A method for broadening the bandwidth of a board-mounted planar inverted F antenna and enabling dynamic tuning

Abstract

The present invention discloses a method for broadening the bandwidth of a board-mounted planar inverted F antenna and dynamically tuning it, and belongs to the field of wireless communication technology. The method includes adding a branch to the end of a conventional PIFA antenna, and setting a length adjustment mechanism on the branch; the branch is used to adjust the relative position of the length adjustment mechanism on the PIFA antenna to adjust the bandwidth of the antenna; the length adjustment mechanism adjusts its own depth on the PIFA to adjust the center frequency of the PIFA antenna. Under the premise of miniaturization of the same-screen device product, the present invention can expand the bandwidth of the PIFA antenna to cover the entire WLAN 5G frequency band range. Compared with conventional PIFA, the bandwidth is increased by more than 1 times. Adding a structural component can meet the method of dynamically adjusting the center frequency while broadening the bandwidth, reducing the design and debugging time and adapting to different models. In addition, the present invention adopts a combination of PIFA and structural components to achieve artificial dynamic tuning and increase bandwidth.

Description

Technical Field

[0001] The invention relates to wireless communications, and in particular to a method for broadening the bandwidth of a board-mounted planar inverted F antenna and enabling dynamic tuning. Background Art

[0002] In the field of wireless communications, the onboard planar inverted F antenna (PIFA) has become the preferred antenna type for many wireless devices due to its miniaturization, cost-effectiveness, and easy integration. However, PIFA antennas also face challenges such as relatively narrow bandwidth and insufficient tuning flexibility, which limits their performance in multi-band and high-performance applications.

[0003] The development of wireless communication and the miniaturization of wireless products have put forward more and more requirements for the design of communication antennas. Planar inverted F antenna (PIFA) has the advantages of small size, light weight, small backward radiation, and low cost, and has become the main form of built-in antennas. The design principle of PIFA antenna is based on planar monopole antenna. By adjusting the structural parameters such as the resonant length, height, and distance between the feed point and the ground point of the antenna, the input impedance, resonant frequency, and impedance bandwidth of the antenna can be affected. However, the shrinking space and the widening of the working frequency band are a huge challenge to the bandwidth design of the antenna. Planar inverted F antenna (PIFA) is a narrowband antenna with a bandwidth of about 5~10%, which corresponds to the current WLAN5G working bandwidth requirements: 5.15-6G, a total of 850M bandwidth, which is far from meeting the requirements. At present, there are many ways to provide the bandwidth of PIFA antennas, such as adding parasitic patches, changing the feed point structure, adding multiple layers of patches or multiple branches, opening rectangular grooves, etc. However, under the premise of miniaturization of design, the above methods are difficult to achieve. Therefore, it is particularly important to develop a method that can widen the bandwidth of the onboard planar inverted F antenna and realize dynamic tuning. Summary of the invention

[0004] Purpose of the invention: The purpose of the present invention is to provide a method for broadening the bandwidth of a board-mounted planar inverted-F antenna and dynamically tuning it, so as to solve the problem that the current antenna bandwidth expansion method is difficult to achieve under the premise of miniaturization of the design.

[0005] Technical solution: A method for broadening the bandwidth of a board-mounted planar inverted F antenna and dynamically tuning it, comprising adding a branch to the end of a conventional PIFA antenna and providing a length adjustment mechanism on the branch; the branch is used to adjust the relative position of the length adjustment mechanism on the PIFA antenna to adjust the bandwidth of the antenna; the length adjustment mechanism adjusts the center frequency of the PIFA antenna by adjusting its own depth on the PIFA.

[0006] Preferably, the length adjustment mechanism is a bolt, a screw hole is provided on the branch line, and the bolt is screwed into the screw hole.

[0007] Preferably, the length adjustment mechanism includes an adjusting rod, which passes through the branch, and the outer wall of the adjusting rod is provided with a plurality of groups of grooves, each group of grooves has two grooves, and are symmetrically distributed along the central axis of the adjusting rod, and a protrusion is movably provided inside the groove, and a spring is fixed between the protrusion and the groove.

[0008] Preferably, the protrusion extends from a section away from the spring to the outside of the groove and has an arc-shaped structure.

[0009] Preferably, the distance between two adjacent groups of grooves is the same as the thickness of the PIFA antenna carrier.

[0010] Preferably, the length adjustment mechanism includes a mounting box fixedly mounted on the PIFA antenna carrier, an encoder mounted on the mounting box, and a screw that penetrates the mounting box and the PIFA antenna carrier; a driving gear is rotatably connected inside the mounting box, a central axis of the driving gear is fixedly connected to an output end of the encoder, a driven gear is rotatably arranged inside the mounting box on one side of the driving gear, the driven gear is meshed with the driving gear, a threaded barrel is fixed in the middle of the driven gear, the threaded barrel is rotatably connected to the mounting box, and the screw is threadedly connected to the threaded barrel.

[0011] Preferably, nuts are fixedly provided at both ends of the screw rod.

[0012] Preferably, the driving gear and the driven gear have the same specifications and sizes, the spacing between two adjacent gaps on the encoding disk in the encoder is the same as the spacing between two adjacent teeth of the driving gear, and the distance that the driven gear rotates one tooth is the same as the pitch of a screw.

[0013] Beneficial effects: Under the premise of miniaturization of the same-screen device product, the present invention can expand the bandwidth of the PIFA antenna to cover the entire WLAN 5G frequency band range. Compared with the conventional PIFA, the bandwidth is increased by more than 1 times. Adding a structural component can not only broaden the bandwidth but also meet the method of dynamically adjusting the center frequency point, reduce the design and debugging time and adapt to different models. In addition, the present invention adopts the combination of PIFA and structural components to realize manual dynamic tuning and increase bandwidth. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic diagram of a conventional PIFA antenna;

[0015] Figure 2 This is the result diagram of conventional PIFA antenna simulation bandwidth;

[0016] Figure 3 is a diagram of the simulation bandwidth result of the antenna of the present invention;

[0017] Figure 4 is a schematic diagram of the antenna structure of Example 1;

[0018] Figure 5 is a schematic diagram of the antenna structure of Example 2;

[0019] Figure 6 It is a partial cross-sectional structural schematic diagram of the adjusting rod;

[0020] Figure 7 is a schematic diagram of the antenna structure of Example 3;

[0021] Figure 8 It is a schematic diagram of the internal structure of the installation box;

[0022] Fig. 9 It is a schematic diagram of the screw-in depth of the length adjustment mechanism.

[0023] In the figure: 100, length adjustment mechanism; 200, PIFA antenna; 300, branch; 1001, bolt; 1002, adjustment rod; 1003, bump; 1004, groove; 1005, spring; 1006, screw rod; 1007, installation box; 1008, encoder; 1009, nut; 10010, driven gear; 10011, threaded barrel; 10012, driving gear. DETAILED DESCRIPTION

[0024] In order to make the technical solution of the present invention clearer, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] Conventional PIFA antennas such as Figure 1 , the antenna size is 7.8*2.6mm, and the corresponding simulation bandwidth results are as follows Figure 2 As shown in the figure, the -10Db bandwidth is in the 5.1G-5.6G frequency band, with a bandwidth of 500MHz. The bandwidth is 9% of the center frequency of S11 (center frequency 5.5G), which is within the performance range of a normal PIFA antenna. Figure 2 The results show that the bandwidth requirement of 850MHz for 5.15-6G products is far from enough. Therefore, the present invention adds a branch 300 at the end of the PIFA antenna 200 and sets a length adjustment mechanism 100 on the branch; the branch 300 is used to adjust the relative position of the length adjustment mechanism 100 on the PIFA antenna 200 to adjust the bandwidth of the antenna. The simulation results are shown in Figure 2. Figure 3 In addition, the length adjustment mechanism 100 adjusts the center frequency of the PIFA antenna 200 by adjusting its depth on the PIFA antenna 200, as shown in FIG. Fig. 9 As shown, the length adjustment mechanism 100 is adjusted to 1mm / 2mm / 3mm away from the board surface for testing, and the relevant results are shown in the following table:

[0026] ; Example 1

[0027] like Figure 4 As shown, the length adjustment mechanism 100 is a bolt 1001 screwed into a screw hole provided on the branch 300. By manually rotating the bolt 1001, the distance from the antenna carrier surface can be adjusted, and the center frequency of the PIFA antenna 200 can be adjusted. Example 2

[0028] like Figure 5 , 6 As shown, the length adjustment mechanism 100 is an adjustment rod 1002 that passes through the branch 300. The outer wall of the adjustment rod 1002 is provided with a plurality of groups of grooves 1004. The number of each group of grooves 1004 is two, and they are symmetrically distributed along the central axis of the adjustment rod 1002. The spacing between two adjacent groups of grooves 1004 is the same as the thickness of the PIFA antenna carrier. A protrusion 1003 is movably provided inside the groove 1004. A spring 1005 is fixed between the protrusion 1003 and the groove 1002. A section of the protrusion 1003 away from the spring 1005 extends to the outside of the groove 1004 and is an arc-shaped structure. By pulling and pressing operations, the distance between the length adjustment mechanism 100 and the antenna carrier surface can be adjusted. Since the end of the protrusion 1003 is an arc-shaped structure, it will not affect the movement of the adjustment rod 1002. At the same time, when the adjustment is in place, the adjacent protrusions 1003 will be stuck on both sides of the antenna carrier to avoid displacement of the adjustment rod 1002, thereby adjusting the center frequency of the PIFA antenna 200. Example 3

[0029] like Figure 7 , 8As shown, the length adjustment mechanism 100 includes a mounting box 1007 fixedly mounted on the PIFA antenna carrier, an encoder 1008 mounted on the mounting box 1007, and a screw 1006 that penetrates the mounting box 1007 and the PIFA antenna carrier. Nuts 1009 are fixedly arranged at both ends of the screw 1006 to prevent the screw 1006 from falling off when adjusting the distance of the screw 1006. The mounting box 1007 is internally rotatably connected to a driving gear 10012, and the central axis of the driving gear 10012 is fixedly connected to the output end of the encoder 1008. Next, the interior of the installation box 1007 is located on one side of the driving gear 10012 and is rotatably provided with a driven gear 10010, the driven gear 10010 is meshed with the driving gear 10012, the driving gear 10012 and the driven gear 10010 have the same size, the spacing between two adjacent gaps on the code disk in the encoder 1008 is the same as the spacing between two adjacent teeth of the driving gear 10012, the distance of each rotation of one tooth of the driven gear 10010 is the same as one pitch of the screw 1006, and the distance of the movement of the screw 1006 can be calculated through the encoder. A threaded barrel 10011 is fixed in the middle of the driven gear 10010, the threaded barrel 10011 is rotatably connected to the installation box 1007, and the screw 1006 is screwed to the threaded barrel 10011. Through the existing remote control technology, the encoder 1008 is controlled to drive the driving gear 10012 to rotate, so that the driven gear 10010 and the threaded barrel 10011 can be rotated, and then the screw 1006 can be moved. At the same time, the movement distance of the screw 1006 can be calculated by the encoder 1008, and fed back to the remote control personnel through the existing data transmission technology (5G / 4G / WIFI, etc.). The distance of the length adjustment mechanism 100 can be adjusted remotely to adjust the distance from the antenna carrier board, and finally the center frequency of the PIFA antenna 200 can be adjusted.

[0030] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for broadening the bandwidth of a board-mounted planar inverted F antenna and dynamically tuning it, characterized in that: The invention comprises adding a branch circuit to a conventional PIFA antenna end and setting a length adjustment mechanism on the branch circuit; the branch circuit is used to adjust the relative position of the length adjustment mechanism on the PIFA antenna to adjust the bandwidth of the antenna; the length adjustment mechanism adjusts the central frequency point of the PIFA antenna by adjusting its depth on the PIFA; The length adjustment mechanism is a bolt, a screw hole is provided on the branch line, and the bolt is screwed into the screw hole; The length adjustment mechanism includes an adjustment rod, the adjustment rod passes through the branch, and the outer wall of the adjustment rod is provided with a plurality of groups of grooves, each group of grooves has two grooves, and the grooves are symmetrically distributed along the central axis of the adjustment rod, and a convex block is movably arranged inside the groove, and a spring is fixed between the convex block and the groove; The length adjustment mechanism includes a mounting box fixedly mounted on a PIFA antenna carrier, an encoder mounted on the mounting box, and a screw rod penetrating the mounting box and the PIFA antenna carrier; a driving gear is rotatably connected inside the mounting box, a central axis of the driving gear is fixedly connected to an output end of the encoder, a driven gear is rotatably arranged inside the mounting box on one side of the driving gear, the driven gear is meshed with the driving gear, a threaded barrel is fixed in the middle of the driven gear, the threaded barrel is rotatably connected to the mounting box, and the screw rod is threadedly connected to the threaded barrel.

2. The method for broadening the bandwidth of a board-mounted planar inverted F antenna and dynamically tuning it according to claim 1, characterized in that: The protrusion extends from a section of the spring to the outside of the groove and is an arc-shaped structure.

3. The method for broadening the bandwidth of a board-mounted planar inverted F antenna and enabling dynamic tuning according to claim 1, characterized in that: The distance between two adjacent groups of grooves is the same as the thickness of the PIFA antenna carrier.

4. The method for broadening the bandwidth of a board-mounted planar inverted-F antenna and dynamically tuning it according to claim 1, characterized in that: Nuts are fixedly arranged at both ends of the screw rod.

5. The method for broadening the bandwidth of a board-mounted planar inverted-F antenna and enabling dynamic tuning according to claim 1, characterized in that: The driving gear and the driven gear have the same specifications and sizes. The distance between two adjacent gaps on the encoding disk in the encoder is the same as the distance between two adjacent teeth of the driving gear. The distance that the driven gear rotates one tooth is the same as the pitch of one screw.

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