Small-area PCB antenna for TWS earphone

Abstract

The utility model provides a small-area PCB antenna used for a TWS earphone, comprising a PCB substrate, the top layer and the bottom layer of the PCB substrate are respectively provided with a copper foil layer, the PCB substrate is provided with a metal via hole penetrating through the top layer and the bottom layer of the PCB substrate, the PCB substrate is provided with an antenna conductor, the antenna conductor comprises two sections of wires, and the two sections of wires are arranged on the PCB substrate. The antenna conductor is arranged at the top layer position of the PCB substrate, the antenna conductor is electrically connected through a metal via hole, and the PCB substrate is also provided with a resonance feed circuit; the antenna conductor is provided with two wiring sections, one wiring section is a bent wiring section, and the other wiring section is a linear wiring section. According to the utility model, the Bluetooth antenna is directly formed on the PCB, and compared with other Bluetooth antennas with the same structure in the market, the Bluetooth antenna has the characteristics of small area, low cost, stable signal and good parameter consistency.

Description

Technical Field

[0001] The utility model relates to the technical field of antennas, and in particular to a small-area PCB antenna for a TWS headset. Background Art

[0002] With the rapid development of the current technology industry, a variety of products have emerged as consumers have higher demands on the configuration and experience of consumer electronic products. Among them, TWS (True Wireless Stereo) headphones, as one of the products closest to consumers, have developed particularly rapidly.

[0003] Traditional wired headphones have the characteristics of low latency and high sound quality, but they also have the limitations of poor portability and high interface compatibility requirements. As major handheld mobile device manufacturers have cancelled the wired headphone interface in order to achieve better industrial design, TWS wireless headphones with the characteristics of small size, stylish appearance and high-quality wireless transmission for both ears have quickly gained unanimous favor from consumers, ushering in an inflection point of exponential growth.

[0004] As an important component for TWS headset signal transmission, the performance of the antenna will directly affect the consumer's experience. Currently, most TWS headset antennas on the market use LDS laser antenna or FPC antenna design.

[0005] With the development of the TWS headset industry, in order to pursue a better user wearing experience and reduce the production cost of headsets, the size of TWS wireless headsets has been designed to be smaller and smaller, so that all components will be integrated into a very narrow headset space, resulting in a worse overall antenna environment. In this environment, the design of common LDS laser engraved antennas or FPC antennas has been difficult to meet the performance requirements of the antenna, and has no cost advantage. Therefore, the design of PCB antennas on TWS headsets has been favored by more and more manufacturers. However, traditional PCB antennas, if they want large bandwidth and high efficiency, will require a larger antenna area, which cannot meet the needs of small-volume TWS headsets.

[0006] Therefore, in order to solve the technical problem of how to design a PCB Bluetooth antenna with large bandwidth, high efficiency and stable transmission in a more extreme antenna environment, the utility model uses a resonant feeding circuit to design a small-area PCB antenna for TWS headphones, which largely solves the current industry problems. Utility Model Content

[0007] In view of the limitations of the current TWS earphones, such as small size, narrow space and poor antenna environment, the utility model designs a small-area PCB for TWS earphones to maximize the use of the antenna environment and a PCB Bluetooth antenna with a resonant feeding circuit.

[0008] The utility model is specifically implemented through the following technical solutions:

[0009] A small-area PCB antenna for a TWS headset comprises a PCB substrate, wherein the top layer and the bottom layer of the PCB substrate are respectively provided with copper foil layers, the PCB substrate is provided with metal vias penetrating the top layer and the bottom layer of the PCB substrate, the PCB substrate is provided with an antenna conductor, the antenna conductor comprises two sections of routing, the antenna conductor is arranged at the top layer position of the PCB substrate, the antenna conductor is electrically connected through the metal vias, and the PCB substrate is further provided with a resonant feeding circuit; the two sections of routing of the antenna conductor, one section is a routing in a bent shape, and the other section is a routing in a straight shape.

[0010] As a further improvement of the present invention, the resonant feeding circuit includes an inductor LF and capacitors CF and CL, the inductor is connected in series to the TWS earphone mainboard, and the capacitors are respectively connected in parallel to the TWS earphone mainboard.

[0011] As a further improvement of the present invention, the bent-shaped routing is located above the PCB substrate area, and the straight-shaped routing is located below the PCB substrate area.

[0012] As a further improvement of the utility model, the antenna conductor is formed by a copper foil layer having a bent shape and a straight shape.

[0013] As a further improvement of the utility model, the PCB substrate is provided with a first feed circuit, a second feed circuit, a first radiation area, and a second radiation area. The first feed circuit is located at the right end area of ​​the straight line, the first feed circuit includes a capacitor CL, the second feed circuit is located at the end areas on both sides of the bent line, the second feed circuit includes an inductor LF and a capacitor CL. The first radiation area is located in the area surrounded by the first vertical area and the first horizontal area, and the second radiation area is located in the area below the second horizontal area.

[0014] As a further improvement of the present invention, the metal via is located in the upper right area of ​​the first vertical area and the upper right area of ​​the first horizontal area, and the metal via is located below the second horizontal area, with one metal via being provided on both sides.

[0015] As a further improvement of the present invention, the diameter of the metal via is 0.1mm, the center distance between the two metal vias of the bent shape routing is W2, W2=2.15mm, and the center distance between the two metal vias of the straight shape routing is W3, W3=3.5mm. The parallel distance between the bent shape routing and the straight shape routing is W4, W4=0.95mm. The length and width of the upper antenna conductor size are W1, L1, and L2 respectively, wherein W1=1.25mm, L1=2.05mm, and L2=3.80mm.

[0016] The beneficial effects of the utility model are: the small-area PCB antenna for TWS headphones of the utility model directly forms a Bluetooth antenna on the PCB board. Compared with other Bluetooth antennas with the same structure on the market, it has the characteristics of small area, low cost, stable signal and good parameter consistency. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the overall structure of the PCB antenna of the utility model. Figure 1 ;

[0018] Figure 2 This is a schematic diagram of the overall structure of the PCB antenna of the utility model. Figure 2 ;

[0019] Figure 3 This is a schematic diagram of the overall structure of the PCB antenna of the utility model. Figure 3 ;

[0020] Among them, 1. PCB substrate; 2. metal via; 3. antenna conductor; 4. resonant feeding circuit; 5. first feeding circuit; 6. second feeding circuit; 7. first radiation area; 8. second radiation area; 9. bending-shaped routing; 10. straight-line routing; 11. first vertical area; 12. first horizontal area; 13. second horizontal area; 21. first metal via; 22. second metal via; 23. third metal via; 24. fourth metal via. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only 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.

[0022] The PCB antenna designed in the utility model is made of FR4 process material. Different from the traditional PCB antenna, the PCB antenna of the utility model requires a very small area, which can meet the environmental requirements of small size and narrow space of TWS headphones.

[0023] like Figure 1-3 As shown, the small-area PCB antenna for TWS earphones of the utility model includes a PCB substrate 1. The top layer and the bottom layer of the PCB substrate are respectively provided with copper foil layers, the PCB substrate 1 is provided with a metal via 2 penetrating the top layer and the bottom layer of the PCB substrate, and the PCB substrate is provided with an antenna conductor 3.

[0024] The antenna conductor 3 includes two sections of wiring. The antenna conductor 3 is arranged on the top layer of the PCB substrate. The two sections of wiring of the antenna conductor 3 are electrically connected through the metal via 2 .

[0025] The PCB substrate 1 is also provided with a resonant feeding circuit 4, which includes an inductor (LF) and two capacitors (CL, CF). The inductor can be connected in series to the TWS earphone motherboard, that is, one end of the inductor is connected to the antenna conductor of the PCB substrate 1, and the other end is connected to the signal pin of the TWS earphone motherboard chip. The two capacitors can be connected in parallel to the TWS earphone motherboard, that is, one end of the capacitor is connected to the antenna conductor of the PCB substrate 1, and the other end is connected to the ground of the TWS earphone motherboard.

[0026] Specifically, in order to facilitate assembly and production, in this embodiment, the antenna conductor 3 is formed by a copper foil layer with one section being a bent shape and the other section being a straight shape. For the antenna conductor 3, it is directly etched on the PCB substrate 1 by copper foil, and does not require manual patch or post-welding processing, which can reduce the impact of human or process factors. Compared with conventional FPC and LDS laser engraving antennas, its signal strength and parameter consistency will be better.

[0027] The two parts of the antenna conductor 3 are respectively arranged in the upper area and the lower area of ​​the top layer of the PCB substrate 1, and the antenna conductor 3 is electrically connected through the metal via 2. As for the relationship between the PCB substrate 1 and the antenna conductor 3, in this embodiment, the PCB substrate 1 is provided with two sections of routing lines with different shapes, one section is a bending-shaped routing line 9, and the other section is a straight-shaped routing line 10. The two sections of routing lines on the PCB substrate 1 are separated into two areas, the bending-shaped routing line is located above the PCB substrate 1 area, and the straight-shaped routing line is located below the PCB substrate 1 area.

[0028] Specifically, there are four metal vias 2, wherein the first metal via 21 and the second metal via 22 are respectively located in the upper right area of ​​the first vertical area 11 and the upper right area of ​​the first horizontal area 12, and the third metal via 23 and the fourth metal via 24 are respectively located on the left and right sides below the second horizontal area 13.

[0029] In order to make the overall size of the PCB substrate 1 smaller, a resonant feeding circuit 4 is provided on the PCB substrate 1. The resonant feeding circuit 4 includes an inductor (LF) and two capacitors (CL, CF). The inductor can be connected in series to the TWS headset mainboard, and the capacitors can be connected in parallel to the TWS headset mainboard respectively. The antenna resonant frequency and impedance position can be adjusted by modifying the capacitance or inductance value of the resonant feeding circuit 4, thereby reducing the area of ​​the PCB antenna, which is suitable for various small TWS Bluetooth headsets.

[0030] In order to stabilize the signal of the antenna conductor 3, in this embodiment, a resonant feeding circuit 4 is provided on the PCB substrate 1, and the resonant frequency of the antenna conductor 3 is adjusted to the best by modifying the value of the capacitor CL, for example, CL=1.0pF. The input impedance of the antenna conductor 3 is adjusted to the best position by modifying the value of the capacitor CF, for example, CF=1.2pF.

[0031] In order to further enhance the bandwidth of the antenna conductor 3, in this embodiment, a resonant feeding circuit 4 is provided on the PCB substrate 1, and broadband impedance matching of the antenna conductor 3 is achieved by selecting appropriate values ​​of the inductor LF and the capacitor CF, for example, LF = 10nH, CF = 1.0pF.

[0032] Specifically, the resonant feeding circuit 4 includes a first feeding circuit 5 and a second feeding circuit 6. The first feeding circuit 5 is located at the right end area of ​​the straight line 10, and the first feeding circuit 5 includes a capacitor CL. The second feeding circuit 6 is located at the end areas on both sides of the bent line 9, and the second feeding circuit 6 includes an inductor LF and a capacitor CL. The antenna conductor 3 includes a first radiation area 7 and a second radiation area 8, wherein the first radiation area 7 is located in the area surrounded by the first vertical area 11 and the first horizontal area 12, and the second radiation area 8 is located in the area below the second horizontal area 13.

[0033] Regarding the specific size of the antenna conductor, in this embodiment, the length of the first arm of the bent shape trace 9 is W1, the length of the second arm is L1, the length of the straight shape trace 10 is L2, and the second arm is parallel to the straight antenna conductor, and W1=1.25mm, L1=2.05mm, L2=3.80mm.

[0034] Furthermore, the diameter of the metal via is 0.1 mm, the center distance between the two metal vias 21, 22 of the bent shape trace 9 is W2, W2 = 2.15 mm, and the center distance between the two metal vias 23, 24 of the straight shape trace 10 is W3, W3 = 3.5 mm. The distance between the second arm of the bent shape trace 9 and the straight shape trace 10 is W4, W4 = 0.95 mm.

[0035] The technical problems and solutions in the antenna design process of the utility model are as follows:

[0036] 1. Due to the size limitation of TWS earphones, it is necessary to design antenna routing on a very small earphone motherboard. Some areas of the motherboard will have sensitivity interference problems. If the antenna routing is in the projection area where interference exists, it will cause sensitivity interference. At present, the main routing design of the PCB antenna avoids the area where interference exists, which not only improves the antenna radiation efficiency, but also does not cause sensitivity interference problems.

[0037] 2. Since the design area of ​​the PCB antenna is very small, the wavelength length required for the antenna resonant frequency is not enough, which will lead to the problem that the antenna frequency resonance cannot reach the optimal level. At present, the PCB antenna is designed with a feeding circuit. This problem is solved by modifying the capacitance value on the feeding circuit and controlling the frequency resonance of the antenna.

[0038] 3. The PCB antenna has a very small design area, so the antenna bandwidth is very narrow and cannot meet the use requirements. At present, the PCB antenna is designed with a feeding circuit, and the bandwidth of the antenna is enhanced by selecting a suitable inductance and capacitance ratio.

[0039] The advantage of the solution of the utility model is that it can obtain the most extreme antenna passive efficiency in a harsh antenna environment, enhance the antenna bandwidth, and have a great effect on the OTA data of the whole machine and the actual measurement effect.

[0040] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0041] The above contents are further detailed descriptions of the present invention in combination with specific preferred implementations, and the specific implementation of the present invention cannot be considered to be limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.

Claims

1. A small-area PCB antenna for TWS earphones, characterized in that: The antenna includes a PCB substrate, the top layer and the bottom layer of the PCB substrate are respectively provided with copper foil layers, the PCB substrate is provided with metal vias penetrating the top layer and the bottom layer of the PCB substrate, the PCB substrate is provided with an antenna conductor, the antenna conductor includes two sections of routing, the antenna conductor is arranged at the top layer of the PCB substrate, the antenna conductor is electrically connected through the metal vias, and the PCB substrate is also provided with a resonant feeding circuit; the two sections of the antenna conductor routing, one section is a bent routing, and the other section is a straight routing.

2. The small-area PCB antenna according to claim 1, characterized in that: The resonant feeding circuit includes an inductor LF and capacitors CF and CL. The inductor is connected in series to the TWS earphone mainboard, and the capacitors are connected in parallel to the TWS earphone mainboard respectively.

3. The small-area PCB antenna according to claim 1, characterized in that: The antenna conductor is formed of a copper foil layer having a bent section and a straight section.

4. The small-area PCB antenna according to claim 1, characterized in that: The bent wiring is located above the PCB substrate area, and the straight wiring is located below the PCB substrate area.

5. The small-area PCB antenna according to claim 1, characterized in that: The PCB substrate is provided with a first feeding circuit, a second feeding circuit, a first radiation area, and a second radiation area; the first feeding circuit is located in the right end area of ​​the straight-shaped routing, the first feeding circuit includes a capacitor CL, the second feeding circuit is located in the end areas on both sides of the bent-shaped routing, the second feeding circuit includes an inductor LF and a capacitor CL; the first radiation area is located in the area surrounded by the first vertical area and the first horizontal area, and the second radiation area is located in the area below the second horizontal area.

6. The small-area PCB antenna according to claim 5, characterized in that: The metal via is located in the upper right area of ​​the first vertical area and the upper right area of ​​the first horizontal area. The metal via is located below the second horizontal area, and one metal via is provided on the left and right sides.

7. The small-area PCB antenna according to claim 1, characterized in that: The diameter of the metal via is 0.1 mm.

8. The small-area PCB antenna according to claim 1, characterized in that: The center distance between the two metal vias of the bent routing is W2, W2 = 2.15 mm, and the center distance between the two metal vias of the straight routing is W3, W3 = 3.5 mm.

9. The small-area PCB antenna according to claim 1, characterized in that: The length of the first arm of the bent shape routing is W1, the length of the second arm is L1, the length of the straight shape routing is L2, the second arm is parallel to the straight antenna conductor, W1=1.25mm, L1=2.05mm, L2=3.80mm; the parallel distance between the bent shape routing and the straight shape routing is W4, W4=0.95mm.

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