Antenna system and terminal equipment

Abstract

The invention provides an antenna system and terminal equipment, which can be applied to the technical field of communication. The antenna system comprises a metal frame and an equivalent filter circuit. At least one antenna area is arranged in the metal frame, a first antenna branch knot and a second antenna branch knot are arranged in the antenna area, and a coupling gap is formed between the first antenna branch knot and the second antenna branch knot; the first antenna branch knot is provided with a first feeding point, and the second antenna branch knot is provided with a second feeding point; the equivalent filter circuit is arranged at the coupling gap, the first end of the equivalent filter circuit is connected with the metal frame, and the second end of the equivalent filter circuit is grounded; the equivalent filter circuit comprises a first inductor and an adjustable capacitor module which are connected in parallel, and the adjustable capacitor module is configured to be capable of dynamically regulating and controlling the self capacitance value. According to the invention, the problem of mutual interference isolation of a breakpoint-free metal frame antenna in medium and high frequency bands is effectively solved, and meanwhile, low-frequency switching coverage of an antenna system can be realized, so that the problem of narrow low-frequency bandwidth of the antenna is solved.

Description

Technical Field

[0001] This application relates to the field of communication technology, and in particular to an antenna system and terminal equipment. Background Technology

[0002] A metal frame antenna is a device that uses the metal frame of a terminal device (such as a smartphone or tablet) as a radiator, converting the metal frame portion into an electromagnetic wave transmitting and receiving unit.

[0003] Existing metal frame antenna designs typically require multiple parallel, discontinuous slots to be created on the metal frame. These discontinuous slots serve as antenna radiators, and the slots isolate the different metal frame segments to prevent coupling interference between the antennas. However, this approach impacts the appearance, structural strength, and cost of the terminal device. Therefore, discontinuous metal frame antennas have emerged.

[0004] However, existing unbroken metal frame antennas suffer from narrow low-frequency bandwidth, which affects the communication quality of the antenna system. Summary of the Invention

[0005] This application provides an antenna system and terminal device to solve the technical problem of narrow low-frequency bandwidth when existing terminal devices use metal frame antenna solutions.

[0006] According to the first aspect disclosed in this application, this application provides an antenna system including a metal frame and an equivalent filter circuit;

[0007] At least one antenna region is provided within the metal frame. A first antenna stub and a second antenna stub are provided within the antenna region. A coupling gap is provided between the first antenna stub and the second antenna stub. The first antenna stub is provided with a first feed point, which is used to receive a first radio frequency signal. The second antenna stub is provided with a second feed point, which is used to receive a second radio frequency signal.

[0008] The equivalent filter circuit is disposed at the coupling gap, the first end of the equivalent filter circuit is connected to the metal frame, and the second end of the equivalent filter circuit is grounded; the equivalent filter circuit includes a first inductor and an adjustable capacitor module connected in parallel, and the adjustable capacitor module is configured to dynamically adjust its own capacitance value.

[0009] In one feasible implementation, the adjustable capacitor module includes a switching circuit and a capacitor bank, wherein the capacitor bank includes a plurality of capacitors with different capacitance values.

[0010] The first terminal of each capacitor in the capacitor bank is connected to the first terminal of the equivalent filter circuit, and the second terminal of each capacitor in the capacitor bank is connected to the first terminal of the switching circuit. The second terminal of the switching circuit is connected to the second terminal of the equivalent filter circuit.

[0011] The switching circuit is configured to control the second terminal of one of the capacitors to be connected to the second terminal of the equivalent filter circuit, and to control the second terminal of the remaining capacitors to be disconnected from the second terminal of the equivalent filter circuit.

[0012] In one feasible implementation, the switching circuit includes a single-pole multi-throw switch, each throw terminal of the single-pole multi-throw switch is connected to the second terminal of the corresponding capacitor, and the common terminal of the single-pole multi-throw switch is connected to the second terminal of the equivalent filter circuit.

[0013] In one feasible implementation, the switching circuit includes a plurality of single-pole single-throw switches, the throw terminal of each single-pole single-throw switch being connected to the second terminal of a corresponding capacitor, and the common terminal of each single-pole single-throw switch being connected to the second terminal of the equivalent filter circuit.

[0014] In one feasible implementation, the first end of the equivalent filter circuit is connected to the first end of the second inductor, and the second end of the second inductor is connected to the metal frame.

[0015] In one feasible implementation, the metal frame is provided with a first grounding point and a second grounding point, and an antenna region is formed between the metal frame, the first grounding point and the second grounding point.

[0016] In one feasible implementation, the first antenna stub is connected to a first end of a third inductor, and the second end of the third inductor is grounded.

[0017] In one feasible implementation, the second terminal of the equivalent filter circuit is connected to the ground plane of the motherboard PCB.

[0018] According to the second aspect disclosed in this application, this application provides a terminal device including an antenna system as described in any one of the first aspects.

[0019] In one feasible implementation, the terminal device further includes a metal back cover, which has a partial slit or a partial slot at a position corresponding to the antenna area of ​​the antenna system.

[0020] Compared with the prior art, this application has the following advantages:

[0021] This application provides an antenna system and terminal device that, by setting an equivalent filter circuit in the antenna region, utilizes the equivalent filter to electrically isolate the radiation space between the metal frame antennas, thereby improving the isolation between the metal frame antennas and blocking coupling interference between them. This effectively solves the problem of mutual interference isolation between metal frame antennas in the mid-to-high frequency bands without needing to create multiple parallel discontinuous gaps in the metal frame. Simultaneously, the capacitive characteristics of the adjustable capacitor module in the equivalent filter circuit can be utilized to achieve low-frequency band switching of the antenna system by adjusting the capacitance value of the adjustable capacitor module. This solves the problem of narrow low-frequency bandwidth in existing antennas, achieving switching coverage of the low-frequency bandwidth and improving the performance of the antenna system. Attached Figure Description

[0022] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0023] Figure 1 This is a schematic diagram of the structure of an antenna system provided in an embodiment of this application;

[0024] Figure 2 A schematic diagram illustrating the decoupling effect of an equivalent filter circuit provided in an embodiment of this application;

[0025] Figure 3 This is a schematic diagram of an equivalent filter circuit provided in an embodiment of this application;

[0026] Figure 4 for Figure 3 The equivalent LC parallel filter circuit of the intermediate efficiency filter circuit;

[0027] Figure 5 A schematic diagram of the equivalent filtering S-parameters of an equivalent filtering circuit provided in an embodiment of this application;

[0028] Figure 6 This is a schematic diagram of another equivalent filter circuit provided in an embodiment of this application;

[0029] Figure 7 for Figure 6 The equivalent LC series-parallel filter circuit of the intermediate efficiency filter circuit;

[0030] Figure 8 A current laminar flow diagram of a metal frame provided in an embodiment of this application;

[0031] Figure 9 A schematic diagram of the S-parameters of an antenna system when switching different capacitance values ​​in an adjustable capacitor module in an equivalent filter circuit provided in this application embodiment;

[0032] Figure 10This is a schematic diagram of the structure of an adjustable capacitor module provided in an embodiment of this application;

[0033] Figure 11 This is a schematic diagram of a switching circuit provided in an embodiment of this application;

[0034] Figure 12 This is a schematic diagram of another switching circuit provided in an embodiment of this application;

[0035] Figure 13 This is a schematic diagram of a metal back cover structure for a terminal device provided in an embodiment of this application;

[0036] Figure 14 A schematic diagram of the metal back cover structure of another terminal device provided in this application embodiment;

[0037] Figure 15 This is a schematic diagram of the metal back cover structure of another terminal device provided in an embodiment of this application.

[0038] Explanation of reference numerals in the attached figures:

[0039] 100 - First antenna stub;

[0040] 101 - First feed point;

[0041] 102 - Third Inductor;

[0042] 200-Metal frame;

[0043] 201 - First grounding point;

[0044] 202 - First Antenna;

[0045] 203 - Second Line;

[0046] 204 - Second grounding point;

[0047] 300 - Second day branch;

[0048] 301 - Second feed point;

[0049] 400-equivalent filter circuit;

[0050] 401 - Adjustable capacitor module;

[0051] 402 - First Inductor;

[0052] 403 - Second Inductor;

[0053] 404 - Switching Circuit;

[0054] 405 - Capacitor Bank;

[0055] 406 - Single-pole multi-throw switch;

[0056] 407 - Single-pole single-throw switch;

[0057] 500 - Motherboard PCB;

[0058] 600-antenna area;

[0059] 601 - Area 1;

[0060] 602 - Second Zone;

[0061] 700 - Metal back cover.

[0062] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0063] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0064] With the rapid development of communication technology, users have placed higher demands on the performance of mobile communication systems, not only pursuing higher communication speeds, greater capacity, and lower latency, but also expecting smaller and more portable mobile devices. Against this backdrop, to meet these needs, fifth-generation (5G) mobile communication systems have emerged, deploying sub-6GHz (Sub-6GHz) frequency band multiple-input multiple-output (MIMO) antennas in terminal devices such as mobile phones and tablets. MIMO technology, by using multiple isolated transmit and receive antennas to construct multiple independent data streams, can thus multiply the capacity of the communication system without increasing bandwidth or transmit power.

[0065] However, with the widespread adoption of full-screen and curved-screen designs in terminal devices, the space occupied by the screen is shrinking, making antenna placement difficult and significantly reducing efficiency. While metal-framed antennas are currently used to address the increased antenna demand and reduced clearance, the number of antennas that can be installed within a metal frame is limited. To meet communication requirements, it's necessary to add numerous additional antennas inside the terminal device besides the metal-framed antennas. This not only affects antenna performance but also increases production costs. Especially with metal back covers or those containing printed circuitry, antennas inside the terminal can be covered, completely losing their radiation performance.

[0066] Furthermore, existing metal frame antenna designs typically require multiple parallel, segmented slots to be created on the metal frame. These segmented sections serve as antenna radiators, and the slots isolate the different metal frame segments to prevent coupling interference between the antennas. However, this approach has several drawbacks. From an aesthetic perspective, creating these slots disrupts the metal frame's appearance and overall integrity, resulting in a less consistent and visually appealing product. From a structural strength perspective, the metal frame's strength decreases significantly after multiple cuts, reducing its durability. From a cost perspective, the cutting and injection molding processes involved in creating the metal frame increase manufacturing costs.

[0067] To address this, seamless metal frame antennas were developed. However, existing seamless metal frame antennas suffer from narrow low-frequency bandwidth, which affects the communication quality of the antenna system.

[0068] To address the aforementioned technical problems, this application proposes an antenna system and terminal device. While effectively solving the mutual interference isolation problem of uninterrupted metal frame antennas in the mid-to-high frequency bands by utilizing an equivalent filter circuit, it can also achieve low-frequency band switching of the antenna system by adjusting the capacitance value of the adjustable capacitor module, thereby solving the problem of narrow low-frequency bandwidth of the antenna, realizing low-frequency bandwidth switching coverage, and significantly improving the radiation performance and communication quality of the antenna system.

[0069] The technical solutions of the antenna system and terminal equipment provided in this application will be described in detail below through specific embodiments. It should be noted that the following embodiments may exist independently or in combination with each other, and the same or similar content may not be described again in different embodiments.

[0070] Figure 1 This is a schematic diagram of an antenna system provided in an embodiment of this application. (See attached diagram.) Figure 1In some embodiments, the antenna system includes a metal frame 200 and an equivalent filter circuit 400; at least one antenna region 600 is disposed within the metal frame 200, and a first antenna stub 100 and a second antenna stub 300 are disposed within the antenna region 600, with a coupling gap between the first antenna stub 100 and the second antenna stub 300; the first antenna stub 100 is provided with a first feed point 101 for receiving a first radio frequency signal; the second antenna stub 300 is provided with a second feed point 301 for receiving a second radio frequency signal; the equivalent filter circuit 400 is disposed at the coupling gap, with a first end of the equivalent filter circuit 400 connected to the metal frame 200 and a second end of the equivalent filter circuit 400 grounded; the equivalent filter circuit 400 includes a first inductor 402 connected in parallel and an adjustable capacitor module 401 configured to dynamically adjust its own capacitance value.

[0071] In this embodiment, when a first radio frequency (RF) signal is fed to the first antenna stub 100 through the first feed point 101, and a second RF signal is fed to the second antenna stub 300 through the second feed point 301, the alternating current carried by the RF signal flows along the antenna stub. Due to the instantaneous change in current, the charge distribution on the antenna stub also changes continuously, generating a changing electromagnetic field in the space around the antenna stub. The electromagnetic field generated by the first antenna stub 100 is then used to excite the metal frame 200 of the antenna region 600, thereby exciting the metal frame 200 to generate a first resonant mode operating in the first frequency band, thus forming the first antenna 202; and the electromagnetic field generated by the second antenna stub 300 is used to excite the metal frame 200 of the antenna region 600, thereby exciting the metal frame 200 to generate a second resonant mode operating in the second frequency band, thus forming the second antenna 203.

[0072] To improve the communication quality of antennas, in multi-antenna systems, the operating frequency bands of the antennas cover low, mid, and high frequency bands as well as the 5G frequency band. For example, the first antenna 202 may operate in low and mid-high frequency bands, while the second antenna 203 may operate in mid-high frequency bands and the 5G frequency band. Therefore, the operating frequency bands of multiple antennas generally overlap in the mid-high frequency band. When the distance between the first antenna 202 and the second antenna 203 is small, electromagnetic coupling may occur between the antennas in the mid-high frequency band, causing antenna signal distortion or interference. To avoid coupling interference between antennas, this application sets an equivalent filter circuit 400 in the antenna region 600. This equivalent filter circuit 400 isolates the radiation space between the first antenna 202 and the second antenna 203 in the mid-high frequency band, thus eliminating the need to create multiple parallel discontinuous gaps on the metal frame 200. This effectively solves the problem of mutual interference isolation between antennas in the mid-high frequency band within the metal frame 200, significantly improving the radiation performance and communication quality of the antenna system. For details on the decoupling effect of the equivalent filter circuit 400, please refer to [link to relevant documentation]. Figure 2 As shown.

[0073] For details, please refer to Figure 3 Since the equivalent filter circuit 400 is composed of a parallel adjustable capacitor module 401 and a first inductor 402, the first inductor 402 and the adjustable capacitor module 401 form an equivalent filter circuit. Figure 4 In an LC parallel resonant circuit, when an AC RF signal passes through it, the inductor L and capacitor C will produce different responses to different signal frequencies. When the signal frequency is low, the LC parallel resonant circuit is equivalent to a large inductor, exhibiting an open-circuit blocking effect; when the signal frequency is high, the LC parallel resonant circuit is equivalent to a small capacitor, exhibiting a short-circuit conducting effect. Its function can be combined with... Figure 5 Understanding the equivalent filter S-parameters.

[0074] See Figure 5 Where S11 represents the input port reflection coefficient, which reflects the return loss of the signal at the input end. In the filter, S11 close to 0 means that the total internal reflection energy is completely reflected to the input port, and no energy is transferred from the input port to the output port. This situation is similar to an open circuit in the equivalent circuit. S21 represents the forward transmission coefficient, which characterizes the gain or attenuation of the signal from the input to the output. S21 close to 0 means that the energy is completely transferred from the input port to the output port, similar to a short circuit in the equivalent circuit.

[0075] Therefore, when the first frequency band in which the first antenna 202 operates is low frequency, the equivalent filter circuit 400 is in an open-circuit blocking state, and the first antenna 202 will use the entire antenna region 600 as its radiation space so that the length of the metal frame 200 meets the requirements of the low-frequency operating wavelength of the first antenna 202. When the first frequency band in which the first antenna 202 operates is mid-high frequency, and the second frequency band in which the second antenna 203 operates is also mid-high frequency, the equivalent filter circuit 400 is in a short-circuit conducting state. At this time, the equivalent filter circuit 400 divides the antenna region 600 into a first region 601 and a second region 602, and uses the first region 601 as the radiation space of the first antenna 202 and the second region 602 as the radiation space of the second antenna 203.

[0076] By isolating the radiation spaces of the first antenna 202 and the second antenna 203, the mid-to-high frequency operating wavelength of the first antenna 202 is limited to the length of the metal frame 200 in the first region 601, and the mid-to-high frequency operating wavelength of the second antenna 203 is limited to the length of the metal frame 200 in the second region 602. This improves the isolation between the first antenna 202 and the second antenna 203 and blocks coupling interference between them. Compared to traditional discontinuous metal frame 200 antenna solutions, this application eliminates the need for multiple parallel discontinuous gaps on the metal frame 200, avoiding the increased costs associated with in-mold injection molding or complex structures, thus reducing the processing cost of the metal frame 200. Furthermore, the discontinuous metal frame 200 of this application does not affect the integrity of the metal frame 200, maintaining its aesthetics and overall appearance, avoiding the problem of inconsistent terminal device appearance, improving product aesthetics and structural strength, and enhancing user experience.

[0077] Meanwhile, the equivalent filter circuit 400 enables the second region 602 to serve as both the low-frequency radiation space of the first antenna 202 and the mid-to-high frequency and 5G frequency band radiation space of the second antenna 203, thus realizing the spatial reuse of the second region 602 and improving the spatial utilization of the antenna region 600.

[0078] See Figure 6 Optionally, the first end of the equivalent filter circuit 400 is connected to the first end of the second inductor 403, and the second end of the second inductor 403 is connected to the metal frame 200.

[0079] In this circuit, a second inductor 403 is added to the equivalent filter circuit 400. At this point, the first inductor 402, the adjustable capacitor module 401, and the second inductor 403 constitute an equivalent filter circuit. Figure 7 The LC series-parallel filter circuit, composed of inductor L, inductor L1 and capacitor C, has both series and parallel resonance characteristics. Through flexible impedance matching and frequency selection capabilities, it can achieve more accurate signal processing in a wider frequency band, while enhancing circuit stability.

[0080] Furthermore, since the reactance of a capacitor is inversely proportional to frequency, the antenna itself is capacitive in the low-frequency range. Adding a capacitor further enhances the antenna's capacitiveness, increasing its equivalent electrical length. This effectively lengthens the current path, thus lowering the antenna's resonant frequency and shifting its operating frequency band towards lower frequencies. For details, please refer to [link to relevant documentation]. Figure 8 It can be seen that in Figure 8 In (a), the length of the metal frame 200 satisfies the ground state mode operating at 1.23 GHz. Figure 8In (b), by loading a capacitor with a capacitance of 0.2pF onto the metal frame 200, the metal frame 200 can operate at 0.88GHz, which is equivalent to the capacitor loading increasing the electrical length of the antenna and shifting the operating frequency to a lower frequency.

[0081] Therefore, while solving the isolation problem between the first antenna 202 and the second antenna 203 through the equivalent filter circuit 400, the capacitive characteristics of the adjustable capacitor module 401 in the equivalent filter circuit 400 can also be utilized. By adjusting the capacitance value of the adjustable capacitor module 401, the low-frequency band switching of the antenna system can be achieved, thereby solving the problem of narrow low-frequency bandwidth in existing antennas and achieving switching coverage of the low-frequency bandwidth to improve the performance of the antenna system. Specifically, when the capacitance value of the adjustable capacitor module 401 in the equivalent filter circuit 400 is changed, the S-parameters of the antenna system are as follows: Figure 9 As shown.

[0082] Specifically, terminal devices operate on different channels in the low-frequency range, such as B28 (703-803MHz), B5 (824-894MHz), and B8 (880-960MHz), as well as other channels. To meet the transmission and reception performance requirements of the entire link, the antenna system needs to cover these frequency bands. When the antenna system cannot fully cover the entire low-frequency band, the capacitance value of the adjustable capacitor module 401 is adjusted to switch the low-frequency bandwidth coverage range of the antenna system. The capacitance value switching logic of the adjustable capacitor module 401 is mainly determined by the RF link operating mechanism. The antenna system only needs to cover the operating frequency band; the low-frequency range of 700-960MHz can be covered by switching between different channels. For example, switching the three different capacitance values ​​of the adjustable capacitor module 401 can cover B28 (703-803MHz), B5 (824-894MHz), and B8 (880-960MHz) respectively.

[0083] For example, when the terminal device is actually making a call, the capacitance value of the adjustable capacitor module 401 can be switched according to the signal strength of the environment in which the terminal device is located, so as to switch different channels.

[0084] In addition to switching the capacitance value of the adjustable capacitor module 401 to achieve low-frequency band switching of the antenna system, the first inductor 402 can also be designed as an adjustable inductor module with a switchable inductance value. By switching the inductance value of the first inductor 402, the low-frequency band switching of the antenna system can also be achieved, thereby realizing the switching coverage of the antenna system in the low-frequency bandwidth.

[0085] Specifically, the reactance characteristics of an inductor are positively correlated with frequency. When different inductance values ​​are applied to an antenna, the effective inductance of the antenna changes, thereby adjusting its resonant frequency. For example, increasing the inductance value increases the effective inductance of the stubs. In the low-frequency band, the antenna, which was originally capacitive, is compensated for by the introduction of inductance, bringing the antenna closer to a resonant state and thus lowering the resonant frequency, allowing the antenna to cover even lower frequency bands. Conversely, decreasing the inductance value decreases the effective inductance of the stubs, increasing the resonant frequency, and shifting the frequency band covered by the antenna accordingly. Therefore, by switching components with different inductance values ​​connected to the antenna, its resonant frequency can be changed, enabling the antenna system to switch between low-frequency bands.

[0086] Specifically, the process of switching the inductance value of the first inductor 402 is similar to the process of switching the capacitance value of the adjustable capacitor module 401, so it will not be described in detail here.

[0087] See Figure 1 Optionally, the first antenna stub 100 is connected to the first end of the third inductor 102, and the second end of the third inductor 102 is grounded.

[0088] The function of connecting one end of the first antenna stub 100 to the third inductor 102 is to form a series resonant circuit between the third inductor 102 and the first antenna stub 100. The inductive reactance of the third inductor 102 is used to offset the capacitive reactance of the first antenna stub 100 in a specific frequency band (or adjust the impedance phase), thereby optimizing the input impedance of the antenna and making it closer to the matching impedance (e.g., ohms) required by the transceiver. This reduces signal reflection loss and improves the radiation efficiency and bandwidth performance of the antenna in the target frequency band. It is especially suitable for compensating for antenna matching accuracy in low-frequency bands or space-constrained scenarios.

[0089] Specifically, the second end of the third inductor 102 is connected to the ground plane of the motherboard PCB 500 to ground the second end of the third inductor 102.

[0090] Optionally, the second terminal of the equivalent filter circuit 400 is connected to the ground plane of the motherboard PCB 500.

[0091] The ground plane of the motherboard PCB500 is a continuous conductive area embedded inside the printed circuit board (PCB) or set on a specific layer. It serves as the reference zero potential reference point for the entire circuit system, providing a stable grounding loop for various electronic components and ensuring the reference consistency of signal transmission.

[0092] Optionally, the first antenna stub 100 is an IFA antenna, and the second antenna stub 300 is a monopole antenna.

[0093] Among them, the first antenna stub 100 is an IFA (inverted-F antenna), which is an antenna that achieves miniaturization and high-efficiency radiation through an inverted F-shaped structure; the second antenna stub 300 is a monopole antenna, which is an omnidirectional radiating antenna composed of a single vertical conductor and a ground plane.

[0094] Specifically, the electrical length of the first antenna stub 100 is one-quarter of the wavelength of its operating frequency.

[0095] Specifically, the electrical length of the second antenna stub 300 is half the wavelength of its operating frequency.

[0096] By setting the electrical lengths of the first antenna stub 100 and the second antenna stub 300, the antenna system can achieve multi-band coverage by utilizing the characteristic that different electrical lengths correspond to different resonant frequencies, and optimize the impedance matching and radiation efficiency of the antenna, thereby improving communication performance.

[0097] See Figure 10 In some embodiments, the adjustable capacitor module 401 includes a switching circuit 404 and a capacitor group 405. The capacitor group 405 includes multiple capacitors with different capacitance values. The first terminal of each capacitor in the capacitor group 405 is connected to the first terminal of the equivalent filter circuit 400, and the second terminal of each capacitor in the capacitor group 405 is connected to the first terminal of the switching circuit 404. The second terminal of the switching circuit 404 is connected to the second terminal of the equivalent filter circuit 400. The switching circuit 404 is configured to control the second terminal of one of the capacitors to be connected to the second terminal of the equivalent filter circuit 400, and to control the second terminals of the remaining capacitors to be disconnected from the second terminal of the equivalent filter circuit 400.

[0098] In this embodiment, the capacitor bank 405 includes multiple capacitors with different capacitance values ​​connected in parallel. When the switching circuit 404 switches to one capacitor being turned on, the remaining capacitors are turned off, thereby adjusting the capacitance value of the adjustable capacitor bank 401 by switching the conduction of different capacitors.

[0099] See Figure 11 Optionally, the switching circuit 404 includes a single-pole multi-throw switch 406, each throw terminal of the single-pole multi-throw switch 406 is connected to the second terminal of the corresponding capacitor, and the common terminal of the single-pole multi-throw switch 406 is connected to the second terminal of the equivalent filter circuit 400.

[0100] Among them, the single-pole multi-throw switch 406 can realize the switching of multiple capacitors with a single switch, reducing the number of switches in the equipment and simplifying the circuit design.

[0101] See Figure 12Optionally, the switching circuit 404 includes multiple single-pole single-throw switches 407, the throw terminal of each single-pole single-throw switch 407 is connected to the second terminal of the corresponding capacitor, and the common terminal of each single-pole single-throw switch 407 is connected to the second terminal of the equivalent filter circuit 400.

[0102] Among them, the single-pole single-throw switch 407 has only two states: on and off. It has a simple mechanical structure, low failure rate, and each single-pole single-throw switch 407 independently controls a single capacitor, which can increase the reliability of the circuit.

[0103] See Figure 1 In some embodiments, the metal frame 200 is provided with a first grounding point 201 and a second grounding point 204, and an antenna region 600 is formed between the metal frame 200, the first grounding point 201 and the second grounding point 204.

[0104] In this embodiment, the area enclosed by the metal frame 200 and the grounding point serves as the antenna region 600 of the antenna stub. The antenna region 600 can limit the propagation direction of electromagnetic waves, reduce back radiation (i.e., energy radiated into the device), thereby enhancing forward gain (energy radiated to the outside of the device), which can significantly improve the radiation efficiency of a specific frequency band.

[0105] Optionally, the distance between the first grounding point 201 and the second grounding point 204 is 110mm-160mm.

[0106] Among them, the antenna region 600 needs to meet the electrical length of the antenna radiation, that is, the length from the first ground point 201 to the second ground point 204 needs to meet at least half the wavelength of the antenna radiation frequency. Since the minimum operating frequency of the antenna system is between 700MHz and 960MHz, the length of the metal frame 200 between the first ground point 201 and the second ground point 204 is at least 110mm.

[0107] Optionally, the first grounding point 201 and the second grounding point 204 are connected to the ground plane of the motherboard PCB 500.

[0108] In some embodiments, this application also provides a terminal device including the antenna system described above.

[0109] In this embodiment, the problem of mutual interference isolation of the metal frame 200 antenna in the low, medium and high frequency bands is effectively solved by using the equivalent filter circuit 400, which significantly improves the radiation performance and communication quality of the antenna system. Therefore, it is not necessary to open multiple parallel break gaps on the metal frame 200, which reduces the processing cost of the metal frame 200, maintains the aesthetics and structural strength of the metal frame 200, and improves the user experience.

[0110] Specifically, terminal devices such as mobile phones, tablets, and smartwatches can bring greater benefits in product forms with limited antenna space due to their seamless metal frame.

[0111] Optionally, the terminal device also includes a metal back cover 700, which has a partial slit or slot at a position corresponding to the antenna area 600 of the antenna system.

[0112] The seamless metal frame 200 and the metal back cover 700 can have partial openings, see reference. Figure 13 The form of the seamless metal frame 200 and the metal back cover 700 can be partially hollowed out; see reference [link / reference]. Figure 14 The form of the seamless metal frame 200 and the metal back cover 700 can also be completely hollowed out; see [reference needed]. Figure 15 The space required for the antenna is formed by connecting the frame to the motherboard ground and the frame to the screen ground. The antenna area 600 can be formed by connecting the frame and the ground layer, which has strong applicability.

[0113] In addition, there can be multiple sets of grounding points, and the antenna area 600 of multiple sets of metal frame 200 antennas can be defined by the grounding points. The length of the antenna area 600 is determined by the length of the metal frame 200 within the area.

[0114] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0115] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0116] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0117] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0118] In the above embodiments, the descriptions of each embodiment have their own emphasis. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments. The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification.

[0119] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this application are indicated by the appended claims.

[0120] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. An antenna system, characterized in that, Includes a metal frame and an equivalent filter circuit; At least one antenna region is provided within the metal frame. A first antenna stub and a second antenna stub are provided within the antenna region. A coupling gap is provided between the first antenna stub and the second antenna stub. The first antenna stub is provided with a first feed point, which is used to receive a first radio frequency signal. The second antenna stub is provided with a second feed point, which is used to receive a second radio frequency signal. The equivalent filter circuit is disposed at the coupling gap, the first end of the equivalent filter circuit is connected to the metal frame, and the second end of the equivalent filter circuit is grounded; the equivalent filter circuit includes a first inductor and an adjustable capacitor module connected in parallel, and the adjustable capacitor module is configured to dynamically adjust its own capacitance value.

2. The antenna system according to claim 1, characterized in that, The adjustable capacitor module includes a switching circuit and a capacitor bank, wherein the capacitor bank includes multiple capacitors with different capacitance values. The first terminal of each capacitor in the capacitor bank is connected to the first terminal of the equivalent filter circuit, and the second terminal of each capacitor in the capacitor bank is connected to the first terminal of the switching circuit. The second terminal of the switching circuit is connected to the second terminal of the equivalent filter circuit. The switching circuit is configured to control the second terminal of one of the capacitors to be connected to the second terminal of the equivalent filter circuit, and to control the second terminal of the remaining capacitors to be disconnected from the second terminal of the equivalent filter circuit.

3. The antenna system according to claim 2, characterized in that, The switching circuit includes a single-pole multi-throw switch, each throw terminal of the single-pole multi-throw switch is connected to the second terminal of the corresponding capacitor, and the common terminal of the single-pole multi-throw switch is connected to the second terminal of the equivalent filter circuit.

4. The antenna system according to claim 2, characterized in that, The switching circuit includes multiple single-pole single-throw switches. The throw terminal of each single-pole single-throw switch is connected to the second terminal of the corresponding capacitor, and the common terminal of each single-pole single-throw switch is connected to the second terminal of the equivalent filter circuit.

5. The antenna system according to claim 1, characterized in that, The first end of the equivalent filter circuit is connected to the first end of the second inductor, and the second end of the second inductor is connected to the metal frame.

6. The antenna system according to any one of claims 1-5, characterized in that, The metal frame is provided with a first grounding point and a second grounding point, and an antenna region is formed between the metal frame, the first grounding point and the second grounding point.

7. The antenna system according to any one of claims 1-5, characterized in that, The first antenna stub is connected to the first end of the third inductor, and the second end of the third inductor is grounded.

8. The antenna system according to any one of claims 1-5, characterized in that, The second terminal of the equivalent filter circuit is connected to the ground plane of the motherboard PCB.

9. A terminal device, characterized in that, Including the antenna system as described in any one of claims 1-8.

10. The terminal device according to claim 9, characterized in that, The terminal device also includes a metal back cover, which has a partial slit or a partial slot at a position corresponding to the antenna area of ​​the antenna system.

Images