Mobile terminal

Abstract

The present application provides a mobile terminal. The mobile terminal comprises a first antenna, a second antenna, a first tuning circuit, and a first control switch. The first antenna comprises a first radiator, and the first radiator comprises a first feed point. The second antenna comprises a second radiator and a third radiator, and the second radiator or the third radiator comprises a second feed point. In addition, both ends of the first radiator are open ends, both ends of the second radiator are open ends, the first radiator and the second radiator are spaced apart by means of a gap, and the second radiator and the third radiator are spaced apart by means of a gap. The distance from a coupling point between the first tuning circuit and the second radiator to the first radiator is less than the distance from the coupling point to the third radiator. By means of the described design solution, when the first antenna and the second antenna work simultaneously, the first control switch can be utilized to control the grounding of the second radiator to reduce the electrical coupling between the first radiator and the second radiator, so as to meet the isolation requirements between the first antenna and the second antenna.

Description

A mobile terminal

[0001] Cross-reference of related applications

[0002] This application claims priority to Chinese Patent Application No. 202510120880.4, filed on January 23, 2025, entitled "A Mobile Terminal", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of communication technology, and in particular to a mobile terminal. Background Technology

[0004] With the rapid development of mobile communication technology and the widespread use of smartphones, people have increasingly higher requirements for mobile terminals, especially for their communication capabilities.

[0005] Antenna systems are a crucial component for communication in mobile terminals. Currently, mobile terminal antenna systems typically consist of multiple antennas coexisting within a limited space, resulting in relatively small spacing between them. This leads to significant mutual coupling between the different antennas. To ensure these antennas can operate simultaneously within a confined space, decoupling design is necessary. However, in some scenarios, utilizing this mutual coupling can actually improve the efficiency of the antenna system. Summary of the Invention

[0006] The mobile terminal provided in this application can improve the efficiency of the antenna system by utilizing the mutual coupling between antennas while meeting the isolation requirements of different antennas, thereby improving the communication performance of the mobile terminal.

[0007] This application provides a mobile terminal, which includes a first antenna, a second antenna, a first tuning circuit, and a first control switch. The first antenna includes a first radiator with a first feed point. The second antenna includes a second radiator and a third radiator, with either the second or third radiator including a second feed point. Additionally, the first radiator includes a first open terminal and a second open terminal, the second radiator includes a third open terminal and a fourth open terminal, and the third radiator includes a fifth open terminal and a first ground terminal. In this application, the second and third open terminals are spaced apart by a gap, and the fourth and fifth open terminals are also spaced apart by a gap. The first tuning circuit is coupled to the second radiator, and the distance from the coupling circuit to the third open terminal is less than the distance to the fourth open terminal. The first control switch is used to control the coupling of the second radiator to the ground through a branch of the first tuning circuit. By adopting the mobile terminal design scheme provided in this application, when the first antenna and the second antenna are working simultaneously, the second radiator can be controlled by the first control switch to couple with the ground through the first tuning circuit to achieve grounding of the second radiator. This reduces the electric field strength between the first radiator and the second radiator, thereby reducing electrical coupling and energy coupling between the first antenna and the second antenna, so as to meet the isolation requirements of the first antenna and the second antenna.

[0008] In one possible implementation of this application, the length L3 of the third radiator satisfies the following relationship with the length L1 of the first radiator: 1 / 4 ≤ L3 / L1 ≤ 1. The length L3 of the third radiator satisfies the following relationship with the length L2 of the second radiator: 1 / 4 ≤ L3 / L2 ≤ 1. Therefore, in this application, the lengths of the first and second radiators are relatively close, so that while the grounding of the second radiator can meet the isolation requirements of the first and second antennas, the impact on the radiation efficiency of the first and second antennas can also be reduced.

[0009] In one possible implementation of this application, the second radiator includes a second feed point. When the frequency f1 at which the first feed point feeds the first radio frequency signal to the first radiator satisfies the condition |f1-f2| / f2≤20% with respect to the frequency f2 at which the second feed point feeds the second radiator, that is, when the frequencies of the radio frequency signals fed to the first and second radiators are close, a higher isolation requirement is required. Then, the first control current controls the second radiator to couple to the ground plane through the first branch of the first tuning circuit to reduce the electrical coupling between the first and second radiators.

[0010] In one possible implementation of this application, the equivalent capacitance of the first branch of the first tuning circuit is greater than or equal to 2pF, in order to meet the requirement of grounding the second radiator.

[0011] In one possible implementation of this application, when the mobile terminal communicates using the first operating frequency band of the first antenna, the first radiator generates a first resonance, and the second radiator and the first tuning circuit generate a second resonance. The resonant frequency f20 of the second resonance is higher than the resonant frequency f10 of the first resonance, making the second resonance a parasitic resonance of the first operating frequency band. This allows the second radiator to function as a parasitic radiator of the first antenna. Because it can fully utilize the gaps between the second and first radiators, as well as the gaps between the second and third radiators, for signal radiation, it can improve the performance of the first antenna.

[0012] In one possible implementation of this application, the resonant frequency f20 of the second resonance and the resonant frequency f10 of the first resonance satisfy the following relationship: 5% × f10 ≤ f20 - f10 ≤ 30% × f10. This allows the second radiator to act as a parasitic radiator of the first antenna, effectively enhancing the performance of the first antenna.

[0013] In this application, when the mobile terminal communicates using the first antenna, the first control switch is also used to control the second radiator to disconnect from the first tuning circuit. This increases the electric field strength between the second radiator and the first radiator, increasing electrical coupling, so that the second radiator can act as a parasitic radiator of the first antenna, thereby improving the performance of the first antenna.

[0014] In one possible implementation of this application, the mobile terminal further includes a second tuning current and a second control switch. The second tuning circuit is coupled to the second radiator, and the distance from the coupling point of the second tuning circuit and the second radiator to the fourth open terminal is less than the distance to the third open terminal. In this implementation, the resonant frequency of the second radiator can be adjusted using the second tuning circuit. Specifically, when the mobile terminal communicates using the first antenna, the first control switch controls the second radiator to disconnect from the first tuning circuit to increase the electrical coupling between the first radiator and the second radiator. Additionally, the second control switch controls the second radiator to couple with the first branch of the second tuning circuit, causing the second radiator and the first branch of the second tuning circuit to generate a second resonance. This allows the second radiator to act as a parasitic radiator of the first antenna, enhancing the radiation performance of the first antenna.

[0015] The equivalent capacitance of the first branch of the second tuning circuit described above is less than or equal to 2pF. This is used to adjust the resonance generated by the second radiator.

[0016] In one possible implementation of this application, the mobile terminal further includes a third tuning circuit and a third control switch. The third tuning circuit is coupled to a third radiator, and the distance from the coupling point of the third tuning circuit and the third radiator to the fifth open terminal is less than the distance to the first ground terminal. When the mobile terminal communicates using the first antenna, the third control switch controls the coupling of the third radiator to the first branch of the third tuning circuit. The third radiator and the first branch of the third tuning circuit generate a third resonance. The resonant frequency of the third resonance is higher than or equal to the resonant frequency of the first resonance, making the third resonance a parasitic resonance of the first operating frequency band, thereby improving the radiation efficiency of the first antenna.

[0017] Alternatively, in another implementation, the aforementioned third control switch controls the third radiator to couple to the ground through the second branch of the third tuning current. In this case, the third radiator does not act as a parasitic radiator of the first antenna, and it can be applied to scenarios where the radiation performance requirements of the first antenna are not high.

[0018] Furthermore, the second radiator includes a second feed point. When the mobile terminal communicates using the second frequency band of the second antenna, the second radiator generates a fourth resonance, and the first radiator generates a fifth resonance. The resonant frequency of the fifth resonance is higher than that of the fourth resonance, making the fifth resonance a parasitic resonance of the second operating frequency band. This allows the first radiator to function as a parasitic radiator of the second antenna, and because it can fully utilize the gaps for signal radiation, it can improve the performance of the first antenna.

[0019] The mobile terminal also includes a fourth tuning circuit and a fourth control switch. The fourth tuning circuit is coupled to the first radiator, and the distance from the fourth tuning circuit to the first open terminal is less than the distance from the fourth tuning circuit to the second open terminal. When the mobile terminal communicates using the second frequency band of the second antenna, the fourth control switch controls the coupling of the first radiator with the first branch of the fourth tuning current, causing the first radiator and the first branch of the fourth tuning circuit to generate a fifth resonance. This allows the first radiator to act as a parasitic radiator for the second antenna, enhancing its radiation performance.

[0020] Furthermore, when the mobile terminal communicates using the second operating frequency band of the second antenna, the third control switch is also used to control the coupling between the third radiator and the second branch of the third tuning circuit. The third radiator and the second branch of the third tuning circuit generate a sixth resonance. The resonant frequency of the sixth resonance is higher than that of the fourth resonance, making the sixth resonance a parasitic resonance of the second operating frequency band. This allows the third radiator to act as a parasitic radiator of the second antenna, thereby improving the performance of the first antenna.

[0021] In one possible implementation of this application, the mobile terminal further includes a fourth radiator and a fifth tuning circuit. The fourth radiator includes a sixth open terminal and a second ground terminal, with the sixth open terminal and the first open terminal separated by a gap. The fifth tuning circuit is coupled to the fourth radiator, and the distance from the coupling point of the fifth tuning circuit and the fourth radiator to the sixth open terminal is less than the distance to the second ground terminal. When the mobile terminal communicates using the first operating frequency band of the first antenna, the first antenna generates a first resonance. The fifth control switch controls the coupling of the fourth radiator with the first branch of the fifth tuning circuit, generating a seventh resonance. The resonant frequency of the seventh resonance is higher than or equal to the resonant frequency of the first resonance, making the seventh resonance a parasitic resonance of the first operating frequency band. This allows the fourth radiator to act as a parasitic radiator of the first antenna, thereby improving the performance of the first antenna.

[0022] In one possible implementation of this application, the mobile terminal further includes a frame that is arranged circumferentially around the mobile terminal. The first radiator, the second radiator, and the third radiator are all disposed on the frame. Therefore, both the first antenna and the second antenna are frame antennas. Thus, the design provided in this application can improve the performance of the two frame antennas while ensuring their isolation.

[0023] Additionally, the frame includes a first frame, at least a portion of the first radiator is located on the first frame, the second radiator is located on the first frame, and at least a portion of the third radiator is located on the first frame. This allows for full utilization of the layout space of the first frame by placing at least a portion of the radiator of the first antenna and at least a portion of the radiator of the second antenna on the first frame.

[0024] In this application, the aforementioned first frame can be a short frame. This effectively reduces the impact of hand grip on the performance of the first and second antennas. Furthermore, by using a short frame to design the radiator, the antenna design for the corresponding operating frequency band in the embodiments of this application can be achieved.

[0025] In one possible implementation of this application, the aforementioned short bezel is, for example, the top bezel. This can further and effectively reduce the impact of hand grip on the performance of the first and second antennas, which is beneficial for further improving the performance of the first and second antennas, and can also improve the communication performance of the mobile terminal in both the first and second antenna communication scenarios.

[0026] Furthermore, in this application, the first open end, second open end, third open end, fourth open end, and fifth open end can all be located on the top frame. This allows the top frame to form a three-slot antenna structure, which can effectively reduce the impact on the structural strength of the mobile terminal's frame while meeting the isolation and performance improvement requirements of the first and second antennas. In one embodiment, the three slots on the top frame are symmetrically distributed along the top edge, improving the aesthetics of the mobile terminal; for example, the middle slot is centrally located, and the two left and right slots are symmetrically positioned about the middle slot. Attached Figure Description

[0027] Figure 1 is a schematic diagram of a mobile terminal provided in an embodiment of this application;

[0028] Figure 2 is a schematic diagram of an antenna system for a mobile terminal provided in an embodiment of this application;

[0029] Figure 3a is a schematic diagram of another structure of the antenna system of the mobile terminal provided in the embodiment of this application;

[0030] Figure 3b is a schematic diagram of another structure of the antenna system of the mobile terminal provided in the embodiment of this application;

[0031] Figure 4a shows the S-parameter curves and efficiency curves of the first and second antennas working simultaneously in the embodiment shown in Figure 2.

[0032] Figure 4b shows another S-parameter curve and efficiency curve in the scenario where the first antenna and the second antenna work simultaneously in the embodiment shown in Figure 2.

[0033] Figure 5 is a schematic diagram of another structure of the antenna system of the mobile terminal provided in the embodiment of this application;

[0034] Figure 6 is a schematic diagram of another structure of the antenna system of the mobile terminal provided in the embodiment of this application;

[0035] Figure 7 is a comparison of the efficiency of the first antenna and the second antenna working simultaneously in the embodiment shown in Figure 6, and the first antenna priority scenario.

[0036] Figure 8 is a schematic diagram of another structure of the antenna system of the mobile terminal provided in the embodiment of this application;

[0037] Figure 9 is a comparison of the efficiency of the first antenna and the second antenna working simultaneously in the embodiment shown in Figure 8, and the second antenna priority scenario.

[0038] Figure 10 is a schematic diagram of another structure of the antenna system provided in an embodiment of this application;

[0039] Figure 11 is a schematic diagram of another structure of the antenna system provided in an embodiment of this application;

[0040] Figure 12 is a schematic diagram of another structure of the antenna system provided in an embodiment of this application;

[0041] Figure 13 is a schematic diagram of a mobile terminal provided in an embodiment of this application.

[0042] Reference numerals: 100-Cover plate; 200-Display / module; 300-Printed circuit board; 400-Middle frame; 500-Back cover; 600-Bezel; 1-RF chip; 101-First port; 102-Second port; 1a-First RF chip; 1b-Second RF chip; 2-First RF front-end module; 3-Second RF front-end module; 4-First radiator; 41-First feed point; 42-First open terminal; 43-Second open terminal; 5-Second radiator; 51-Second feed point; 52-Third open terminal; 53-Fourth open terminal; 6-Third radiator; 61-Fifth open terminal; 62-First ground terminal; 7-First tuning circuit; 8-Second tuning circuit; 9-Third tuning circuit; 10-Fourth tuning circuit; 11-Gap-crossing device; 13-Fourth radiator; 131-Sixth open terminal; 132-Second ground terminal; 14-Fifth tuning circuit; 15-First frame / top frame; 16-Bottom frame. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings. However, the exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein. The same reference numerals in the figures denote the same or similar structures, and therefore repeated descriptions of them will be omitted. The terms expressing position and direction described in the embodiments of this application are illustrative based on the accompanying drawings, but changes can be made as needed, and all such changes are included within the scope of protection of this application. The accompanying drawings of the embodiments of this application are only for illustrating relative positional relationships and do not represent actual scale.

[0044] It should be noted that specific details are set forth in the following description to facilitate understanding of this application. However, the embodiments of this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the embodiments of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0045] The following explains the terminology that may appear in the embodiments of this application.

[0046] Radiator: In an antenna, this is the device used to receive / transmit electromagnetic wave radiation. In some cases, the term "antenna" is narrowly defined as a radiator, which converts guided wave energy from the transmitter into radio waves, or converts radio waves into guided wave energy, for radiating and receiving radio waves. The modulated high-frequency current energy (or guided wave energy) generated by the transmitter is transmitted to the transmitting radiator via a feed line, where it is converted into electromagnetic wave energy of a specific polarization and radiated in the desired direction. The receiving radiator converts the electromagnetic wave energy of a specific polarization from a specific direction in space back into modulated high-frequency current energy, which is then transmitted to the receiver input via a feed line.

[0047] Ground / Plug: This can broadly refer to at least a portion of any grounding layer, ground plane, or grounding metal layer within a mobile terminal (such as a mobile phone), or at least a portion of any combination of the aforementioned grounding layers, ground planes, or grounding components. "Ground / Plug" can be used for grounding components within the mobile terminal. In one embodiment, "Ground / Plug" may include any one or more of the following: a grounding layer of the mobile terminal's circuit board, a ground plane formed by the mobile terminal's frame, a grounding metal layer formed by a thin metal film beneath the screen, a conductive grounding layer of the battery, and conductive or metallic components electrically connected to the aforementioned grounding layer / ground plane / metal layer. In one embodiment, the circuit board may be a printed circuit board (PCB), such as an 8-layer, 10-layer, or 12-14-layer board with 8, 10, 12, 13, or 14 layers of conductive material, or components separated and electrically insulated by dielectric or insulating layers such as glass fiber or polymers.

[0048] Any of the aforementioned grounding layers, ground planes, or grounding metal layers are made of conductive materials. In one embodiment, the conductive material may be any of the following: 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 on an insulating substrate and tin-plated copper, graphite-impregnated cloth, graphite-coated substrates, copper-plated substrates, brass-plated substrates, and aluminum-plated substrates. Those skilled in the art will understand that grounding layers / ground planes / grounding metal layers may also be made of other conductive materials.

[0049] Radio frequency (RF) chips are a combination of all components used for receiving and transmitting radio frequency (RF) signals. They can be considered to include the RF front end and the transceiver. In the case of a receiving antenna, the RF chip can be considered the antenna section from the first amplifier to the front-end transmitter. In a transmitting antenna, the RF chip can be seen as the section after the last power amplifier. In some cases, the RF chip can also be understood as the feed unit. Typically, it is considered part of the antenna system, used to convert radio waves into electrical signals, and vice versa. Antenna design should consider the maximum power transfer capability and efficiency. For this purpose, the antenna feed impedance must be matched to the load resistance. The antenna feed impedance is a combination of resistance, capacitance, and inductance. To ensure maximum power transfer conditions, the two impedances (load resistance and feed impedance) should be matched. This matching can be achieved by considering frequency requirements and antenna design parameters such as gain, directivity, and radiation efficiency.

[0050] In some contexts, the term "power supply / feeding circuit" narrowly refers to a radio frequency integrated circuit (RFIC). A power supply circuit converts radio waves (e.g., RF signals) into electrical signals (e.g., digital signals). It is typically considered part of the RF component.

[0051] In some embodiments, the electronic device may also include a test socket (or, RF socket or RF test socket). This test socket can be used to insert a coaxial cable to test the characteristics of the RF front-end circuitry or the radiator of the antenna. The RF front-end circuitry can be considered as the circuitry coupled between the test socket and the transceiver.

[0052] In some embodiments, the radio frequency front-end circuit can be integrated into a radio frequency front-end chip in an electronic device, or the radio frequency front-end circuit and the transceiver can be integrated into a radio frequency chip in an electronic device.

[0053] It should be understood that any two feed circuits in the first / second / ...Nth feed circuit of this application can share the same transceiver, for example, by transmitting signals through a radio frequency channel (e.g., a port (pin) of a radio frequency chip) in a transceiver; they can also share a radio frequency front-end circuit, for example, by processing signals through a switch or amplifier in a radio frequency front-end.

[0054] It should also be understood that the two feed circuits in the first / second / ...Nth feed circuit of this application typically correspond to two RF test sockets in an electronic device.

[0055] Feed line: Also called a transmission line, it refers to the connection line between the antenna's radio frequency chip and the radiator. Depending on the frequency and form, the transmission line can directly transmit current waves or electromagnetic waves. The connection point on the radiator where it connects to the transmission line is usually called the feed point. Transmission lines include conductive transmission lines, coaxial transmission lines, waveguides, or microstrip lines, etc. Depending on the implementation, transmission lines can include bracket antenna bodies or glass antenna bodies, etc. Depending on the carrier, transmission lines can be made of liquid crystal polymer (LCP), flexible printed circuit boards (FPC), or printed circuit boards (PCBs), etc.

[0056] Resonant frequency: The resonant frequency is also called the resonance frequency. The resonant frequency can have a frequency range, that is, the frequency range in which resonance occurs. The resonant frequency can be a frequency range where the return loss characteristic is less than -6dB. The point of strongest resonance can be called the resonant point, and the frequency corresponding to the resonant point is the center frequency. The return loss characteristic of the center frequency can be less than -20dB. It should be understood that, unless otherwise specified, when the antenna / radiator in this application generates "first / second...resonance," the first resonance should be the fundamental mode resonance generated by the antenna / radiator, or in other words, the lowest frequency resonance generated by the antenna / radiator. It should be understood that the antenna / radiator can generate one or more antenna modes according to a specific design, and each antenna mode can correspond to a fundamental mode resonance.

[0057] Resonant frequency band: The range of resonant frequencies is the resonant frequency band. The return loss characteristics at any frequency point within the resonant frequency band can be less than -6dB or -5dB.

[0058] Communication / Operating Frequency Band: Regardless of the type of antenna, it always operates within a certain frequency range (bandwidth). For example, an antenna supporting the B40 band operates within the frequency range of 2300MHz to 2400MHz, or in other words, its operating frequency band includes the B40 band. The frequency range that meets the specifications can be considered the antenna's operating frequency band. The width of the operating frequency band is called the operating bandwidth. The operating bandwidth of an omnidirectional antenna may reach 3-5% of the center frequency. The operating bandwidth of a directional antenna may reach 5-10% of the center frequency. Bandwidth can be considered as a frequency range on both sides of the center frequency (e.g., the resonant frequency of a dipole), where the antenna characteristics are within the acceptable range of the center frequency.

[0059] The resonant frequency band and the operating frequency band can be the same or different, or their frequency ranges can partially overlap. In one embodiment, the resonant frequency band of the antenna can cover multiple operating frequency bands of the antenna.

[0060] Phase shifter: Located between the radiator and the RF chip, on the connection line between them, it is used to adjust the phase of the signal fed into the radiator. Specifically, the phase of the signal fed into the radiator can be adjusted by changing the electrical length of the connection line between the radiator and the RF chip.

[0061] Medium wavelength: refers to the wavelength of electromagnetic waves propagating in a medium at the operating frequency band. For example, if the operating frequency band is [f1, f2], the corresponding medium wavelength is also the range [w1, w2]. Alternatively, to simplify calculations, the above-mentioned medium wavelength can also refer to the wavelength of electromagnetic waves propagating in the medium at the center frequency f0 of the operating frequency band. In this case, the medium wavelength is a specific value w0.

[0062] Antenna return loss: This can be understood as the ratio of the signal power reflected back to the antenna port after passing through the antenna circuit to the transmit power at the antenna port. The smaller the reflected signal, the larger the signal radiated into space through the antenna, and the higher the antenna's radiation efficiency. Conversely, the larger the reflected signal, the smaller the signal radiated into space through the antenna, and the lower the antenna's radiation efficiency.

[0063] Antenna return loss can be represented by the S11 parameter, which is one of the S-parameters. S11 represents the reflection coefficient, and this parameter characterizes the antenna's transmission efficiency.

[0064] In one embodiment, the S11 diagram can be understood as a schematic diagram representing the resonance generated by the antenna. In one embodiment, the resonance shown in the S11 diagram within the range of -6dB can be understood as the resonant frequency / frequency range / operating frequency band generated by the antenna. The S11 parameter is usually negative. The smaller the S11 parameter, the smaller the antenna return loss, the less energy reflected back by the antenna itself, which means more energy actually enters the antenna, and the higher the antenna radiation efficiency; the larger the S11 parameter, the greater the antenna return loss, and the lower the antenna radiation efficiency.

[0065] It should be noted that in engineering, an S11 value of -6dB is generally used as the standard. When the S11 value of an antenna is less than -6dB, the antenna can be considered to be working normally, or the antenna can be considered to have good transmission efficiency.

[0066] Antenna radiation pattern: also known as radiation pattern. It refers to the graph showing how the relative field strength (normalized modulus) of the antenna's radiated field changes with direction at a certain distance from the antenna. It is usually represented by two mutually perpendicular planar radiation patterns passing through the direction of maximum radiation of the antenna.

[0067] Antenna radiation patterns typically have multiple radiating beams. The beam with the highest radiating intensity is called the main lobe, and the remaining beams are called side lobes. Among the side lobes, the side lobe in the opposite direction to the main lobe is also called the back lobe.

[0068] Radiation efficiency refers to the ratio of the power radiated by an antenna into space (i.e., the power effectively converted into electromagnetic waves) to the active power input to the antenna. The active power input to the antenna equals the antenna's input power minus the power loss. Power loss mainly includes return loss power, ohmic loss power of the metal, and / or dielectric loss power. Both metal loss and dielectric loss are factors affecting radiation efficiency.

[0069] Those skilled in the art will understand that radiation efficiency is generally expressed as a percentage, and there is a corresponding conversion relationship between it and dB. The closer the radiation efficiency is to 0 dB, the better the radiation efficiency of the antenna.

[0070] dB: This stands for decibel, a logarithmic concept with base 10. Decibels are used to evaluate the proportional relationship between two physical quantities; they themselves have no physical dimensions. 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 = 20 dB; B / D = 10 dB; C / D = 7 dB; B / C = 3 dB. In other words, a 10-decibel difference between two quantities is a 10-fold difference, a 20-decibel difference is a 100-fold difference, and so on. A 3-decibel difference is a 2-fold difference between the two quantities.

[0071] The term "end" in the context of the main radiator's first / second / third / fourth / grounded / open ends should not be narrowly interpreted as a point or end physically disconnected from other radiators. It can also refer to a segment of the main radiator including the first endpoint, which is the endpoint of the main radiator at the gap. For example, the first end of the main radiator can be considered a segment of the main radiator within a range of one-eighth of a first wavelength from the first endpoint. The first wavelength can be the wavelength corresponding to the operating frequency band of the main radiator, the wavelength corresponding to the center frequency of the operating frequency band, or the wavelength corresponding to the resonant point. In one embodiment, "end / point" can include a connection / coupling region on the radiator that is coupled to other conductive structures. For example, a feed end / feed point can be a coupling region on the antenna radiator that is coupled to a feed structure (e.g., a region facing a part of the feed structure). Similarly, a ground end / grounding point can be a connection / coupling region on the antenna radiator that is coupled to a ground structure.

[0072] Open and Closed Terminals: In some embodiments, open and closed terminals are defined relative to whether or not they are grounded; the closed terminal is grounded, and the open terminal is not grounded. In one embodiment, the open terminal may also be referred to as a floating terminal, a free terminal, an open terminal, or an open-circuit terminal. In one embodiment, the closed terminal may also be referred to as a grounded terminal or a short-circuit terminal. It should be understood that in some embodiments, other conductors can be coupled through the open terminal to transfer coupled energy (which can be understood as transferring current).

[0073] In some embodiments, the open end and the closed end are, for example, relative to other conductors, with the closed end electrically connected to other conductors and the open end not electrically connected to other conductors.

[0074] To put it simply, the "open end" of a radiator can be defined as one end of the radiator that is spaced apart from the floor or coupled to the floor through a capacitive device.

[0075] To put it simply, the "grounding terminal" of a radiator can be understood as: if one end of the radiator is directly connected to the floor or coupled to the floor through an inductive device, it can be regarded as the grounding terminal of the radiator.

[0076] In some embodiments, the understanding of "closed end" can also be from the perspective of current distribution. A closed end or ground end can be understood as a point of high current or low electric field on a radiator. In one embodiment, coupling electronic devices (e.g., inductive devices) through a closed end can maintain the current distribution characteristics of the point of high current / low electric field. In one embodiment, opening a slit at or near the closed end (e.g., filling the slit with insulating material) can maintain the current distribution characteristics of the point of high current / low electric field.

[0077] In some embodiments, the understanding of "open terminal" can also be from the perspective of current distribution. An open terminal or a floating terminal can be understood as a point with a small current or a point with a large electric field on the radiator. In one embodiment, coupling electronic devices (e.g., capacitive devices) through an open terminal can maintain the current distribution characteristics of the point with a small current or a large electric field.

[0078] It should be understood that when an electronic device (e.g., capacitor, inductor, etc.) is coupled at the radiator end of a gap (which, from the perspective of the radiator's structure, resembles a radiator at the opening of an open or suspended end), the radiator end can be a point with a large current / small electric field. In this case, it should be understood that the radiator end at the gap is actually a closed end or a grounded end, etc.

[0079] Capacitance: can be understood as lumped capacitance and / or distributed capacitance. Lumped capacitance includes capacitive components, such as capacitor elements; distributed capacitance (or distributed capacitance) includes the equivalent capacitance formed by two conductive components separated by a certain gap.

[0080] Electrical length: Electrical length can be expressed as the ratio of physical length (i.e., mechanical length or geometric length) multiplied by the time it takes for an electrical or electromagnetic signal to travel in a medium to the time required for that signal to travel a distance in free space equal to the physical length of the medium. Electrical length can be expressed by the following formula:

[0081] Where L is the physical length, a is the transmission time of the electrical or electromagnetic signal in the medium, and b is the transmission time in free space.

[0082] Alternatively, electrical length can also refer to the ratio of physical length (i.e., mechanical length or geometric length) to the wavelength of the transmitted electromagnetic wave, and electrical length can satisfy the following formula:

[0083] Where L is the physical length and λ is the wavelength of the electromagnetic wave.

[0084] In some embodiments of this application, the physical length of the radiator can be understood as within ±20% of the electrical length of the radiator, for example, within ±10% or within ±5%.

[0085] In the embodiments of this application, the wavelength in a certain wavelength mode of the antenna (such as half-wavelength mode, etc.) can refer to the wavelength of the signal radiated by the antenna. It should be understood that the wavelength of the radiated signal in air can be calculated as follows: Wavelength = Speed ​​of light / Frequency, where the frequency is the frequency of the radiated signal. The wavelength of the radiated signal in a medium can be calculated as follows: ) / frequency, where ε is the relative permittivity of the medium and frequency is the frequency of the radiated signal.

[0086] Coupling: In this application, it can be understood as indirect coupling, and "coupled connection" can be understood as indirect coupling connection. "Indirect coupling" can be understood as two conductors conducting electricity through a gap / non-contact manner. In one embodiment, indirect coupling can also be called capacitive coupling, for example, signal transmission is achieved by forming an equivalent capacitance through coupling between the gaps between two conductive parts.

[0087] The limitations mentioned in the embodiments of this application, such as symmetry (e.g., axial symmetry, or central symmetry), parallelism, perpendicularity, and similarity (e.g., same length, same width, etc.), are all relative to the current technological level, and not absolute and strict mathematical definitions. There can be a predetermined angular deviation between two mutually parallel or perpendicular structures. In one embodiment, the predetermined threshold can be less than or equal to a threshold of 1 mm, for example, the predetermined threshold can be 0.5 mm or 0.1 mm. In one embodiment, the predetermined angle can be an angle within the range of ±10°, for example, the predetermined angle deviation is ±5°.

[0088] It is worth noting that in the embodiments of this application, "perpendicular" means that there can be a predetermined angle deviation between the two. For example, the predetermined angle can be 85°, 86°, 87°, 88°, 89°, 90°, 91°, 92°, 93°, 94° or 95°, etc.

[0089] It is worth noting that in the embodiments of this application, "parallel" means that there can be a predetermined angular deviation between the two. For example, the predetermined angle can be 0°, 0.5°, 1°, 1.5°, 2°, 3°, 4°, 4.5°, or 5°, etc.

[0090] To facilitate understanding of the mobile terminal provided in this application embodiment, its application scenario is first introduced below. The mobile terminal in this application embodiment refers to a terminal with communication functions. Specifically, it can refer to a mobile terminal employing one or more of the following communication technologies: Bluetooth (BT) communication technology, Global Positioning System (GPS) communication technology, Wireless Fidelity (Wi-Fi) communication technology, Global System for Mobile Communications (GSM) communication technology, Wideband Code Division Multiple Access (WCDMA) communication technology, Long Term Evolution (LTE) communication technology, 5G communication technology, and other future communication technologies. The mobile terminal in this application embodiment can include mobile phones, tablets, laptops, smart bracelets, smartwatches, smart helmets, and smart glasses, etc. Furthermore, the aforementioned mobile terminal can also be a handheld device with wireless communication functions, a computing device or other processing device connected to a wireless modem, an in-vehicle device, a mobile terminal in a 5G network, or a mobile terminal in a future evolved public land mobile network (PLMN), etc., which are not limited in this application embodiment.

[0091] Figure 1 illustrates a schematic diagram of a mobile terminal provided in an embodiment of this application. In this embodiment, a mobile phone is used as an example for illustration. As shown in Figure 1, in one embodiment, the mobile terminal includes a cover 100, a display / module 200, a printed circuit board (PCB) 300, a middle frame 400, and a rear cover 500. It should be understood that in some embodiments, the cover 100 may be a glass cover, or it may be replaced with a cover made of other materials, such as an ultra-thin glass cover, a polyethylene terephthalate (PET) cover, etc. In one embodiment, the cover 100, display 200, middle frame 400, and rear cover 500 can all be considered as a housing.

[0092] The cover plate 100 can be set close to the display screen 200, and can be mainly used to protect the display screen 200 from dust.

[0093] In one embodiment, the display screen 200 may include a liquid crystal display (LCD), a light emitting diode (LED) display panel, or an organic light-emitting diode (OLED) display panel, etc., and this application does not limit it.

[0094] The mid-frame 400 primarily serves to support the entire device. Figure 1 shows the PCB 300 positioned between the mid-frame 400 and the back cover 500. It should be understood that in one embodiment, the PCB 300 may also be positioned between the mid-frame 400 and the display screen 200; this application does not impose any limitations on this. The PCB 300 can be made of flame-retardant material (FR-4), Rogers substrate, or a hybrid substrate of Rogers and FR-4, etc. Here, FR-4 is a designation for a flame-retardant material grade, and Rogers substrate is a high-frequency board. Electronic components, such as radio frequency chips, are mounted on the PCB 300.

[0095] In one embodiment, a metal layer may be disposed on the PCB 300. This metal layer can be used to ground electronic components carried on the PCB 300, or to ground other components such as bracket antennas, frame antennas, etc. This metal layer may be referred to as a ground plane, grounding plate, or grounding layer. In one embodiment, this metal layer can be formed by etching metal onto the surface of any layer of the dielectric substrate in the PCB 300. In one embodiment, the grounding metal layer may be disposed on the side of the PCB 300 near the middle frame 400. In one embodiment, the edge of the printed circuit board PCB 300 can be considered as the edge of its grounding layer. In one embodiment, the metal middle frame 400 can also be used for grounding the aforementioned components. The mobile terminal may also have other ground planes / grounding plates, as previously described, which will not be repeated here.

[0096] The mobile terminal may also include a battery (not shown in the figure). The battery may be located between the middle frame 400 and the back cover 500, or between the middle frame 400 and the display screen 200; this application does not impose any limitations on this. In some embodiments, the PCB 300 is divided into a motherboard and a daughterboard, and the battery may be located between the motherboard and the daughterboard. Specifically, the motherboard may be located between the middle frame 400 and the upper edge of the battery, and the daughterboard may be located between the middle frame 400 and the lower edge of the battery.

[0097] The mobile terminal may also include a frame 600, which may be formed of a conductive material such as metal. The frame 600 may be disposed between the display screen 200 and the back cover 500 and extend circumferentially around the periphery of the mobile terminal. The frame 600 may have four sides surrounding the display screen 200 to help secure the display screen 200. In one implementation, the frame 600 made of metal can be directly used as the metal frame of the mobile terminal, forming a metal frame appearance, suitable for industrial design (ID). In another implementation, the outer surface of the frame 600 may also be made of a non-metallic material, such as a plastic frame, forming a non-metallic frame appearance, suitable for non-metallic ID.

[0098] The mid-frame 400 may include a border 600. The mid-frame 400, including the border 600, is a single unit that supports the electronic components within the device. The cover plate 100 and the rear cover 500 respectively cover the upper and lower edges of the border 600 to form the outer shell or housing of the mobile terminal. Alternatively, the border 600 may not be considered part of the mid-frame 400. In one embodiment, the border 600 may be connected to the mid-frame 400 and integrally formed. In another embodiment, the border 600 may include inwardly extending protrusions to connect with the mid-frame 400, for example, via spring clips, screws, welding, etc. In one embodiment, the cover plate 100, the rear cover 500, the border 600, and the mid-frame 400 may be collectively referred to as the outer shell or housing of the mobile terminal. It should be understood that "outer shell or housing" can be used to refer to part or all of any one of the cover plate 100, rear cover 500, frame 600 or middle frame 400, or to part or all of any combination of the cover plate 100, rear cover 500, frame 600 or middle frame 400.

[0099] The back cover 500 can be made of metal; it can also be made of non-conductive materials, such as glass or plastic; or it can be made of both conductive and non-conductive materials.

[0100] In one embodiment, the frame 600 can at least partially function as a radiator to transmit / receive radio frequency signals. This portion of the frame acting as the radiator may have gaps between itself and other parts of the middle frame 400, or between itself and the middle frame 400, thereby ensuring a good radiation environment for the radiator. In one embodiment, an aperture may be provided near this portion of the frame acting as the radiator. In one embodiment, the aperture may include an aperture disposed inside the mobile terminal, for example, an aperture not visible from the exterior of the mobile terminal. In one embodiment, the internal aperture may be formed by any one or multiple of the middle frame 400, battery, PCB 300, back cover 500, display screen 200, and other internal conductive components; for example, the internal aperture may be formed by a structural component of the middle frame 400. In one embodiment, the aperture may also include a gap / slit / opening on the frame 600. In one embodiment, the gap / slit / opening on the frame 600 may be a slit formed on the frame 600, at which the frame 600 is divided into two parts without a direct connection. In one embodiment, the aperture may further include a slit / gap / aperture provided on the back cover 500 or the display screen 200. In one embodiment, the back cover 500 includes a conductive material, and the aperture provided in the conductive material may communicate with a slit or gap in the frame to form a continuous aperture on the surface of the mobile terminal.

[0101] In one embodiment, the radiator of the mobile terminal may also be disposed within the frame 600. The frame 600 comprises a non-conductive material, and the radiator of the antenna may be located within the mobile terminal and disposed along the frame 600, or the radiator may be at least partially embedded within the non-conductive material of the frame. In one embodiment, the radiator is disposed close to the non-conductive material of the frame 600 to minimize the volume occupied by the radiator and to be closer to the outside of the mobile terminal, thereby achieving better signal transmission performance. It should be noted that "disposed close to the frame 600" means that the radiator can be disposed tightly against the frame 600 or close to the frame 600, for example, there may be a small gap between the radiator and the frame 600.

[0102] In one embodiment, the radiator of the mobile terminal may also be disposed within the housing, such as a bracket antenna disposed on a circuit board (not shown in Figure 1). A gap may exist between the radiator disposed within the housing and other conductive components inside the housing, thereby ensuring a good radiation environment for the radiator. In one embodiment, an aperture may be disposed near the radiator. In one embodiment, the aperture may include an aperture disposed inside the mobile terminal, for example, an aperture not visible from the exterior of the mobile terminal. In one embodiment, the internal aperture may be formed by any one or multiple of the frame 600, mid-frame 400, battery, PCB 300, back cover 500, display screen 200, and other internal conductive components; for example, the internal aperture may be formed by a structural component of the mid-frame 400. In one embodiment, the aperture may also include a gap / slit / opening on the frame 600. In one embodiment, the gap / slit / opening on the frame 600 may be a slit formed on the frame, at which the frame 600 is divided into two parts without a direct connection. In one embodiment, the aperture may further include a slot / slit / aperture disposed on the back cover 500 or the display screen 200. In one embodiment, the back cover 500 comprises a conductive material, and the aperture disposed on the conductive material may communicate with a slot or gap in the frame to form a continuous aperture on the surface of the mobile terminal. In one embodiment, the aperture on the back cover 500 or the display screen may also be used to house other devices, such as a camera, and / or a sensor, and / or a microphone, and / or a speaker, etc.

[0103] In one embodiment, the antenna can be based on a flexible printed circuit (FPC), a laser-direct-structuring (LDS) antenna, or a microstrip disk antenna (MDA), among other forms. In another embodiment, the antenna can be a transparent or semi-transparent structure embedded within the screen of the mobile terminal, making it a transparent antenna unit embedded within the screen of the mobile terminal.

[0104] Figure 1 only schematically shows some of the components included in the mobile terminal; the actual shape, size, and construction of these components are not limited to those in Figure 1.

[0105] As discussed above regarding mobile terminals, the antenna system is a crucial component for communication. To ensure signal transmission and reception performance, antennas are typically positioned on or near the edge of the device. Due to the limited space available for antennas in mobile terminals, the spacing between antennas covering the same or different frequency bands is small, leading to significant mutual coupling. Therefore, decoupling design is necessary to maintain the communication performance of each antenna. However, in some scenarios, this mutual coupling can actually improve the performance of the antenna system.

[0106] In view of this, the mobile terminal provided in this application meets the isolation requirements for multiple antennas operating simultaneously in an antenna system through the configuration of the tuning circuit, and makes it possible to improve the performance of the antenna system by utilizing the mutual coupling between antennas. To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0107] To realize the communication function of the mobile terminal, the mobile terminal includes an antenna system. Figure 2 is a schematic diagram of an antenna system of a mobile terminal provided in an embodiment of this application. The antenna system of the mobile terminal includes a first antenna, a second antenna, a first tuning circuit 7, and a first control switch (not shown in Figure 2). In a specific configuration, as shown in Figure 2, the first antenna includes a first radiator 4, and the first radiator 4 includes a first feed point 41. In addition, the second antenna includes a second radiator 5 and a third radiator 6, and the second radiator 5 includes a second feed point 51.

[0108] Referring again to Figure 2, in this application, the first radiator 4 further includes a first open end 42 and a second open end 43; the second radiator 5 further includes a third open end 52 and a fourth open end 53; and the third radiator 6 further includes a fifth open end 61 and a first ground end 62. The second open end 43 and the third open end 52 are separated by a gap, and the fourth open end 53 and the fifth open end 61 are also separated by a gap. Thus, the first radiator 4 and the second radiator 5 are separated by gaps, and the second radiator 5 and the third radiator 6 are also separated by gaps. Furthermore, since a gap is also formed at the first open end 42 of the first radiator 4, the radiators of the first and second antennas can transmit signals using these three gaps.

[0109] As shown in Figure 2, in this embodiment, the first tuning circuit 7 is coupled to the second radiator 5, and the distance from the coupling point of the first tuning circuit 7 and the second radiator 5 to the third open end 52 is less than the distance to the fourth open end 53. Furthermore, in this application, the first control switch is used to control the coupling of the second radiator 5 to the floor through the first tuning circuit 7.

[0110] Based on this, it can be understood that, using the antenna system design scheme of the mobile terminal provided in this application, when the first antenna and the second antenna are working simultaneously, the second radiator 5 can be controlled by the first control switch to couple with the ground through the first tuning circuit 7 to achieve grounding of the second radiator 5, thereby reducing the electric field strength between the first radiator 4 and the second radiator 5, thereby reducing the electric coupling, thereby reducing the energy coupling between the first antenna and the second antenna, and improving the isolation between the first antenna and the second antenna.

[0111] In the embodiment shown in Figure 2, the distance from the first feed point 41 to the first open end 42 is less than the distance from the first feed point 41 to the second open end 43. Exemplarily, in one possible embodiment of this application, the distance d1 from the first feed point 41 to the first open end 42 and the length L1 of the first radiator 4 satisfy the following condition: 0 ≤ d1 ≤ 40% × L1.

[0112] In one possible embodiment, the length L1 of the first radiator 4 satisfies: (1 / 4)×λ1≤L1≤(1 / 2)×λ1, and the distance d1 from the first feed point 41 to the first open end 42 satisfies: d1≤(1 / 10)×λ1, where λ1 is the dielectric wavelength corresponding to the resonant frequency of the resonance generated by the first radiator 4.

[0113] Similarly, as shown in Figure 2, the distance from the second feed point 51 to the fourth open end 53 is less than the distance from the second feed point 51 to the third open end 52. Exemplarily, in one possible embodiment, the distance d2 from the second feed point 51 to the fourth open end 53 satisfies the following relationship with the length L2 of the second radiator 5: 0 ≤ d2 ≤ 40% × L2.

[0114] In one possible embodiment, the length L2 of the second radiator 5 satisfies: (1 / 4)×λ2≤L2≤(1 / 2)×λ2, and the distance d2 from the first feed point 41 to the first open end 42 satisfies: d2≤(1 / 10)×λ2, where λ2 is the dielectric wavelength corresponding to the resonant frequency of the resonance generated by the second radiator 5.

[0115] It is worth mentioning that, in this application, the length L3 of the third radiator 6 and the length L1 of the first radiator 4 satisfy the following relationship: 1 / 4 ≤ L3 / L1 ≤ 1. Furthermore, the length L3 of the third radiator 6 and the length L2 of the second radiator 5 satisfy the following relationship: 1 / 4 ≤ L3 / L2 ≤ 1. In one possible embodiment, the length L3 of the third radiator 6 satisfies: (1 / 4) × λ3 ≤ L3 ≤ (1 / 2) × λ3, where λ3 is the wavelength of the medium corresponding to the resonant frequency generated by the third radiator 6. In this application, the lengths of the first radiator 4 and the second radiator 5 are relatively close, so that while the isolation requirements of the first and second antennas can be met by utilizing the grounding of the second radiator 5, the impact on the radiation efficiency of the first and second antennas can also be reduced.

[0116] In practical applications, the radiator can be fed through the coupling of the radio frequency link and the feed point. For specific implementation, refer to Figure 3a, which is another structural schematic diagram of the antenna system of the mobile terminal provided in this embodiment. In this embodiment, the mobile terminal further includes a radio frequency chip 1, a first radio frequency front-end module 2, and a second radio frequency front-end module 3. The radio frequency chip 1 is coupled to the first feed point 41 through the first radio frequency front-end module 2, so that the radio frequency chip 1 can feed a first radio frequency signal to the first radiator 4 through the first radio frequency front-end module 2 and the first feed point 41. Additionally, the radio frequency chip 1 is coupled to the second feed point 51 through the second radio frequency front-end module 3, so that the radio frequency chip 1 can feed a second radio frequency signal to the second radiator 5 through the second radio frequency front-end module 3 and the second feed point 51.

[0117] Referring again to FIG3a, the RF chip 1 may include a first port 101 and a second port 102, wherein the first port 101 and the second port 102 are typically used to provide RF signals of different frequency bands. In this embodiment of the present application, the first port 101 can be coupled to the first feed point 41 through the first RF front-end module 2 to feed a first RF signal to the first antenna. The second port 102 can be coupled to the second feed point 51 through the second RF front-end module 3 to feed a second RF signal to the second antenna.

[0118] It is worth noting that Figure 3a only illustrates one possible configuration of the radio frequency link. Additionally, referring to Figure 3b, which is a schematic diagram of another structure of the antenna system of the mobile terminal provided in this application, the mobile terminal may further include two radio frequency chips, such as a first radio frequency chip 1a and a second radio frequency chip 1b. The first radio frequency chip 1a is coupled to a first feed point 41 through a first radio frequency front-end module 2, so that the first radio frequency chip 1a feeds a first radio frequency signal to the first radiator 4 through the first radio frequency front-end module 2 and the first feed point 41. The second radio frequency chip 1b is coupled to a second feed point 51 through a second radio frequency front-end module 3, so that the radio frequency chip 1b feeds a second radio frequency signal to the second radiator 5 through the second radio frequency front-end module 3 and the second feed point 51.

[0119] As described above, by adopting the design scheme provided in this application, when the operating frequency bands of the first antenna and the second antenna are relatively close, the isolation between the first antenna and the second antenna can be improved by grounding the second radiator 5. For ease of understanding, the following explanation will use an example where the first antenna is a Wi-Fi antenna and the second antenna is a cellular antenna.

[0120] In practical applications, when the first antenna includes the 2.4GHz Wi-Fi band and the second antenna includes the Band41 (or B41) band, which is the 2.5GHz-2.7GHz band, it can be understood that the frequency f1 of the first radio frequency signal fed from the first feed point 41 to the first radiator 4 and the frequency f2 of the second radio frequency signal fed from the second feed point 51 to the second radiator 5 satisfy the following condition: |f1-f2| / f2≤20%. Therefore, to reduce the coupling between the first and second antennas, the second radiator 5 can be grounded by using the first control switch to control the coupling of the second radiator 5 to the ground through the first branch of the first tuning circuit.

[0121] In this application, the branch of the tuning circuit can be formed by a single device or a combination of multiple devices, and there is no limitation on it.

[0122] It is worth mentioning that, in one possible embodiment of this application, the equivalent capacitance value of the first branch of the first tuning circuit can be greater than or equal to 2pF, so as to achieve the coupling grounding effect of the second radiator 5.

[0123] In addition, in the scenario where the first antenna and the second antenna operate simultaneously, the operating mode of the first antenna can be considered as differential mode (or, 1 / 2 wavelength mode), while the operating mode of the second antenna is more inclined to common mode (or, 1 / 4 wavelength mode).

[0124] Referring to Figure 4a, which shows the S-parameter curves and efficiency curves of the first and second antennas in the embodiment shown in Figure 2 operating simultaneously. In this embodiment, taking the first antenna operating in the 2.4GHz-2.5GHz Wi-Fi band and the second antenna operating in the B41 band as an example, the isolation and performance between the first and second antennas are explained. In Figure 4a, the solid line represents the system efficiency curve of the second antenna, the dashed line represents the S11 curve of the first antenna, and the dotted line represents the S22 curve of the second antenna. Additionally, the dotted line represents the isolation curve between the first and second antennas.

[0125] Figure 4b shows another S-parameter curve and efficiency curve for the scenario where the first and second antennas operate simultaneously in the embodiment shown in Figure 2. In Figure 4b, taking the example of the first antenna operating in the 2.4GHz-2.5GHz Wi-Fi band and the second antenna operating in the B41 band, the isolation and performance between the first and second antennas are explained. In Figure 4b, the solid line represents the system efficiency curve of the first antenna, the dashed line represents the S11 curve of the first antenna, and the dotted line represents the S22 curve of the second antenna. Additionally, the dotted line represents the isolation curve between the first and second antennas.

[0126] As can be seen from Figures 4a and 4b, by adopting the antenna system design scheme provided in this application, when the first antenna and the second antenna are working simultaneously, the isolation between the first antenna and the second antenna can be reduced to below -10dB, or even below -12dB, while ensuring that the first antenna and the second antenna have high radiation efficiency. This satisfies the isolation requirement when the first antenna and the second antenna are working simultaneously, thereby satisfying the communication requirements of the first antenna and the second antenna.

[0127] It is understandable that in some other embodiments, where the first antenna and the second antenna still operate simultaneously, but the difference in their operating frequency bands is large, for example, the first antenna operates in the Wi-Fi 2.4GHz-2.5GHz band, while the second antenna operates in the cellular Band 3 (or B3) band, which is the 1.71GHz-1.88GHz band, the isolation between the first antenna and the second antenna is already relatively large in this scenario. In this case, the first control switch can be used to disconnect the second radiator 5 from the first tuning circuit to increase the energy coupling between the first radiator 4 and the second radiator 5. This is beneficial for increasing the current intensity of the first radiator 4 and the second radiator 5, thereby enabling the performance of the first antenna and the second antenna to be improved through mutual coupling.

[0128] As can be understood from the above introduction, the antenna system design provided in this application can not only meet the isolation requirements between two antennas operating at similar frequencies, but also improve the performance of two antennas operating at frequencies that meet the isolation requirements when they are operating simultaneously. Therefore, it has a wide range of applications.

[0129] Referring again to Figure 2, in the first antenna priority scenario, which can also be understood as the scenario where the mobile terminal uses the first operating frequency band of the first antenna for communication, the first radiator 4 can generate the first resonance. Furthermore, the second radiator 5 does not receive power through the second feed point 51, and the second radiator 5 is used to generate the second resonance. The resonant frequency f20 of the second resonance is higher than the resonant frequency f10 of the first resonance, making the second resonance a parasitic resonance of the first operating frequency band. This allows the second radiator 5 to act as a parasitic radiator of the first antenna. Because it can fully utilize the gaps between the second radiator 5 and the first radiator 4, as well as the gap between the second radiator 5 and the third radiator 6, for signal radiation, it can improve the performance of the first antenna.

[0130] In one specific embodiment, the resonant frequency f20 of the second resonance and the resonant frequency f10 of the first resonance satisfy the following condition: 5% × f10 ≤ f20 - f10 ≤ 30% × f10. For example, 10% × f10 ≤ f20 - f10 ≤ 20% × f10 can be made. This allows the second radiator 5 to act as a parasitic radiator of the first antenna, thereby improving the performance of the first antenna.

[0131] It is worth mentioning that, in the embodiment shown in Figure 2, the first control switch can be used to disconnect the second radiator 5 from the first tuning circuit, so that the second radiator 5 generates a second resonance. Therefore, the first control switch can also adjust the resonance of the second radiator 5.

[0132] Figure 5 is a schematic diagram of another structure of the antenna system of the mobile terminal provided in an embodiment of this application. Compared with the embodiment shown in Figure 2 above, in the embodiment shown in Figure 5, the antenna system of the mobile terminal further includes a second tuning circuit 8 and a second control switch, and the second tuning circuit 8 is coupled to the second radiator 5. In addition, as shown in Figure 5, the distance from the coupling point of the second tuning circuit 8 and the second radiator 5 to the fourth open end 53 is less than the distance to the third open end 52.

[0133] In the first antenna priority scenario, when the first radiator 4 generates the first resonance, the first control switch can control the second radiator 5 to disconnect from the first tuning circuit 7, and the second control switch can control the second radiator 5 to couple with the first branch of the second tuning circuit 8, thereby causing the second radiator 5 and the first branch of the second tuning circuit 8 to generate the second resonance.

[0134] When the first antenna operates in Wi-Fi 2.4GHz-2.5GHz, the equivalent capacitance of the first branch of the second tuning circuit 8 can be less than or equal to 2pF to adjust the resonance generated by the second radiator 5. Thus, the second radiator 5 can be used as a parasitic radiator of the first antenna to improve the radiation efficiency of the first antenna.

[0135] In some other possible embodiments of this application, the equivalent capacitance or equivalent inductance value of the first branch of the second tuning circuit 8 can be set according to the requirements of the resonant frequency of the resonance that the second radiator 5 can generate and its physical length under specific application scenarios.

[0136] It is understandable that in the embodiment shown in Figure 5, since the first tuning circuit 7 is closer to the first radiator 4 than the second tuning circuit 8, controlling the first radiator 4 to disconnect from the first tuning circuit 7 by the first control switch can couple more of the energy generated when the first antenna is working to the second radiator 5, so that the second resonance excited on the second radiator 5 has a more obvious effect on the performance of the first antenna.

[0137] Furthermore, since the second tuning circuit 8 is farther away from the first radiator 4 than the first tuning circuit 7, the second tuning circuit 8 can be used to adjust the frequency of the resonance generated by the second radiator 5 in a wider frequency band, thereby making the adjustment of the resonance of the second radiator 5 by the second tuning circuit 8 more flexible and its effect on improving the efficiency of the first radiator 4 more obvious.

[0138] Figure 6 is a schematic diagram of another structure of the antenna system of the mobile terminal provided in the embodiment of this application. Compared with the embodiment shown in Figure 5 above, in the embodiment shown in Figure 6, the antenna system of the mobile terminal further includes a third tuning circuit 9, which is coupled to a third radiator 6. Specifically, the distance from the third tuning circuit 9 to the fifth open terminal 61 of the third radiator 6 is less than the distance from the third tuning circuit 9 to the first ground terminal 62, and the third tuning circuit 9 includes a third tuning circuit and a third control switch.

[0139] In the first antenna priority scenario, the first control switch can be used to disconnect the second radiator 5 from the first tuning circuit 7, and the second control switch can be used to couple the second radiator 5 with the first branch of the second tuning circuit 8, so that the second radiator 5 can generate a second resonance.

[0140] Furthermore, the third control switch couples the third radiator 6 with the first branch of the third tuning circuit 9, causing the third radiator 6 and the first branch of the third tuning circuit 9 to generate a third resonance. The resonant frequency of the third resonance is higher than or equal to the resonant frequency of the first resonance, making the third resonance a parasitic resonance in the first operating frequency band. This allows the third radiator 6 to also function as a parasitic radiator of the first antenna, thereby enhancing the radiation performance of the first antenna.

[0141] In some other possible embodiments of this application, the third control switch controls the third radiator 6 to couple to the ground through the second branch of the third tuning circuit 9, thereby achieving grounding of the third radiator 6. In this embodiment, only the second radiator 5 is used as a parasitic radiator of the first antenna to improve the performance of the second radiator 5.

[0142] It is worth mentioning that, in the embodiment shown in Figure 6, in the first antenna priority scenario, the current mode deviation mode of the second antenna.

[0143] Figure 7 compares the efficiency of the first antenna and the second antenna in the embodiment shown in Figure 6 under the scenarios of simultaneous operation of the first antenna and the first antenna priority. In Figure 7, the solid line represents the system efficiency in the first antenna priority scenario, and the dashed line represents the radiation efficiency of the first antenna in the first antenna priority scenario; the single-dotted-dashed line represents the radiation efficiency of the first antenna in the scenario of simultaneous operation of the first antenna and the second antenna, and the double-dotted-dashed line represents the system efficiency in the scenario of simultaneous operation of the first antenna and the second antenna. As can be seen from Figure 7, the radiation efficiency and system efficiency of the first antenna in the first antenna priority scenario are both better than those in the scenario of simultaneous operation of the first antenna and the second antenna.

[0144] Referring again to Figure 6, in the scenario where the second antenna is prioritized, i.e., when the mobile terminal uses the second operating frequency band of the second antenna for communication, the first radiator 4 does not receive the first radio frequency signal through the first feed point 41, while the second radiator 5 receives the second radio frequency signal through the second feed point 51. The first control switch controls the second radiator 5 to disconnect from the first tuning circuit 7, thereby increasing the coupling between the first radiator 4 and the second radiator 5. The second tuning circuit 8 is used to adjust the operating frequency band of the second radiator 5 so that the second radiator 5 generates a fourth resonance.

[0145] In the second antenna priority scenario, the first radiator 4 serves as a parasitic radiator for the second antenna. Specifically, referring to Figure 8, which is another structural schematic diagram of the antenna system of the mobile terminal provided in this application embodiment, the antenna system also includes a fourth tuning circuit 10 and a fourth control switch. The fourth tuning circuit 10 is coupled to the first radiator 4. In the second antenna priority scenario, the first radiator 4 is coupled to the first branch of the fourth tuning circuit 10, and the first radiator 4 and the first branch of the fourth tuning circuit 10 generate a fifth resonance. The resonant frequency of the fifth resonance is higher than the resonant frequency of the fourth resonance generated by the second radiator 5, making the fifth resonance a parasitic resonance of the second operating frequency band. Thus, the first radiator 4 can serve as a parasitic radiator for the second antenna to improve the radiation efficiency of the second antenna.

[0146] It is worth mentioning that, in the embodiment shown in Figure 8, the third control switch can also be used to control the coupling between the third radiator 6 and the second branch of the third tuning circuit 9, so that the third radiator 6 and the second branch of the third tuning circuit 9 generate a sixth resonance. The resonant frequency of the sixth resonance is higher than the resonant frequency of the fourth resonance generated by the second radiator 5, making the sixth resonance a parasitic resonance of the second operating frequency band. Thus, the third radiator 6 also acts as a parasitic radiator of the second antenna, which can be used to improve the efficiency of the second antenna.

[0147] Figure 9 compares the efficiency of the first and second antennas operating simultaneously in the embodiment shown in Figure 8 with that of the second antenna-first scenario. In Figure 9, the solid line represents the system efficiency in the second antenna-first scenario, and the dashed line represents the radiation efficiency of the second antenna in the second antenna-first scenario; the single-dotted-dashed line represents the radiation efficiency of the second antenna in the scenario where the first and second antennas operate simultaneously, and the double-dotted-dashed line represents the system efficiency in the scenario where the first and second antennas operate simultaneously. As can be seen from Figure 9, the radiation efficiency and system efficiency of the second antenna in the second antenna-first scenario are both better than those in the scenario where the first and second antennas operate simultaneously.

[0148] In the above embodiments, the specific configuration of the antenna system is described using the example of the first feed point 41 of the first antenna being located at the first radiator 4 and the second feed point 51 of the second antenna being located at the second radiator 5. It can be understood that by adjusting the location of the feed points, the current mode of the antenna can be adjusted, thereby meeting the communication requirements of the antenna system. Based on this, please refer to Figure 10, which is another structural schematic diagram of the antenna system provided in this application embodiment. Compared with the antenna system shown in Figure 8, in the embodiment shown in Figure 10, the third radiator 6 includes the second feed point 51, so the third radiator 6 can receive radio frequency signals through the second feed point 51. Therefore, in the embodiment shown in Figure 10, the first radiator 4 and the third radiator 6 are feed radiators. Furthermore, in the embodiment shown in Figure 10, the configuration of the radio frequency front-end module and radio frequency chip in the mobile terminal used to feed the second feed point 51 can refer to the above embodiments, and will not be elaborated here.

[0149] It is understood that, in the embodiment shown in Figure 10, the distance from the coupling point of the second feed point 51 and the third radiator 6 to the fifth open end 61 is less than the distance to the first ground end 62. Since the distance between the first feed point 41 and the third feed point 63 is relatively large, it can meet the isolation requirements of the two antennas when the first antenna and the second antenna are working simultaneously, thereby satisfying their respective signal transmission requirements.

[0150] In addition, in the first antenna priority scenario, each tuning circuit can still be adjusted according to the above embodiments to utilize at least one of the second radiator 5 and the third radiator 6 as a parasitic radiator of the first antenna to improve the performance of the first antenna.

[0151] In a second antenna priority scenario, at least one of the first radiator 4 and the second radiator 5 can serve as a parasitic radiator for the second antenna. For example, in one possible embodiment, the first radiator 4 is coupled to the third branch of the fourth tuning circuit 10 such that the resonant frequency of the resonance generated by the first radiator 4 is higher than the resonant frequency of the resonance generated by the third radiator 6, thereby enabling the first radiator 4 to function as a parasitic radiator for the third radiator 6, thus improving the efficiency and other performance characteristics of the third radiator 6.

[0152] In another possible embodiment of this application, in the second antenna priority scenario, the second radiator 5 is disconnected from the first tuning circuit and coupled to the third branch of the second tuning circuit, so that the resonant frequency of the resonance generated by the second radiator is higher than the resonant frequency of the resonance generated by the third radiator 6, so that the second radiator 5 is used as a parasitic radiator of the third radiator 6, thereby improving the efficiency and other performance of the third radiator 6.

[0153] In other possible embodiments of this application, the first radiator 4 and the second radiator 5 may also be used as parasitic radiators. The adjustment method of the fourth tuning circuit 10 for the resonance of the first radiator 4 and the adjustment method of the first tuning circuit 7 and the second tuning circuit 8 for the resonance of the second radiator 5 can refer to the above embodiments, and will not be described in detail here.

[0154] Referring to Figure 11, which is a schematic diagram of another antenna system provided in an embodiment of this application, compared with the antenna system shown in Figure 10, the antenna system of the mobile terminal in the embodiment shown in Figure 11 further includes a slot-crossing device 11, which is coupled to the second radiator 5 and the third radiator 6. When the second radiator 5 and the third radiator 6 are coupled through the slot-crossing device 11, the second radiator 5 and the third radiator 6 are connected as the same radiator, which can be used to generate the same resonance.

[0155] In addition, when the second radiator 5 is used as a parasitic radiator for the first radiator 4 or the third radiator 6, the second radiator 5 and the third radiator 6 are disconnected through the slit device 11 so that the second radiator 5 and the third radiator 6 can work independently.

[0156] The antenna system design provided in Figure 11 enables the antenna system to meet the communication requirements in more scenarios, thus making it applicable to a wide range of scenarios.

[0157] Figure 12 is a schematic diagram of another structure of the antenna system provided in an embodiment of this application. Compared with the above embodiment, the antenna system shown in Figure 12 further includes a fourth radiator 13, a fifth tuning circuit 14, and a fifth control switch. The fourth radiator 13 includes a sixth open terminal 131 and a second ground terminal 132, with the sixth open terminal 131 and the first open terminal 42 separated by a gap. In this embodiment, the fourth radiator 13 can be used as a parasitic radiator for the first antenna and the second antenna. Its specific arrangement is similar to that of the third radiator 6. Simply put, the fourth radiator 13 is coupled to the fifth tuning circuit 14, which is used to adjust the resonance generated by the fourth radiator 13. When used as a parasitic radiator of the first antenna, the fourth radiator 13 can be coupled to the first branch of the fifth tuning circuit 14 using the fifth tuning circuit 14, so that the fourth radiator 13 and the first branch of the fifth tuning circuit 14 generate a seventh resonance. The resonant frequency of the seventh resonance is higher than or equal to the resonant frequency of the first resonance, so that the seventh resonance serves as a parasitic resonance of the first operating frequency band, which is used to improve the radiation frequency and other performance of the first operating frequency band of the first antenna.

[0158] In addition, when the fourth radiator 13 is used as a parasitic radiator of the second antenna, the fifth tuning circuit 14 can be used to modulate the resonant frequency of the resonance generated by the fourth radiator 13 to be higher than the resonant frequency of the resonance generated by the second radiator 5, so as to improve the frequency and other performance of the second antenna.

[0159] The design of other structures of the antenna system shown in Figure 12 can be referred to the above embodiments, and will not be described in detail here.

[0160] It is worth mentioning that, in other possible embodiments of this application, based on the antenna system design provided in Figure 11, a fourth radiator 13 can also be added. The design method is similar to that shown in Figure 12, and will not be described in detail here.

[0161] As described above, the mobile terminal also includes a frame, which is arranged around the circumference of the mobile terminal. Referring to Figure 13, which is a schematic diagram of a mobile terminal structure provided in an embodiment of this application, in this embodiment, the first radiator 4, the second radiator 5, and the third radiator 6 are all disposed on the frame. Therefore, both the first antenna and the second antenna are frame antennas. Thus, the design provided in this application can improve the performance of the two frame antennas while ensuring the isolation between them.

[0162] In practical applications, as shown in Figure 13, the border may include a first border 15. In the embodiment shown in Figure 13, the first radiator 4 is located on the first border 15, the second radiator 5 is located on the first border 15, and a portion of the third radiator 6 is located on the first border 15. That is, at least a portion of the first antenna's radiator and at least a portion of the second antenna's radiator are both disposed on the first border 15 to fully utilize the layout space of the first border 15.

[0163] Referring again to Figure 13, in this embodiment, the first frame 15 is the short frame of the mobile terminal. Since the long frame is the area typically held during normal use, placing at least a portion of the radiators of the first and second antennas on the short frame reduces the impact of hand grip on the performance of the first and second antennas. Furthermore, by placing the radiators of this embodiment on the short frame, the antenna design for the corresponding operating frequency band in this embodiment can be achieved.

[0164] It is understood that the short bezel of the mobile terminal includes a top bezel 15 and a bottom bezel 16. The top bezel 15 and the bottom bezel 16 are positioned opposite each other, and compared to the bottom bezel 16, the top bezel 15 is the uppermost bezel when the mobile terminal is in a vertical position and the user is in a normal grip posture. Since the top bezel 15 is usually unobstructed, in this embodiment, the first open end 42 and the second open end 43 of the first radiator 4, the third open end 52 and the fourth open end 53 of the second radiator 5, and the fifth open end 61 of the third radiator 6 can all be located on the top bezel 15. That is, the three gaps used by the first antenna and the second antenna for signal transmission are all located on the top bezel 15. This allows the top bezel to form an antenna structure with three gaps, which can effectively reduce the impact on the structural strength of the mobile terminal's bezel while meeting the isolation and performance improvement requirements of the first antenna and the second antenna. It should be understood that when the gaps are located at the corners of the bezel, it is not conducive to the structural strength and reliability of the bezel. This application embodiment can reduce the impact on the structural strength of the mobile terminal's frame while meeting the isolation requirements and radiation efficiency requirements of the first and second antennas. In one embodiment, the three gaps on the top frame are symmetrically distributed at the top edge to ensure the aesthetic appearance of the mobile terminal. In one embodiment, the middle gap (e.g., the gap formed by the second open end 43 and the third open end 52) is centrally located, and the two left and right gaps (e.g., the gap formed by the first open end 42 and the gap formed by the fourth open end 53 and the fifth open end 61) are symmetrically located about the middle gap.

[0165] In addition, the antenna's radiation advantage is significant because the top bezel 15 is not easily gripped. Therefore, placing the slots for signal transmission of both the first and second antennas on the top bezel is beneficial for optimizing the performance of both cellular and non-cellular antennas.

[0166] The above embodiments are merely exemplary descriptions of possible configurations of the antenna system for the mobile terminal provided in this application. In the various embodiments of this application, unless otherwise specified or logically conflicting, the terms and / or descriptions between different embodiments are consistent and can be referenced in each other. The technical features in different embodiments can be combined to form new embodiments based on their inherent logical relationships.

[0167] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A mobile terminal, characterized by comprising: The mobile terminal includes a first antenna, a second antenna, a first tuning circuit, and a first control switch, wherein: The first antenna includes a first radiator, and the first radiator includes a first feed point; the second antenna includes a second radiator and a third radiator, and the second radiator or the third radiator includes a second feed point; The first radiator further includes a first open terminal and a second open terminal, and the second radiator further includes a third open terminal and a fourth open terminal. The third radiator includes a fifth open terminal and a first ground terminal. The second open terminal and the third open terminal are separated by a gap, and the fourth open terminal and the fifth open terminal are separated by a gap. The first tuning circuit is coupled to the second radiator, and the distance from the coupling point of the first tuning circuit and the second radiator to the third open terminal is less than the distance to the fourth open terminal. The first control switch is used to control the second radiator to couple to the floor through a branch of the first tuning circuit.

2. The mobile terminal of claim 1, wherein, The length L3 of the third radiator satisfies the following relationship with the length L1 of the first radiator: 1 / 4 ≤ L3 / L1 ≤ 1; the length L3 of the third radiator satisfies the following relationship with the length L2 of the second radiator: 1 / 4 ≤ L3 / L2 ≤ 1.

3. The mobile terminal of claim 1 or 2, wherein The second radiator includes a second feed point. When the frequency f1 of the first radio frequency signal fed into the first radiator by the first feed point and the frequency f2 of the second radio frequency signal fed into the second radiator by the second feed point satisfy the condition that |f1-f2| / f2≤20%, the first control switch controls the second radiator to couple with the ground through the first branch of the first tuning circuit.

4. The mobile terminal as described in claim 3, characterized in that, The equivalent capacitance of the first branch of the first tuning circuit is greater than or equal to 2pF.

5. The mobile terminal as described in any one of claims 1 to 4, characterized in that, When the mobile terminal communicates using the first operating frequency band of the first antenna, the first radiator generates a first resonance, and the second radiator and the first tuning circuit generate a second resonance. The resonant frequency f20 of the second resonance is higher than the resonant frequency f10 of the first resonance, so that the second resonance is a parasitic resonance of the first operating frequency band.

6. The mobile terminal as described in claim 5, characterized in that, The resonant frequency f20 of the second resonance and the resonant frequency f10 of the first resonance satisfy the following condition: 5% × f10 ≤ f20 - f10 ≤ 30% × f10.

7. The mobile terminal as described in claim 5 or 6, characterized in that, When the mobile terminal communicates using the first operating frequency band of the first antenna, the first control switch is also used to control the second radiator to disconnect from the first tuning circuit.

8. The mobile terminal as described in any one of claims 5 to 7, characterized in that, The mobile terminal further includes a second tuning circuit and a second control switch. The second tuning circuit is coupled to the second radiator, and the distance from the coupling point of the second tuning circuit and the second radiator to the fourth open end is less than the distance to the third open end. When the mobile terminal communicates using the first antenna, the first control switch controls the second radiator to disconnect from the first tuning circuit, and the second control switch controls the second radiator to couple with the first branch of the second tuning circuit, so that the second radiator and the first branch of the second tuning circuit generate the second resonance.

9. The mobile terminal as described in claim 8, characterized in that, The equivalent capacitance of the first branch of the second tuning circuit is less than or equal to 2pF.

10. The mobile terminal as described in claim 8 or 9, characterized in that, The mobile terminal also includes a third tuning circuit and a third control switch. The third tuning circuit is coupled to the third radiator. The distance from the coupling point of the third tuning circuit and the third radiator to the fifth open terminal is less than the distance to the first ground terminal. When the mobile terminal communicates using the first antenna, the third control switch controls the third radiator to couple with the first branch of the third tuning circuit, and the third radiator and the first branch of the third tuning circuit generate a third resonance. The resonant frequency of the third resonance is higher than or equal to the resonant frequency of the first resonance, so that the third resonance is a parasitic resonance of the first operating frequency band; or the third control switch controls the third radiator to couple with the ground through the second branch of the third tuning circuit.

11. The mobile terminal as described in claim 10, characterized in that, The second radiator includes a second feed point. When the mobile terminal uses the second antenna for communication, the second radiator generates a fourth resonance. The first radiator generates a fifth resonance. The resonant frequency of the fifth resonance is higher than that of the fourth resonance, so that the fifth resonance serves as a parasitic resonance of the second operating frequency band.

12. The mobile terminal as described in claim 11, characterized in that, The mobile terminal further includes a fourth tuning circuit and a fourth control switch. The fourth tuning circuit is coupled to the first radiator, and the distance from the fourth tuning circuit to the first open end is less than the distance from the fourth tuning circuit to the second open end. When the mobile terminal communicates using the second frequency band of the second antenna, the fourth control switch controls the first radiator to couple with the first branch of the fourth tuning circuit, and the first radiator and the first branch of the fourth tuning circuit generate the fifth resonance.

13. The mobile terminal as described in any one of claims 10 to 12, characterized in that, When the mobile terminal communicates using the second operating frequency band of the second antenna, the third control switch is also used to control the coupling of the third radiator with the second branch of the third tuning circuit. The third radiator and the second branch of the third tuning circuit generate a sixth resonance. The resonant frequency of the sixth resonance is higher than the resonant frequency of the fourth resonance, so that the fourth resonance is a parasitic resonance of the second operating frequency band.

14. The mobile terminal as described in any one of claims 1 to 13, characterized in that, The mobile terminal further includes a fourth radiator, a fifth tuning circuit, and a fifth control switch. The fourth radiator includes a sixth open terminal and a second ground terminal. The sixth open terminal and the first open terminal are separated by a gap. The fifth tuning circuit is coupled to the fourth radiator, and the distance from the coupling point of the fifth tuning circuit to the fourth radiator to the sixth open terminal is less than the distance to the second ground terminal. When the mobile terminal communicates using the first operating frequency band of the first antenna, the first antenna generates a first resonance. The fifth control switch controls the coupling of the fourth radiator with the first branch of the fifth tuning circuit. The fourth radiator and the first branch of the fifth tuning circuit generate a seventh resonance. The resonant frequency of the seventh resonance is higher than or equal to the resonant frequency of the first resonance, so that the seventh resonance serves as a parasitic resonance of the first operating frequency band.

15. The mobile terminal as described in claim 1 or 2, characterized in that, The third radiator includes a second feed point, and the mobile terminal further includes a slit-crossing device. The slit-crossing device is coupled to the second radiator and the third radiator. When the second radiator and the third radiator are coupled through the slit-crossing device, the second radiator and the third radiator are used to generate the same resonance.

16. The mobile terminal according to any one of claims 1 to 15, characterized in that, The mobile terminal also includes a frame, which is arranged around the circumference of the mobile terminal; the first radiator, the second radiator and the third radiator are all disposed on the frame.

17. The mobile terminal as described in claim 16, characterized in that, The frame includes a first frame, at least a portion of the first radiator is located on the first frame, the second radiator is located on the first frame, and at least a portion of the third radiator is located on the first frame.

18. The mobile terminal as described in claim 17, characterized in that, The first border is the short border of the mobile terminal.

19. The mobile terminal as described in claim 17 or 18, characterized in that, The first border is the top border of the mobile terminal.

20. The mobile terminal as described in claim 19, characterized in that, The first open end, the second open end, the third open end, the fourth open end, and the fifth open end are all located on the top border.

Images