Multi-frequency broadband notch antenna and manufacturing method thereof

Abstract

The invention relates to the technical field of multi-frequency broadband notch antennas, in particular to a multi-frequency broadband notch antenna and a manufacturing method thereof. Comprising a signal feed-in point, a two-section PIFA antenna and an open-circuit linear wave trap. The double-section type PIFA antenna comprises a low-frequency PIFA oscillator which extends along one side of a signal feed-in point, a high-frequency PIFA oscillator which extends along the other side of the signal feed-in point, a ground plane which has a height difference with the low-frequency PIFA oscillator and the high-frequency PIFA oscillator, and a short-circuit pin which is arranged on the ground plane and is used for connecting the low-frequency PIFA oscillator and the high-frequency PIFA oscillator. The low-frequency PIFA oscillator and the high-frequency PIFA oscillator are in a U-shaped structure with the whole grounding surface through short-circuit pins. Therefore, the antenna can meet the transmission requirements of signals with different frequencies at the same time, for example, in the communication field, the antenna can adapt to frequency bands corresponding to various communication standards, for example, communication equipment with different frequency bands such as WIFI 6 (the working frequency band comprises 2.4 GHz frequency band), WIFI 6E or WIFI 7 (the working frequency band comprises about 5GHz frequency band) and the like can be adapted at the same time, and the universality of the antenna is effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of multi-frequency broadband notch antennas, and in particular to a multi-frequency broadband notch antenna and a manufacturing method thereof. Background Art

[0002] Now with the rapid development of short-range wireless communication network technology, the penetration rate of various mobile terminal devices in society is increasing very rapidly. WIFI network and 5G network are a huge market with great development space. The ultra-wideband backbone network brings rich network information resources. This high-speed broadband network can be used to establish various personal demand information. It can also allow individuals, families and enterprises to realize remote control and other application scenarios through the network. New market forms, among which the most convenient and fastest way of communication is wireless access, because wireless access saves a lot of network laying costs, easily realizes flexible access anytime and anywhere, and maintenance is relatively simple. WIFI6E and WIFI7 technology is an ultra-high-speed ultra-wideband communication technology. This technology uses the superposition of ultra-wideband frequency range and ultra-fast channel technology to easily achieve a single-channel operating rate of more than 1200Mbps. However, these technologies have an inherent problem. The doubled harmonic signal of the 2.4G band (frequency range 2.4GHz-2.5GHz) always interferes with the 5.8G band (5.125GHz-5.8125GHz). The doubled frequency of 2.5GHz is 5.0GHz, which is only 0.125GHz away from 5.125GHz. It is very easy to form sideband interference, resulting in a sharp drop in the communication quality of the lowest channel of 5.8GHz, or even unusable. In order to overcome this technical difficulty, notching at specific frequency points is an effective way.

[0003] Conventional single-frequency PIFA antennas have the advantages of simple structure, light weight, conformability, low manufacturing cost, and high radiation efficiency. Figure 1 The figure shows a typical PIFA antenna structure. By matching the length of 1 / 4λ with the center frequency, the effect of resonant radiation of electromagnetic waves can be achieved. Due to the simple structure of the PIFA antenna, it is very suitable for on-chip systems. Moreover, the PIFA antenna only needs to use a metal conductor with an appropriate feeder to access the signal port, so the production cost is low and it can be directly soldered to the PCB circuit board. However, the isolation degree generated by the conventional PIFA antenna with a bandwidth of 200MHz (4.925GHz-5.125GHz) is generally only about 2dB, and there is basically no isolation effect. Figure 2 shown. Summary of the invention

[0004] In order to overcome the above-mentioned shortcomings, the present invention aims to provide a technical solution that can solve the above-mentioned problems.

[0005] A multi-frequency broadband trap antenna comprises a signal feeding point, a double-section PIFA antenna and an open-circuit trap, wherein the double-section PIFA antenna comprises a low-frequency PIFA vibrator extending along one side of the signal feeding point, a high-frequency PIFA vibrator extending along the other side of the signal feeding point, a ground plane with a height difference with the low-frequency PIFA vibrator and the high-frequency PIFA vibrator, and a short-circuit pin arranged on the ground plane for connecting the low-frequency PIFA vibrator and the high-frequency PIFA vibrator; the low-frequency PIFA vibrator and the high-frequency PIFA vibrator are connected to the ground plane through the short-circuit pin to form a U-shaped structure as a whole; The open-line type trap adopts a 1 / 4λ open-line for a specific frequency point. The open-line is synchronously extended into an open-line at the signal feeding point, forming infinite absorption for the specific frequency point, and forming an absorption frequency point with the ground to improve the isolation of the antenna. Among them, λ in 1 / 4λ=C / f, C represents the speed of light in free space, and f is the operating frequency of the antenna.

[0006] Preferably, the height difference between the low-frequency PIFA vibrator and the ground plane is set to form a first waveguide coupling coefficient, thereby forming open radiation, and the end of the ground plane corresponding to the side of the low-frequency PIFA vibrator is bent and raised to form a coupling node of secondary coupling; the height difference between the high-frequency PIFA vibrator and the ground plane is set to form a second waveguide coupling coefficient, thereby forming open radiation.

[0007] Preferably, the length of the low-frequency PIFA vibrator and the high-frequency PIFA vibrator is calculated from the signal feeding point to the end of each resonant node, and the length is determined according to the formula 0.2λ, where λ=C / f, C represents the speed of light in free space, and f is the antenna operating frequency; the low-frequency PIFA vibrator resonates at a frequency point of 2.45 GHz, and the high-frequency PIFA vibrator resonates at a frequency point of 5.5 GHz.

[0008] Preferably, the low-frequency PIFA vibrator and the coupling node are configured to form a coupling capacitor C, and the coupling capacitor C is used for parallel calculation with the capacitive reactance value Cε in the air equivalent radiation to obtain the shortening coefficient of the low-frequency PIFA vibrator, forming an effective resonance in the frequency band of 2.4GHz-2.5GHz; the high-frequency PIFA vibrator adopts a conventional length design of 1 / 4λ to form an effective resonance in the frequency band of 5.125GHz-5.8125GHz.

[0009] Preferably, the signal feed point of the multi-band broadband trap antenna, the double-section PIFA antenna and the open-circuit trap are all manufactured by metal stamping technology, and the multi-band broadband trap antenna is connected to the product by cable.

[0010] Preferably, the signal feeding point of the multi-frequency broadband trap antenna, the double-section PIFA antenna and the open-line trap are all formed by welding a plurality of PCBs.

[0011] A method for manufacturing a multi-frequency broadband notch antenna, used to manufacture the multi-frequency broadband notch antenna described above, comprises the following steps: Step 1, determine the signal feeding point, set a trapezoidal structure, and determine the signal feeding point at the center position of the trapezoidal structure; Step 2, making a double-section PIFA antenna, including a low-frequency PIFA vibrator extending along one side of a signal feeding point, a high-frequency PIFA vibrator extending along the other side of the signal feeding point, a ground plane with a height difference with the low-frequency PIFA vibrator and the high-frequency PIFA vibrator, and a short-circuit pin arranged on the ground plane for connecting the low-frequency PIFA vibrator and the high-frequency PIFA vibrator; setting the height difference between the low-frequency PIFA vibrator and the ground plane to form a first waveguide coupling coefficient to form open radiation, and making the end of the ground plane corresponding to the side of the low-frequency PIFA vibrator bend and rise to form a coupling section of secondary coupling; setting the height difference between the high-frequency PIFA vibrator and the ground plane to form a second waveguide coupling coefficient to form open radiation; making the low-frequency PIFA vibrator and the high-frequency PIFA vibrator The oscillators are connected to the ground plane through the short-circuit pin to form a U-shaped structure as a whole; the lengths of the low-frequency PIFA oscillator and the high-frequency PIFA oscillator are calculated from the signal feeding point to the end of each resonant node, and the lengths are determined according to the formula 0.2λ, so that the low-frequency PIFA oscillator resonates at a frequency point of 2.45GHz and the high-frequency PIFA oscillator resonates at a frequency point of 5.5GHz; the low-frequency PIFA oscillator and the coupling node are set to form a coupling capacitor C, and the shortening coefficient of the low-frequency PIFA oscillator is calculated in parallel with the capacitive reactance value Cε in the air equivalent radiation to form an effective resonance in the frequency band of 2.4GHz-2.5GHz, and the high-frequency PIFA oscillator is designed with a conventional length of 1 / 4λ to form an effective resonance in the frequency band of 5.125GHz-5.8125GHz; Step 3, make an open-line type trap, using a 1 / 4λ open-line for a specific frequency point. The open-line is synchronously extended into an open-line at the signal feeding point, so that it forms infinite absorption for the specific frequency point, and forms an absorption frequency point with the ground to improve the isolation of the antenna, where λ in 1 / 4λ = C / f, C represents the speed of light in free space, and f is the operating frequency of the antenna.

[0012] Preferably, the signal feed point of the multi-band broadband trap antenna, the dual-section PIFA antenna and the open-circuit trap are all manufactured by metal stamping technology and then connected to the product by cables.

[0013] Preferably, the signal feed point of the multi-band broadband trap antenna, the dual-section PIFA antenna and the open-line trap are all formed by welding a plurality of PCBs.

[0014] Compared with the prior art, the present invention has the following beneficial effects: 1) Multi-band working advantage: This multi-band broadband notch antenna can work effectively in multiple frequency bands. Through the design of the dual-section PIFA antenna, the low-frequency PIFA vibrator can effectively resonate in the frequency band of 2.4GHz-2.5GHz (resonating at 2.45GHz), and the high-frequency PIFA vibrator can effectively resonate in the frequency band of 5.125GHz-5.8125GHz (resonating at 5.5GHz). This allows the antenna to meet the transmission requirements of signals of different frequencies at the same time. For example, in the field of communications, it can adapt to the frequency bands corresponding to multiple communication standards, such as adapting to communication equipment of different frequency bands such as WIFI6 (working frequency band includes 2.4GHz band) and WIFI6E or WIFI7 (working frequency band includes around 5GHz band), which effectively improves the versatility of the antenna.

[0015] 2) Good radiation characteristics: The low-frequency PIFA vibrator and the high-frequency PIFA vibrator form a height difference with the ground plane, and set the first waveguide coupling coefficient and the second waveguide coupling coefficient respectively, thereby forming open radiation. This open radiation design enables the antenna to effectively transmit and receive signals within the corresponding frequency band. In addition, the grounding end of one side of the low-frequency PIFA vibrator is bent and raised to form a secondary coupling node, which enhances the radiation effect in the low-frequency band, helps to improve the performance of the antenna in the low-frequency band, and improves the signal transmission quality.

[0016] 3) Size optimization: For the low-frequency PIFA vibrator, the shortening factor is obtained by forming a coupling capacitor C with the coupling node and calculating it in parallel with the capacitive reactance value Cε in the air equivalent radiation, which effectively reduces the length of the low-frequency PIFA resonant node. This design is conducive to the miniaturization of the antenna while ensuring the low-frequency resonance performance, so that it can be better used in devices with limited space, such as in small mobile terminal devices, which can save space and will not affect its working performance in the low frequency band due to size limitations.

[0017] 4) Improved notch function and isolation: The open-line notch filter uses a 1 / 4λ open-line for a specific frequency point, which is synchronously extended into an open line at the signal feed point, forming infinite absorption for the specific frequency point and forming an absorption frequency point with the ground. This notch function can effectively suppress signals outside the frequency band and significantly improve the isolation of the antenna. For example, in a complex electromagnetic environment with signal interference in multiple frequency bands, it can suppress unwanted interference frequency bands, so that when the antenna resonates at multiple frequencies, the isolation between each frequency band is improved, reducing interference between frequency bands and improving the purity of signal transmission.

[0018] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention 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 present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0020] Figure 1 It is a structural diagram of a PIFA antenna in the prior art; Figure 2 It is a curve diagram of the PIFA antenna of the prior art at the rated frequency point; Figure 3 is an equivalent principle diagram of the wave trap of the present invention; Figure 4 is a graph of an original antenna of the multi-band notch antenna of the present invention; Figure 5 is a curve diagram of the multi-band notch antenna of the present invention at a nominal frequency point; Figure 6 It is a schematic diagram of the structure of the multi-band notch antenna of the present invention processed by a metal stamping process; Figure 7 It is a structural schematic diagram of a multi-band trap antenna of the present invention formed by welding multiple PCBs.

[0021] The reference numerals and names in the figures are as follows: Signal feeding point 10 , low frequency PIFA oscillator 21 , high frequency PIFA oscillator 22 , ground plane 23 , short circuit pin 24 , coupling node 25 , open line type trap 30 , U-shaped structure 40 . DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] [Example 1] Please refer to Figure 3-6 A multi-frequency broadband trap antenna comprises a signal feeding point 10, a double-section PIFA antenna and an open-circuit trap 30, wherein the signal feeding point 10, the double-section PIFA antenna and the open-circuit trap 30 are all manufactured by a metal stamping process, and the multi-frequency broadband trap antenna is connected to the product by a cable; A trapezoidal structure is set, and the signal feeding point 10 is determined by the center position of the trapezoidal structure. The double-section PIFA antenna uses an open radiation section. The double-section PIFA antenna includes a low-frequency PIFA vibrator 21 extending along one side of the signal feeding point 10, a high-frequency PIFA vibrator 22 extending along the other side of the signal feeding point 10, a ground plane 23 with a height difference between the low-frequency PIFA vibrator 21 and the high-frequency PIFA vibrator 22, and a short-circuit pin 24 arranged on the ground plane 23 for connecting the low-frequency PIFA vibrator 21 and the high-frequency PIFA vibrator 22; the low-frequency PIFA vibrator 21 and the high-frequency PIFA vibrator 22 are both connected to the ground plane 23 through the short-circuit pin 24 to form a U-shaped structure 40 as a whole, and the short-circuit pin 24 provides a ground current loop for the multi-frequency broadband trap antenna; The open-line type wave trap 30 adopts a 1 / 4λ open-line for a specific frequency point, and the open-line is synchronously extended into an open-line at the signal feeding point 10, wherein λ in 1 / 4λ=C / f, C represents the speed of light in free space, and f is the antenna operating frequency; according to the principle of 1 / 4λ impedance transformation in microstrip line transmission theory, when N in N*1 / 4λ is an odd multiple, the impedance of the open-line is Z=∞infinity, and within the length range of 0≤L≤1 / 4λ, this open-line forms an equivalent inductive reactance for the specific frequency point, and the equivalent inductive reactance forms a current coupling loop with the ground plane 23. The final result of this characteristic is to form a signal notch absorption absorption point for the specific frequency point, and this absorption point can significantly improve the suppression degree of a specific frequency band to a signal at a specific frequency point outside the frequency band, and improve the isolation between each frequency band when the antenna resonates at multiple frequencies.

[0024] The open-circuit type wave trap 30 obtains the signal current from the signal feeding point 10 and forms a current coupling circuit loop with the ground 23. The equivalent impedance Z of this loop generates a wave trap absorption frequency point, thereby generating a wave trap effect. The equivalent circuit of the wave trap is as follows: Figure 3 Specifically, after the open-line type trap filter 30 obtains the signal current from the signal feeding point 10, the signal current forms an infinite impedance at a specific frequency point on the 1 / 4λ open line, and forms a coupling current with the ground plane 23, absorbing the signal current at the rated frequency point on the resonant node and introducing it into the ground, and finally forming a trap effect in the radiated frequency band, providing a strong suppression effect on specific frequency points.

[0025] The height difference between the low-frequency PIFA vibrator 21 and the ground plane 23 is set to form a first waveguide coupling coefficient, thereby forming open radiation, and the end of the ground plane 23 corresponding to one side of the low-frequency PIFA vibrator 21 is bent and raised to form a coupling node 25 for secondary coupling, thereby enhancing the end radiation effect; the height difference between the high-frequency PIFA vibrator 22 and the ground plane 23 is set to form a second waveguide coupling coefficient, thereby forming open radiation.

[0026] The lengths of the low-frequency PIFA vibrator 21 and the high-frequency PIFA vibrator 22 are calculated from the signal feeding point 10 to the end of each resonant node, and are determined according to the formula 0.2λ, where λ=C / f, C represents the speed of light in free space, and f is the antenna operating frequency; the low-frequency PIFA vibrator 21 resonates at a frequency point of 2.45 GHz, and the high-frequency PIFA vibrator 22 resonates at a frequency point of 5.5 GHz.

[0027] The low-frequency PIFA vibrator 21 and the coupling node 25 are configured to form a coupling capacitor C, which is used to calculate in parallel with the capacitive reactance value Cε in the air equivalent radiation to obtain the shortening coefficient of the low-frequency PIFA vibrator 21, forming an effective resonance in the frequency band of 2.4GHz-2.5GHz; the high-frequency PIFA vibrator 22 adopts a conventional length design of 1 / 4λ to form an effective resonance in the frequency band of 5.125GHz-5.8125GHz.

[0028] [Example 2] Please refer to Figure 3-5 as well as Figure 7 A multi-frequency broadband trap antenna comprises a signal feeding point 10, a double-section PIFA antenna and an open-line trap 30, wherein the signal feeding point 10, the double-section PIFA antenna and the open-line trap 30 are all formed by welding a plurality of PCBs; A trapezoidal structure is set, and the signal feeding point 10 is determined by the center position of the trapezoidal structure. The double-section PIFA antenna uses an open radiation section. The double-section PIFA antenna includes a low-frequency PIFA vibrator 21 extending along one side of the signal feeding point 10, a high-frequency PIFA vibrator 22 extending along the other side of the signal feeding point 10, a ground plane 23 with a height difference between the low-frequency PIFA vibrator 21 and the high-frequency PIFA vibrator 22, and a short-circuit pin 24 arranged on the ground plane 23 for connecting the low-frequency PIFA vibrator 21 and the high-frequency PIFA vibrator 22; the low-frequency PIFA vibrator 21 and the high-frequency PIFA vibrator 22 are both connected to the ground plane 23 through the short-circuit pin 24 to form a U-shaped structure 40 as a whole, and the short-circuit pin 24 provides a ground current loop for the multi-frequency broadband trap antenna; The open-line type wave trap 30 adopts a 1 / 4λ open-line for a specific frequency point, and the open-line is synchronously extended into an open-line at the signal feeding point 10, wherein λ in 1 / 4λ=C / f, C represents the speed of light in free space, and f is the antenna operating frequency; according to the principle of 1 / 4λ impedance transformation in microstrip line transmission theory, when N in N*1 / 4λ is an odd multiple, the impedance of the open-line is Z=∞infinity, and within the length range of 0≤L≤1 / 4λ, this open-line forms an equivalent inductive reactance for the specific frequency point, and the equivalent inductive reactance forms a current coupling loop with the ground plane 23. The final result of this characteristic is to form a signal notch absorption absorption point for the specific frequency point, and this absorption point can significantly improve the suppression degree of a specific frequency band to a signal at a specific frequency point outside the frequency band, and improve the isolation between each frequency band when the antenna resonates at multiple frequencies.

[0029] The open-circuit type wave trap 30 obtains the signal current from the signal feeding point 10 and forms a current coupling circuit loop with the ground 23. The equivalent impedance Z of this loop generates a wave trap absorption frequency point, thereby generating a wave trap effect. The equivalent circuit of the wave trap is as follows: Figure 3 Specifically, after the open-line type trap filter 30 obtains the signal current from the signal feeding point 10, the signal current forms an infinite impedance at a specific frequency point on the 1 / 4λ open line, and forms a coupling current with the ground plane 23, absorbing the signal current at the rated frequency point on the resonant node and introducing it into the ground, and finally forming a trap effect in the radiated frequency band, providing a strong suppression effect on specific frequency points.

[0030] The height difference between the low-frequency PIFA vibrator 21 and the ground plane 23 is set to form a first waveguide coupling coefficient, thereby forming open radiation, and the end of the ground plane 23 corresponding to one side of the low-frequency PIFA vibrator 21 is bent and raised to form a coupling node 25 for secondary coupling, thereby enhancing the end radiation effect; the height difference between the high-frequency PIFA vibrator 22 and the ground plane 23 is set to form a second waveguide coupling coefficient, thereby forming open radiation.

[0031] The lengths of the low-frequency PIFA vibrator 21 and the high-frequency PIFA vibrator 22 are calculated from the signal feeding point 10 to the end of each resonant node, and are determined according to the formula 0.2λ, where λ=C / f, C represents the speed of light in free space, and f is the antenna operating frequency; the low-frequency PIFA vibrator 21 resonates at a frequency point of 2.45 GHz, and the high-frequency PIFA vibrator 22 resonates at a frequency point of 5.5 GHz.

[0032] The low-frequency PIFA vibrator 21 and the coupling node 25 are configured to form a coupling capacitor C, which is used to calculate in parallel with the capacitive reactance value Cε in the air equivalent radiation to obtain the shortening coefficient of the low-frequency PIFA vibrator 21, forming an effective resonance in the frequency band of 2.4GHz-2.5GHz; the high-frequency PIFA vibrator 22 adopts a conventional length design of 1 / 4λ to form an effective resonance in the frequency band of 5.125GHz-5.8125GHz.

[0033] The antenna signal feed point 10, the dual-section PIFA antenna and the open-circuit trap 30 can be manufactured by metal stamping or by welding multiple PCBs. The metal stamping process is suitable for large-scale production, can ensure the consistency and stability of the product, and may have advantages in cost control; while the PCB welding method is more convenient for integration in complex circuit design, so that the antenna can better cooperate with other electronic components, facilitate the cable connection between the antenna and the product, improve the electromagnetic compatibility and overall performance of the entire product, and can flexibly select the manufacturing method according to different product needs and design requirements.

[0034] Based on the above two embodiments, from the performance advantage, the frequency response curve voltage reflection coefficient of the conventional dual-band antenna Figure 4 , the isolation degree that can be obtained at two frequency points with a frequency interval of 200MHz is 3.5dBi, which is approximately equal to a reduction of 1 / 2 according to the signal power calculation. This reduction is not enough to reduce the interference. After adding the open-circuit notch filter 30, as shown in Figure 5 As shown in the figure, the isolation at two frequency points with a frequency interval of 200MHz is increased from 3.5dBi to 8dBi, which significantly improves the isolation and reduces interference. It is a kind of antenna design feature that can produce a notch function by using the open line characteristics in the principle of microstrip line filter on a conventional PIFA antenna, and can produce strong suppression at a rated frequency point. In terms of the scope of application, it can be applied to the WIFI6 / WIFI6E / WIFI7 frequency bands, but is not limited to these frequencies, and can be applied to the notch requirements of antennas at any frequency point.

[0035] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

Claims

1. A multi-frequency broadband notch antenna, characterized in that: The invention comprises a signal feeding point (10), a double-section PIFA antenna and an open-circuit type wave trap (30); the double-section PIFA antenna comprises a low-frequency PIFA vibrator (21) extending along one side of the signal feeding point (10), a high-frequency PIFA vibrator (22) extending along the other side of the signal feeding point (10), a ground plane (23) having a height difference with the low-frequency PIFA vibrator (21) and the high-frequency PIFA vibrator (22), and a short-circuit pin (24) arranged on the ground plane (23) for connecting the low-frequency PIFA vibrator (21) and the high-frequency PIFA vibrator (22); the low-frequency PIFA vibrator (21) and the high-frequency PIFA vibrator (22) are connected to the ground plane (23) through the short-circuit pin (24) to form a U-shaped structure (40) as a whole; The open-line type wave trap (30) adopts a 1 / 4λ open-line for a specific frequency point. The open-line is synchronously extended into an open-line at a signal feed point (10), forms infinite absorption for the specific frequency point, and forms an absorption frequency point with the ground to improve the isolation of the antenna, wherein λ in 1 / 4λ=C / f, C represents the speed of light in free space, and f is the antenna operating frequency.

2. The multi-band wideband notch antenna according to claim 1, characterized in that: The height difference between the low-frequency PIFA vibrator (21) and the ground plane (23) is set to form a first waveguide coupling coefficient, thereby forming open radiation, and the end of the ground plane (23) corresponding to one side of the low-frequency PIFA vibrator (21) is bent and raised to form a coupling node (25) of secondary coupling; the height difference between the high-frequency PIFA vibrator (22) and the ground plane (23) is set to form a second waveguide coupling coefficient, thereby forming open radiation.

3. The multi-band wideband notch antenna according to claim 1, characterized in that: The lengths of the low-frequency PIFA oscillator (21) and the high-frequency PIFA oscillator (22) are calculated from the signal feed point (10) to the end of each resonant node, and are determined according to the formula 0.2λ, where λ=C / f, C represents the speed of light in free space, and f is the antenna operating frequency; the low-frequency PIFA oscillator (21) resonates at a frequency point of 2.45 GHz, and the high-frequency PIFA oscillator (22) resonates at a frequency point of 5.5 GHz.

4. The multi-band wideband notch antenna according to claim 1, characterized in that: The low-frequency PIFA vibrator (21) and the coupling node (25) are configured to form a coupling capacitor C. The coupling capacitor C is used to calculate in parallel with the capacitive reactance value Cε in the air equivalent radiation to obtain the shortening coefficient of the low-frequency PIFA vibrator (21) and form an effective resonance in the frequency band of 2.4 GHz to 2.5 GHz. The high-frequency PIFA vibrator (22) is designed with a conventional length of 1 / 4λ to form an effective resonance in the frequency band of 5.125 GHz to 5.8125 GHz.

5. The multi-frequency broadband notch antenna according to claim 1, characterized in that: The signal feed point (10) of the multi-band broadband trap antenna, the double-section PIFA antenna and the open-circuit trap (30) are all manufactured by metal stamping technology, and the multi-band broadband trap antenna is connected to the product by cable.

6. The multi-band wideband notch antenna according to claim 1, characterized in that: The signal feed point (10) of the multi-frequency broadband trap antenna, the double-section PIFA antenna and the open-line trap filter (30) are all formed by welding a plurality of PCBs.

7. A method for manufacturing a multi-frequency broadband notch antenna, used for manufacturing a multi-frequency broadband notch antenna according to any one of claims 1 to 4, characterized in that: The steps include: Step 1, determining a signal feeding point (10), setting a trapezoidal structure, and determining the signal feeding point (10) at the center position of the trapezoidal structure; Step 2, manufacturing a double-section PIFA antenna, comprising a low-frequency PIFA vibrator (21) extending along one side of a signal feeding point (10), a high-frequency PIFA vibrator (22) extending along the other side of the signal feeding point (10), a ground plane (23) having a height difference with the low-frequency PIFA vibrator (21) and the high-frequency PIFA vibrator (22), and a short-circuit pin (24) arranged on the ground plane (23) for connecting the low-frequency PIFA vibrator (21) and the high-frequency PIFA vibrator (22); setting the height difference between the low-frequency PIFA vibrator (21) and the ground plane (23) to form a first waveguide coupling coefficient to form open radiation, and making the end of the ground plane (23) corresponding to one side of the low-frequency PIFA vibrator (21) bend and rise to form a coupling section (25) of secondary coupling; setting the height difference between the high-frequency PIFA vibrator (22) and the ground plane (23) to form a second waveguide coupling coefficient to form open radiation; making the low-frequency PIFA vibrator The low-frequency PIFA vibrator (21) and the high-frequency PIFA vibrator (22) are connected to the ground plane (23) through a short-circuit pin (24) to form a U-shaped structure (40); the length of the low-frequency PIFA vibrator (21) and the high-frequency PIFA vibrator (22) is calculated from the signal feeding point (10) to the end of each resonant node, and the length is determined according to the formula 0.2λ, so that the low-frequency PIFA vibrator (21) resonates at a frequency point of 2.45 GHz and the high-frequency PIFA vibrator (22) resonates at a frequency point of 5.5 GHz; the low-frequency PIFA vibrator (21) and the coupling node (25) are set to form a coupling capacitor C, and the shortening coefficient of the low-frequency PIFA vibrator (21) is calculated in parallel with the capacitive reactance value Cε in the air equivalent radiation, so as to form an effective resonance in the frequency band of 2.4 GHz-2.5 GHz; the high-frequency PIFA vibrator (22) is designed with a conventional length of 1 / 4λ, so as to form an effective resonance in the frequency band of 5.125 GHz-5.8125 GHz; Step 3, making an open-line type trap (30), using a 1 / 4λ open-line for a specific frequency point, the open-line is synchronously extended into an open-line at the signal feeding point (10), so that it forms infinite absorption for the specific frequency point, and forms an absorption frequency point with the ground to improve the isolation of the antenna, wherein λ in 1 / 4λ=C / f, C represents the speed of light in free space, and f is the antenna operating frequency.

8. The method for manufacturing a multi-frequency broadband notch antenna according to claim 1, characterized in that: The signal feed point (10) of the multi-band broadband trap antenna, the double-section PIFA antenna and the open-circuit trap (30) are all manufactured by metal stamping technology and connected to the product by cables.

9. The method for manufacturing a multi-frequency broadband notch antenna according to claim 1, characterized in that: The signal feed point (10) of the multi-band broadband trap antenna, the double-section PIFA antenna and the open-circuit trap (30) are all formed by welding a plurality of PCBs.

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