CN115117597A

CN115117597A - Antenna structure and terminal equipment

Info

Publication number: CN115117597A
Application number: CN202110285309.XA
Authority: CN
Inventors: 陈鹏宇
Original assignee: Beijing Xiaomi Mobile Software Co Ltd
Current assignee: Beijing Xiaomi Mobile Software Co Ltd
Priority date: 2021-03-17
Filing date: 2021-03-17
Publication date: 2022-09-27
Anticipated expiration: 2041-03-17
Also published as: CN115117597B

Abstract

The present disclosure relates to an antenna structure and a terminal device, wherein the antenna structure includes: the first resonant branch, the first matching circuit, the second resonant branch and the second matching circuit; the first resonant branch is connected with a feed port of a terminal device PCB through the first matching circuit, the second resonant branch is connected with the feed port through the second matching circuit, and a preset gap is formed between the first resonant branch and the second resonant branch; the first resonant branch section resonates at least two antenna signal frequency bands through the first matching circuit, and the second resonant branch section resonates at least one antenna signal frequency band through the second matching circuit. The antenna structure realizes the connection of the two antenna branches by one feed port, thereby effectively avoiding the problem of poor isolation caused by multiple feed ports on a PCB and further ensuring the receiving and transmitting performance of the antenna.

Description

Antenna structure and terminal equipment

Technical Field

The present disclosure relates to the field of communications, and in particular, to an antenna structure and a terminal device.

Background

The antenna is an indispensable structure for realizing communication functions of terminal equipment such as a mobile phone, and along with the development of wireless networks and 5G technologies, the antenna of the mobile phone needs to support multiple communication frequency bands.

In the related art, in order to meet the increasing communication demand, a method of transmitting and receiving signals by using a plurality of antennas is generally adopted. While the multiple antennas usually adopt a dual-feed or multi-feed manner to implement frequency band matching, that is, two or more feed ports need to be arranged on the PCB. The increase of the feed ports on the PCB board easily causes the problem of poor isolation between the feed ports, thereby affecting the transceiving performance between adjacent antennas.

Disclosure of Invention

To overcome the problems in the related art, the present disclosure provides an antenna structure and a terminal device.

According to a first aspect of the embodiments of the present disclosure, there is provided an antenna structure, including: the first resonant branch, the first matching circuit, the second resonant branch and the second matching circuit;

the first resonance branch is connected with a feed port of a terminal device PCB through the first matching circuit, the second resonance branch is connected with the feed port through the second matching circuit, and a preset gap is formed between the first resonance branch and the second resonance branch;

the first resonant branch section resonates at least two antenna signal frequency bands through the first matching circuit, and the second resonant branch section resonates at least one antenna signal frequency band through the second matching circuit.

Optionally, the first resonant branch at least resonates an L1 frequency band of the GPS and a 2.4G frequency band of the WIFI.

Optionally, the second resonant branch at least resonates an L5 frequency band of the GPS.

Optionally, one end of each of the first resonant branch and the second resonant branch, which is far away from the preset gap, is grounded;

the first resonance branch comprises a first radiation part close to the preset gap, and the second resonance branch comprises a parasitic part close to the preset gap; the parasitic portion is coupled with the first radiating portion to resonate at least one antenna signal band.

Optionally, the parasitic part is coupled with the first radiating part to resonate a 6E frequency band of WIFI.

Optionally, a first feeding point is disposed on the first resonant branch, and the first radiating portion is located between the first feeding point and the preset gap; and a second feeding point is arranged on the second resonance branch node, and the parasitic part is positioned between the second feeding point and the preset gap.

Optionally, the length of the first radiating part and/or the parasitic part is 1mm-3 mm.

Optionally, the first matching circuit comprises: the first resonant branch node is connected with a first end of the first main circuit through a first feeding point, and a second end of the first main circuit is connected with the feeding port;

a first grounding branch, a first parallel branch, a second capacitor, a second grounding branch and a second inductor are arranged between the first end and the second end of the first main circuit; the first parallel branch comprises a first capacitor and a first inductor which are connected in parallel.

Optionally, the second matching circuit comprises: the second main path is connected with a first end of the second main path through a second feeding point, and a second end of the second main path is connected with the feeding port;

a third grounding branch and a third inductor are arranged between the first end and the second end of the second main circuit; wherein the third grounding branch comprises a third capacitor.

Optionally, the length of the first resonant stub is 16mm to 22mm, and the length of the second resonant stub is 10mm to 20 mm.

According to a second aspect of the embodiments of the present disclosure, a terminal device is provided, which includes a PCB and the antenna structure of any one of the above embodiments, where the PCB is provided with a feeding port, and the antenna structure is electrically connected to the feeding port.

The technical scheme provided by the embodiment of the disclosure can have the following beneficial effects: this disclosed antenna structure, through first matching circuit realize the first resonance minor matters and the PCB feed port be connected, through second matching circuit realize the second resonance minor matters and the same feed port be connected to realize the resonance of corresponding antenna signal frequency channel. The connection of two antenna branches is realized by one feed port, so that the problem of poor isolation caused by multiple feed ports on a PCB is effectively avoided, and the receiving and transmitting performance of the antenna is further ensured.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and together with the description, serve to explain the principles of the invention.

Fig. 1 is a schematic diagram of an antenna structure shown in accordance with an example embodiment.

Fig. 2 is a schematic diagram illustrating the main radiating areas in an antenna structure according to an exemplary embodiment.

Fig. 3 is a schematic diagram illustrating the main radiating areas in an antenna structure according to an exemplary embodiment.

Fig. 4 is a schematic diagram illustrating the main radiating areas in an antenna structure according to an exemplary embodiment.

Fig. 5 is a schematic diagram illustrating the main radiating areas in an antenna structure according to an exemplary embodiment.

FIG. 6 is an antenna echo state curve shown in accordance with an exemplary embodiment.

Fig. 7 is a graph illustrating antenna efficiency according to an example embodiment.

Detailed Description

Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, like numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the invention, as detailed in the appended claims.

The antenna is an indispensable structure for realizing a communication function of terminal equipment such as a mobile phone, and along with the development of a wireless network and a 5G technology, the antenna of the mobile phone needs to support multiple communication frequency bands, such as different frequency bands of Wi-Fi and GPS. At present, the development trend of mobile phone antennas is towards miniaturization and integration, and 5G devices need to meet the requirements of MIMO (Multiple Input Multiple Output) technology, and the demand for the number of antennas increases.

In the related art, in order to meet the increasing communication demand, a method of transmitting and receiving signals by providing a plurality of antennas is generally used. For example, one antenna is matched with GPS L1, WIFI2.4G and WIFI 5G; the 1 antenna implementation matches GPS L5. The multiple antennas need to adopt a dual feed or multi feed mode to realize frequency band matching, that is, two or more feed ports need to be arranged on the PCB board to realize the corresponding connection between the two or more antenna structures and the feed ports on the PCB board. Therefore, the antenna structure with multiple antennas and multiple feeding ports in the related art has at least the following problems:

in a first aspect, the performance of the antenna is affected. For the area where the feed ports are disposed on the PCB, the number of feed ports is increased, and the isolation between the feed ports is poor, which easily affects the transceiving performance between adjacent antennas. Moreover, the bandwidth of the WIFI frequency band of the antenna structure in the related art is narrow, and the WIFI6E cannot be covered in the full frequency band.

In a second aspect, the internal layout of the terminal device is affected. The number of the antenna branches is large, and the occupied space is large. And feed ports are increased on the PCB, and the occupied space of wiring based on antenna connection is large, so that the layout of other electronic elements on the PCB is not facilitated, and the layout of other structures in the terminal equipment is also not facilitated.

In a third aspect, the appearance of the terminal device is affected. In order to realize multi-antenna transceiving multi-band, a metal middle frame of the terminal equipment also needs to be provided with a plurality of slots, so that the appearance layout of the terminal equipment is not attractive.

To solve the problems in the related art, the present disclosure provides an antenna structure, including: the first resonant branch, the first matching circuit, the second resonant branch and the second matching circuit; the first resonant branch is connected with a feed port of the terminal equipment PCB through a first matching circuit, the second resonant branch is connected with the feed port through a second matching circuit, and a preset gap is formed between the first resonant branch and the second resonant branch; the first resonant branch resonates at least two antenna signal frequency bands through the first matching circuit, and the second resonant branch resonates at least one antenna signal frequency band through the second matching circuit. According to the antenna structure, the first resonance branch is connected with the PCB feed port through the first matching circuit, and the second resonance branch is connected with the same feed port through the second matching circuit, so that resonance of corresponding antenna signal frequency bands is realized. The connection of two antenna branches is realized by one feed port, so that the problem of poor isolation caused by multiple feed ports on a PCB is effectively avoided, and the receiving and transmitting performance of the antenna is further ensured.

In an exemplary embodiment, as shown in fig. 1 to 5, the antenna structure of the present embodiment includes: a first resonant stub 10, a second resonant stub 20, a first matching circuit 30 and a second matching circuit 40. In this embodiment, the first resonant stub 10 is connected to the feeding port 100 of the terminal device PCB through the first matching circuit 30, and the second resonant stub 20 is connected to the feeding port 100 through the second matching circuit 40. The first resonant branch 10 resonates at least two antenna signal frequency bands via the first matching circuit 30, and the second resonant branch 20 resonates at least one antenna signal frequency band via the second matching circuit 40. The feed port 100 is a radio frequency connection port on the PCB board.

As shown in fig. 1 to 5, a predetermined gap 50 is formed between the first resonant stub 10 and the second resonant stub 20. The first resonant branch 10 and the second resonant branch 20 may be part of a middle frame of the terminal device, and a gap (a preset gap 50) may be formed between the first resonant branch 10 and the second resonant branch 20 to ensure the aesthetic property of the terminal device.

In this embodiment, a single feed scheme is adopted, and two matching circuits are used to respectively electrically connect two antenna branches. That is, the two antenna branches are connected with the same feed port 100 (radio frequency connection port) on the PCB through the corresponding matching circuits, so that a plurality of feed ports do not need to be arranged on the PCB, and the problem of poor isolation between the plurality of feed ports is avoided. Meanwhile, the wiring space on the PCB is saved.

In an exemplary embodiment, as shown in fig. 1, the first resonant stub 10 resonates at least the L1 frequency band (1.575GHz) for GPS and the 2.4G frequency band (2.4GHz-2.48GHz) for WIFI. The length of the first resonance branch 10 is 16mm-22mm, and the height of the antenna signal frequency resonated by the first resonance branch 10 can be adjusted by adjusting the length of the first resonance branch 10. For example, the longer the first resonant stub 10, the lower the resonant frequency.

In this embodiment, the second resonant stub 20 resonates at least the L5 frequency band (1.172GHz) of the GPS. The length of the second resonant branch 20 is 10mm-20 mm. By adjusting the length of the second resonance stub 20, the level of the antenna signal frequency at which the second resonance stub 20 resonates can be adjusted. For example, the longer the second resonant stub 10, the lower the resonant frequency.

In addition, in this embodiment, the first resonant branch 10 and the second resonant branch 20 are both longer, and the longer branches are used to implement low frequency bands (GPS L1 and L5 bands), so that the antenna efficiency of the low frequency antenna band can be ensured to be the maximum.

In an exemplary embodiment, as shown in fig. 5, the first resonant stub 10 includes a first radiating portion 11 adjacent to the predetermined slot 50. The first resonant branch 10 is provided with a first feeding point (or called as a first upper frame point) 101, and the first feeding point 101 divides the first resonant branch 10 into a first radiation portion 11 and a second radiation portion 12. The first radiation portion 11 is located between the first feeding point 101 and the predetermined slot 50.

The second resonant stub 20 includes a parasitic portion 21 adjacent to the predetermined slot 50. As shown in fig. 5, a second feeding point 201 is disposed on the second resonant branch 20, and the second feeding point 201 divides the second resonant branch 20 into a parasitic portion 21 and a third radiating portion 22. The parasitic portion 21 is located between the second feeding point 201 and the predetermined slot 50.

In this embodiment, the ends of the first resonant branch 10 and the second resonant branch 20 away from the predetermined slot 50 are Grounded (GND).

In one example, the first resonant branch 10 and the second resonant branch 20 are upper sides of the middle frame, one end of the first resonant branch 10 away from the predetermined gap 50 is connected to one side frame of the middle frame for grounding, and one end of the second resonant branch 20 away from the predetermined gap 50 is connected to the other side frame of the middle frame for grounding.

In another example, the first resonant branch 10 and the second resonant branch 20 are one side of the middle frame, one end of the first resonant branch 10 away from the predetermined gap 50 is connected to the upper side of the middle frame for grounding, and one end of the second resonant branch 20 away from the predetermined gap 50 is connected to the lower side of the middle frame for grounding.

In another example, the first resonant stub 10 and the second resonant stub 20 are located on adjacent sides of the middle frame, and the predetermined slot 50 is located at a corner of the middle frame. One end of the first resonant branch 10 far away from the preset gap 50 is connected with the corresponding side edge to be grounded, and one end of the second resonant branch 20 far away from the preset gap 50 is connected with the corresponding side edge to be grounded.

In this embodiment, the parasitic portion 21 is coupled to the first radiating portion 11 to resonate at least one antenna signal band.

In one exemplary embodiment, as shown in fig. 1 to 5, the parasitic part 21 is coupled with the first radiating part 11 to resonate a 6E band (5-7.2GHz) of WIFI. The 6E frequency band of WIFI includes a WIFI 5G frequency band, that is, the antenna structure in this embodiment can effectively widen the bandwidth on the basis of supporting WIFI 5G, and the full frequency band covers WIFI 6E.

In this embodiment, the length of the first radiating part 11 and/or the parasitic part 21 is 1mm to 3mm, and the length of the predetermined gap 50 is 0.5mm to 3 mm. The bandwidth can be adjusted adaptively by adjusting the length of the preset gap 50.

In an exemplary embodiment, as shown in fig. 1 to 5, the first matching circuit 30 includes: a first main path 31. The first resonant stub 10 is connected to a first end of the first main path 31 through the first feeding point 101, and a second end of the first main path 31 is connected to the feeding port 100.

In this embodiment, a first grounding branch 301, a first parallel branch 302, a second capacitor 303, a second grounding branch 304 and a second inductor 305 are disposed between a first end and a second end of the first main circuit 31. The first parallel branch 302 includes a first capacitor 3021 and a first inductor 3022 connected in parallel. The first grounding branch 301 includes a grounding inductor 3011, and the second grounding branch 304 includes a grounding capacitor 3041.

In this embodiment, the first resonant branch 10 can realize grounding at both ends, one end is Grounded (GND) through the connection with the middle frame, and the ground is realized at the feed point of the other end through the grounding branch in the first matching circuit 30.

In one example, the main radiating area of the antenna structure when the first resonant stub 10 resonates the GPS L1 frequency band is shown in fig. 2. As can be seen, the first resonant stub 10 (black filled portion in the figure) participates in the radiation. The length of the first resonant stub 10 may be, for example, 16mm to 22 mm. By adjusting the size of the grounding inductor 3011 in the first grounding branch 301 and the size of the second capacitor 303, impedance matching at a corresponding frequency point of a GPS L1 frequency band is achieved, so as to obtain a better signal gain.

In another example, when the first resonant stub 10 resonates the WIFI2.4G frequency band, the main radiating area of the antenna structure is as shown in fig. 3. As can be seen, the first resonant stub 10 and the first feeding point 101 are mainly involved in the radiation. By adjusting the size of the first inductor 3022 of the first parallel branch 302, impedance matching at a corresponding frequency point of the WIFI2.4G frequency band is achieved.

In an exemplary embodiment, as shown in fig. 1 to 5, the second matching circuit 40 includes: and a second main path 41. The second resonant branch 20 is connected to the first end of the second main path 41 through the second feeding point 201, and the second end of the second main path 41 is connected to the feeding port 100. In this embodiment, a third grounding branch 401 and a third inductor 402 are disposed between the first end and the second end of the second main circuit 41; the third ground branch 401 includes a third capacitor 4011.

In this embodiment, the second resonant branch 20 can also realize grounding at two ends, one end is connected to the middle frame to realize Grounding (GND), and the feed point at the other end is grounded through the grounding branch in the second matching circuit 40.

In one example, the main radiating area of the antenna structure when the second resonant stub 20 resonates the GPS L5 frequency band is shown in fig. 4. As can be seen, the second resonant stub 20 and the second feeding point 201 participate in the radiation. Wherein the length of the second resonant stub 20 may be, for example, 10mm to 20 mm. By adjusting the size of the third capacitor 4011 and the size of the third inductor 402 of the third grounding branch 401, impedance matching at a corresponding frequency point of the GPS L5 frequency band is achieved, so as to obtain a better signal gain. In this example, unlike the related art in which the GPS L5 is matched using the same matching circuit as the GPS L1, the GPS L5 band matching is realized by providing the second matching circuit 40.

Generally, the inductance device in the matching circuit belongs to low-pass filtering, and the inductance in the circuit is increased to increase the inductance impedance. The capacitance device in the circuit belongs to high-pass filtering, and the capacitance in the circuit is increased to reduce the capacitance impedance. Series inductance devices or parallel capacitance devices mainly affect the matching of higher frequency points (high frequency signals are sensitive to parallel capacitance and series inductance); series capacitor devices or parallel inductor devices mainly affect the matching of lower frequency points. The low-frequency signal GPS L5 can be adjusted by a parallel capacitor series inductor or a parallel capacitor series capacitor.

In this example, as shown in fig. 1 to 5, the second matching circuit 40 adopts a parallel capacitor series inductor low-pass filter circuit matching mode, that is, low-frequency signals can normally pass through, and high-frequency signals exceeding a set threshold are blocked and attenuated. For example, a low-pass filtering form with a large capacitor and a large inductor is adopted. The low-pass filtering matching mode has the effects of short-circuit to the ground, isolation and open-circuit matching to the first resonance branch 10 on the WIFI6E frequency band while adjusting and matching the GPS L5 frequency band, so that the influence of the matching value of the second resonance branch 20 on the first resonance branch 10 is minimum. That is, by using the open circuit effect of the low-pass filter matching circuit, the independent tuning between the second resonance branch 20 tuning the corresponding frequency band signal (for example, GPS L5) and the first resonance branch 10 tuning the corresponding frequency band signal (for example, GPS L1, WIFI2.4G, and WIFI 5G) can be achieved.

In another example, when the first radiating part 11 in the first resonant stub 10 and the parasitic part 21 of the second resonant stub 20 are coupled through the preset slot 50 to jointly realize the resonant WIFI6E frequency band, the main radiating area of the antenna structure is as shown in fig. 5. As can be seen from the figure, the first radiating portion 11, the first feeding point 101, the parasitic portion 21, and the second feeding point 201 are mainly involved in radiation. The lengths of the first radiation part 11 and the parasitic part 21 may be set to be 1mm-3mm, and the length of the predetermined gap 50 is 0.5mm-3 mm.

With reference to fig. 6, in the present example, when tuning a WIFI6E signal frequency band, due to the grounding arrangement at the two ends of the second resonance branch 20 and the low-pass filtering matching characteristic of the second matching circuit 40, the second resonance branch 20 generates two resonances, and expands the antenna bandwidth, thereby implementing WIFI6E (5.15-7.2GHz) full-band coverage. In fig. 6, frequency point 5 and frequency point 6 represent the first resonance, and frequency point 7 represents the second resonance (the resonance newly increased due to the structure and circuit characteristics). By adjusting the corresponding circuit elements in the first matching circuit 30, the impedance of the WIFI6E signal frequency band can be adjusted, making the two resonances deeper. Such as: by adjusting the size of the first capacitor 3021 of the first parallel branch 302, the size of the ground capacitor 3041 in the second ground branch 304, and the size of the second inductor 305, impedance matching at a corresponding frequency point (such as frequency point 5, frequency point 6, or frequency point 7) of the WIFI6E frequency band is achieved, so as to obtain a better signal gain.

It can be known from the above two examples that the matching between the second resonant stub 20 and the second matching circuit 40 can adjust the resonant frequency of the GPS L5 on the one hand, and can realize the coverage of the WIFI6e frequency band on the other hand. When the WIFI6E frequency band is tuned, the length of the parasitic part 21 may also be adjusted to adjust the frequency of the coupled signal.

In one example, as shown in fig. 1 to 5, in the first matching circuit 30, in the case where the antenna branches are appropriate in length: the ground inductance 3011 of the ground branch 301 may be 22nH (nanohenries), the first inductance 3022 of the first parallel branch 302 may be 5nH, the first capacitance 3021 may be 0.6pF (picofarads), the second capacitance 303 may be 0.4pF, the ground capacitance 3041 of the second ground branch 304 may be 0.1pF, and the second inductance 305 may be 1.5 nH. In the second matching circuit 40: the third capacitor 4011 of the third ground branch 401 may be, for example, 2.8pF, and the third inductor 402 may be, for example, 35 nH. The effect of impedance matching, first resonance stub 10 resonance GPS L1 and WIFI2.4G frequency channel, second resonance stub 20 resonance GPS L5 frequency channel, first radiation portion 11 and parasitic portion 21 coupling resonance WIFI6E frequency channel is in order to realize. The antenna efficiency curve of the antenna structure after matching is completed is shown in fig. 7.

It should be noted that the impedance matching process in the above embodiments can be adjusted by using a network analyzer. And adjusting the sizes of the corresponding circuit elements according to the obtained impedance values. And the impedance matching can be realized more quickly by debugging in combination with a Smith chart. It will be appreciated that a variety of parameters of the antenna structure may be obtained from the network analyzer, such as input reflection coefficient, output reflection coefficient, voltage standing wave ratio, impedance (or admittance), attenuation (or gain), and other transmission parameters, as well as isolation.

In an exemplary embodiment, the present disclosure provides a terminal device, which includes a PCB and an antenna structure according to any of the above embodiments. The PCB is provided with a feed port, and the antenna structure is electrically connected with the feed port. The first resonant stub and the second resonant stub of the antenna structure may be part of the middle frame or assembled with the middle frame.

For example, the first resonant branch and the second resonant branch are the upper sides of the middle frame, and the upper sides are slit to form the preset slit. And one ends of the two branches close to the preset gap are respectively provided with a feed point (or an upper frame point).

The antenna structure of this embodiment, through the single port feed, support GPS L1 frequency channel, GPS L5 frequency channel, WIFI2.4G frequency channel and WIFI6E frequency channel simultaneously, realized multiband receiving and dispatching, can also satisfy 5G terminal equipment's communication demand. Moreover, by adopting the antenna structure disclosed by the invention, the PCB of the terminal equipment has no problem of poor isolation among multiple feed ports, and meanwhile, the PCB wiring in the single feed port scheme is less, so that the PCB space is effectively saved. Compared with a single-feed GPS and WIFI antenna in the related technology, the antenna not only increases the resonance of GPS L5, but also effectively increases the bandwidth and can cover the whole WIFI6E frequency band.

Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.

It will be understood that the invention is not limited to the precise arrangements that have been described above and shown in the drawings, and that various modifications and changes can be made without departing from the scope thereof. The scope of the invention is limited only by the appended claims.

Claims

1. An antenna structure, comprising: the first resonant branch, the first matching circuit, the second resonant branch and the second matching circuit;

2. The antenna structure of claim 1, wherein the first resonant stub resonates at least the L1 frequency band of GPS and the 2.4G frequency band of WIFI.

3. The antenna structure according to claim 1, characterized in that the second resonant stub resonates at least the L5 frequency band of the GPS.

4. The antenna structure according to claim 1, wherein the ends of the first resonant stub and the second resonant stub away from the predetermined slot are grounded;

5. The antenna structure of claim 4, wherein the parasitic portion is coupled with the first radiating portion to resonate for the 6E band of WIFI.

6. The antenna structure according to claim 4, wherein the first resonant stub is provided with a first feeding point, and the first radiating portion is located between the first feeding point and the predetermined slot; and a second feeding point is arranged on the second resonance branch node, and the parasitic part is positioned between the second feeding point and the preset gap.

7. An antenna structure according to claim 6, characterized in that the length of the first radiating part and/or the parasitic part is 1-3 mm.

8. The antenna structure according to any one of claims 1 to 7, characterized in that the first matching circuit comprises: the first resonant branch node is connected with a first end of the first main circuit through a first feeding point, and a second end of the first main circuit is connected with the feeding port;

a first grounding branch circuit, a first parallel branch circuit, a second capacitor, a second grounding branch circuit and a second inductor are arranged between the first end and the second end of the first main circuit; the first parallel branch comprises a first capacitor and a first inductor which are connected in parallel.

9. The antenna structure according to any one of claims 1 to 7, characterized in that the second matching circuit comprises: the second main path is connected with a first end of the second main path through a second feeding point, and a second end of the second main path is connected with the feeding port;

a third grounding branch and a third inductor are arranged between the first end and the second end of the second main circuit; wherein the third ground branch comprises a third capacitor.

10. An antenna structure according to any one of claims 1 to 7, wherein the first resonant stub has a length of 16mm-22mm and the second resonant stub has a length of 10mm-20 mm.

11. A terminal device, comprising a PCB and an antenna structure according to any of claims 1 to 10, wherein the PCB is provided with a feeding port, and the antenna structure is electrically connected to the feeding port.