Antenna structure and mobile terminal

Abstract

The utility model relates to the field of mobile communication, in particular to an antenna structure and a mobile terminal. The antenna structure comprises an antenna substrate and a floor, a radiation branch knot is laid on one side of the antenna substrate, and the radiation branch knot comprises a top layer branch knot and a bottom layer branch knot; the bottom layer branch knot is connected with the floor; the top-layer branch knot is connected with the coaxial feeder line and is connected with the floor through the coaxial feeder line; the top-layer branch knot comprises a monopole, an L-shaped branch knot, a snakelike branch knot and a U-shaped branch knot which are connected in sequence. Only the top layer branch knot and the single bottom layer branch knot are laid on the antenna substrate, a complex lumped device or a matching network does not need to be loaded, the overall structure is simple, and the technical problem that an existing built-in antenna is complex in structure is solved.

Description

Technical Field

[0001] The utility model relates to the field of mobile communications, in particular to an antenna structure and a mobile terminal. Background Art

[0002] In mobile communication systems, antennas are the basic units of wireless communication networks, used to provide radiation and receive radio waves for radio systems, and to complete the mutual conversion between radio waves in free space and guided waves on transmission lines.

[0003] The antenna of a mobile terminal can be divided into two types according to the setting position: external antenna and internal antenna. Because the external antenna is placed outside the mobile terminal body, it has little effect on the internal circuit of the mobile phone. The radiation and reception signals of the external antenna are also relatively stable. In addition, the external mobile phone antenna has the advantages of easy processing and manufacturing, low cost, and omnidirectional radiation. Therefore, early mobile terminal antennas mostly use external antennas. However, the external antenna is usually exposed to the outside and protrudes from the surface of the mobile terminal. It is easy to be damaged during use and is easily disturbed by human contact. Therefore, as time goes by, the external antenna is quickly replaced by the internal antenna. The internal antenna is set inside the mobile terminal to avoid electromagnetic radiation to the human body and the influence of human contact during use. However, since the internal antenna needs to be set inside the mobile terminal, it will be affected by the circuit limitations inside the mobile terminal. In order to adapt to the internal circuit of the mobile terminal, the existing internal antenna is usually loaded with lumped elements (capacitors, inductors) or matching circuits to achieve antenna multi-band, which will make the overall structure of the antenna complex.

[0004] Therefore, how to build a built-in mobile phone antenna with a simple structure and good performance has become a technical problem waiting to be solved. Utility Model Content

[0005] The embodiment of the utility model discloses an antenna structure and a mobile terminal, which are used to solve the technical problem of the complex structure of the existing built-in antenna.

[0006] An embodiment of the utility model provides an antenna structure, including: an antenna substrate and a floor; a radiation branch is laid on one side of the antenna substrate, and the radiation branch includes a top branch and a bottom branch; the bottom branch is connected to the floor; the top branch is connected to a coaxial feeder and is connected to the floor through the coaxial feeder; the top branch includes a monopole, an L-shaped branch, a serpentine branch and a U-shaped branch connected in sequence.

[0007] Optionally, the bottom layer branches are of an inverted F-shaped structure.

[0008] Optionally, the monopole and the L-shaped branch are distributed on one side of a connection between the coaxial feed line and the top-layer branch, and the serpentine branch and the U-shaped branch are distributed on the other side of the connection.

[0009] Optionally, a gap having a width of a first preset threshold is provided between the top-layer branches and the floor.

[0010] Optionally, the antenna substrate is a PCB board.

[0011] Optionally, the dielectric constant of the antenna substrate is 4.4.

[0012] Optionally, the dielectric loss tangent of the antenna substrate is 0.02.

[0013] Optionally, the dielectric material used for the radiation branch is copper.

[0014] Optionally, the floor is arranged below the antenna substrate.

[0015] The utility model also provides a mobile terminal, comprising the antenna structure as described above.

[0016] It can be seen from the above technical solutions that the embodiments of the utility model have the following advantages:

[0017] The embodiment of the utility model provides an antenna structure and a mobile terminal, including: an antenna substrate and a floor;

[0018] A radiation branch is laid on one side of the antenna substrate, and the radiation branch includes a top branch and a bottom branch; the bottom branch is connected to the floor; the top branch is connected to the coaxial feeder and connected to the floor through the coaxial feeder; the top branch includes a monopole, an L-shaped branch, a serpentine branch and a U-shaped branch connected in sequence.

[0019] In the utility model, only the top-layer branches and a single bottom-layer branch are laid on the antenna substrate. There is no need to load more complex lumped devices or matching networks. The overall structure is relatively simple, which solves the technical problem of the complex structure of existing built-in antennas. In the utility model, the top-layer branches and the bottom-layer branches constitute a double-layer branch coupled in the low-frequency band to produce dual resonance; and the top-layer branches are provided with monopoles, L-shaped branches, serpentine branches and U-shaped branches connected in sequence, which provides multi-band coverage for the antenna as a whole, thereby achieving better performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0021] Figure 1 A schematic diagram of an antenna structure provided in an embodiment of the present utility model;

[0022] Figure 2 A parameter diagram of an antenna structure provided in an embodiment of the utility model;

[0023] Figure 3 A schematic diagram of specific numerical parameters of an antenna structure provided in an embodiment of the present utility model;

[0024] Figure 4 A return loss diagram of the first antenna part to the third antenna part provided in an embodiment of the utility model;

[0025] Figure 5 Return loss diagrams of the fourth antenna portion to the sixth antenna portion provided in the embodiment of the present utility model;

[0026] Figure 6 A schematic diagram of the efficiency and peak gain of an antenna structure in a low-frequency band and a mid-frequency band provided in an embodiment of the utility model;

[0027] Figure 7 A schematic diagram of the efficiency and peak gain of a high frequency band of an antenna structure provided in an embodiment of the utility model;

[0028] In the figure:

[0029] 1 is the antenna substrate; 2 is the floor; 3 is the bottom branch; 4 is the coaxial feeder; 5 is the monopole; 6 is the L-shaped branch; 7 is the serpentine branch; and 8 is the U-shaped branch. DETAILED DESCRIPTION

[0030] The built-in antenna of a mobile terminal generally adopts the form of a monopole antenna, an inverted F antenna, a planar inverted F antenna, a loop antenna, a slot antenna, etc. The main methods to achieve multi-band, miniaturization, and broadband of the built-in antenna are: multi-branch technology, high-order mode resonance, slot coupling, slotting on the antenna surface, and using lumped elements to increase the matching network. Taking the slot antenna as an example, the slot antenna is achieved by opening a slot on the antenna patch to change the current path on the patch surface to achieve a multi-resonance mode. It is usually composed of a planar radiation patch, a patch slot, a ground plate, a feed pin, and a ground pin. The slot antenna has the advantages of compact structure and simple manufacturing, but it is difficult to achieve multi-band coverage and broadband of the antenna while ensuring the miniaturization of the antenna. Therefore, it is difficult for the existing built-in antenna structure to achieve multi-band coverage of the antenna with a simple structure. The structure is complex, and the actual gain of the antenna is not large. The omnidirectionality in the high frequency band (3.5GHz, 4.9GHz) is average.

[0031] The utility model discloses an antenna structure and a mobile terminal, which are used to solve the technical problem of the existing complex internal antenna structure.

[0032] The technical solution of the utility model will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0033] In the description of the present invention, it should be noted that the terms "front", "rear", "upper", "lower", "two ends", "center", "horizontal", "inner", "outer", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as a limitation on the present invention. Relational terms such as "first", "second", etc. are only used to distinguish one entity from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities.

[0034] Unless otherwise clearly specified and limited, the terms "install", "connect", "connect", "fix", and "set" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this utility model can be understood according to specific circumstances.

[0035] The professional terms involved in this utility model will be explained below.

[0036] In a popular sense, my country's mobile wireless communication frequency bands are mainly divided into 2G, 3G, 4G and 5G bands. The main 2G frequency bands are GSM: 850 / 900 / 1800 / 1900; the main 3G frequency bands are WCDMA (third-generation mobile communications: wideband code division multiple access technology): 2100MHz / 1900MHz / 850MHz (China Unicom 3G), TD-SCDMA (time division coordinated code division multiple access): 1880-1920MHz / 2010-2025MHz (China Mobile 3G), CDMA2000: 1920-1935MHz / 2110-2125MHz (China Telecom 3G), 4G frequency bands are TDD-LTE (frequency division duplex long term evolution technology): 1900MHz / 2300MHz / 2600MHz (China Mobile 4G), FDD-LTE (time division duplex long term evolution technology): 1800MHz / 2600MHz (China Telecom and China Unicom 4G). Currently, the mainstream 5G frequency band is sub-6GHz (frequency band below 6G), and the first sub-6GHz frequency bands deployed in China are mainly n78 (3300MHz-3800GHz) and n79 (4400MHz-5000GHz). Among them, the frequency bands allocated to China Mobile are mainly 2.6GHz (2515-2615MHz) and 4800-4960MHz, and China Telecom and China Unicom are 3.5GHz (3400-3600MHz).

[0037] In the present invention, the mobile terminal may be a mobile phone. The present invention may be applied to full coverage of 2G, 3G, 4G and the new generation of mobile communication 5G frequency bands.

[0038] See also Figure 1 An embodiment of an antenna structure provided in an embodiment of the utility model includes: an antenna substrate and a floor; a radiation branch is laid on one side of the antenna substrate, and the radiation branch includes a top branch and a bottom branch; the bottom branch is connected to the floor; the top branch is connected to a coaxial feeder and connected to the floor through the coaxial feeder; the top branch includes a monopole, an L-shaped branch, a serpentine branch and a U-shaped branch connected in sequence.

[0039] It should be noted that the top-level branches are fed by coaxial cables.

[0040] The monopole and L-shaped branch in this embodiment can be obtained by bending the top of the monopole antenna by 90 degrees to form an inverted L-shaped antenna. The inverted L-shaped antenna effectively reduces the height occupied by the antenna, solves the antenna height problem, and increases the inductive properties of the inverted L-shaped antenna by connecting the L-shaped branch to the coaxial feeder and connecting to the floor through the coaxial feeder, avoiding the problem of increased capacitance due to antenna bending, thereby more reasonably matching the antenna resonance. This embodiment provides resonance in the mid-frequency band for the entire antenna by setting the monopole and L-shaped branch.

[0041] This embodiment provides resonance for the antenna as a whole in low and high frequency bands by setting serpentine branches and U-shaped branches, and can increase the electrical length without occupying more clearance area, so that the monopole antenna can produce good resonance to cover the required frequency bands. At the same time, through coupling feeding with the underlying branches, the antenna impedance capacitance is supplemented, so that the impedance matching of the antenna is better, thereby stimulating the antenna to produce multiple resonance modes.

[0042] In this embodiment, only the top-layer branches and a single bottom-layer branch are laid on the antenna substrate, and there is no need to load a more complex lumped device or matching network. The overall structure is relatively simple. In addition, in the utility model, the top-layer branches and the bottom-layer branches form a double-layer branch coupling in the low frequency band to achieve dual resonance. The top-layer branches are provided with monopoles, L-shaped branches, serpentine branches and U-shaped branches connected in sequence, providing multi-band coverage for the antenna as a whole, thereby achieving better performance. Therefore, the antenna structure provided in this embodiment solves the technical problem of the complex structure of the existing built-in antenna, and realizes the miniaturization and multi-band of the built-in antenna of the mobile terminal.

[0043] In a specific embodiment, the bottom branch is an inverted F-shaped structure.

[0044] It should be noted that the bottom branch in this embodiment adopts an F-shaped structure, which is connected to the floor, and the F-shaped branch is located above the floor.

[0045] In a specific embodiment, the serpentine branch may adopt a loop antenna, wherein the loop antenna is formed by a metal strip after a certain bending process. In actual use, multiple resonance modes can be generated, and the loop antenna is a closed path, so the floor has a relatively small impact on the antenna.

[0046] In a specific embodiment, the monopole and the L-shaped branch are distributed on one side of the connection between the coaxial feed line and the top-layer branch, and the serpentine branch and the U-shaped branch are distributed on the other side of the connection.

[0047] It should be noted that, in this embodiment, Figure 1As shown, the top-level branches are divided into a left half and a right half by taking the coaxial feed line as the dividing line. The left half includes a monopole and an L-shaped branch, and the right half includes a serpentine branch and a U-shaped branch.

[0048] In a specific embodiment, a gap having a width of a first preset threshold is provided between the top-layer branches and the floor.

[0049] It should be noted that the first preset threshold may be 0.2 mm.

[0050] In this embodiment, the gap is provided to enable the antenna structure to produce better resonance in the high frequency band.

[0051] In a specific embodiment, the antenna substrate is a PCB board.

[0052] In a specific embodiment, the dielectric constant of the antenna substrate is 4.4.

[0053] In a specific embodiment, the dielectric loss tangent of the antenna substrate is 0.02.

[0054] It should be noted that the antenna substrate in this embodiment adopts FR4_proxy (PCB) with a dielectric constant of 4.4 and a dielectric loss tangent of 0.02.

[0055] In a specific embodiment, the dielectric material used for the radiation branch is copper.

[0056] In a specific embodiment, the floor is disposed below the antenna substrate.

[0057] In a specific embodiment, the coaxial feed line is a 50Ω microstrip line.

[0058] It should be noted that the top-layer branches are fed through a 50Ω microstrip coaxial line.

[0059] In a specific embodiment, the overall size of the antenna structure is 155×73×0.8 mm 3 .

[0060] It should be noted that if Figure 2 As shown, the length L1 of the antenna structure is 155 mm, the width L2 is 73 mm, and the thickness L4 is 0.8 mm.

[0061] In a specific embodiment, the clearance area occupied by the radiation branches is 15×73 mm 2 .

[0062] It should be noted that the radiation branches are located at the top and bottom of the entire antenna structure, such as Figure 2As shown, the side length L3 of the area where the radiation branches are laid is 15 mm, and the other side length is equal to the width L2 of the antenna structure, which is 73 mm, so the occupied clearance area is 15×73 mm 2 .

[0063] In a specific embodiment, the area of ​​the floor can be 140×73 mm 2 .

[0064] It should be noted that if Figure 2 As shown, the length of the floor is L1-L3=155-15mm=140mm. The width of the floor is equal to the width L2 of the antenna structure, which is 73mm.

[0065] In a specific embodiment, the structural dimension parameters of the monopole are: L3=15±0.5mm, L5=6±0.5mm, L6=6.5±0.5mm, L7=7.5±0.5mm.

[0066] In a specific embodiment, the structural dimension parameter of the L-shaped branch is: L8=1.5±0.5mm.

[0067] In a specific embodiment, the structural size parameters of the serpentine branches are: L11=48±0.5mm, L12=7±0.5mm, L13=1.5±0.5mm, L14=1.5±0.5mm, L15=4.5±0.5mm, L16=2.5±0.5mm, L17=20.5±0.5mm.

[0068] In a specific embodiment, the structural dimension parameters of the U-shaped branch are: L17=20.5±0.5mm, L23=11±0.5mm, L22=2.5±0.5mm, L21=25±0.5mm.

[0069] In a specific embodiment, the structural dimension parameters of the bottom branch are: L9=1.5±0.5mm, L18=13±0.5mm, L19=8±0.5mm, L24=45±0.5mm, L20=18±0.5mm

[0070] In a specific embodiment, the structural dimension parameter of the coaxial line is: L10=1.5 mm.

[0071] In a specific application example, the effect achieved by an antenna structure provided by the utility model will be further described in combination with simulation results.

[0072] This application example uses Figure 3Taking the antenna parameter values ​​(in millimeters) shown in the figure as an example, the antenna structure of this embodiment is built, and the left half of the top branch (hereinafter referred to as the first antenna part), the right half of the top branch (hereinafter referred to as the second antenna part), the entire top branch (hereinafter referred to as the third antenna part), the right half of the top branch and the bottom branch (hereinafter referred to as the fourth antenna part), the left half of the top branch and the bottom branch (hereinafter referred to as the fifth antenna part), and the overall antenna structure (hereinafter referred to as the fifth antenna part) are simulated respectively, and the simulation results of each part are obtained as shown in the figure Figure 4-Figure 7 shown.

[0073] Among them, the structural size parameters of the radiation branches and coaxial lines are as follows: Figure 3 Shown: L3=15mm, L5=6mm, L6=6.5mm, L7=7.5mm, L8=1.5mm, L11=48mm, L12=7mm, L13=1.5mm, L14=1.5mm, L15=4.5mm, L16=2.5mm, L 17=20.5mm, L17=20.5mm, L23=11mm, L22=2.5mm, L21=25mm, L9=1.5mm, L18=13mm, L19=8mm, L24=45mm, L20=18mm, L10=1.5mm.

[0074] in, Figure 5 In the figure, the two curves on the far left represent low-band gain and low-band efficiency, and the two curves on the far right represent mid-band gain and mid-band efficiency. Figure 6 The two leftmost curves in the figure represent the gain and efficiency curves near 3.5 GHz, and the two rightmost curves represent the gain and efficiency curves near 4.9 GHz.

[0075] For the first antenna part (only the left half of the top branch): according to Figure 3 From the curve indicated by Ant1, it can be seen that the first antenna part can achieve -6dB resonance at 1.48GHz-3.2GHz, and the resonance includes two modes (analyzed by the input impedance diagram). This shows that the left half of the branch provides the overall antenna with mid-frequency resonance.

[0076] For the second antenna part (only the right half of the top branch): according to Figure 3 From the curve indicated by Ant2 in , it can be seen that the antenna only produces -10 dB resonance at 4.63GHz-5.06GHz and -6dB resonance at 1.58GHz-1.82GHz, and the antenna also has certain resonance near 800MHz and 2.8GHz. Therefore, the right half of the branches on the top layer provide resonance for the antenna as a whole in the low and high frequency bands.

[0077] For the third antenna section (only the top left and right branches): Figure 3 From the curve indicated by Ant3 in FIG, it can be seen that the antenna achieves a -10dB bandwidth in the mid-frequency band (1.7GHz-2.7GHz), meeting the required mid-frequency band indicators, and also meets the -10dB bandwidth in the 4.5GHz-4.83GHz range.

[0078] For the fourth antenna part (the right half of the top branch and the bottom branch): according to Figure 4 From the curve indicated by Ant4, we can see that compared with the first antenna part and the second antenna part, the branches constituting the fourth antenna part enhance the resonance of the antenna in all frequency bands, especially in the low frequency band, where the -6dB bandwidth reaches 820MHz-990MHz, meeting the required low frequency band indicators. It can be seen that the coupling between the bottom branch and the top branch supplements the capacitance of the antenna impedance, making the antenna impedance match better and thus the antenna resonance better.

[0079] For the fifth antenna part (consisting of the top left half of the branches and the bottom branches): according to Figure 4 From the curve indicated by Ant5, it can be seen that the -6dB bandwidth of the fifth antenna part reaches 1.53GHz-4.65GHz, which increases the frequency band near 3.5GHz required by the first antenna part compared to the first antenna part.

[0080] For the sixth antenna part: according to Figure 4 It can be seen from the curve indicated by Ant6 that the overall antenna structure of the utility model reaches -6dB bandwidth in the low frequency band (824GHz-960GHz), -10dB bandwidth in the mid-frequency band (1.7GHz-2.7GHz), and the return loss in the high frequency band (3.4GHz-3.6GHz, 4.8-5.0GHz) reaches -10dB bandwidth; 4.8GHz-5GHz reaches -10dB bandwidth, and according to Figure 5-Figure 6 It can be seen that the overall efficiency of the antenna in each frequency band is greater than 50%, the gain in the low frequency band is greater than 0.5dBi, and the gain in the medium and high frequency bands is greater than 2dBi.

[0081] From the above simulation analysis, it can be seen that the antenna structure provided by the utility model can cover a wider frequency band by setting the top branch and the bottom branch coupling, and can achieve a better matching effect without using lumped elements or matching networks. The structure is relatively simple, the cost is low, and it is easy to mass produce.

[0082] The utility model also provides a mobile terminal, comprising any antenna structure as described above.

[0083] The utility model is based on the principle of generating multiple resonance modes by coupling multiple branches. By adding radiation branches to basic types of antennas (such as monopole, loop antenna, inverted F antenna, etc.), different resonance frequencies are generated by coupling branches of different lengths, thereby widening the bandwidth.

[0084] The utility model designs an antenna structure with a relatively simple structure and low cost to achieve equal or even better performance, can easily cover a wider frequency band, and can achieve better matching effect without using lumped elements or matching networks. The structure is relatively simple, the cost is low, and it is easy to mass produce.

[0085] The above is a detailed introduction to an antenna structure and a mobile terminal provided by the utility model. For a person skilled in the art, according to the idea of ​​the embodiment of the utility model, there may be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the utility model.

Claims

1. An antenna structure, characterized in that: include: Antenna substrates and floors; A radiation branch is laid on one side of the antenna substrate, and the radiation branch includes a top branch and a bottom branch; the bottom branch is connected to the floor; The top-layer branches are connected to the coaxial feeder and connected to the floor through the coaxial feeder; the top-layer branches include monopoles, L-shaped branches, serpentine branches and U-shaped branches that are connected in sequence.

2. The antenna structure according to claim 1, characterized in that: The underlying branches have an inverted F-shaped structure.

3. The antenna structure according to claim 2, characterized in that: The monopole and the L-shaped branch are distributed on one side of the connection between the coaxial feed line and the top-layer branch, and the serpentine branch and the U-shaped branch are distributed on the other side of the connection.

4. The antenna structure according to claim 3, characterized in that: A gap having a width of a first preset threshold is provided between the top-layer branches and the floor.

5. The antenna structure according to claim 1, characterized in that: The antenna substrate is a PCB board.

6. The antenna structure according to claim 5, characterized in that: The dielectric constant of the antenna substrate is 4.

4.

7. The antenna structure according to claim 5, characterized in that: The dielectric loss tangent of the antenna substrate is 0.

02.

8. The antenna structure according to claim 5, characterized in that: The dielectric material used in the radiation branches is copper.

9. The antenna structure according to claim 1, characterized in that: The floor is arranged below the antenna substrate.

10. A mobile terminal, characterized in that: It comprises the antenna structure as described in any one of claims 1 to 9.

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