S11 represents the reflection coefficient, which can characterize the quality of the antenna transmission efficiency.

[0094] In one embodiment, the S11 diagram can be understood as a schematic diagram for representing the resonance generated by the antenna. In one embodiment, the resonance shown in the S11 diagram in the portion less than -6dB can be understood as the resonant frequency / frequency range / operating frequency band generated by the antenna. The S11 parameter is usually a negative number. The smaller the S11 parameter is, the smaller the antenna return loss is, and the smaller the energy reflected back by the antenna itself is, which means that more energy actually enters the antenna and the higher the system efficiency of the antenna is; the larger the S11 parameter is, the greater the antenna return loss is, and the lower the system efficiency of the antenna is.

[0095] It should be noted that in engineering, the S11 value is generally -6dB as the standard. When the S11 value of an antenna is less than -6dB, it can be considered that the antenna can work normally, or that the antenna has good transmission efficiency.

[0096] Isolation: refers to the ratio of the signal received by another antenna when an antenna transmits a signal to the signal of the transmitting antenna. Isolation is a physical quantity used to measure the degree of mutual coupling between antennas. Assuming that two antennas form a two-port network, the isolation between the two antennas is the S21 and S12 between the antennas. Antenna isolation can be represented by the S21 and S12 parameters, which are also a type of S parameters. The S21 and S12 parameters are usually negative numbers. The smaller the S21 and S12 parameters are, the greater the isolation between the antennas and the smaller the mutual coupling between the antennas; the larger the S21 and S12 parameters are, the smaller the isolation between the antennas and the greater the mutual coupling between the antennas. The isolation of the antenna depends on the antenna radiation pattern, the spatial distance between the antennas, the antenna gain, etc.

[0097] Ground state: corresponds to a section of a radiator, or a radiator in a certain antenna mode, the lowest frequency resonance produced. Among them, "ground state position" or "ground state resonant frequency" refers to the frequency range or resonant frequency corresponding to the ground state of the radiator in a specific antenna mode (for example, the lowest frequency resonance produced). "Ground state" can also be called "fundamental mode". Corresponding to the "ground state" are "higher order" or "higher order mode / higher order mode", or it can also be called "frequency doubling" (for example, triple frequency, quintupling frequency). Unless otherwise specified, the "resonance" in the embodiments of the present application refers to the resonance in the ground state, or the resonance produced by the fundamental mode.

[0098] Figure 1 is a schematic diagram of a structure of an electronic device in an embodiment of the present application, such as Figure 1 As shown, the electronic device 10 is taken as an example as a mobile phone.

[0099] like Figure 1 As shown, the electronic device 10 may include: a cover 13, a display screen / module (display) 15, a printed circuit board (PCB) 17, a middle frame (middle frame) 19 and a rear cover (rear cover) 21. It should be understood that in some embodiments, the cover 13 may be a glass cover, or may be replaced by a cover made of other materials, such as an ultra-thin glass material cover, a PET (Polyethylene terephthalate) material cover, etc.

[0100] The cover plate 13 may be arranged close to the display screen 15 , and may be mainly used to protect the display screen 15 and prevent dust.

[0101] In one embodiment, the display screen 15 may include a liquid crystal display panel (LCD), a light emitting diode (LED) display panel or an organic light emitting semiconductor (OLED) display panel, etc., which is not limited in the present application.

[0102] The middle frame 19 mainly supports the entire device. Figure 1It is shown that PCB17 is arranged between the middle frame 19 and the back cover 21. It should be understood that in one embodiment, PCB17 can also be arranged between the middle frame 19 and the display screen 15, and the present application does not limit this. Among them, the printed circuit board PCB17 can adopt a flame retardant material (FR-4) dielectric board, a Rogers dielectric board, a mixed dielectric board of Rogers and FR-4, and so on. Here, FR-4 is a code for a grade of flame retardant material, and Rogers dielectric board is a high-frequency board. PCB17 carries electronic components, such as radio frequency chips.

[0103] In one embodiment, a metal layer may be provided on the printed circuit board PCB17. The metal layer may be used for grounding the electronic components carried on the printed circuit board PCB17, and may also be used for grounding other components, such as a bracket antenna, a frame antenna, etc. The metal layer may be referred to as a floor, or a grounding plate, or a grounding layer. In one embodiment, the metal layer may be formed by etching metal on the surface of any layer of a dielectric plate in PCB17. In one embodiment, the metal layer used for grounding may be provided on one side of the printed circuit board PCB17 close to the middle frame 19. In one embodiment, the edge of the printed circuit board PCB17 may be regarded as the edge of its grounding layer. In one embodiment, the metal middle frame 19 may also be used for grounding the above-mentioned components. The electronic device 10 may also have other floors / grounding plates / grounding layers, as described above, which will not be repeated here.

[0104] Due to the compactness of the interior of the electronic device, a floor / grounding plate / grounding layer is usually provided in the internal space 0-2 mm away from the inner surface of the frame (for example, a printed circuit board, a middle frame, a metal layer of a screen, a battery, etc. can all be regarded as part of the floor). In one embodiment, a medium is filled between the frame and the floor, and the inner surface contour of the filling medium and the length and width of the rectangle enclosed by the medium can be simply regarded as the length and width of the floor; the length and width of the rectangle enclosed by the contour formed by superimposing all the conductive parts inside the frame can also be regarded as the length and width of the floor.

[0105] The electronic device 10 may further include a battery (not shown). The battery may be disposed between the middle frame 19 and the back cover 21, or between the middle frame 19 and the display screen 15, and the present application does not limit this. In some embodiments, the PCB 17 is divided into a main board and a sub-board, and the battery may be disposed between the main board and the sub-board, wherein the main board may be disposed between the middle frame 19 and the upper edge of the battery, and the sub-board may be disposed between the middle frame 19 and the lower edge of the battery.

[0106] The electronic device 10 may further include a frame 11, which may be formed of a conductive material such as metal. The frame 11 may be disposed between the display screen 15 and the back cover 21 and extend circumferentially around the periphery of the electronic device 10. The frame 11 may have four sides surrounding the display screen 15 to help fix the display screen 15. In one implementation, the frame 11 made of a metal material may be directly used as a metal frame of the electronic device 10, forming the appearance of a metal frame, which is suitable for a metal industrial design (industrial design, ID). In another implementation, the outer surface of the frame 11 may also be a non-metallic material, such as a plastic frame, forming the appearance of a non-metallic frame, which is suitable for a non-metallic ID.

[0107] The middle frame 19 may include a frame 11, and the middle frame 19 including the frame 11 as an integral part may support the electronic devices in the whole machine. The cover plate 13 and the back cover 21 are respectively covered along the upper and lower edges of the frame to form a housing or shell (housing) of the electronic device. Alternatively, the frame 11 may not be regarded as a part of the middle frame 19. In one embodiment, the frame 11 may be connected to the middle frame 19 and formed as one piece. In another embodiment, the frame 11 may include a protrusion extending inward to be connected to the middle frame 19, for example, by means of shrapnel, screws, welding, etc. In one embodiment, the cover plate 13, the back cover 21, the frame 11, and the middle frame 19 may be collectively referred to as the housing or shell of the electronic device 10. It should be understood that "shell or shell" may be used to refer to part or all of any one of the cover plate 13, the back cover 21, the frame 11, or the middle frame 19, or to refer to part or all of any combination of the cover plate 13, the back cover 21, the frame 11, or the middle frame 19.

[0108] The back cover 21 can be a back cover made of metal material; it can also be a back cover made of non-conductive material, such as a glass back cover, a plastic back cover or other non-metallic back cover; it can also be a back cover made of both conductive material and non-conductive material.

[0109] In one embodiment, the back cover 21 including a conductive material can replace the middle frame 19 and be integrated with the frame 11 to support the electronic devices in the whole machine.

[0110] In one embodiment, the middle frame 19 and / or the conductive parts in the back cover 21 can be used as the reference ground of the electronic device 10, wherein the frame 11, PCB 17, etc. of the electronic device can be grounded through electrical connection with the middle frame.

[0111] In one embodiment, the frame 11 can at least partially serve as an antenna radiator to receive / transmit radio frequency signals. There can be a gap between this part of the frame serving as a radiator and other parts of the middle frame 19, or between the frame 19 and the middle frame 19, so as to ensure that the antenna radiator has a good radiation environment. In one embodiment, an aperture can be set near this part of the frame serving as an antenna radiator. In one embodiment, the aperture can include an aperture set inside the electronic device 10, for example, an aperture that is not visible from the exterior surface of the electronic device 10. In one embodiment, the internal aperture can be formed by any one of the middle frame, battery, circuit board, back cover, display screen, and other internal conductive parts, or by a plurality of them together, for example, the internal aperture can be formed by a structural member of the middle frame. In one embodiment, the aperture can also include a slit / slit / opening set on the frame 11. In one embodiment, the slit / slit / opening on the frame 11 can be a break formed on the frame, and the frame 11 is divided into two parts that are not directly connected at the break. In one embodiment, the aperture can also include a slit / slit / opening set on the back cover 21 or the display screen 15. In one embodiment, the back cover 21 includes a conductive material, and the apertures provided at the conductive material may be connected to the slits or gaps of the frame to form a continuous aperture on the exterior surface of the electronic device 10 .

[0112] In one embodiment, the frame 11 includes a protrusion extending inwardly, which is used to connect with other parts of the middle frame 19, or to connect with the middle frame 19 (in one embodiment, it can also be integrally formed). In one embodiment, the protrusion includes a conductive material and can also be used to receive a feed signal or connect to a floor, so that the corresponding frame portion receives / transmits a radio frequency signal.

[0113] In one embodiment, the antenna of the electronic device 10 may also be disposed in the frame 11. The frame 11 includes a non-conductive material, and the antenna radiator may be located in the electronic device 10 and disposed along the frame 11, or the antenna radiator may be at least partially embedded in the non-conductive material of the frame. In one embodiment, the antenna radiator is disposed close to the non-conductive material of the frame 11 to minimize the volume occupied by the antenna radiator and to be closer to the outside of the electronic device 10 to achieve a better signal transmission effect. It should be noted that the antenna radiator being disposed close to the frame 11 means that the antenna radiator may be disposed close to the frame 11, or may be disposed close to the frame 11, for example, there may be a certain small gap between the antenna radiator and the frame 11.

[0114] In one embodiment, the antenna of the electronic device 10 may also be disposed in the housing, such as a bracket antenna ( Figure 1(not shown). There may be a gap between the antenna disposed in the housing and other conductive parts inside the housing, so as to ensure that the antenna radiator has a good radiation environment. In one embodiment, an aperture may be provided near the antenna radiator. In one embodiment, the aperture may include an aperture provided inside the electronic device 10, for example, an aperture that is not visible from the exterior surface of the electronic device 10. In one embodiment, the internal aperture may be formed by any one of the frame, the middle frame, the battery, the circuit board, the back cover, the display screen, and other internal conductive parts or formed by a plurality of them together, for example, the internal aperture may be formed by the structural member of the middle frame. In one embodiment, the aperture may also include a slit / opening / opening provided on the frame 11. In one embodiment, the slit / opening / opening on the frame 11 may be a break formed on the frame, and the frame 11 is divided into two parts that are not directly connected at the break. In one embodiment, the aperture may also include a slit / opening / opening provided on the back cover 21 or the display screen 15. In one embodiment, the back cover 21 includes a conductive material, and the aperture provided at the conductive material may be connected to the slit or break of the frame to form a continuous aperture on the exterior surface of the electronic device 10. In one embodiment, the apertures on the back cover 21 or the display screen may also be used to place other devices, such as cameras, and / or sensors, and / or microphones, and / or speakers, etc.

[0115] In one embodiment, the antenna may be in the form of an antenna based on a flexible printed circuit (FPC), an antenna based on laser direct structuring (LDS), or a microstrip disk antenna (MDA). In one embodiment, the antenna may also be a transparent or semi-transparent structure embedded in the screen of the electronic device 10, so that the antenna is a transparent antenna unit embedded in the screen of the electronic device 10.

[0116] Figure 1 Only some components of the electronic device 10 are schematically shown, and the actual shapes, sizes and structures of these components are not subject to the present invention. Figure 1 limited.

[0117] It should be understood that in the embodiments of the present application, the surface where the display screen of the electronic device is located can be considered as the front side, the surface where the back cover is located can be considered as the back side, and the surface where the frame is located can be considered as the side side.

[0118] It should be understood that in the embodiments of the present application, it is considered that when a user holds the electronic device (usually vertically and facing the screen), the electronic device is located at a position having a top, a bottom, a left side, and a right side.

[0119] In one embodiment, the electronic device 10 includes an antenna system 2, which is at least partially disposed in the housing. The antenna system 2 is used to receive / send electromagnetic waves, thereby realizing the communication function of the electronic device. The efficiency of the antenna system 2 plays a decisive role in the communication capability of the electronic device.

[0120] In one embodiment, at least part of the radiator of the antenna system 2 may include part of the structure of the housing. For example, the frame of the housing of the electronic device may form the main radiator of the antenna system 2, thereby simplifying the structure of the electronic device. Alternatively, in another embodiment, the antenna system may be disposed inside the housing.

[0121] Figure 2 This is a schematic diagram of the structure of the antenna system in the embodiment of the present application. Please refer to Figure 2, the antenna system 2 in the embodiment of the present application includes a first antenna 3 and a ground, the first antenna 3 includes a first branch 31 and a second branch 32, and also includes a first feeding circuit and an electrical device 34. Among them, the first branch 31 and the second branch 32 are coupled and connected at a first connection point 33. In one embodiment, the second branch 32 includes two open ends, and the first connection point 33 is arranged between the two open ends. The second branch 32 includes a first sub-branch 321 and a second sub-branch 322, and the first sub-branch 321 and the second sub-branch 322 are respectively located on both sides of the first connection point 33. It should be understood that the second branch 32 is divided into a first sub-branch 321 and a second sub-branch 322 by the first connection point 33 for the convenience of describing the scheme, and does not only mean that the first sub-branch 321 and the second sub-branch 322 are two independent structures that can be divided. In one embodiment, the first sub-branch 321 and the second sub-branch 322 can also be an integrally formed structure. In one embodiment, the first connection point 33 divides the second branch 32 into two parts of different lengths, or in other words, the lengths of the first sub-branch 321 and the second sub-branch 322 are different. In one embodiment, the length of the first sub-branch 321 is greater than the length of the second sub-branch 322. In one embodiment, the main radiator of the first antenna 3 is the second branch 32, and electromagnetic waves are received and / or transmitted through the second branch 32. In one embodiment, the main radiator of the first antenna 3 is the second branch 32 and the first branch 31, wherein the first branch 31 is coupled to the ground, so that the first antenna 3 is grounded through the first branch 31. In one embodiment, the first sub-branch 321 is coupled to the first feeding circuit, thereby feeding the first antenna 3. In one embodiment, the second sub-branch 322 is coupled to the ground through the electrical device 34. In one embodiment, the electrical device 34 may include a lumped element, and / or a distributed element. The above-mentioned electrical device 34 can be used to adjust the equivalent electrical length of the second sub-branch 322. When the electrical device 34 is capacitive, the equivalent electrical length of the second sub-branch 322 can be increased. When the electrical device 34 is inductive, the equivalent electrical length of the second sub-branch 322 can be reduced. It should be understood that the inductive or capacitive electrical device 34 can include a capacitor or an inductor, or can include a capacitor and an inductor. By setting the feeding position, the grounding position and the coupling connection position of the electrical device 34 through the first branch 31 and the second branch 32 respectively, this solution can improve the antenna efficiency of the first antenna 3, and the structure is relatively simple and occupies less space.

[0122] In one embodiment, the frame of the housing of the electronic device may form a second branch 32, wherein the two open ends of the second branch 32 may correspond to the cracks on the frame. In one embodiment, the cracks on the frame are insulating cracks, which may be filled with a dielectric. In one embodiment, the raised portion inside the frame of the housing of the electronic device may form a first branch 31.

[0123] In one embodiment, the first sub-branch and the second sub-branch extend in the same straight line. In other words, the extension direction of the first sub-branch is the same as the extension direction of the second sub-branch. At this time, the induced current on the floor generated by the current of the first sub-branch and the second sub-branch flows in the same direction, which is conducive to enhancing the effect of far-field radiation.

[0124] In a specific embodiment, when the physical length of the second sub-branch 322 is less than the physical length of the first sub-branch 321, the electrical device 34 is capacitive, for example, the electrical device 34 is a capacitor, and the equivalent electrical length of the second sub-branch 322 can be increased by capacitive loading. In one embodiment, the equivalent electrical length of the second sub-branch 322 is slightly greater than or close to the equivalent electrical length of the first sub-branch 321 by the capacitive electrical device 34.

[0125] In a specific embodiment, when the physical length of the second sub-branch 322 is greater than the physical length of the first sub-branch 321, the electrical device 34 is inductive, for example, the electrical device 34 is an inductor, and the equivalent electrical length of the second sub-branch 322 can be reduced by inductive loading. In one embodiment, the equivalent electrical length of the second sub-branch 322 is slightly greater than or close to the equivalent electrical length of the first sub-branch 321 by the inductive electrical device 34.

[0126] Figure 3 For the S parameter curve of the first antenna in the embodiment of the present application, please refer to Figure 3 In one embodiment, the first antenna 3 generates a first resonance A and a second resonance B. The center frequency of the first resonance A is higher than the center frequency of the second resonance B. The first resonance is used to cover the operating frequency of the first antenna, and the second resonance is used to improve the system efficiency of the first resonance, that is, to improve the system efficiency of the operating frequency band of the first antenna.

[0127] In one embodiment, the frequency difference between the center frequency of the first resonance and the center frequency of the second resonance is less than or equal to 15% of the lower center frequency. The lower center frequency refers to the lower center frequency of the center frequency of the first resonance and the center frequency of the second resonance. In a specific embodiment, the frequency difference between the center frequency of the first resonance and the center frequency of the second resonance may be less than or equal to 350MHz. For example, the frequency difference may be less than or equal to 250MHz. Specifically, the smaller the frequency difference between the center frequency of the first resonance and the center frequency of the second resonance, the better the system efficiency improvement for the working frequency band of the first antenna.

[0128] Figure 4 This is a current diagram of the antenna system in the embodiment of the present application. Figure 3 and Figure 4In one embodiment, the first sub-branch 321, the second sub-branch 322 and the first capacitor 34 are used to generate the first resonance A, and the current corresponding to the first resonance A is the same direction current on the first sub-branch 321 and the second sub-branch 322. Figure 4 The hollow arrow on the right side indicates the direction of the current generated by the first sub-branch 321, the second sub-branch 322 and the first capacitor 34, and the hollow arrow on the left side indicates the direction of the current generated / induced at the position adjacent to the floor and the first sub-branch 321 and the second sub-branch 322.

[0129] Please continue to refer to Figure 3 and Figure 4 In a specific embodiment, the second sub-branch 322 and the first capacitor 34 are used to generate the second resonance B, and the current corresponding to the second resonance B is the same-direction current on the second sub-branch 322 . Figure 4 The black arrow on the right side indicates the current generated by the second sub-branch 322 and the first capacitor 34, and the black arrow on the left side indicates the current between the floor and the edge of the second sub-branch 322. The current corresponding to the second resonance B can enhance the current of the first resonance A to improve the system efficiency of the antenna system. In one embodiment, the frequency difference between the center frequency of the first resonance A and the center frequency of the second resonance B is less than or equal to 350MHz, and the center frequency of the second resonance B is less than the center frequency of the first resonance A. The second resonance B can be used to improve the efficiency of the first resonance A, thereby improving the system efficiency of the antenna system. Secondly, the corresponding current generated on the floor is also a unidirectional current, which can further enhance the radiation efficiency of the first antenna 3 in its operating frequency band. It should be understood that the floor currents in the embodiment of the present application are in the same direction and are in-phase superposition in the far field, so the radiation efficiency of the first antenna 3 can be enhanced.

[0130] When the equivalent electrical length of the second sub-branch 322 is greater than the equivalent electrical length of the first sub-branch 321, it can be expressed in the S parameter as follows: the resonance point frequency of the second resonance generated by the second sub-branch 322 is lower than the resonance point frequency of the first resonance generated by the first sub-branch 321. When the first resonance and the second resonance are adjacent, the efficiency of the first antenna 3 in its operating frequency band is improved. In one embodiment, the resonant frequency band of the first resonance and the resonant frequency band of the second resonance respectively overlap with the operating frequency band of the first antenna 3 in part. In one embodiment, the resonant frequency band of the first resonance is used to cover the operating frequency band of the first antenna 3, and the resonant frequency band of the second resonance is adjacent to the operating frequency band of the first antenna 3. Specifically, in terms of current distribution, the current on the first sub-branch 321 and the current distribution on the second sub-branch 322 are distributed in the same direction.

[0131] Figure 5 is a current diagram of an antenna system without the first capacitor. Figure 5As shown, the length of the first sub-branch 321 is greater than the length of the second sub-branch 322, and the above-mentioned first capacitor is not set. The first sub-branch 321 generates a resonant current, which is opposite to the direction of the resonant current generated by the second sub-branch 322, and the corresponding current generated / induced on the floor is also in the opposite direction. The resonance generated by the first sub-branch 321 can cover the operating frequency band of the first antenna 3. However, due to the reverse current of the floor, the system efficiency of the first antenna 3 in its operating frequency band cannot be improved. The present application solves this problem better.

[0132] Please refer to Figure 2 In one embodiment, the above-mentioned second branch 32 includes a first open end 323 and a second open end 324, the first open end 323 is located at the end of the first sub-branch 321 away from the second sub-branch 322, and the second open end 324 is located at the end of the second sub-branch 322 away from the first sub-branch 321.

[0133] Figure 6 is an efficiency curve diagram of the first antenna in the embodiment of the present application, such as Figure 6 As shown, the inventors analyzed the embodiments of the present application and the comparative examples, wherein the comparative examples include a first comparative example and a second comparative example. In the first comparative example, the second sub-branch 322 is directly coupled to the ground; in the second comparative example, the second sub-branch 322 is disconnected from the ground; in the embodiment of the present application, the second sub-branch 322 is coupled to the ground via a 2.5pF capacitor as an example. In one embodiment, the electrical device 34 may be, for example, a capacitor, and the capacitance value of the capacitor is 2.5pF. In one embodiment, the electrical device 34 may be, for example, one or more capacitors, and / or one or more inductors, and the equivalent capacitance value of the electrical device 34 is 2.5pF. Please continue to refer to Figure 6 In the figure, the dotted line a represents the efficiency curve of the first antenna 3 in the embodiment of the present application, the dashed line b represents the efficiency curve of the antenna in the first comparative example, and the solid line c represents the efficiency curve of the antenna in the second comparative example; it can be seen that when the second sub-branch 322 is coupled to the ground through the electrical device 34, the antenna efficiency is the highest, and the present application can improve the efficiency of the first antenna 3.

[0134] In one embodiment, when the above-mentioned first capacitor is specifically set, the distance between the position where the first capacitor is coupled to the second sub-branch 322 and the second open end 324 is within 40% of the total length of the second sub-branch 322. For example, the above-mentioned distance is 30% of the total length of the second sub-branch 322, 20% of the total length of the second sub-branch 322, 15% of the total length of the second sub-branch 322, 10% of the total length of the second sub-branch 322, or 5% of the total length of the second sub-branch 322. This solution is conducive to making full use of the physical length of the second branch. Specifically, the distance between the position where the first capacitor is coupled to the second sub-branch 322 and the second open end 324 can be within 10 mm, for example, within 5 mm or shorter, which can be specifically set in combination with the preparation process and structural layout.

[0135] It is worth noting that in this application, Figure 2 In the example, the main radiator of the first antenna 3 is a T-shaped branch, that is, the main radiator of the first antenna 3 only includes the first branch 31 and the second branch 32. However, in other embodiments, the main radiator of the first antenna 3 may include other branches in addition to the first branch 31 and the second branch 32, that is, the main radiator may also be a more complex branch structure.

[0136] In a specific embodiment, the electrical device 34 may be an adjustable device, which may include a device with an adjustable capacitance value or an adjustable inductance value, or may include a switch and a plurality of devices to switch between different capacitances and / or inductances. In short, by adding the adjustable device, the equivalent electrical length of the second sub-branch 322 may be adjusted. Specifically, the equivalent electrical length of the second sub-branch 322 may be adjusted according to actual needs, so that the first antenna 3 may have a higher efficiency.

[0137] In a specific embodiment, the electrical device 34 may be a lumped capacitor, such as a fixed capacitance capacitor, an adjustable capacitor, etc., which is not limited in the present application.

[0138] In addition, in a specific embodiment, the above-mentioned electrical device may be a metal structure that can provide distributed capacitance or distributed inductance, and its implementation method may be but is not limited to a flexible circuit board, a laser-formed structure or a frame metal structure.

[0139] In addition, with the development of technology, the scenarios in which electronic devices need to communicate are becoming more and more diverse, and the number of antennas set in electronic devices is also increasing. Electronic devices are also gradually becoming miniaturized, and the space for setting antennas is small. The distance between antennas is too small, which easily leads to poor isolation between antennas. To this end, the present application also provides embodiments to solve the above problems.

[0140] Figure 7For another schematic diagram of the structure of the antenna system in the embodiment of the present application, please refer to Figure 7 In the embodiment of the present application, the antenna system 2 further includes a second antenna 4, which includes a third branch 41, a fourth branch 42 and a second feeding circuit, wherein the fourth branch 42 is coupled to the third branch 41, wherein the main radiator of the second antenna 4 includes the fourth branch 42, which is used to receive and / or send electromagnetic waves. In one embodiment, the third branch 41 is coupled to the first end of the fourth branch 42. In one embodiment, the third branch 41 is coupled to the ground, so that the second antenna 4 is grounded through the third branch 41. One end of the third branch 41 coupled to the ground is a grounding end, and the other end is coupled to the first end of the fourth branch 42. The second end of the fourth branch 42 away from the third branch 41 is an open end, and the second end is arranged opposite to the second sub-branch 322. In one embodiment, the fourth branch 42 is coupled to the second feeding circuit, so as to realize the feeding of the second antenna 4, and the point where the fourth branch 42 is coupled to the second feeding circuit is located between the end where the fourth branch 42 is coupled to the third branch 41 and the open end. The second end of the fourth branch 42 is arranged adjacent to the second sub-branch 322 of the first antenna 3, and there is a gap between the second end of the fourth branch 42 and the second sub-branch 322. Specifically, the first antenna 3 and the second antenna 4 can share the above-mentioned gap, that is, the fourth branch 42 and the second sub-branch 322 are both formed as open ends through the gap, thereby, the first antenna 3 and the second antenna 4 are arranged more compactly and occupy less space. In this scheme, the second sub-branch 322 is connected to the electrical device 34, and the setting of the electrical device 34 can make the equivalent electrical length of the second sub-branch 322 slightly larger than or close to the equivalent electrical length of the fourth branch 42 and the equivalent electrical length of the first sub-branch 321, so as to achieve symmetry in electrical characteristics of the components, adjust the working mode of the first antenna 3 and the second antenna 4, and improve the isolation between the first antenna 3 and the second antenna 4.

[0141] When the second antenna 4 is specifically implemented, the third branch 41 may be a structure such as a spring or a reed for grounding, and the present application does not impose any limitation on this.

[0142] Figure 8 For the S parameter curve of the second antenna in the embodiment of the present application, please refer to Figure 8 In one embodiment, the second antenna 4 generates a third resonance C and a fourth resonance D, the center frequency of the third resonance C is higher than the center frequency of the fourth resonance D, and the third resonance C is used to cover the working frequency band of the second antenna 4.

[0143] In one embodiment, the operating frequency band of the first antenna 3 is the same as the operating frequency band of the second antenna 4 (for example, a same-frequency antenna). In one embodiment, the operating frequency band of the first antenna 3 is at least partially the same as the operating frequency band of the second antenna 4. In one embodiment, the center frequency point of the operating frequency band of the first antenna 3 is adjacent to the center frequency point of the operating frequency band of the second antenna 4 (for example, an adjacent frequency antenna), for example, less than or equal to 100 MHz.

[0144] In one embodiment, the frequency difference between the center frequency of the third resonance C and the center frequency of the second resonance D is less than or equal to 15% of the lower center frequency. The lower center frequency refers to the lower center frequency of the center frequency of the third resonance C and the center frequency of the fourth resonance D. In a specific embodiment, the frequency difference between the center frequency of the third resonance and the center frequency of the fourth resonance may be greater than or equal to 100 MHz. For example, the frequency difference may be greater than or equal to 200 MHz. Specifically, the greater the frequency difference between the center frequency of the third resonance and the center frequency of the fourth resonance, the better the isolation effect between the first antenna and the second antenna.

[0145] Fig. 9 This is a current diagram of the antenna system in the embodiment of the present application. Figure 8 and Fig. 9 In one embodiment, when the third resonance C is specifically formed, the fourth branch 42, the second sub-branch 322 and the first capacitor 34 can be used to generate the third resonance C, and the current corresponding to the third resonance C is the reverse current on the fourth branch 42 and the second sub-branch 322. The black arrow on the right side of the figure indicates the direction of the current generated by the fourth branch 42, and the black arrow on the left side indicates the direction of the current at the position adjacent to the floor and the fourth branch 42; the hollow arrow on the right side indicates the direction of the current generated by the second sub-branch 322, and the hollow arrow on the left side indicates the direction of the current at the position adjacent to the floor and the second sub-branch 322. It can be seen that the direction of the current generated by the fourth branch 42 is opposite to the current generated by the second sub-branch 322.

[0146] In addition, the second sub-branch and the first electrical device are used to generate the fourth resonance, and the current corresponding to the fourth resonance is the same-direction current on the second sub-branch.

[0147] It should be understood that when the first antenna 3 and the second antenna 4 are co-frequency or adjacent frequency antennas, or the working frequency bands of the first antenna 3 and the second antenna 4 partially overlap, the second sub-branch 322 and the first electrical device are used to generate the second resonance B of the first antenna 3, and also to generate the fourth resonance D of the second antenna 4. Since the second resonance B is close to the first resonance A, the system efficiency of the first antenna 3 can be improved, and when the fourth resonance D is far away from the first resonance A, the system efficiency of the second antenna 4 can be improved. In one embodiment, the length of each branch can be adjusted, and the electrical length of the second sub-branch 322 can be adjusted by setting a suitable first electrical device, so that the frequency difference between the center frequency of the first resonance A and the center frequency of the second resonance B is greater than or equal to 100MHz and less than or equal to 350MHz, for example, between 200-250MHz, and / or the frequency difference between the center frequency of the third resonance C and the center frequency of the fourth resonance D is greater than or equal to 100MHz and less than or equal to 350MHz, for example, between 200-250MHz, to balance the radiation performance of the first antenna 3 and the second antenna 4.

[0148] Fig.10 is an S parameter curve diagram of the first antenna and the second antenna in the embodiment of the present application, such as Fig.10 As shown, in a specific embodiment of the present application, when the operating frequency band of the antenna system 2 includes at least a part of 2.4 GHz to 2.5 GHz, the first resonance and the fourth resonance are used to cover the operating frequency band, and there is an obvious isolation pit in the S parameter curve, and the isolation is less than -20 dB. By setting an electrical device 34 in the second sub-branch 322 and adjusting the equivalent electrical length of the second sub-branch 322, the resonance generated by the second sub-branch and the electrical device 34 (for example, including the frequency 2.1 GHz) is lower than the operating frequency of the antenna system of the first antenna 3 and the second antenna 4 (for example, including the frequency 2.4 GHz). This has the effect of improving the isolation and improving the efficiency of the first antenna 3.

[0149] Fig.11 is an S parameter curve diagram of the first antenna and the second antenna when the second sub-branch is directly coupled to the ground, such as Fig.11 As shown, when the second sub-branch 322 is not connected to the electrical device 34, the isolation between the first antenna 3 and the second antenna 4 is only -10db.

[0150] When the fourth branch 42 is specifically provided, the fourth branch 42 includes a third open end 421, and the third open end 421 is located at the second end of the fourth branch 42. There is the above-mentioned gap between the third open end 421 and the second sub-branch 322.

[0151] The width of the above-mentioned gap may specifically be 0.5 mm to 2 mm. For example, the width of the gap may be 0.8 mm, 1 mm, 1.2 mm, 1.5 mm, 1.7 mm or 1.8 mm, etc. In this solution, the first antenna 3 and the second antenna 4 are arranged relatively compactly, which is conducive to reducing the space occupied by the antenna.

[0152] In one embodiment, the physical length of the fourth branch 42 is within 30% of the physical length of the first sub-branch 321. In a specific embodiment, the closer the physical length of the fourth branch 42 is to the physical length of the first sub-branch 321, the more beneficial it is to improve the antenna efficiency of the first antenna 3, and the more beneficial it is to improve the isolation between the first antenna 3 and the second antenna 4 in the antenna system.

[0153] In one embodiment, the frame of the housing of the electronic device may form the fourth branch 42, wherein the open end of the fourth branch 42 may correspond to the insulating gap on the frame.

[0154] Fig.12a This is the current distribution diagram of the first antenna in the embodiment of the present application. Figure 12b : is the current distribution diagram of the second antenna in the embodiment of the present application. Fig.12a As shown, when the first antenna 3 receives feeding, the first sub-branch 321 and the second sub-branch 322 are used as a whole structure as a linear antenna, and the current flows around the entire first branch 31 and the second branch 32 to form a first resonance; Figure 12b As shown, the second sub-branch 322 and the fourth branch 42 share the above-mentioned gap, and the current flows around the second sub-branch 322 and the fourth branch 42 respectively, forming an open slot antenna, generating a third resonance. The center frequency of the above-mentioned first harmonic point (the center frequency of the first antenna 3) is the same as or adjacent to the center frequency of the third resonance (the center frequency of the second antenna 4). In addition, after the above-mentioned second sub-branch 322 is loaded with the electrical device 34, the second resonance and the fourth resonance are generated, and the center frequencies of the second resonance and the fourth resonance are less than the center frequencies of the above-mentioned first resonance and the third resonance. In the embodiment of the present application, by setting the electrical device 34, the working mode of the antenna is adjusted, so that a better isolation can be formed between the above-mentioned first antenna 3 and the second antenna 4.

[0155] Specifically, the operating frequency band of the linear antenna includes the first frequency band, the operating frequency band of the open slot antenna includes the second frequency band, and the first frequency band and the second frequency band at least partially overlap, then the antenna system in the embodiment of the present application can improve the isolation and reduce the interference between the antennas. The frequency difference between the center frequency of the first frequency band and the center frequency of the second frequency band is less than or equal to 15% of the lower center frequency.

[0156] Fig.13: is a working structure diagram of the first antenna and the second antenna in the embodiment of the present application, such as Fig.13 As shown, the first antenna 3 and the second antenna 4 in the embodiment of the present application work together. In the communication system, the first antenna 3 and the second antenna 4 enter the RF processing unit and the baseband processing unit through the RF front end to form a dual-antenna working mode. In a specific application, the first antenna 3 and the second antenna 4 can be communication systems of the same standard or communication systems of different standards; for example, the first antenna 3 is a cellular system antenna, and the second antenna 4 is a WiFi antenna; under different working standards, the antennas are connected to their respective RF front ends and systems. This does not affect the working principle of the antenna of the present invention.

[0157] When the first antenna 3 and the second antenna 4 are specifically formed, the fourth branch 42 and the second sub-branch 322 can be located in the same structural member, for example, the structural member can be the frame of the mobile terminal. It should be understood that "located in the same structural member" can be understood as at least a portion of the fourth branch 42 includes a first portion of a structural member, and at least a portion of the second sub-branch 322 includes a second portion of the structural member. In one embodiment, the structural member has the above-mentioned gap (for example, an insulating gap), and when the fourth branch 42 and the second sub-branch 322 are specifically formed, the gap can be directly formed on the above-mentioned structural member, and the fourth branch 42 and the second sub-branch 322 can be formed. In addition, the fourth branch 42 and the second sub-branch 322 can also be located in the same plane, which is convenient for preparing the antenna system 2 and helps to reduce the space occupied by the antenna system 2.

[0158] Similarly, in this application, Figure 7 In the example, the main radiator of the second antenna 4 is an L-shaped branch, that is, the main radiator of the first antenna 3 only includes the third branch 41 and the fourth branch 42. However, in other embodiments, the main radiator of the second antenna 4 may include other branches in addition to the third branch 41 and the fourth branch 42, that is, the main radiator may also be a more complex branch structure.

[0159] In another specific embodiment, the length of the second sub-branch 322 is 20% to 95% of the length of the first sub-branch 321. Further, the length of the second sub-branch 322 can also be 30% to 95% of the length of the first sub-branch 321. For example, the length of the second sub-branch 322 is 23%, 25%, 28%, 30%, 35%, 39%, 40%, 41%, 45%, 47%, 50%, 52%, 55%, 57%, 60%, 63%, 65%, 67%, 70%, 72%, 75%, 77%, 80%, 81%, 82%, 85% or 88% of the length of the first sub-branch 321, and they are not listed one by one here.

[0160] The equivalent capacitance of the above-mentioned capacitor is between 0.2pf and 6pf. The capacitance value within this range can meet the requirements of increasing the efficiency of the antenna and improving the isolation. Specifically, when the electrical device 34 is a fixed-value capacitor, an electrical device 34 with a suitable equivalent capacitance can be selected according to the actual working conditions. For example, the equivalent capacitance of the above-mentioned fixed-value capacitor can be 0.4pf, 0.5pf, 0.8pf, 1pf, 1.2pf, 1.5pf, 1.8pf, 2pf, 2.4pf, 2.5pf, 3pf, 3.5pf, 3.6pf, 4pf, 4.2pf, 4.5pf, 5pf or 5.5pf, etc.

[0161] In another embodiment, the capacitive device may include one or more capacitive devices. In this case, the capacitance value of each capacitive device is in the range of 0.2 pf to 6 pf.

[0162] The above-mentioned capacitor device can also be an adjustable capacitor. In this case, the adjustable capacitance value range of the adjustable capacitor can at least partially overlap with the above-mentioned 0.2pf to 6pf. In a specific embodiment, the adjustable capacitor can refer to switching between capacitors with fixed capacitances through a switch; or, turning on one or more switch branches to form a series and / or parallel capacitor; of course, it can also be an adjustable capacitor with stepless adjustment capacity.

[0163] When the above-mentioned electrical device 34 is specifically set, the electrical device 34 is coupled and connected to the second sub-branch 322 at the second connection point. The distance between the second connection point and the gap is smaller than the distance between the second connection point and the first connection point 33. In other words, the electrical device 34 is coupled and connected to the end of the second sub-branch 322 on the side closer to the gap. Specifically, the distance between the above-mentioned second connection point and the gap can refer to the distance between the second connection point and the end face of the second sub-branch 322 on the side closer to the gap. In this solution, the length of the second sub-branch 322 itself can be fully utilized, that is, the structure of the second sub-branch 322 itself can be fully utilized to radiate the signal.

[0164] Fig.14 is another structural schematic diagram of the antenna system in the embodiment of the present application, such as Fig.14 As shown, the antenna system 2 includes a third antenna 5, and the third antenna 5, the second antenna 4 and the first antenna 3 are arranged in sequence. Specifically, the third antenna 5 includes a fifth branch 51, and the fifth branch 5 is arranged on the side of the fourth branch 42 away from the second sub-branch 322. In one embodiment, the fifth branch 51 is connected to the fourth branch 42. Alternatively, the end of the fifth branch 51 facing the fourth branch 42 is an open end, the fifth branch 51 is arranged opposite to the fourth branch 42, and there is a gap between the open end of the fifth branch 51 and the fourth branch 42.

[0165] Fig.15is another structural schematic diagram of the antenna system in the embodiment of the present application, such as Fig.15 As shown, in another embodiment, when the antenna system 2 includes the third antenna 5', the second antenna 4, the first antenna 3 and the third antenna 5' are arranged in sequence. The fifth branch 51' is arranged on the side of the first sub-branch 321 away from the fourth branch 42. Similarly, the end of the fifth branch 51' facing the first sub-branch 321 is an open end. The fifth branch 51' is arranged opposite to the first sub-branch 321, and there is a gap between the open end of the fifth branch 51' and the first sub-branch 321. Alternatively, in another embodiment, the fifth branch 51' is connected to the first sub-branch 321. This application does not limit this.

[0166] In summary, in this solution, the number of antennas included in the antenna system 2 is not limited in this application.

[0167] like Fig.14 and Fig.15 As shown, in the embodiment of the present application, the part where the antenna is coupled to the second feed circuit can make the antenna directly coupled to the second feed circuit, or can make the antenna coupled to the second feed circuit by connecting an electrical device, which can be an adjustable device. For example, an adjustable device is coupled to the second branch 32 and the second feed circuit, so that the operating frequency band of the first antenna 3 can be switched; similarly, an adjustable device can be coupled to the fourth branch 42 and the second feed circuit, so that the operating frequency band of the second antenna 4 can be switched. In addition, the antenna back to the ground can also be coupled and connected by an electrical device, that is, the first branch 31 can be coupled and connected to the ground by an electrical device, and the third branch 41 can also be coupled and connected to the ground by an electrical device. This application does not impose any restrictions on this.

[0168] Fig.16 is another structural schematic diagram of the antenna system in the embodiment of the present application, such as Fig.15 As shown, in another embodiment, the second antenna and the third antenna are similar to the first antenna. Alternatively, it can be understood that a plurality of first antennas 3 are arranged in sequence, a gap is provided between two adjacent first antennas 3, and the isolation between adjacent antennas is improved by setting electrical components, thereby forming an antenna array with a high isolation.

[0169] The above are only specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. An antenna system, characterized in that: The invention comprises a first antenna and a ground, wherein the first antenna comprises: A first feed circuit and an electrical device; A first branch and a second branch, wherein the second branch is coupled to the first branch at a first connection point, the second branch includes a first sub-branch and a second sub-branch, the first sub-branch and the second sub-branch are located on both sides of the first connection point, the second branch includes a first open end and a second open end, the first open end is located at an end of the first sub-branch away from the second sub-branch, and the second open end is located at an end of the second sub-branch away from the first sub-branch; The first branch is coupled to the ground, the first sub-branch is coupled to the first feeding circuit, the second sub-branch is coupled to the ground via an electrical device, the coupling position between the electrical device and the second sub-branch is within 40% of the total length of the second sub-branch from the second open end, and the length of the second sub-branch is different from the length of the first sub-branch; The first antenna generates a first resonance and a second resonance, the center frequency of the first resonance is higher than the center frequency of the second resonance, and the first resonance is used to cover the working frequency band of the first antenna. The first sub-branch, the second sub-branch and the electrical device are used to generate the first resonance. And wherein, the first sub-branch node and the second sub-branch node extend on the same straight line.

2. The antenna system according to claim 1, characterized in that The length of the second sub-branch is smaller than that of the first sub-branch, the electrical device is a capacitor, and the equivalent capacitance of the capacitor is in the range of 0.2pf~6pf.

3. The antenna system according to claim 2, characterized in that The electrical device includes one or more capacitors, and the capacitance value of each capacitor is in the range of 0.2pf~6pf.

4. The antenna system according to claim 3, characterized in that The electrical device includes an adjustable capacitor.

5. The antenna system according to claim 1, wherein: The length of the second sub-branch is 30% to 95% of the length of the first sub-branch.

6. The antenna system according to claim 1, characterized in that A frequency difference between a center frequency of the first resonance and a center frequency of the second resonance is less than or equal to 15% of the lower center frequency.

7. The antenna system according to claim 1, characterized in that The second sub-branch and the electrical device are used to generate the second resonance.

8. The antenna system according to claim 1, characterized in that The current corresponding to the first resonance is the same-direction current on the first sub-branch and the second sub-branch.

9. The antenna system according to claim 1, characterized in that The current corresponding to the second resonance is the same-direction current on the second sub-branch.

10. The antenna system according to claim 1, wherein: The coupling position between the electrical device and the second sub-branch is within 30% of the total length of the second sub-branch from the second open end.

11. The antenna system according to any one of claims 1 to 10, characterized in that: Also included is a second antenna, the second antenna comprising: a second feeding circuit; A third branch and a fourth branch, the first end of the fourth branch is coupled to the third branch, the third branch is coupled to the ground, the fourth branch is coupled to the second feeding circuit, the second end of the fourth branch is arranged opposite to the second sub-branch, and there is a gap between the second end of the fourth branch and the second sub-branch.

12. The antenna system according to claim 11, characterized in that The fourth branch includes a third open end, and the third open end is the second end of the fourth branch.

13. The antenna system according to claim 11, characterized in that The width of the gap is 0.5 mm to 2 mm.

14. The antenna system according to claim 11, characterized in that The physical length L4 of the fourth branch and the physical length L11 of the first sub-branch satisfy: L4 = L11*(100±30)%.

15. The antenna system according to claim 11, characterized in that The second antenna generates a third resonance and a fourth resonance, the center frequency of the third resonance is higher than the center frequency of the fourth resonance, and the third resonance is used to cover the working frequency band of the second antenna.

16. The antenna system according to claim 15, characterized in that A frequency difference between a center frequency of the third resonance and a center frequency of the fourth resonance is less than or equal to 15% of the lower center frequency.

17. The antenna system according to claim 15, characterized in that The fourth branch, the second sub-branch and the electrical device are used to generate the third resonance, and the current corresponding to the third resonance is the reverse current on the fourth branch and the second sub-branch.

18. The antenna system according to claim 17, characterized in that The second sub-branch and the electrical device are used to generate the fourth resonance, and the current corresponding to the fourth resonance is the same-direction current on the second sub-branch.

19. The antenna system according to claim 11, characterized in that The operating frequency band of the first antenna includes a first frequency band; The operating frequency band of the second antenna includes a second frequency band, and a frequency difference between a center frequency of the first frequency band and a center frequency of the second frequency band is less than or equal to 15% of the lower center frequency.

20. An electronic device, characterized in that: It comprises a shell and the antenna system as described in any one of claims 1 to 19, wherein a partial structure of the shell forms the second branch; or, the antenna system is arranged in the shell.

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