Low-frequency antenna structure and terminal device

Abstract

The application provides a low-frequency antenna structure and a terminal device. The low-frequency antenna structure comprises an antenna main body and a parasitic branch. The antenna main body comprises a first metal frame, a second metal frame and a feeding point. The first metal frame and the second metal frame are oppositely arranged and located outside the second metal frame. The feeding point is arranged at one end of the first metal frame. The parasitic branch is arranged on the second metal frame and located at an end away from the feeding point. A side of the parasitic branch facing the first metal frame is spaced apart from the first metal frame. Through the above arrangement, the parasitic branch forms a distributed coupling capacitance towards the first metal frame. It is not necessary to weld a capacitor at the circumferential gap of the metal frame, thereby saving the welding cost and reducing the difficulty of spot welding. In this way, the parasitic branch can interact with the antenna main body, so that the resonance thereof can work cooperatively with the antenna main body.

Description

Technical Field

[0001] This application relates to the field of antennas, and more particularly to a low-frequency antenna structure and terminal equipment. Background Technology

[0002] Low-frequency signals (such as 700MHz) can achieve a single base station coverage radius of 5-10 kilometers, solving the problem of network blind spots in sparsely populated areas; they can achieve deep indoor coverage, and the ability of low-frequency electromagnetic waves to penetrate concrete and brick walls is significantly better than that of high-frequency signals (such as 2.6GHz). In scenarios such as underground parking lots, shopping malls, and the interior of high-rise buildings, low-frequency signal strength has a significant advantage; in high-speed mobile environments such as high-speed rail and highways, low-frequency signals have smaller Doppler frequency shift, reducing handover failure rate and improving mobility continuity.

[0003] Currently, common low-frequency antenna structures suffer from high manufacturing costs and high performance risks. Utility Model Content

[0004] This application provides a low-frequency antenna structure and terminal device to solve at least one of the above-mentioned technical problems.

[0005] In a first aspect, this application provides a low-frequency antenna structure for use in terminal equipment, comprising an antenna body and parasitic stubs, wherein the antenna body includes a first metal frame, a second metal frame, and a feed point.

[0006] The first metal frame and the second metal frame are arranged opposite to each other along a first direction and are located outside the second metal frame. The power supply point is located at one end of the first metal frame, and the parasitic branch is located at the end of the second metal frame away from the power supply point. Along the first direction, the side of the parasitic branch facing the first metal frame is spaced apart from the first metal frame.

[0007] Optionally, an antenna slot is formed between the first metal frame and the second metal frame; along the first direction, the length of the antenna slot is greater than the length of the interval between the parasitic branch and the first metal frame.

[0008] Optionally, along the first direction, the length of the antenna slot is 1mm-1.5mm; and / or

[0009] Along the first direction, the length of the interval between the parasitic branch and the first metal frame is 0.4mm-0.8mm.

[0010] Optionally, the parasitic branch has a plurality of grooves on one side of the second metal frame in the thickness direction.

[0011] Optionally, the opening size of the groove portion facing the first metal frame is smaller than the size of the groove bottom portion away from the first metal frame.

[0012] Optionally, a plurality of grooves are arranged at intervals along a second direction, the second direction being perpendicular to the first direction, and the thickness direction of the second metal frame being perpendicular to both the first and second directions.

[0013] Optionally, a connecting rib is included, which is disposed between the power supply point and the parasitic branch, and the connecting rib connects the first metal frame and the second metal frame.

[0014] Optionally, the distance between the connecting rib and the power supply point is less than the distance between the connecting rib and the parasitic branch.

[0015] Optionally, the parasitic segment is a magnetic parasitic segment.

[0016] Secondly, this application provides a terminal device, the terminal device including the low-frequency antenna structure as described in the first aspect.

[0017] The above configuration allows the parasitic stubs to form distributed coupling capacitors towards the first metal frame, eliminating the need to weld capacitors into the circumferential gaps of the metal frame, thus saving welding costs and reducing the difficulty of spot welding. This enables the parasitic stubs to interact with the antenna body, allowing their resonance to work in tandem with the antenna body. Attached Figure Description

[0018] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure.

[0019] Figure 1 The diagram shown is a schematic diagram of one embodiment of the terminal device of this application.

[0020] Figure 2 The diagram shown is a schematic representation of an embodiment of the low-frequency antenna structure of this application.

[0021] Figure 3 As shown Figure 2 The diagram shows a partially enlarged view of the low-frequency antenna structure.

[0022] Figure 4 As shown Figure 2 The diagram shows a partially enlarged view of the low-frequency antenna structure from another perspective.

[0023] Figure 5 This is a radiation efficiency-frequency table for one embodiment of the low-frequency antenna structure of this application.

[0024] Explanation of reference numerals in the attached figures:

[0025] 100. Low-frequency antenna structure; 10. Antenna body; 11. First metal frame; 12. Second metal frame; 13. Feed point; 14. Connecting rib; 15. Antenna slot; 20. Parasitic branch; 21. Groove; 200. Terminal equipment; 210. Screen. Detailed Implementation

[0026] The technical solutions in the embodiments (or "implementations") of this application will be clearly and completely described herein with reference to the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements.

[0027] If the embodiments of this application contain terms relating to directional indications or positional relationships (such as up, down, left, right, front, back, inside, outside, top, bottom, center, vertical, horizontal, longitudinal, transverse, length, width, counterclockwise, clockwise, axial, radial, circumferential, etc.), such terms are only used to explain the relative positional relationships and movements between components in a specific posture (as shown in the attached figures); if the specific posture changes, the directional indications or positional relationships will also change accordingly. Furthermore, the terms "first" and "second" used in the embodiments of this application are only for descriptive convenience and should not be construed as indicating or implying relative importance.

[0028] This application provides a low-frequency antenna structure and terminal device. The low-frequency antenna structure and terminal device of this application will be described in detail below with reference to the accompanying drawings. Unless otherwise specified, the features of the following embodiments and implementations can be combined with each other.

[0029] See Figure 1 As shown, this application provides a terminal device 200, which may specifically be a smartphone, tablet computer, etc. The terminal device 200 includes a low-frequency antenna structure 100.

[0030] See Figure 1 and Figure 2As shown, the low-frequency antenna structure 100 includes an antenna body 10 and a parasitic stub 20. The antenna body 10 includes a first metal frame 11, a second metal frame 12, a feed point 13, and the parasitic stub 20. The first metal frame 11 and the second metal frame 12 are arranged opposite to each other along a first direction X, and the parasitic stub 20 is located outside the second metal frame 12. Specifically, the terminal device 200 includes a screen 210, and the second metal frame 12 is disposed on the side of the first metal frame 11 near the screen 210, where the first direction X is the width direction of the screen 210 of the terminal device. The feed point 13 is disposed at one end of the first metal frame 11, and the parasitic stub 20 is disposed on the second metal frame 12 at the end away from the feed point 13, with a gap between the parasitic stub 20 and the first metal frame 11 on the side facing the first metal frame 11.

[0031] With the above configuration, the parasitic stub 20 forms a distributed coupling capacitor towards the first metal frame 11, eliminating the need to weld capacitors at the circumferential gaps of the metal frame, thus saving welding costs and reducing the difficulty of spot welding. This allows the parasitic stub 20 to interact with the antenna body 10, enabling its resonance to work in tandem with the antenna body 10.

[0032] In an optional embodiment, see Figures 1-3 As shown, an antenna slot 15 is formed between the first metal frame 11 and the second metal frame 12; along the first direction X, the length of the antenna slot 15 is greater than the length of the gap between the parasitic branch 20 and the first metal frame 11. In this embodiment, the gap between the first metal frame 11 and the second metal frame 12 is 1.2 mm, and the gap between the parasitic branch 20 and the first metal frame 11 is 0.6 mm. In other alternative embodiments, the gap between the first metal frame 11 and the second metal frame 12 can be set to 1 mm-1.5 mm according to actual structural requirements, specifically 1 mm, 1.1 mm, or 1.3 mm, and the gap between the parasitic branch 20 and the first metal frame 11 can be set to 0.4 mm-0.8 mm according to actual structural requirements, specifically 0.5 mm, 0.7 mm, or 0.8 mm.

[0033] By setting the antenna slot 15, the antenna body 10 can radiate and receive electromagnetic waves, achieving better antenna efficiency while reducing the thickness of the antenna body 10. The parasitic branch 20 is set adjacent to the antenna body 10, allowing the parasitic branch 20 to interact with the antenna body 10, so that its resonance can work in coordination with the antenna body 10.

[0034] In an optional embodiment, a gap is formed between the parasitic branch 20 and the first metal frame 11 by cutting. In a preferred embodiment, the gap between the parasitic branch 20 and the first metal frame 11 is processed by a saw blade.

[0035] This helps reduce the manufacturing difficulty of the low-frequency antenna structure 100, and compared with the existing manufacturing method of spot welding capacitors, it can shorten the manufacturing time and thus reduce the manufacturing cost.

[0036] In an optional embodiment, see Figure 3 As shown, and Figure 4 As shown, the parasitic branch 20 has a plurality of grooves 21 on one side of the second metal frame 12 in the thickness direction Z.

[0037] Thus, by controlling the number of grooves 21 and the opening area of ​​the grooves 21, the area of ​​the parasitic branch 20 facing the first metal frame 11 is controlled. The capacitance value of the distributed capacitor is directly proportional to the area S of the parasitic branch 20 facing the first metal frame 11 and inversely proportional to the distance D of the parasitic branch 20 facing the first metal frame 11.

[0038] The specific formula can be expressed as:

[0039]

[0040] Where: C is the capacitance value (unit: farad, F), ε0 is the vacuum permittivity (approximately 8.85 × 10⁻⁶). -12 F / m), ε r Let A be the relative permittivity of the medium (unitless, 1 in vacuum), A be the area of ​​the two plates facing each other, and in this application, S be the area of ​​the parasitic branch 20 facing the first metal frame 11 (unit: square meters, m). 2 ), where d is the distance between the two plates, and in this application, it is the distance D (unit: meter, m) between the parasitic branch 20 and the first metal frame 11.

[0041] In an optional embodiment, see Figure 3 As shown, the opening size of the groove portion 21 facing the first metal frame 11 is smaller than the size of the groove bottom of the groove portion 21 away from the first metal frame 11.

[0042] This facilitates the cutting and processing of the parasitic branch 20 and the first metal frame 11, especially by using a saw blade, which helps to reduce the manufacturing difficulty and cost of the low-frequency antenna structure 100.

[0043] Specifically, the groove 21 has a trapezoidal cross-sectional shape in the direction parallel to the screen 210, which facilitates the processing of the parasitic branch 20 and the first metal frame 11 by cutting.

[0044] In an optional embodiment, a plurality of recessed portions are arranged at intervals along a second direction Y. The second direction Y is perpendicular to the first direction X, and the thickness direction Z of the second metal frame is perpendicular to both the first direction X and the second direction Y. In this embodiment, the second direction Y is the length direction of the screen 210 of the terminal device 200.

[0045] In an optional embodiment, the low-frequency antenna structure 100 includes a connecting rib 14 disposed between the feed point 13 and the parasitic stub 20, and the connecting rib 14 connects the first metal frame 11 and the second metal frame 12.

[0046] In this way, the "large T" antenna structure is realized, which is conducive to the transfer of the radiated energy of the antenna body 10 to the entire first metal frame 11, enhances the radiation and reception of electromagnetic waves by the antenna body 10, and achieves better antenna efficiency.

[0047] In an optional embodiment, participants Figure 1 As shown, the distance d1 between the connecting rib 14 and the power supply point 13 is less than the distance d2 between the connecting rib 14 and the parasitic branch 20. In this embodiment, the distance d1 between the connecting rib 14 and the power supply point 13 is 41 mm, and the distance d2 between the connecting rib 14 and the parasitic branch 20 is 57 mm. The width d3 of the connecting rib 14 is 1 mm.

[0048] In this way, the resonant frequency of the antenna body 10 and the frequency of the parasitic branch 20 are adjusted. According to the size of the terminal device 200, the area of ​​the parasitic branch 20 facing the first metal frame 11, the distance between the parasitic branch 20 and the first metal frame 11, and the distances between the parasitic branch 20 and the feed point 13 and the connecting rib 14 are set accordingly, so that its resonance can work in coordination with the antenna body 10.

[0049] In an optional embodiment, the radiation frequency of the parasitic branch 20 is lower than the radiation frequency of the antenna body 10.

[0050] In this way, the parasitic stub 20 can interact with the antenna body 10, and the resonance of the parasitic stub 20 can work in coordination with the antenna body 10, which is beneficial to improving the antenna efficiency of the antenna body 10.

[0051] In this embodiment, the antenna body 10 is a B28 antenna. Figure 5 The diagram shows the radiation efficiency-frequency table for the B28 TX state, where the radiation frequency of parasitic stub 20 corresponds to point B in the figure, and the radiation frequency of the antenna body corresponds to point A. This structural configuration improves the performance of the B28 antenna by more than 2 dB.

[0052] In an optional embodiment, the parasitic branch 20 is a magnetic parasitic branch.

[0053] This is beneficial for improving the antenna efficiency of the antenna body 10, for canceling the coupling between adjacent antennas, for improving the isolation between antennas, and for reducing the sensitivity to dielectric materials such as human tissue. In the case of handheld terminal device 200, it has a small frequency shift and good anti-interference ability.

[0054] This disclosure achieves improved overall efficiency of the low-frequency antenna structure 100 while maintaining low manufacturing costs. In practical applications, it can improve the radiation efficiency of the N28 antenna to -8dB and the B5 / B8 antenna to -10dB. This enhances the user experience of terminal devices in sparsely populated areas such as rural or remote regions; indoor environments such as underground parking lots, shopping malls, and high-rise building interiors; and high-speed mobile environments such as high-speed rail and highways.

[0055] It should be noted that the technical solutions or features described in the above embodiments can be combined or supplemented with each other without conflict. The scope of protection of this application is not limited to the precise structures described in the above embodiments and shown in the accompanying drawings; all modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A low-frequency antenna structure, characterized in that, Applied to terminal equipment, the antenna includes a main body and parasitic stubs. The main body includes a first metal frame, a second metal frame, and a feed point. The first metal frame and the second metal frame are arranged opposite to each other along a first direction and are located outside the second metal frame. The power supply point is located at one end of the first metal frame, and the parasitic branch is located at the end of the second metal frame away from the power supply point. Along the first direction, the side of the parasitic branch facing the first metal frame is spaced apart from the first metal frame.

2. The low-frequency antenna structure according to claim 1, characterized in that, An antenna slot is formed between the first metal frame and the second metal frame; along the first direction, the length of the antenna slot is greater than the length of the interval between the parasitic branch and the first metal frame.

3. The low-frequency antenna structure according to claim 2, characterized in that, Along the first direction, the length of the antenna slot is 1mm-1.5mm; and / or Along the first direction, the length of the interval between the parasitic branch and the first metal frame is 0.4mm-0.8mm.

4. The low-frequency antenna structure according to claim 1, characterized in that, The parasitic branch has multiple grooves on one side of the second metal frame in the thickness direction.

5. The low-frequency antenna structure according to claim 4, characterized in that, The opening size of the groove on the side facing the first metal frame is smaller than the size of the groove bottom away from the first metal frame.

6. The low-frequency antenna structure according to claim 5, characterized in that, Multiple grooves are arranged at intervals along a second direction, which is perpendicular to the first direction. The thickness direction of the second metal frame is perpendicular to both the first and second directions.

7. The low-frequency antenna structure according to claim 1, characterized in that, It includes a connecting rib, which is disposed between the power supply point and the parasitic branch, and the connecting rib connects the first metal frame and the second metal frame.

8. The low-frequency antenna structure according to claim 7, characterized in that, The distance between the connecting bar and the power supply point is less than the distance between the connecting bar and the parasitic branch.

9. The low-frequency antenna structure according to claim 1, characterized in that, The parasitic segment is a magnetic parasitic segment.

10. A terminal device, the terminal device comprising a low-frequency antenna structure as described in any one of claims 1-9.

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