阅读说明：本技术 一种闪电宽带磁场信号探测天线系统 (Lightning broadband magnetic field signal detection antenna system ) 是由 吕凡超 秦子龙 陆高鹏 于 2021-09-22 设计创作，主要内容包括：本申请公开了一种闪电宽带磁场信号探测天线系统,包括磁天线以及与磁天线连接的放大电路；所述的磁天线包括两个垂直交叉分布的磁环,所述的磁环以所在平面的中心线为轴交叉设置。本申请利用磁环天线自身独有的磁场变化率(dB/dt)测量特性,控制频带内高频端的截止频率,并通过放大电路,将整个频带始终保持dB/dt的增益特性,这样可以使得高频端的信号获得超过20dB的增益,有效保证了对高频脉冲信号的测量,使得低频定位系统可以获得更多的高频辐射源定位信息,进一步丰富了低频定位系统的适用场景。(The application discloses a lightning broadband magnetic field signal detection antenna system, which comprises a magnetic antenna and an amplifying circuit connected with the magnetic antenna; the magnetic antenna comprises two magnetic rings which are vertically distributed in a crossed manner, and the magnetic rings are arranged in a crossed manner by taking the central line of the plane where the magnetic rings are located as an axis. The application utilizes the unique magnetic field change rate (dB/dt) measurement characteristic of the magnetic loop antenna, controls the cut-off frequency of the high-frequency end in the frequency band, and keeps the gain characteristic of the dB/dt of the whole frequency band all the time through the amplifying circuit, so that the signal of the high-frequency end can obtain the gain exceeding 20dB, the measurement of high-frequency pulse signals is effectively ensured, the low-frequency positioning system can obtain more high-frequency radiation source positioning information, and the application scenes of the low-frequency positioning system are further enriched.)

1. A lightning broadband magnetic field signal detection antenna system characterized in that: the magnetic antenna comprises a magnetic antenna and an amplifying circuit connected with the magnetic antenna; the magnetic antenna comprises two magnetic rings which are vertically distributed in a crossed manner, and the magnetic rings are arranged in a crossed manner by taking the central line of the plane where the magnetic rings are located as an axis.

2. The lightning broadband magnetic field signal detection antenna system according to claim 1, characterized in that: the magnetic ring is composed of multiple turns of single-layer enameled wires.

3. The lightning broadband magnetic field signal detection antenna system according to claim 2, characterized in that: the magnetic antenna comprises two annular frames which are vertically crossed, and a plurality of turns of single-layer enameled wires are wound on each annular frame.

4. The lightning broadband magnetic field signal detection antenna system according to claim 3, characterized in that: the annular frame is provided with a groove, and the multi-turn single-layer enameled wire is wound in the groove.

5. The lightning broadband magnetic field signal detection antenna system of claim 4, wherein: the annular frame adopts a circular frame, a groove which is concentric with the circular frame is arranged on the outer circular surface of the circular frame, and the two circular frames form a spherical frame.

6. The lightning broadband magnetic field signal detection antenna system according to claim 5, characterized in that: the spherical frame comprises an upper hemisphere and a lower hemisphere, and the lower hemisphere and the upper hemisphere are fixed through a supporting connecting frame.

7. The lightning broadband magnetic field signal detection antenna system according to claim 5, characterized in that: the diameters of the two magnetic rings are 248mm, each magnetic ring is provided with 32 turns of single-layer enameled wires which are tightly arranged on the magnetic ring in each direction, and the diameter of each enameled wire is 0.41 mm.

8. A lightning broadband magnetic field signal detection antenna system according to any one of claims 1-7, characterised in that: the amplifying circuit comprises a first amplifying circuit and a second amplifying circuit, wherein the signal input end of the first amplifying circuit is in signal connection with one magnetic ring, and the signal input end of the second amplifying circuit is in signal connection with the other magnetic ring; the first amplifying circuit comprises a chopping resonance adjusting circuit (6), a high-pass filtering amplifying circuit (7), a low-pass filtering amplifying circuit (8), a matching circuit (9) and a power supply circuit (10); the signal of the magnetic ring is connected with a chopping resonance adjusting circuit (6), the output end of the chopping resonance adjusting circuit (6) is connected with the input end of a high-pass filtering amplifying circuit (7), the output end of the high-pass filtering amplifying circuit (7) is connected with the input end of a low-pass filtering amplifying circuit (8), and the output end of the low-pass filtering amplifying circuit (8) is connected with the input end of a matching circuit (9); the power supply circuit (10) supplies power to the chopping resonance adjusting circuit (6), the high-pass filtering amplifying circuit (7), the low-pass filtering amplifying circuit (8) and the matching circuit (9); the second amplifying circuit and the first amplifying circuit have the same structure.

Technical Field

The invention relates to an antenna system, in particular to a lightning broadband magnetic field signal detection antenna system.

Background

The lightning signal has an extremely wide radiation frequency band, but has extremely strong energy in a low frequency band (generally 30 kHz-100 kHz), and can be transmitted on the surface of the earth for thousands of kilometers, so that the low frequency band signal becomes one of the most widely applied frequency bands for remote measurement and positioning of lightning. Recently, with the development of technology, low-frequency electromagnetic signals are also gradually applied to the construction of a local three-dimensional lightning location network. The system obtains the three-dimensional position of the lightning radiation source by erecting more than 5 electromagnetic measurement stations which work in a low-frequency band (30 kHz-300 kHz) and are synchronous in time and utilizing a time difference positioning algorithm.

At present, a vertical electric field sensor system is mostly used in domestic three-dimensional positioning systems, and the system mainly measures the vertical electric field change characteristic of a radiation source in the lightning discharge process. The system can directly obtain the discharge polarity of the radiation source of the positioned discharge process, and the attenuation speed of a detected signal is controlled by adding an integrating circuit with different time constants in circuit design. Most of the electric antennas used in positioning systems have an integration time of several to tens of milliseconds, giving an operating band with an almost fixed gain characteristic. Similar to a common electric antenna, a few three-dimensional positioning systems using a horizontal magnetic field sensor often have a frequency band characteristic of a fixed gain in a system operating frequency band (3 dB bandwidth) and a variation characteristic of approximately uniform gain in a wide frequency band range, that is, a so-called B antenna or an integral antenna (V = n × B), by designing a circuit (controlling the size of a chopper resistor or adding an integral circuit).

According to the conventional measurement of the frequency spectrum of the electromagnetic signal of lightning, the electromagnetic signal of lightning radiation has extremely strong energy in a low frequency band, and the frequency spectrum of the electromagnetic signal generated by discharge has a characteristic of decreasing (1/f) with increasing frequency in a wide low frequency band range, and a specific change curve is shown in fig. 1. Therefore, the low-frequency broadband measuring system of the electric field and the magnetic field with consistent frequency band characteristics, which is used at present, can cause the high-frequency end of the measuring signal in the frequency band range to be lower than the low-frequency end of the measuring signal to generate signal intensity attenuation of more than 20 dB. Resulting in a relatively strong detection capability of the whole measurement system in the low frequency band of 30kHz and a relatively weak detection capability in the slightly higher frequency band, such as 100-300 kHz. This strong low frequency signal and the relatively weak high frequency signal cause: 1) reducing the number of signal pulses, the number of events available for localization during a single lightning event is reduced, 2) reducing the time resolution of the signal. Therefore, a low frequency antenna with overall band gain somewhat limits its application in a positioning system, which may result in: 1) few positioning radiation sources are used in a single lightning process; 2) the positioning precision is low; moreover, the cloud flash location capability of the detection antenna is weak due to the fact that the discharge process in the cloud has a relatively small space scale and a relatively high radiation frequency.

Disclosure of Invention

The application aims to provide a lightning broadband magnetic field signal detection antenna system for the problem that when lightning broadband signals are measured, high-frequency signals are weak, so that the positioning accuracy is low or the number of positioning radiation sources is small.

The application provides a lightning broadband magnetic field signal detection antenna system, the following technical scheme who adopts:

a lightning broadband magnetic field signal detection antenna system comprises a magnetic antenna and an amplifying circuit connected with the magnetic antenna; the magnetic antenna comprises two magnetic rings which are vertically distributed in a crossed manner, and the magnetic rings are arranged in a crossed manner by taking the central line of the plane where the magnetic rings are located as an axis.

By the technical scheme, the cut-off frequency of the high-frequency end in the frequency band is controlled by utilizing the unique magnetic field change rate (dB/dt) measuring characteristic of the magnetic loop antenna, and the whole frequency band is always kept with the gain characteristic of dB/dt through the amplifying circuit, so that the signal of the high-frequency end can obtain the gain exceeding 20dB, the measurement of high-frequency pulse signals is effectively ensured, and a low-frequency positioning system can obtain more high-frequency radiation source positioning information.

Optionally, the magnetic ring is formed by multiple turns of single-layer enameled wires.

According to the technical scheme, the magnetic ring is made of the multi-turn single-layer enameled wire, so that various parameters of the magnetic ring antenna can be conveniently controlled, and the cutoff frequency of the high-frequency end can be controlled by selecting appropriate shapes and parameters.

Optionally, the magnetic antenna includes two ring frames perpendicularly crossed, and a plurality of turns of single-layer enameled wires are wound on each ring frame.

Through the technical scheme, the annular frame is arranged, and the multi-turn single-layer enameled wire is wound on the annular frame, so that the two magnetic ring antennas can be stable and firm in position.

Optionally, a groove is formed in the annular frame, and the multi-turn single-layer enameled wire is wound in the groove.

Through above-mentioned technical scheme, establish in the slot through winding multiturn individual layer enameled wire, can guarantee setting that the enameled wire can be stable on ring frame, can prevent that the enameled wire from the ring frame landing when using.

Optionally, the annular frame is a circular frame, a groove concentric with the circular frame is arranged on the outer circular surface of the circular frame, and the two circular frames form a spherical frame.

Through the technical scheme, the circular frame is adopted, the groove which is concentrically arranged with the circular frame is formed in the outer circular surface of the circular frame, and the arrangement of the magnetic ring on the circular frame can be realized by winding the enameled wires on the groove on the circular frame in multiple turns.

Optionally, the spherical frame includes an upper hemisphere and a lower hemisphere, and the lower hemisphere and the upper hemisphere are fixed by a support connecting frame.

Through above-mentioned technical scheme, set ball frame into last hemisphere and lower hemisphere, it is fixed through supporting the link between lower hemisphere and the last hemisphere, both be convenient for ball frame's preparation and installation, also guaranteed ball frame's intensity and firm nature simultaneously, and then guaranteed the perpendicular angle between two magnetic rings and stereotype.

Optionally, the diameters of the two magnetic rings are 248mm, each magnetic ring is provided with 32 turns of single-layer enameled wires which are tightly arranged on the magnetic ring in each direction, and the diameter of each enameled wire is 0.41 mm.

Through the technical scheme, the low-frequency end and the high-frequency section have the gain difference of 100 times through the parameters, so that the amplification factor of a high-frequency end signal is obviously improved, the high-frequency end component with a larger effect on positioning accuracy and quantity and more high-frequency components obtained by a measuring system are obtained.

Optionally, the amplifying circuit includes a first amplifying circuit and a second amplifying circuit, wherein a signal input end of the first amplifying circuit is in signal connection with one of the magnetic rings, and a signal input end of the second amplifying circuit is in signal connection with the other magnetic ring; the first amplifying circuit comprises a chopping resonance adjusting circuit, a high-pass filtering amplifying circuit, a low-pass filtering amplifying circuit, a matching circuit and a power circuit; the signal of the magnetic ring is connected with the chopping resonance adjusting circuit, the output end of the chopping resonance adjusting circuit is connected with the input end of the high-pass filtering amplifying circuit, the output end of the high-pass filtering amplifying circuit is connected with the input end of the low-pass filtering amplifying circuit, and the output end of the low-pass filtering amplifying circuit is connected with the input end of the matching circuit; the power supply circuit supplies power for the chopping resonance adjusting circuit, the high-pass filtering amplifying circuit, the low-pass filtering amplifying circuit and the matching circuit; the second amplifying circuit and the first amplifying circuit have the same structure.

Through the technical scheme, the first amplifying circuit is connected with the signal of one magnetic ring, the second amplifying circuit is connected with the signal of the other magnetic ring, and the signals of the two magnetic rings can be subjected to chopping, high-pass filtering amplification, low-pass filtering amplification and the like, so that the low-frequency end and the high-frequency end in the frequency band have relatively consistent gain characteristics, and the bandwidth of the whole detection system has the frequency band characteristic consistent with the magnetic field change rate measured by the magnetic ring antenna.

In summary, the present application includes at least one of the following beneficial technical effects:

1. according to the method, the cutoff frequency of the high-frequency end in the frequency band is controlled by utilizing the unique magnetic field change rate (dB/dt) measurement characteristic of the magnetic ring antenna, and the whole frequency band is always kept with the gain characteristic of dB/dt through the amplifying circuit, so that the signal of the high-frequency end can obtain the gain exceeding 20dB, the measurement of high-frequency pulse signals is effectively guaranteed, and more high-frequency radiation source positioning information can be obtained by a low-frequency positioning system.

2. According to the magnetic loop antenna, the multi-turn single-layer enameled wire is wound in the groove to form the magnetic loop antenna, so that various parameters of the magnetic loop antenna can be conveniently controlled, and the cut-off frequency of a high-frequency end can be controlled by selecting proper shapes and parameters; and the enameled wire can be stably arranged on the annular frame, the enameled wire can be prevented from sliding off the annular frame when the antenna is used, and the stability of the magnetic ring antenna can be ensured.

3. The diameter of each of the two magnetic rings is set to be 248mm, 32 turns of single-layer enameled wires are arranged on each magnetic ring and are tightly arranged on the magnetic ring in each direction, and the diameter of each enameled wire is 0.41 mm; the antenna design enables the low-frequency end and the high-frequency section to have gain difference of 100 times, so that the amplification factor of a high-frequency end signal is obviously improved, and the high-frequency end component with a larger effect on positioning accuracy and quantity and more high-frequency components obtained by a measuring system are enabled.

Drawings

FIG. 1 is a frequency spectrum characteristic diagram of an electromagnetic wave signal of a natural lightning discharge process;

FIG. 2 is a schematic structural diagram of a lightning broadband magnetic field signal detection antenna according to the present application;

FIG. 3 is a schematic structural diagram of a frame of the lightning broadband magnetic field signal detection antenna of the present application;

FIG. 4 is a schematic diagram of an amplifying circuit according to an embodiment of the present disclosure;

FIG. 5 is a graph of the spectral characteristics of electromagnetic wave signals produced by a lightning discharge process recorded by an electromagnetic measuring device having different frequency band characteristics;

figure 6 is a graph of lightning signals recorded by an electromagnetic measurement system having two different spectral characteristics.

Fig. 7 is a graph of the overall frequency band of the antenna and the amplifier circuit.

Description of reference numerals:

1. a first ring frame; 2. a second annular frame; 3. a support link; 4. a first magnetic ring; 5. a second magnetic ring; 6. a chopper resonance adjusting circuit; 7. a high-pass filter amplifying circuit; 8. a low-pass filter amplifying circuit; 9. a matching circuit; 10. a power supply circuit; 11. a base; 12. mounting holes; 101. a first trench; 201. a second trench.

Detailed Description

The present application is described in further detail below with reference to figures 2-7.

Referring to fig. 2 and 3, the present embodiment discloses a lightning broadband magnetic field signal detection antenna system, which includes a magnetic antenna and an amplifying circuit connected to the magnetic antenna; the magnetic antenna comprises an antenna frame, wherein the antenna frame comprises a first annular frame 1 and a second annular frame 2, the first annular frame 1 and the second annular frame 2 are both circular frames, and the first annular frame 1 and the second annular frame 2 are crossed and vertically distributed by taking a center line of a plane as an axis, so that the first annular frame 1 and the second annular frame 2 form a spherical frame.

The first annular frame 1 and the second annular frame 2 are connected through a supporting connecting frame 3, and the first annular frame 1 and the second annular frame 2 are produced by adopting ABS engineering plastics 3D printing. In the specific manufacturing process, a mode of combining an upper hemisphere and a lower hemisphere is adopted. The upper hemisphere and the lower hemisphere are printed in a 3D mode respectively and then are spliced to form a complete spherical frame, the combination portion of the upper hemisphere and the lower hemisphere is fixed through plastic screws and nuts, the lower portion of the lower hemisphere is provided with a base 11, and the base 11 is provided with a mounting hole 12 for fixedly mounting an antenna.

A first groove 1011 is formed in the outer circumferential surface of the first annular frame 1, the first groove 1011 is concentric with the first annular frame 1, and a plurality of turns of single-layer enameled wires are wound in the first groove 101 to form a first magnetic ring 4. A second groove 201 is formed in the outer circular surface of the second annular frame 2, the second groove 201 and the second annular frame 2 are arranged concentrically, a plurality of turns of single-layer enameled wires are wound in the second groove 201 to form a second magnetic ring 5, and the second magnetic ring 5 and the first magnetic ring 4 are in crossed and vertical crossed distribution by taking the center line of the plane where the second magnetic ring is located as an axis.

When the antenna is erected, the two vertical crossed rings face to the east and west directions and the south and north directions respectively according to the magnetic field direction, and the two vertical crossed rings are used for measuring magnetic field change rate signals from the east and west directions and the south and north directions respectively.

According to the Faraday's law of electromagnetic induction, the voltage produced by the magnetic field across the magnetic ring at both ends of the magnetic ring line due to the change in the magnetic field across the magnetic ring is:

（1）

wherein N is the number of turns of the coil, A is the area of the ring,is the magnetic flux, B is the magnetic induction,a voltage is output for the signal across the coil.

Referring to fig. 4, two ends of an enameled wire of the first magnetic ring 4 are respectively connected to the first amplifying circuit, and a signal of the first magnetic ring 4 is sent to the first amplifying circuit for processing; two ends of the enameled wire of the second magnetic ring 5 are respectively connected to the second amplifying circuit, and the signal of the second magnetic ring 5 is sent to the second amplifying circuit for processing.

The first amplification circuit includes a chopper resonance adjustment circuit 6, a high-pass filter amplification circuit 7, a low-pass filter amplification circuit 8, a matching circuit 9, and a power supply circuit 10.

The output end of the chopping resonance adjusting circuit 6 is connected with the input end of the high-pass filtering amplifying circuit 7, the output end of the high-pass filtering amplifying circuit 7 is connected with the input end of the low-pass filtering amplifying circuit 8, and the output end of the low-pass filtering amplifying circuit 8 is connected with the input end of the matching circuit 9. The chopped wave resonance adjusting circuit 6 initially adjusts the signal frequency band of the first magnetic ring 4, and removes the self resonance of the signal of the first magnetic ring 4. And the high-pass filtering amplifying circuit 7 is used for carrying out high-pass filtering on the output signal of the chopping resonance adjusting circuit 6, removing power frequency and resonance frequency noise thereof and amplifying the signal. The low-pass filtering amplifying circuit 8 performs low-pass filtering on the output signal of the high-pass filtering amplifying circuit 7, removes high-frequency noise and amplifies the signal. The matching circuit 9 amplifies the output of the low-pass filter amplifying circuit 8 in an equal ratio and adjusts the amplified output to be an output end matched with the impedance of the long transmission line. The power supply circuit 10 supplies power to the chopping resonance adjusting circuit 6, the high-pass filtering amplifying circuit 7, the low-pass filtering amplifying circuit 8 and the matching circuit 9; the second amplifying circuit has the same structure as the first amplifying circuit.

The chopper resonance adjusting circuit 6 comprises an instrumentation amplifier U1, the model of the instrumentation amplifier U1 is AD8429, ports-IN and + IN of the instrumentation amplifier U1 are respectively connected to two ends of an enameled wire of the first magnetic ring 4, ports-IN and + IN of the instrumentation amplifier U1 are respectively connected with two ends of a capacitor C6, ports-IN and + IN of the instrumentation amplifier U1 are respectively connected with two ends of a resistor R17, a port-IN of the instrumentation amplifier U1 is grounded through a resistor R1, a port + IN of the instrumentation amplifier U1 is grounded through a resistor R2, and two ports RG of the instrumentation amplifier U1 are respectively connected with two ends of the resistor R3. The + VS port of the instrumentation amplifier U1 is connected with the + VCCO port of the power supply circuit, the-VS port of the instrumentation amplifier U1 is connected with the-VCCO port of the power supply circuit, the REF port of the instrumentation amplifier U1 is grounded, and the VOUT port of the instrumentation amplifier U1 is connected with the high-pass filtering amplification circuit 7.

The high-pass filtering amplifying circuit 7 comprises an operational amplifier U2, the operational amplifier U2 is IN the type of ADA4898, a + IN port of the operational amplifier U2 is connected with a VOUT port of an instrumentation amplifier U1 through a capacitor C3 and receives an output signal of the chopper resonance adjusting circuit 6, and a + IN port of the operational amplifier U2 is grounded through a resistor R4. The + VS port of the operational amplifier U2 is connected with the + VCCO port of the power supply circuit, the-VS port of the operational amplifier U2 is connected with the-VCCO port of the power supply circuit, and the-IN port of the operational amplifier U2 is grounded through a resistor R5. The VOUT port of the operational amplifier U2 is connected to the low-pass filter amplifier circuit 8, and the VOUT port of the operational amplifier U2 is also connected to ground via the resistors R6 and R5.

The low-pass filtering amplifying circuit comprises an operational amplifier U8 and an operational amplifier U7, wherein the + IN port of the operational amplifier U8 is connected with the VOUT port of the operational amplifier U2 through a resistor R16 and a resistor R15 and receives an output signal of the high-pass filtering amplifying circuit 7, and the + IN port of the operational amplifier U8 is grounded through a capacitor C8. The + VS port of the operational amplifier U8 is connected with the + VCCO port of the power supply circuit, and the-VS port of the operational amplifier U8 is connected with the-VCCO port of the power supply circuit. the-IN port of the operational amplifier U8 is connected to the VOUT port of the operational amplifier U2 via a capacitor C9 and a resistor R15, and the-IN port of the operational amplifier U8 is also connected to the VOUT port of the operational amplifier U8.

The VOUT port of the operational amplifier U8 is connected to the + IN port of the operational amplifier U7 through a resistor R19 and a resistor R20, and the + IN port of the operational amplifier U7 is also connected to ground through a capacitor C10. The + VS port of the operational amplifier U7 is connected with the + VCCO port of the power supply circuit, and the-VS port of the operational amplifier U7 is connected with the-VCCO port of the power supply circuit. the-IN port of the operational amplifier U7 is connected to the VOUT port of the operational amplifier U8 through a capacitor C11 and a resistor R19, the-IN port of the operational amplifier U7 is also connected to the VOUT port of the operational amplifier U7, the VOUT port of the operational amplifier U7 is connected to the matching circuit 9, and the VOUT port of the operational amplifier U7 is also grounded through a resistor R10.

The matching circuit 9 comprises an operational amplifier U15, wherein the + IN port of the operational amplifier U15 is connected with the VOUT port of the operational amplifier U7, the + VS port of the operational amplifier U15 is connected with the + VCCO port of the power supply circuit, and the-VS port of the operational amplifier U15 is connected with the-VCCO port of the power supply circuit.

The second amplification circuit is the same as the first amplification circuit, and similarly includes a chopper resonance adjustment circuit 6, a high-pass filter amplification circuit 7, a low-pass filter amplification circuit 8, a matching circuit 9, and a power supply circuit 10. The second amplifying circuit is used for processing the signal of the second magnetic ring 5. The processing mode is the same as the signal processing mode of the first magnetic ring 4 by the first amplifying circuit.

Referring to fig. 5, the overall band gain of the measurement signals obtained by the systems with different frequency bands can be seen that the antenna with dB/dt makes the received lightning radiation signal have a gain curve relatively consistent with that of the low frequency end at the high frequency end, so that the signal at the high frequency end can obtain more than 20dB more gain than that of the common B or E type antenna, the measurement of the high frequency pulse signal is effectively ensured, and the positioning system can theoretically obtain more radiation source positioning information.

Referring to fig. 6, a time domain waveform of a lightning discharge process obtained by an electromagnetic wave recording system with two spectrum characteristics is visually shown. Compared with the time periods marked by the dashed boxes in the figure, the system with dB/dt spectrum characteristics has better pulse richness, so that the lightning positioning system using the antenna type can identify more pulse radiation sources which can be positioned in the same time window, and more radiation source positioning results are obtained, so that the lightning overall process detection is more accurate.

In this embodiment, the diameter of the first groove 11 is 248mm, the number of winding turns of the single-layer enameled wire is 32, and the diameter of the enameled wire is 0.41 mm. The diameter of the second groove 21 is 248mm, the number of winding turns of the single-layer enameled wire is 32, and the diameter of the enameled wire is 0.41 mm.

Therefore, in the present embodiment, . Substituting the parameters into the formula (1) to obtain the measurement sensitivity of the magnetic ring of the embodiment to the magnetic field change rate as follows:

。

referring to fig. 7, the low-frequency end and the high-frequency end have gain difference of 100 times through the antenna design, so that the amplification factor of the high-frequency end signal is obviously improved, and more high-frequency components are obtained by the measurement system for the high-frequency end component with larger positioning accuracy and quantity.