An antenna and a mobile terminal

Abstract

This application provides an antenna and a mobile terminal. The antenna may include the following structure: a main branch, a first parasitic branch, and / or a second parasitic branch; wherein the first and second parasitic branches are arranged on both sides of the main branch; the first and second parasitic branches are used to excite resonance to improve the efficiency of the main resonant or extend the bandwidth. In specific connection, the first parasitic branch is connected to the main branch through electric field coupling, and the frequency of the resonance excited by the first parasitic branch is greater than the resonant frequency of the main branch; the second parasitic branch is connected to the main branch through electric and magnetic field coupling, and the resonant frequency excited by the second parasitic branch is less than the resonant frequency of the main branch. In the above technical solution, by using the first and second parasitic branches to couple to the main branch through electric field coupling or electric and magnetic field coupling, resonance is excited to improve the efficiency of the antenna and extend the bandwidth, thereby improving the performance of the antenna.

Description

Technical Field

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

[0002] In the mobile phone industry, all-ceramic (or glass) exteriors are becoming the mainstream direction for mobile phone evolution. This means that the previously exposed metal frame (antenna radiator) will be recessed into the screen or battery cover. The reduced internal clearance of the phone leads to a sharp decline in antenna performance. Current antenna technologies improve performance by adding parasitic stubs, but the degree to which parasitic stubs improve antenna performance is limited. Summary of the Invention

[0003] This application provides an antenna and a mobile terminal, which aim to improve the performance of the antenna.

[0004] Firstly, an antenna is provided for use in mobile terminals, such as mobile phones, tablets, or laptops. The antenna may include the following structure: a main branch, a first parasitic branch, and / or a second parasitic branch; wherein the first and second parasitic branches are arranged on opposite sides of the main branch; the first and second parasitic branches are used to excite resonance to improve the main resonant efficiency or extend the bandwidth. In specific connection, the first parasitic branch is connected to the main branch via electric field coupling, and the frequency of the resonance excited by the first parasitic branch is greater than the excitation resonant frequency of the main branch; the second parasitic branch is connected to the main branch via electric and magnetic field coupling, and the resonant frequency excited by the second parasitic branch is less than the excitation resonant frequency of the main branch. In the above technical solution, by using the first and second parasitic branches to couple to the main branch via electric field coupling or electric and magnetic field coupling, resonance is excited to improve the antenna efficiency and extend the bandwidth, thereby improving the antenna performance.

[0005] In one specific implementation, the first parasitic branch and the second parasitic branch can be configured in different ways. For example, the antenna may include both the first and second parasitic branches; or, the antenna may include only the first parasitic branch; or, the antenna may include only the second parasitic branch.

[0006] In one specific implementation, when the antenna contains only a first parasitic stub or a second parasitic stub, the first or second parasitic stub is a parasitic stub that can be excited to produce two different modes of resonance. This improves the antenna's performance by providing different resonances.

[0007] In a specific feasible implementation, when the antenna includes a first parasitic stub and a second parasitic stub, the first and second parasitic stubs can be parasitic stubs that excite different modes of resonance. For example, both the first and second parasitic stubs can excite two different modes of resonance; or both the first and second parasitic stubs can be parasitic stubs that excite only one mode of resonance. Different parasitic stubs can improve antenna performance.

[0008] In one specific implementation, the first parasitic stub is a parasitic stub used to excite two different modes of resonance; the second parasitic stub is a parasitic stub used to excite two different modes of resonance. Exciting two different resonances through the first and second parasitic stubs improves the antenna's performance.

[0009] In one specific implementation, the resonance of the two different modes mentioned above can include: 1 / 4λ mode, 1 / 2λ mode, 3 / 4λ mode, or any two of λ; where λ is the wavelength corresponding to the operating frequency of the antenna. The performance of the antenna is improved by resonating different modes.

[0010] In one specific implementation scheme, the main branch has a first end and a second end; the first parasitic branch is connected to the first end via electric field coupling; the second parasitic branch is connected to the second end via electric field and magnetic field coupling.

[0011] The main branch is provided with a first grounding point, which is close to the second end;

[0012] The first parasitic branch is provided with a second grounding point, which is located away from the end of the first parasitic branch that is closer to the second end;

[0013] The second parasitic branch is provided with a third grounding point, which is located away from the end of the second parasitic branch and close to the first end. The electric field coupling between the first parasitic branch and the main branch, and the electric and magnetic field coupling between the second parasitic branch and the main branch are achieved through the provision of the first grounding point, the second grounding point, and the third grounding point.

[0014] In one specific implementation scheme, the main branch has a first end and a second end; the first parasitic branch is connected to the first end via electric field coupling; the second parasitic branch is connected to the second end via electric field and magnetic field coupling.

[0015] The main branch is provided with a first grounding point, which is far away from the second end;

[0016] The first parasitic branch is provided with a second grounding point, which is located away from the end of the first parasitic branch that is closer to the second end;

[0017] The second parasitic branch is provided with a third grounding point, which is located near the end of the second parasitic branch that is close to the first end. The first, second, and third grounding points enable electric field coupling between the first parasitic branch and the main branch, and electric and magnetic field coupling between the second parasitic branch and the main branch.

[0018] In one specific implementation, the second grounding point is connected to a filter circuit that passes the high-frequency group to the low-frequency group. The filter circuit enables the first parasitic stub to generate a dual-mode resonance.

[0019] In one specific implementation scheme, the main branch has a first end and a second end; the first parasitic branch is connected to the first end via electric field coupling; the second parasitic branch is connected to the second end via electric field and magnetic field coupling.

[0020] The main branch is provided with a first grounding point, which is far away from the second end;

[0021] The first parasitic branch is provided with a second grounding point, which is located away from the end of the first parasitic branch that is closer to the second end;

[0022] The second parasitic branch is provided with a third grounding point and a fourth grounding point; the third grounding point is located near the end of the second parasitic branch that is close to the first end; the fourth grounding point is located near the other end of the second parasitic branch. The first, second, third, and fourth grounding points enable electric field coupling between the first parasitic branch and the main branch, and electric and magnetic field coupling between the second parasitic branch and the main branch.

[0023] In one specific implementation, the second grounding point, the third grounding point, or the fourth grounding point can be connected to an adjustable device or a fixed-value device, respectively. The grounding connection is achieved through these different devices.

[0024] In one specific implementation scheme, the fixed-value device can be any one of fixed resistor-capacitor-inductor components, distributed inductors-capacitors, or filter circuits; the adjustable device can be any one of a switch or a variable capacitor.

[0025] In one specific implementation, the antenna includes a first parasitic stub and a second parasitic stub; the first parasitic stub is used to excite a first mode of resonance; the second parasitic stub is used to excite a second mode of resonance, wherein the first mode and the second mode can be the same or different. In this way, the antenna performance can be improved by exciting different or the same resonances through different parasitic stubs.

[0026] In one specific implementation, the resonance of one mode may include any one of: 1 / 4λ mode, 1 / 2λ mode, 3 / 4λ mode, or λ; where λ is the wavelength corresponding to the operating frequency of the antenna. The performance of the antenna is improved by resonating different modes.

[0027] In one specific implementation scheme, the main branch has a first end and a second end; the first parasitic branch is connected to the first end via electric field coupling; the second parasitic branch is connected to the second end via electric field and magnetic field coupling.

[0028] The main branch is provided with a first grounding point, which is far away from the second end;

[0029] The first parasitic branch is provided with a second grounding point, which is located away from the end of the first parasitic branch that is closer to the second end;

[0030] The second parasitic branch is provided with a third grounding point, which is located away from the end of the second parasitic branch and close to the first end. The electric field coupling between the first parasitic branch and the main branch, and the electric and magnetic field coupling between the second parasitic branch and the main branch are achieved through the provision of the first grounding point, the second grounding point, and the third grounding point.

[0031] Secondly, a mobile terminal is provided, comprising a housing and an antenna as described above disposed within the housing. In the above technical solution, by employing a first parasitic stub and a second parasitic stub coupled to the main stub via electric field coupling or electric and magnetic field coupling, resonance is excited to improve the antenna efficiency and expand the bandwidth, thereby enhancing the antenna performance.

[0032] In one specific feasible implementation, the first parasitic branch, the main branch, and the second parasitic branch can be located at any position on the housing, including but not limited to the top and bottom short sides, the left and right long sides, and the four corners where the long and short sides meet. This facilitates antenna installation.

[0033] In one specific implementation scheme, the antenna can be implemented in ways including, but not limited to, fabricating the main branch, the first parasitic branch, and the second parasitic branch using a metal frame, embedded metal, laser-formed structure, flexible circuit board, or other metal materials within a housing. The main branch, the first parasitic branch, and the second parasitic branch can be fabricated using different methods. Attached Figure Description

[0034] Figure 1 This is a schematic diagram illustrating the application scenario of the antenna provided in the embodiments of this application;

[0035] Figures 2-4 A schematic diagram illustrating the coupling between antenna stubs;

[0036] Figure 5 This is a schematic diagram of the structure of an antenna provided in an embodiment of this application;

[0037] Figure 6 This is a schematic diagram of a specific antenna structure in the prior art;

[0038] Figure 7 This is a schematic diagram of another specific antenna structure in the prior art;

[0039] Figure 8 Simulation diagrams for three types of antennas;

[0040] Figures 9a to 9f A schematic diagram of the current in different modes of the antenna provided in the embodiments of this application;

[0041] Figure 10 This is a schematic diagram illustrating the efficiency of three types of antennas;

[0042] Figure 11 This is another schematic diagram of an antenna structure provided in an embodiment of this application;

[0043] Figures 12a to 12f This is a current simulation diagram of the antenna provided in an embodiment of this application;

[0044] Figure 13 This is another schematic diagram of an antenna structure provided in an embodiment of this application;

[0045] Figures 14a-14c This is a current simulation diagram of the antenna provided in an embodiment of this application;

[0046] Figure 15 This is another schematic diagram of an antenna structure provided in an embodiment of this application;

[0047] Figures 16a-16c A schematic diagram of the antenna current provided in the embodiments of this application;

[0048] Figure 17 This is another schematic diagram of an antenna structure provided in an embodiment of this application;

[0049] Figures 18a-18c A schematic diagram of the antenna current provided in the embodiments of this application;

[0050] Figure 19 This is a schematic diagram of another antenna structure provided in an embodiment of this application;

[0051] Figure 20 This is a schematic diagram of another antenna structure provided in an embodiment of this application. Detailed Implementation

[0052] The embodiments of this application will now be described in further detail with reference to the accompanying drawings.

[0053] To facilitate understanding of the antenna provided in the embodiments of this application, its application scenarios are first described. The antenna provided in the embodiments of this application can be applied to mobile terminals, including but not limited to: mobile phones, tablets, smart wearable devices (such as wristbands or smartwatches), and other common portable communication devices. Figure 1 The diagram illustrates the structure of an antenna application in a mobile phone. The phone includes a housing 100 and a motherboard 300 disposed within the housing 100. It also includes an antenna 200 disposed within the housing 100, electrically connected to and powered by the motherboard 300. However, with the trend towards thinner mobile phones, the internal space is becoming increasingly limited, significantly impacting the performance of the antenna 200. Therefore, this application provides an antenna to improve its performance. The antenna provided in this application embodiment will be described below with reference to specific drawings and embodiments.

[0054] First, the coupling concepts involved in this application will be explained, as follows:

[0055] The main branch and parasitic branch include a near-ground end and a far-ground end, where the near-ground end has a grounding point, and the far-ground end is far from the grounding point. The main branch and parasitic branch involve the following types of coupling: such as... Figure 2 In the antenna shown, the far-ground ends of the main stub 1 and the parasitic stub 2 are adjacent and coupled, and the main stub 1 and the parasitic stub 2 are coupled through an electric field. Figure 3 In the antenna described, the near-ground ends of the parasitic branch 2 at the near-ground end of the main branch 1 are adjacent and coupled, and the main branch 1 and the parasitic branch 2 are coupled through a magnetic field. Figure 4 In the antenna shown, the near-ground end of the main branch 1 and the far-ground end of the parasitic branch 2 are adjacent and coupled, and the main branch 1 and the parasitic branch 2 are coupled through electric and magnetic fields. Alternatively, the far-ground end of the main branch 1 and the near-ground end of the parasitic branch 2 are adjacent and coupled, and the main branch 1 and the parasitic branch 2 are also coupled through electric and magnetic fields.

[0056] For ease of description, in the embodiments of this application, the end of the radiator near the grounding point is named the grounding end, and the end away from the grounding point is named the free end.

[0057] Figure 5 This diagram illustrates the structure of an antenna according to an embodiment of this application. The antenna includes a main branch 10, a first parasitic branch 20, and a second parasitic branch 30. The main branch 10 serves as the main radiating structure of the antenna, and the first parasitic branch 20 and the second parasitic branch 30 are coupled and connected to the main branch 10 to extend the bandwidth of the antenna.

[0058] The main branch 10 can be a long strip-shaped metal structure. It can be the metal frame of a mobile terminal, or an embedded metal layer, laser-formed structure, flexible circuit board, or other metal structure within the housing 100 of the mobile terminal. The two ends of the main branch 10 are a first end a and a second end b. A feed point c is located near the second end b of the main branch 10, for connection to a feed wire; a first grounding point d is located near the first end a, for connection to a grounding wire. The length (current path length) of the main branch 10 is not specifically limited in this application and can be adjusted according to the antenna's operating frequency.

[0059] The first parasitic stub 20 can be a resonant parasitic stub used to excite two different modes. For example... Figure 5 As shown, the first parasitic branch 20 can be a long strip structure. The first parasitic branch 20 can be the metal frame of a mobile terminal, or it can be an embedded metal layer, laser-formed structure, flexible circuit board, or other metal structure within the housing 100 of the mobile terminal. The first parasitic branch 20 has a third end e and a fourth end f. A second grounding point g is provided at a position away from the third end e of the first parasitic branch 20. A gap exists between the third end e of the first parasitic branch 20 and the second end b of the main branch 10. The first parasitic branch 20 and the main branch 10 are coupled together through the gap between the second end b and the third end e. Since both the second end b and the third end e are free ends, the first parasitic branch 20 and the main branch 10 can be coupled together through an electric field.

[0060] In one alternative embodiment, the end of the first parasitic branch 20 furthest from the main branch 10 has a bent structure, which may be a bent structure formed along the shape within the phone housing 100. Within the permissible space within the phone housing 100, the first parasitic branch 20 may be bent along the space within the phone housing 100 to ensure the current path length of the first parasitic branch 20.

[0061] The second parasitic stub 30 can be used to excite two different modes of resonance parasitic stub. For example... Figure 5 As shown, the second parasitic branch 30 can be a long strip structure, having a fifth end h and a sixth end i. A third grounding point j is provided on the second parasitic branch 30 at a position away from the fifth end h. There is a gap between the fifth end h of the second parasitic branch 30 and the first end a of the main branch 10. The second parasitic branch 30 and the main branch 10 are coupled together through the gap between the first end a and the fifth end h. Since the fifth end h is a free end and the first end a is a grounded end, the second parasitic branch 30 and the main branch 10 can be coupled together through electric and magnetic fields.

[0062] In one alternative embodiment, the end of the second parasitic branch 30 furthest from the main branch 10 has a bent structure, which can be a bent structure formed along the shape within the phone housing 100. Within the permissible space within the phone housing 100, the second parasitic branch 30 can be bent along the space within the phone housing 100 to ensure the current path length of the second parasitic branch 30.

[0063] In one optional scheme, the second grounding point g and the third grounding point j can be connected to adjustable devices or fixed devices, respectively. For example, the fixed device can be any one of a fixed resistor-capacitor-inductor element, a distributed inductor-capacitor, or a filter circuit; the adjustable device can be any one of a switch or a variable capacitor. Either of the above devices can be selectively connected to the second grounding point g and the third grounding point j to adjust the current path length of the first parasitic stub 20 and the second parasitic stub 30. In specific connections, different devices can be selected: the second grounding point g can be connected to a fixed device, and the third grounding point j can be connected to a fixed device; or, the second grounding point g can be connected to an adjustable device, and the third grounding point j can be connected to an adjustable device; or, the second grounding point g can be connected to an adjustable device, and the third grounding point j can be connected to a fixed device, etc., etc.

[0064] To facilitate understanding of the differences between the antenna performance provided in this application and antennas in the prior art, simulations are performed on antennas in the prior art and antennas provided in this application. For example... Figure 6 and Figure 7 As shown, Figure 6 This illustrates a specific antenna structure in the prior art. Figure 6 The antenna shown only includes the main stub 1. For ease of description, it will be... Figure 6 The antenna shown is called Case 1; Figure 7 The antenna shown includes a main branch 1 and a first parasitic branch 2, and the main branch 1 and the first parasitic branch 2 are coupled together by electric field coupling. For ease of description, [the following is a simplified description:] Figure 7 The antenna shown is called Case 2. This application Figure 5 The antenna shown is called Case 3.

[0065] Please refer to the above. Figure 8 , Figure 8Simulation diagrams for three antennas are shown. In Case 1, the main stub can excite two resonant modes: the first resonant mode is the main stub's 1 / 4 mode, and the second resonant mode is the main stub's 1 / 2 mode. Case 2 can be seen as adding a first parasitic stub in the upper right corner to Case 1. When Case 2 is working, in addition to the main stub's 1 / 2 mode and 1 / 4 mode, it also excites two new resonant modes through the first parasitic stub: the common-mode mode and the differential-mode mode of the first parasitic stub, achieving improved efficiency and bandwidth compared to Case 1. The antenna provided in this application embodiment, in addition to the main stub and the first parasitic stub, may also include a second parasitic stub coupled to the main stub through electric and magnetic fields. In this embodiment, two resonant modes can be excited by the main branch, two resonant modes can be excited by the first parasitic branch, and two more resonant modes can be excited by the second parasitic branch: the common mode and the differential mode of the second parasitic branch. This can further improve the efficiency of the main resonant mode and the bandwidth expansion, and achieve full-band coverage of N3, N1, N41 and N77.

[0066] Please refer to the above. Figures 9a to 9f , Figures 9a to 9f The following is a schematic diagram illustrating the current of six modes of the antenna provided in the embodiments of this application.

[0067] First refer to Figure 9a Current flows from the fifth terminal h and the sixth terminal i of the second parasitic stub 30 to the third grounding point j, and this current excites the common-mode of the second parasitic stub 30. (See also...) Figure 8 The common-mode resonance excited by the second parasitic branch 30 is located at 1.6 GHz.

[0068] refer to Figure 9b Current flows from the second end b of the main branch 10 to the first grounding point d, and this current excites the main branch 10 to produce a 1 / 4 mode. (See also...) Figure 8 The resonant of the 1 / 4 mode excited by the circuit on the main branch 10 is located at 1.7 GHz.

[0069] refer to Figure 9c Current flows from the fourth terminal f of the first parasitic stub 20 to the second grounding point g, and simultaneously from the third terminal e to the second grounding point g. This current excites the common-mode of the first parasitic stub 20. (See also...) Figure 8 The common-mode resonance excited by the first parasitic branch 20 is located at 1.95 GHz.

[0070] refer to Figure 9d Current flows from the fifth terminal h of the second parasitic stub 30 to the sixth terminal i, and simultaneously from the third grounding point j to the sixth terminal i. This current excites the differential mode of the second parasitic stub 30. (See also...) Figure 8The differential mode excited by the second parasitic stub 30 resonates at 2.35 GHz.

[0071] refer to Figure 9e Current flows from the third terminal e of the first parasitic stub 20 to the fourth terminal f, and simultaneously, current flows from the second grounding point g to the fourth terminal f. This current excites the differential mode of the first parasitic stub 20. (See also...) Figure 8 The resonance of the differential mode excited by the first parasitic stub 20 is located at 2.55 GHz.

[0072] refer to Figure 9f Current flows from the first end a of the main branch 10 to the second end b and the first grounding point d. Simultaneously, current flows from the feed point c to the second end b. This current excites the main branch 10 to achieve a 1 / 2 mode. (See also...) Figure 8 The resonant of the 1 / 2 mode excited by the circuit on the main branch 10 is located at 3.3 GHz.

[0073] Referring to the above Figures 9a-9e as well as Figure 8 It can be seen that when using the first parasitic stub 20 and the second parasitic stub 30, the main stub 10 can be excited to produce two resonant modes; the first parasitic stub 20 can be excited to produce two resonants, and the frequency of the resonant excited by the first parasitic stub 20 is greater than the resonant frequency of the main stub 10; the second parasitic stub 30 can be excited to produce two resonants, and the resonant frequency of the second parasitic stub 30 is less than the resonant frequency of the main stub 10. By exciting two different resonants with the first parasitic stub 20 and the second parasitic stub 30, the performance of the antenna can be improved, and the main resonant efficiency and bandwidth can be further improved, achieving full-band coverage of N3, N1, N41, and N77.

[0074] To facilitate understanding of the above Figure 6 and Figure 7 The antenna shown is compared with the antenna of this application in terms of their performance. Simulation results are as follows: Figure 10 As shown, the solid line represents the system efficiency, and the dashed line represents the radiation efficiency. (From...) Figure 10 It can be seen that the system efficiency and radiation efficiency of cases 1 and 2 are both lower than those of case 3 provided in the embodiments of this application in the region between 1.5 and 2.2 GHz.

[0075] Figure 11 A schematic diagram of another antenna structure provided in an embodiment of this application is shown. The antenna includes a main branch 10, a first parasitic branch 20, and a second parasitic branch 30. The main branch 10 serves as the main radiating structure of the antenna, and the first parasitic branch 20 and the second parasitic branch 30 are respectively coupled and connected to the main branch 10 to extend the bandwidth of the antenna.

[0076] The main branch 10 can be a long strip of metal structure. It can be the metal frame of a mobile terminal, or an embedded metal layer, laser-formed structure, flexible circuit board, or other metal structure within the housing 100 of the mobile terminal. The two ends of the main branch 10 are a first end a and a second end b. A feed point c is located near the second end b of the main branch 10, for connection to a feed wire; a first grounding point d is located near the first end a, for connection to a grounding wire. The length (current path length) of the main branch 10 is not specifically limited in this application and can be adjusted according to the antenna's operating frequency.

[0077] In an alternative embodiment, the main branch 10 extends to the edge of the phone housing 100 and has a bending structure to ensure the current path length of the main branch 10.

[0078] The first parasitic stub 20 is a resonant parasitic stub used to excite two different modes. For example... Figure 11 As shown, the first parasitic branch 20 can be a metal frame of the mobile terminal, or it can be an embedded metal layer, laser-formed structure, flexible circuit board, or other metal structure within the housing 100 of the mobile terminal. The first parasitic branch 20 can be a long strip structure, having a third end e and a fourth end f. The first parasitic branch 20 has two grounding points, a second grounding point g and a fifth grounding point l. The second grounding point g is located away from the third end e of the first parasitic branch 20, and the fifth grounding point l is located on the side of the first parasitic branch 20 closer to the fourth end f. The second grounding point g is the short-circuit point of the first parasitic branch 20 when operating at high frequency, and the fifth grounding point l is the short-circuit point of the first parasitic branch 20 when operating at low frequency. There is a gap between the third end e of the first parasitic branch 20 and the second end b of the main branch 10. The first parasitic branch 20 and the main branch 10 are coupled together through the gap between the second end b and the third end e. Since both the second end b and the third end e are free ends, the first parasitic branch 20 and the main branch 10 can be coupled through an electric field.

[0079] The second parasitic stub 30 is a resonant parasitic stub that can be used to excite two different modes. For example... Figure 11As shown, the second parasitic branch 30 can be a metal frame of the mobile terminal, or it can be an embedded metal layer, laser-formed structure, flexible circuit board, or other metal structure within the housing 100 of the mobile terminal. The second parasitic branch 30 can be a long strip structure, having a fifth end h and a sixth end i. The second parasitic branch 30 has two grounding points, namely a third grounding point j and a fourth grounding point k. The third grounding point j is located near the fifth end h of the second parasitic branch 30, and the fourth grounding point k is located on the side of the second parasitic branch 30 near the sixth end i. The third grounding point j is the short-circuit point of the second parasitic branch 30 when operating at high frequency, and the fourth grounding point k is the short-circuit point of the second parasitic branch 30 when operating at low frequency. There is a gap between the fifth end h of the second parasitic branch 30 and the first end a of the main branch 10. The second parasitic branch 30 and the main branch 10 can be coupled together through the gap between the first end a and the fifth end h. Since the fifth end h is a free end and the first end a is a grounded end, the second parasitic branch 30 and the main branch 10 can be coupled through electric and magnetic fields.

[0080] In one alternative embodiment, the end of the second parasitic branch 30 furthest from the main branch 10 has a bent structure, which is a bent structure formed along the shape inside the phone housing 100. Within the permissible space inside the phone housing 100, the second parasitic branch 30 can be bent along the space inside the phone housing 100 to ensure the current path length of the second parasitic branch 30.

[0081] In one alternative embodiment, adjustable or fixed-value devices can be connected between the second grounding point g, the third grounding point j, the fifth grounding point l, and the fourth grounding point k, respectively. For example, the fixed-value device can be any one of a fixed resistive-capacitive-inductive element, a distributed inductor-capacitor, or a filter circuit; the adjustable device can be any one of a switch or a variable capacitor. The second grounding point g, the third grounding point j, the fifth grounding point l, and the fourth grounding point k can be selectively connected to any of the aforementioned devices to adjust the current path length of the first parasitic stub 20 and the second parasitic stub 30.

[0082] Please refer to the above. Figures 12a to 12f , Figures 12a to 12f The diagram shows a current simulation of the antenna.

[0083] First refer to Figure 12a Current flows from the sixth terminal i to the fifth terminal h of the second parasitic stub 30, exciting a quarter-mode of the second parasitic stub 30. The resonance of the quarter-mode excited by the second parasitic stub 30 is located at 0.89 GHz.

[0084] refer to Figure 12bCurrent flows from the second end b to the first end a of the main branch 10, and this current excites a 1 / 4 mode of the main branch 10. The resonance of the 1 / 4 mode excited by the circuit on the main branch 10 is located at 0.93 GHz.

[0085] refer to Figure 12c A current flows from the third terminal e to the fourth terminal f of the first parasitic stub 20, exciting a 1 / 4 mode of the first parasitic stub 20. The resonance of the 1 / 4 mode excited by the first parasitic stub 20 is located at 1.01 GHz.

[0086] refer to Figure 12d The current flows from the fourth grounding point k of the second parasitic stub 30 to the fifth terminal h. This current excites the 3 / 4 mode of the second parasitic stub 30, and the resonance of the 3 / 4 mode excited by the second parasitic stub 30 is located at 2.6 GHz.

[0087] refer to Figure 12e Current flows from the main branch 10 to the first end a and the second end b, respectively. This current excites the 3 / 4 mode of the main branch 10, and the resonance of the 3 / 4 mode excited by the main branch 10 is located at 2.7 GHz.

[0088] refer to Figure 12f The current flows from the third end e of the first parasitic stub 20 to the middle, and at the same time, it flows from the fifth grounding point l to the middle. This current excites the 3 / 4 mode of the first parasitic stub 20, and the resonance of the 3 / 4 mode excited by the first parasitic stub 20 is located at 2.75 GHz.

[0089] Referring to the above Figures 12a-12e It can be seen that when the first parasitic branch 20 and the second parasitic branch 30 are used, the main branch 10 can be excited to produce two resonant modes; the first parasitic branch 20 can be excited to produce two resonants, and the resonant frequency excited by the first parasitic branch 20 is greater than the resonant frequency of the main branch 10; the second parasitic branch 30 can be excited to produce two resonants, and the resonant frequency excited by the second parasitic branch 30 is less than the resonant frequency of the main branch 10.

[0090] As can be seen from the above, when the first parasitic branch 20 and the second parasitic branch 30 provided in the embodiments of this application are working, the resonance of the above two different modes may include: 1 / 4λ mode, 1 / 2λ mode, 3 / 4λ mode or any two of λ; where λ is the wavelength corresponding to the operating frequency of the antenna.

[0091] The first parasitic stub 20's 1 / 4 mode, following the main stub 10's 1 / 4 mode, enhances the efficiency of the original low-frequency resonance; the first parasitic stub 20's 3 / 4 mode, following the main stub 10's 3 / 4 mode, enhances the efficiency of the original high-frequency resonance. The second parasitic stub 30's 1 / 4 mode, preceding the main stub 10's 1 / 4 mode, further enhances the low-frequency efficiency and bandwidth; the second parasitic stub 30's 3 / 4 mode, preceding the main stub 10's 3 / 4 mode, further enhances the high-frequency efficiency and bandwidth. This further improves the antenna's performance.

[0092] Figure 13 A schematic diagram of another antenna structure provided in an embodiment of this application is shown. Figure 13 For the same labels, please refer to Figure 11 The same label in the text. Figure 13 The antenna in is Figure 11 One variation of the antenna shown. Figure 13 The antenna shown is Figure 11 The difference in the antenna shown is that a filter circuit 40 for passing high frequencies and low frequencies is connected to the second grounding point g. The filter circuit 40 enables the first parasitic stub 20 to generate dual-mode resonance. When the second grounding point g of the first parasitic stub 20 is replaced with a high-pass, low-impedance filter circuit 40, the effect of exciting dual-resonance modes can be achieved. However, one of the parasitic modes of the first parasitic stub 20 is changed from the original 3 / 4 mode of the first parasitic stub 20 to the 1 / 4 filter mode of the second grounding point g returning to ground.

[0093] refer to Figures 14a-14c The current distribution of each branch on the antenna when using high frequencies. For example... Figure 14a As shown, current flows from the fourth grounding point k of the second parasitic stub 30 to point A, and current also flows from the fifth terminal h of the second parasitic stub 30 to point A, where the electric field strength is strongest. This current excites a 3 / 4 mode of the second parasitic stub 30. The resonance of the 3 / 4 mode excited by the second parasitic stub 30 is located at 2.6 GHz. Figure 14b As shown, current flows from point B of the main stub 10 to the first end a and the second end b, with point B being the point of strongest electric field. This current excites a 3 / 4 mode of the second parasitic stub 30, and the resonance of the 3 / 4 mode excited by the main stub 10 is located at 2.7 GHz. Figure 14c As shown, current flows from the third terminal e of the first parasitic stub 20 to the first ground point d, and this current excites a 1 / 4 mode of the first parasitic stub 20. The resonance of the 1 / 4 mode excited by the first parasitic stub 20 is located at 2.8 GHz.

[0094] Figure 13 The low-frequency resonances excited by the various stubs of the antenna shown can be referenced. Figure 11 The relevant description in [the text]. Figures 14a-14c Only the resonance in the high-frequency band is shown as an example.

[0095] Figure 15 A schematic diagram of another antenna structure provided in an embodiment of this application is shown. The antenna includes a main branch 10, a first parasitic branch 20, and a second parasitic branch 30. The main branch 10 serves as the main radiating structure of the antenna, and the first parasitic branch 20 and the second parasitic branch 30 are respectively coupled and connected to the main branch 10 to extend the bandwidth of the antenna.

[0096] The main branch 10 can be a long strip of metal structure. It can be the metal frame of a mobile terminal, or an embedded metal layer, laser-formed structure, flexible circuit board, or other metal structure within the housing 100 of the mobile terminal. The two ends of the main branch 10 are a first end a and a second end b. A feed point c is located near the second end b of the main branch 10, for connection to a feed line; a first grounding point d is located near the first end a, away from the second end b, for connection to a grounding line. The length (current path length) of the main branch 10 is not specifically limited in this application and can be adjusted according to the antenna's operating frequency.

[0097] The first parasitic stub 20 is a resonant parasitic stub used to excite the first mode. For example... Figure 15 As shown, the first parasitic branch 20 can be a long strip structure, such as the metal frame of a mobile terminal, or it can be an embedded metal layer, laser-formed structure, flexible circuit board, or other metal structure within the housing 100 of the mobile terminal. The first parasitic branch 20 has a third end e and a fourth end f. A second grounding point g is provided at a position away from the third end e of the first parasitic branch 20. A gap is spaced between the third end e of the first parasitic branch 20 and the second end b of the main branch 10. The first parasitic branch 20 and the main branch 10 are coupled together through the gap between the second end b and the third end e. Since both the second end b and the third end e are free ends, the first parasitic branch 20 and the main branch 10 can be coupled together through an electric field.

[0098] In one alternative embodiment, the end of the first parasitic branch 20 furthest from the main branch 10 has a bent structure, which may be a bent structure formed along the shape within the phone housing 100. Within the permissible space within the phone housing 100, the first parasitic branch 20 may be bent along the space within the phone housing 100 to ensure the current path length of the first parasitic branch 20.

[0099] The second parasitic stub 30 is a resonant parasitic stub that can be used to excite the second mode. For example... Figure 15As shown, the second parasitic branch 30 can be a long strip structure, having a fifth end h and a sixth end i. A third grounding point j is provided on the second parasitic branch 30 away from the fifth end h, that is, the third grounding point j is located away from the end of the second parasitic branch 30 closest to the first end a. There is a gap between the fifth end h of the second parasitic branch 30 and the first end a of the main branch 10. The second parasitic branch 30 and the main branch 10 are coupled together through the gap between the first end a and the fifth end h. Since the fifth end h is a free end and the first end a is a grounded end, the second parasitic branch 30 and the main branch 10 are coupled through electric and magnetic fields.

[0100] In one alternative embodiment, the end of the second parasitic branch 30 furthest from the main branch 10 has a bent structure, which is a bent structure formed along the shape inside the phone housing 100. Within the permissible space inside the phone housing 100, the second parasitic branch 30 can be bent along the space inside the phone housing 100 to ensure the current path length of the second parasitic branch 30.

[0101] In one optional scheme, adjustable devices or fixed-value devices can be connected between the second ground point g and the third ground point j, respectively. For example, the fixed-value device can be any one of a fixed resistive-capacitive-inductive element, a distributed inductor-capacitor, or a filter circuit; the adjustable device can be any one of a switch or a variable capacitor. Either of these devices can be selectively connected between the second ground point g and the third ground point j to adjust the current path length of the first parasitic stub 20 and the second parasitic stub 30. In specific connections, different devices can be selected: the second ground point g can be connected to a fixed-value device, and the third ground point j can be connected to a fixed-value device; or, the second ground point g can be connected to an adjustable device, and the third ground point j can be connected to an adjustable device; or, the second ground point g can be connected to an adjustable device, and the third ground point j can be connected to a fixed-value device, etc. In one optional scheme, a selection switch can also be provided between the second ground point g and the third ground point j to select different fixed-value devices or adjustable devices. This allows for switching as needed to improve the antenna bandwidth.

[0102] The resonances of the first and second modes can be the same or different. The following explanation uses the example of their difference.

[0103] Please refer to the above. Figures 16a-16c , Figures 16a-16c A schematic diagram of the current of the antenna provided in an embodiment of this application is shown.

[0104] First refer to Figure 16aCurrent flows from the fifth terminal h of the second parasitic stub 30 to the third grounding point j, and this current excites the half-mode of the second parasitic stub 30. The resonance of the half-mode excited by the second parasitic stub 30 is located at 1.6 GHz.

[0105] refer to Figure 16b Current flows from the first end a to the second end b of the main stub 10, and this current excites a 1 / 4 mode of the main stub 10. The resonance of the 1 / 4 mode excited by the circuit on the main stub 10 is located at 1.75 GHz.

[0106] refer to Figure 16c Current flows from the fourth terminal f of the first parasitic stub 20 to the third terminal e, and this current excites a 1 / 4 mode of the first parasitic stub 20. The resonance of the 1 / 4 mode excited by the first parasitic stub 20 is located at 2.0 GHz.

[0107] As described above, by exciting a 1 / 4 mode through the main stub 10 and then exciting a 1 / 2 mode (with a 1pF small capacitor at the end connected to ground) after the main mode, the in-band efficiency can be improved from -4.9 to -2.4, while the 5mm body SAR efficiency decreases from 1.96 to 1.44. Furthermore, by exciting a 1 / 2 mode through the second parasitic stub 30 and placing it before the 1 / 4 mode of the main stub 10 (with a 3pF small capacitor at the end connected to ground), the in-band efficiency can be further improved from -2.4 to -1.5, while the 5mm body SAR efficiency decreases from 1.44 to 0.76. This improves both the antenna bandwidth and efficiency.

[0108] In one alternative scheme, in Figure 15 Based on the antenna, the fixed capacitors 3pF and 1pF are replaced with adjustable devices such as switches SW1 and SW2, which can realize the switching of the two parasitic 1 / 2 modes in the entire frequency band below Sub6G.

[0109] Figure 17 A schematic diagram of another antenna structure provided in an embodiment of this application is shown. The antenna includes a main branch 10, a first parasitic branch 20, and a second parasitic branch 30. The main branch 10 serves as the main radiating structure of the antenna, and the first parasitic branch 20 and the second parasitic branch 30 are respectively coupled and connected to the main branch 10 to extend the bandwidth of the antenna.

[0110] The main branch 10 is a long strip-shaped metal structure, which can be the metal frame of a mobile terminal, or an embedded metal layer, laser-formed structure, flexible circuit board, or other metal structure within the housing 100 of the mobile terminal. The two ends of the main branch 10 are a first end a and a second end b. A feed point c is located near the second end b of the main branch 10, and feed point c is used to connect to the feed line; a first grounding point d is located near the first end a, away from the second end b, and is used to connect to the grounding line. The length (current path length) of the main branch 10 is not specifically limited in this application, and the specific length of the main branch 10 can be adjusted according to the operating frequency of the antenna.

[0111] The first parasitic stub 20 is a parasitic stub used to excite the resonance of the first mode. For example... Figure 17 As shown, the first parasitic branch 20 is a long strip structure, which can be the metal frame of the mobile terminal, or an embedded metal layer, laser-formed structure, flexible circuit board, or other metal structure within the housing 100 of the mobile terminal. The first parasitic branch 20 has a third end e and a fourth end f. A second grounding point g is provided at a position away from the third end e of the first parasitic branch 20. A gap exists between the third end e of the first parasitic branch 20 and the second end b of the main branch 10. The first parasitic branch 20 and the main branch 10 are coupled together through the gap between the second end b and the third end e. Since both the second end b and the third end e are free ends, the first parasitic branch 20 and the main branch 10 are coupled together through an electric field.

[0112] The second parasitic stub 30 is a parasitic stub used to excite the resonance of the second mode. For example... Figure 15 As shown, the second parasitic segment 30 is an elongated structure with a fifth end h and a sixth end i. A third grounding point j is located on the second parasitic segment 30 away from the fifth end h, i.e., the third grounding point j is located away from the end of the second parasitic segment 30 closest to the first end a. There is a gap between the fifth end h of the second parasitic segment 30 and the first end a of the main segment 10. The second parasitic segment 30 and the main segment 10 are coupled together through the gap between the first end a and the fifth end h. Since the fifth end h is a free end and the first end a is a grounded end, the second parasitic segment 30 and the main segment 10 are coupled through electric and magnetic fields.

[0113] In one optional scheme, the second grounding point g and the third grounding point j can be connected to adjustable devices or fixed devices, respectively. For example, the fixed device can be any one of a fixed resistor-capacitor-inductor element, a distributed inductor-capacitor, or a filter circuit; the adjustable device can be any one of a switch or a variable capacitor. Either of the above devices can be selectively connected to the second grounding point g and the third grounding point j to adjust the current path length of the first parasitic stub 20 and the second parasitic stub 30. In specific connections, different devices can be selected: the second grounding point g can be connected to a fixed device, and the third grounding point j can be connected to a fixed device; or, the second grounding point g can be connected to an adjustable device, and the third grounding point j can be connected to an adjustable device; or, the second grounding point g can be connected to an adjustable device, and the third grounding point j can be connected to a fixed device, etc., etc.

[0114] In an alternative scheme, the second grounding point g and the third grounding point j can also be equipped with a selection switch, which allows selection of different fixed-value or adjustable devices. This enables switching as needed and improves the antenna bandwidth.

[0115] The resonances of the first and second modes can be the same or different. The following explanation uses the example of their difference.

[0116] Please refer to the above. Figures 18a-18c , Figures 18a-18c A schematic diagram of the current of the antenna provided in an embodiment of this application is shown.

[0117] First refer to Figure 18a Current flows from the fifth terminal h to the sixth terminal i of the second parasitic stub 30, exciting a quarter-mode of the second parasitic stub 30. The resonance of the quarter-mode excited by the second parasitic stub 30 is located at 1.65 GHz.

[0118] refer to Figure 18b Current flows from the first grounding point d of the main branch 10 to the second end b, and this current excites the 1 / 4 mode of the main branch 10. The resonance of the 1 / 4 mode excited by the circuit on the main branch 10 is located at 1.75 GHz.

[0119] refer to Figure 18c Current flows from the second grounding point g of the first parasitic stub 20 to the third terminal e, and this current excites a 1 / 4 mode of the first parasitic stub 20. The resonance of the 1 / 4 mode excited by the first parasitic stub 20 is located at 2.0 GHz.

[0120] As can be seen from the above description, by exciting a 1 / 4 mode through the main branch 10, exciting a 1 / 4 mode through the first parasitic branch 20, and exciting a 1 / 2 mode through the second parasitic branch 30, and placing it in the 1 / 4 mode of the main branch 10, the radiation efficiency of both the front and back halves of the main resonance (the resonance excited by the main branch 10) is improved.

[0121] Figure 19 A schematic diagram of another antenna structure provided in an embodiment of this application is shown. Figure 19 The antenna shown includes a first parasitic stub 20 and a main stub 10. The main stub 10 serves as the main radiating structure of the antenna, and the first parasitic stub 20 is coupled to the main stub 10 to extend the bandwidth of the antenna.

[0122] The main branch 10 is a long strip-shaped metal structure, which can be the metal frame of a mobile terminal, or an embedded metal layer, laser-formed structure, flexible circuit board, or other metal structure within the housing 100 of the mobile terminal. The two ends of the main branch 10 are a first end a and a second end b. A feed point c is located near the second end b of the main branch 10, for connection to a feed line; a first grounding point d is located near the first end a, for connection to a grounding line. The length (current path length) of the main branch 10 is not specifically limited in this application, and its specific length can be adjusted according to the antenna's operating frequency.

[0123] The first parasitic stub 20 is a parasitic stub used to excite two different modes of resonance. For example... Figure 5 As shown, the first parasitic branch 20 is a long strip structure, which can be the metal frame of the mobile terminal, or an embedded metal layer, laser-formed structure, flexible circuit board, or other metal structure within the housing 100 of the mobile terminal. The first parasitic branch 20 has a third end e and a fourth end f. A second grounding point g is provided at a position away from the third end e of the first parasitic branch 20. A gap exists between the third end e of the first parasitic branch 20 and the second end b of the main branch 10. The first parasitic branch 20 and the main branch 10 are coupled together through the gap between the second end b and the third end e. Since both the second end b and the third end e are free ends, the first parasitic branch 20 and the main branch 10 are coupled together through an electric field.

[0124] In one alternative embodiment, the end of the first parasitic branch 20 furthest from the main branch 10 has a bent structure, which is a bent structure formed along the shape inside the phone housing 100. Within the permissible space inside the phone housing 100, the first parasitic branch 20 can be bent along the space inside the phone housing 100 to ensure the current path length of the first parasitic branch 20.

[0125] In one alternative, the two second grounding points g can be connected to adjustable devices or fixed devices respectively. For example, the fixed device can be any one of fixed resistor-capacitor-inductor components, distributed inductors-capacitors, or filter circuits; the adjustable device can be a switch or a variable capacitor.

[0126] Figure 20 A schematic diagram of another antenna structure provided in an embodiment of this application is shown. Figure 19 The antenna shown includes a second parasitic stub 30 and a main stub 10. The main stub 10 serves as the main radiating structure of the antenna, and the second parasitic stub 30 is coupled to the main stub 10 to extend the antenna's bandwidth.

[0127] The main branch 10 is a long strip-shaped metal structure, which can be the metal frame of a mobile terminal, or an embedded metal layer, laser-formed structure, flexible circuit board, or other metal structure within the housing 100 of the mobile terminal. The two ends of the main branch 10 are a first end a and a second end b. A feed point c is located near the second end b of the main branch 10, for connection to a feed line; a first grounding point d is located near the first end a, for connection to a grounding line. The length (current path length) of the main branch 10 is not specifically limited in this application, and its specific length can be adjusted according to the antenna's operating frequency.

[0128] The second parasitic stub 30 is a parasitic stub used to excite two different modes of resonance. For example... Figure 5 As shown, the second parasitic segment 30 is an elongated structure with a fifth end h and a sixth end i. A third grounding point j is located on the second parasitic segment 30 away from the fifth end h. A gap exists between the fifth end h of the second parasitic segment 30 and the first end a of the main segment 10. The second parasitic segment 30 and the main segment 10 are coupled together through the gap between the first end a and the fifth end h. Since the fifth end h is a free end and the first end a is a grounding end, the second parasitic segment 30 and the main segment 10 are coupled through electric and magnetic fields.

[0129] In one alternative embodiment, the end of the second parasitic branch 30 furthest from the main branch 10 has a bent structure, which is a bent structure formed along the shape inside the phone housing 100. Within the permissible space inside the phone housing 100, the second parasitic branch 30 can be bent along the space inside the phone housing 100 to ensure the current path length of the second parasitic branch 30.

[0130] In one alternative, the first grounding point d and the third grounding point j can be connected to an adjustable device or a fixed device, respectively. For example, the fixed device can be any one of a fixed resistor-capacitor-inductor element, a distributed inductor-capacitor, or a filter circuit; the adjustable device can be a switch or a variable capacitor.

[0131] exist Figure 19 and Figure 20 In the antenna shown, although it contains only one parasitic stub (either the first parasitic stub 20 or the second parasitic stub 30), the first parasitic stub 20 is capable of generating two different modes of resonance, and the second parasitic stub 30 is also capable of generating two different modes of resonance. In the above technical solution, by using the first parasitic stub 20 and the second parasitic stub 30 to be coupled to the main stub 10 through electric field coupling or electric and magnetic field coupling, resonance is generated to improve the antenna efficiency and expand the bandwidth, thereby enhancing the antenna performance.

[0132] This application embodiment also provides a mobile terminal, which includes a housing 100 and an antenna as described above disposed within the housing 100. In the above technical solution, by employing electric field coupling or electric and magnetic field coupling between the first parasitic stub 20 and the second parasitic stub 30 and the main stub 10, resonance is excited to improve the antenna efficiency and expand the bandwidth, thereby enhancing the antenna performance.

[0133] In a specific feasible implementation, the first parasitic branch 20, the main branch 10, and the second parasitic branch 30 can be disposed at any position on the housing 100, including but not limited to the upper and lower short sides, the left and right long sides, and the four corners where the long and short sides meet. This facilitates antenna placement. The aforementioned upper and lower short sides can refer to the edges near the earpiece and microphone of the mobile phone, respectively. The left and right long sides are the other two sides adjacent to the upper and lower short sides. In the illustrations of the embodiments of this application, although only the placement of the antenna on the upper short side of the housing 100 is shown, the above illustration is merely an example illustrating the antenna structure. The antenna provided in the embodiments of this application can also be disposed on the lower short side, the left and right long sides, or the corners where the long and short sides meet on the housing 100.

[0134] In one specific implementation scheme, the antenna can be implemented in ways including but not limited to fabricating the main branch 10, the first parasitic branch 20, and the second parasitic branch 30 using a metal frame, embedded metal, laser-formed structure, flexible circuit board, or other metal materials within the housing 100. These materials are commonly used as radiators in mobile phones and will not be described in detail here.

[0135] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A mobile terminal, characterized in that, It includes a frame and an antenna, the antenna including a main branch, a first parasitic branch, and a second parasitic branch; The first parasitic segment, the main segment, and the second parasitic segment extend sequentially in the extension direction of the border; The main branch includes a first end and a second end. The main branch is provided with a first grounding point. The first grounding point is closer to the first end relative to the second end. The first end is the grounding end, and the second end is the free end. The first parasitic segment and the second parasitic segment are located on both sides of the main segment; The first parasitic segment includes a third end and a fourth end, and the second parasitic segment includes a fifth end and a sixth end; the first parasitic segment is coupled to the main segment through a first gap between the second end and the third end; the second parasitic segment is coupled to the main segment through a second gap between the first end and the fifth end; wherein, the third end and the fifth end are free ends; The first parasitic branch is provided with a second grounding point; The second parasitic branch is provided with a third grounding point; Wherein, the resonant frequency excited by the first parasitic branch through the first gap coupling is greater than the resonant frequency excited by the main branch; and the resonant frequency excited by the second parasitic branch through the second gap coupling is less than the resonant frequency excited by the main branch.

2. The mobile terminal as described in claim 1, characterized in that, The resonant frequency excited by the first parasitic branch through the first gap is the resonant frequency of the first 1 / 4 mode. The resonant frequency excited by the second parasitic branch through the second gap is the resonant frequency of the second 1 / 4 mode.

3. A mobile terminal, characterized in that, It includes a frame and an antenna, the antenna including a main branch, a first parasitic branch, and a second parasitic branch; The first parasitic segment, the main segment, and the second parasitic segment extend sequentially in the extension direction of the border; The main branch includes a first end and a second end. The main branch is provided with a first grounding point. The first grounding point is closer to the first end relative to the second end. The first end is the grounding end, and the second end is the free end. The first parasitic segment and the second parasitic segment are located on both sides of the main segment; The first parasitic segment includes a third end, and the second parasitic segment includes a fifth end; the first parasitic segment is coupled to the main segment through a first gap between the second end and the third end; the second parasitic segment is coupled to the main segment through a second gap between the first end and the fifth end; wherein the third end and the fifth end are free ends; The first parasitic branch is excited to generate a first 1 / 4 mode through the first gap coupling; The second parasitic branch is excited to generate a second 1 / 4 mode through the second gap coupling; The resonant frequency of the first 1 / 4 mode excited by the first parasitic branch is greater than the resonant frequency excited by the main branch; and the resonant frequency of the second 1 / 4 mode excited by the second parasitic branch is less than the resonant frequency excited by the main branch.

4. The mobile terminal as described in any one of claims 1 to 3, characterized in that, The first parasitic stub is a resonant parasitic stub used to excite two different modes; or The second parasitic stub is a resonant parasitic stub used to excite two different modes.

5. The mobile terminal as described in claim 4, characterized in that, The two different modes of resonance include: 1 / 4λ mode, 1 / 2λ mode, 3 / 4λ mode, or any two of λ; where λ is the wavelength corresponding to the operating frequency of the antenna.

6. The mobile terminal as described in claim 1 or 2, characterized in that, The second grounding point is closer to the fourth terminal than the third terminal; The third grounding point is closer to the sixth terminal than the fifth terminal.

7. The mobile terminal as described in claim 6, characterized in that, The fourth and sixth terminals are grounding terminals.

8. The mobile terminal as described in claim 1 or 2, characterized in that, The second grounding point is connected to a filter circuit that allows high frequencies to pass while blocking low frequencies.

9. The mobile terminal as described in claim 1 or 2, characterized in that, The second parasitic branch is also provided with a fourth grounding point; the fourth grounding point is far away from the sixth end relative to the fifth end.

10. The mobile terminal as described in claim 9, characterized in that, The second grounding point, the third grounding point, or the fourth grounding point are respectively connected to an adjustable device or a fixed value device.

11. The mobile terminal as described in claim 10, characterized in that, The fixed-value device is any one of a fixed resistive element, a fixed capacitive element, a fixed inductive element, a distributed inductor, a distributed capacitor, and a filter circuit. The adjustable device is either a switch or a variable capacitor.

12. The mobile terminal as described in any one of claims 1 to 3, characterized in that, The main branch, the first parasitic branch, and the second parasitic branch are elongated metal structures.

13. The mobile terminal as described in claim 12, characterized in that, It also includes a housing, wherein the main branch, the first parasitic branch and the second parasitic branch are at least one of the following: the metal frame of the mobile terminal, an embedded metal layer within the housing, a laser-formed structure, a flexible circuit board structure, or other metal structures within the housing.

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