CN115267355A - Method and system for coupling thunder and lightning electromagnetic wave signals based on magnetic antenna - Google Patents

Method and system for coupling thunder and lightning electromagnetic wave signals based on magnetic antenna Download PDF

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CN115267355A
CN115267355A CN202210905174.7A CN202210905174A CN115267355A CN 115267355 A CN115267355 A CN 115267355A CN 202210905174 A CN202210905174 A CN 202210905174A CN 115267355 A CN115267355 A CN 115267355A
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antenna
magnetic
electromagnetic wave
magnetic antenna
lightning
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卜令兵
赖锴婕
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Nanjing University of Information Science and Technology
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Nanjing University of Information Science and Technology
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R29/00—Arrangements for measuring or indicating electric quantities not covered by groups G01R19/00 - G01R27/00
    • G01R29/08—Measuring electromagnetic field characteristics
    • G01R29/0807—Measuring electromagnetic field characteristics characterised by the application
    • G01R29/0814—Field measurements related to measuring influence on or from apparatus, components or humans, e.g. in ESD, EMI, EMC, EMP testing, measuring radiation leakage; detecting presence of micro- or radiowave emitters; dosimetry; testing shielding; measurements related to lightning
    • G01R29/0842—Measurements related to lightning, e.g. measuring electric disturbances, warning systems
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R29/00—Arrangements for measuring or indicating electric quantities not covered by groups G01R19/00 - G01R27/00
    • G01R29/08—Measuring electromagnetic field characteristics
    • G01R29/0864—Measuring electromagnetic field characteristics characterised by constructional or functional features
    • G01R29/0871—Complete apparatus or systems; circuits, e.g. receivers or amplifiers
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R29/00—Arrangements for measuring or indicating electric quantities not covered by groups G01R19/00 - G01R27/00
    • G01R29/08—Measuring electromagnetic field characteristics
    • G01R29/10—Radiation diagrams of antennas

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Abstract

The invention discloses a method and a system for coupling thunder and lightning electromagnetic wave signals based on a magnetic antenna, which comprises the following steps: establishing a magnetic antenna equivalent circuit model according to a basic receiving theory of the magnetic antenna; establishing a magnetic antenna signal processing circuit based on the magnetic antenna equivalent circuit model; simulating a thunder and lightning electromagnetic environment generated by a lightning channel by building a Helmholtz ring coil test bed to generate a uniform magnetic field; the method comprises the steps of testing influences caused by different parameters based on a magnetic antenna coupling lightning electromagnetic wave system, processing obtained data and analyzing a frequency response curve. The equivalent circuit of the multi-turn loop antenna for receiving the lightning electromagnetic wave signals is established, the Helmholtz circular coil test bed is set up to generate a uniform magnetic field to simulate the lightning electromagnetic environment generated by a lightning channel, the influence of different sampling parameters of the multi-turn loop antenna on the coupling lightning electromagnetic wave capacity in the electromagnetic environment is analyzed, important parameters influencing the receiving performance of the antenna are obtained, and therefore the detection precision of the magnetic antenna is improved based on the important parameters.

Description

Method and system for coupling thunder and lightning electromagnetic wave signals based on magnetic antenna
Technical Field
The invention relates to lightning science, in particular to a method and a system for coupling lightning electromagnetic wave signals based on a magnetic antenna.
Background
Lightning is a discharge phenomenon in which a sharp discharge occurs between charged clouds or between a charged cloud and the earth (or an object), often accompanied by lightning and thunderstorm. Two kinds of harmful direct lightning and lightning stroke electromagnetic pulses are often caused in the discharging process of lightning. The lightning stroke electromagnetic pulse is an electromagnetic phenomenon of transient lightning discharge which has stronger destructive capability than that of a direct lightning stroke; after the antenna is coupled with a lightning stroke electromagnetic pulse signal with strong energy, the amplifying circuit device and other electronic equipment of the antenna can be damaged, so that the equipment facilities can be invalid or permanently damaged, and a plurality of serious and bad effects are caused to daily production life of people. In order to research various physical characteristics of lightning, researches on the design of a magnetic antenna and the use of the magnetic antenna to receive and couple electromagnetic wave pulse signals thereof have been receiving increasing attention from more and more scholars.
Disclosure of Invention
The purpose of the invention is as follows: the invention aims to provide a method and a system for coupling lightning electromagnetic wave signals based on a magnetic antenna, so that the change trend that the magnitudes of the lightning electromagnetic waves and lightning current and the ratio of voltage to magnetic induction intensity change along with the change of frequency under the selection and combination of different parameters is accurately reflected.
The technical scheme is as follows: the invention relates to a method for coupling thunder and lightning electromagnetic wave signals based on a magnetic antenna, which is characterized in that an equivalent circuit of a multi-turn loop antenna for receiving the thunder and lightning electromagnetic wave signals is established by utilizing a method combining theory and experiment, a Helmholtz loop coil test bed is built to generate a uniform magnetic field to simulate a thunder and lightning electromagnetic environment generated by a lightning channel, the influence of different sampling parameters of the multi-turn loop antenna on the capacity of coupling thunder and lightning electromagnetic waves in the electromagnetic environment is analyzed, and the variation trend that the sizes of the thunder and lightning electromagnetic waves and lightning current and the ratio of voltage to magnetic induction intensity change along with the change of frequency under the selection and combination of different parameters is accurately reflected, and the method specifically comprises the following steps:
(1) And establishing a magnetic antenna equivalent circuit model according to a basic receiving theory of the magnetic antenna.
(1.1) surface area of Loop antenna AL；BNIs a planar normal phase magnetic field component of the loop antenna; rLIs C, C0、R0Resistance values after parallel connection; l is the inductance of the loop antenna; the relational expression among the parameters is derived from the circuit principle:
Figure BDA0003772118070000011
in the formula of U0Representing the load resistance R0The output voltage across the terminals.
(1.2) in the simplest case, the loop antenna is a rectangular planar coil coaxial with the axis of rotation OO and coincident with the axis of symmetry of the loop; the loop antenna is assumed to be located in a vertical plane and has its propagation direction in a horizontal plane in line with the loop coil plane
Figure BDA0003772118070000012
The angle vertically polarized wave passes through; since it is a vertically polarized wave, electromotive forces are induced only on the plumb wires α σ and δ τ of the ring; the electromagnetic wave first reaches the wire δ τ and induces an electromotive force therein:
eθz＝Em sinωt
when the annular coil has N turns, the electromotive force induced on the N leads is as follows:
Figure BDA0003772118070000021
in the formula, EmIs the amplitude of the electric field strength.
(2) And establishing a magnetic antenna signal processing circuit based on the magnetic antenna equivalent circuit model.
(3) A Helmholtz ring coil test bed is set up to generate a uniform magnetic field to simulate a thunder and lightning electromagnetic environment generated by a lightning channel.
a is the radius of the Helmholtz ring, h is the distance between the two rings, r<In the region a, the magnetic field generated by the coil 1 is set as B(1)The magnetic field generated by the coil 2 is B(2)According to the additive property of the magnetic field, the axial component of the composite magnetic field of the coil 1 and the coil 2 is:
Figure BDA0003772118070000022
wherein L isnRepresents the nth order magnetic field coefficient of a single toroid, β = h/a.
The central magnetic field is:
Figure BDA0003772118070000023
wherein mu0＝4π×10-7And I is the current of the Helmholtz ring coil.
(4) The method comprises the steps of testing influences caused by different parameters based on a magnetic antenna coupling lightning electromagnetic wave system, processing obtained data and analyzing a frequency response curve.
The system can realize the method for coupling the lightning electromagnetic wave signals based on the magnetic antenna, and comprises a lightning electromagnetic field receiving system and a magnetic antenna signal processing circuit, wherein the lightning electromagnetic field receiving system is used for receiving, storing and outputting the electromagnetic wave signals and data thereof, and the magnetic antenna signal processing circuit is used for modulating the electromagnetic wave signals in the magnetic antenna equivalent circuit.
A computer storage medium having stored thereon a computer program which, when being executed by a processor, carries out a method of coupling lightning electromagnetic wave signals based on a magnetic antenna as described above.
A computer device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, the processor implementing a method for coupling lightning electromagnetic wave signals based on a magnetic antenna as described above when executing the computer program.
Has the advantages that: compared with the prior art, the invention has the following advantages:
1. the invention uses ferrite material with higher resistivity and non-reciprocity characteristic as the magnetic core, compared with the prior magnetic loop wire antenna which uses hollow or common material, the invention inhibits the generation of eddy current loss and reduces the energy loss; the microwave signal transmission direction can be modulated through intrinsic magnetic anisotropy, and the receiving performance of the antenna is improved;
2. according to the invention, the Helmholtz circular coil test bed is built to simulate the magnetic field in the environment of lightning electromagnetic waves, so that a high-uniformity magnetic field can be created, the constancy of the magnetic field is fully ensured, and the actual requirement is met;
3. according to the invention, the capacitance and the resistance value in the equivalent circuit model of the magnetic antenna are changed to obtain important parameters influencing the receiving performance of the antenna, so that the detection precision of the magnetic antenna is improved based on the parameters.
Drawings
FIG. 1 is a flow chart of the steps of the method of the present invention;
FIG. 2 is a schematic diagram of a resonant equivalent circuit;
FIG. 3 is a schematic view of a multi-turn toroidal coil; wherein FIG. 3 (a) is a schematic view, FIG. 3 (b) is an equivalent view, and FIG. 3 (c) is an exploded view of a multi-turn ring;
FIG. 4 is a diagram of deriving loop antenna pattern equations;
FIG. 5 is a schematic diagram of a multi-turn loop antenna;
FIG. 6 is a pattern of a loop antenna;
FIG. 7 is a schematic diagram of a magnetic antenna signal processing circuit;
FIG. 8 is a schematic view of a Helmholtz toroid;
FIG. 9 is a schematic diagram of a test waveform with a frequency of 1 kHz; wherein, fig. 9 (a) is a normal waveform, and fig. 9 (b) is a distorted waveform;
FIG. 10 is a graph showing frequency response curves of the same resistor and different capacitors; wherein, fig. 10 (a) is a frequency response curve of different capacitors at 10 Ω, fig. 10 (b) is a frequency response curve of different capacitors at 20 Ω, fig. 10 (c) is a frequency response curve of different capacitors at 30 Ω, fig. 10 (d) is a frequency response curve of different capacitors at 40 Ω, and fig. 10 (e) is a frequency response curve of different capacitors at 50 Ω;
FIG. 11 is a graph showing frequency response curves of the same capacitor with different resistances; fig. 11 (a) is a frequency response curve of different resistors at 50pF, fig. 11 (b) is a frequency response curve of different resistors at 100pF, fig. 11 (c) is a frequency response curve of different resistors at 1000pF, and fig. 11 (d) is a frequency response curve of different resistors at 0.01 μ F.
Detailed Description
The technical scheme of the invention is further explained by combining the attached drawings.
The invention provides a system and a method for coupling lightning electromagnetic wave signals based on a magnetic antenna, as shown in figure 1, the method comprises the following steps:
(1) Establishing a magnetic antenna equivalent circuit model according to a basic receiving theory of the magnetic antenna; the method specifically comprises the following steps: according to Faraday's law of electromagnetic induction, when loop antenna arranges in the magnetic field of change, loop antenna can produce induced electromotive force, and loop antenna arranges in the even alternating magnetic field that angular frequency is omega, and when the axis of winding and magnetic field intensity H paralleled, loop antenna was at the voltage of its both ends production:
Figure BDA0003772118070000031
wherein mu0For initial permeability, n is the number of turns of the coil and a is the area of each coil.
In the frequency domain it is assumed that:
B(t)＝B0·ej2πft (2)
then there are:
V＝-j·N·A·ω·B0·ejωt (3)
thereby calculating the scale factor of the induction coil:
|V/B|＝|V/B0|＝N·A·ω (4)
and simultaneously calculating the induced electromotive force Ee at the two ends of the antenna as follows:
Ee＝μ0μrωHAn (5)
in the formula, mu0Is the permeability of air, murIs the relative magnetic permeability.
According to the electromagnetic field theory, the relationship between the magnetic field strength H and the electric field strength E is:
Figure BDA0003772118070000041
namely:
Figure BDA0003772118070000042
in the formula
Figure BDA0003772118070000043
The propagation velocity of electromagnetic wave in vacuum is 3 × 108m/s。
In the above formula, E/c0Carry-over (2.5) gives:
Figure BDA0003772118070000044
in the formula, λ represents the wavelength of electromagnetic waves, and the unit is expressed in meters.
In order to facilitate the calculation processing of the numerical value, the loop antenna can be analyzed in a frequency domain; as shown in FIG. 2, UL(ω) is the induced electromotive force formed by the magnetic lines of force passing through the closed loop of the loop antenna, L in the figure is the inductance of the loop antenna, the internal resistance of the antenna is negligible, and therefore it can be derived from faraday's law of electromagnetic induction:
UL(ω)＝AL·j·ω·BN (9)
wherein the loop antenna has a surface area of ALThe unit is m2；BNIs the planar normal phase magnetic field component of the loop antenna and has the unit of T. The load resistance R can be derived from the circuit principle0The output voltages at the two terminals are:
Figure BDA0003772118070000045
in the above formula, C, C0、R0The resistance value after parallel connection is RL。
In the simplest case, the loop antenna is a rectangular planar coil having a common axis of rotation OO, which coincides with the axis of symmetry of the loop. As shown in FIG. 3, it is assumed that the loop antenna is located in the vertical plane and has its propagation direction in the horizontal plane in line with the loop coil plane
Figure BDA0003772118070000046
The vertically polarized waves of the angle pass through. Since the waves are vertically polarized waves, electromotive forces are induced only in the plumb wires α σ and δ τ of the ring. The electromagnetic wave first reaches the wire δ τ and induces an electromotive force therein:
eθz＝Em sinωt (11)
wherein E ismIs the amplitude of the electric field strength.
The electromagnetic wave then passes through the wire α σ due to the path difference of the wave
Figure BDA0003772118070000047
Lags behind in phase
Figure BDA0003772118070000048
And (4) an angle. At this time, the electromotive force induced in the wire is:
Figure BDA0003772118070000051
using the known trigonometric formula, we can obtain:
Figure BDA0003772118070000052
the resulting expression is changed to:
Figure BDA0003772118070000053
when there are N turns in the toroidal coil, as shown in fig. 4, considering that the electromotive forces induced on all N wires on one side of the toroidal coil are the same in both value and phase, this result should be increased by a factor of N, that is:
Figure BDA0003772118070000054
in the long and medium wavelength bands, m < λ, so that:
Figure BDA0003772118070000055
Figure BDA0003772118070000056
considering again the area S = hm of the loop coil, we can write the formula of the instantaneous value of the resulting electromotive force in the loop coil in the form:
Figure BDA0003772118070000057
the amplitude of this electromotive force is equal to:
Figure BDA0003772118070000058
from the above formula, the following conclusions can be drawn:
the loop antenna has directivity in a horizontal plane, and its pattern is in a figure 8 shape. As shown in fig. 5, in a direction perpendicular to the plane of the toroid
Figure BDA0003772118070000059
The electromagnetic wave has no path difference to the two opposite plumb wires on the toroidal coil, and therefore the electromotive force induced on the wire on one side of the toroidal coil is completely cancelled by the electromotive force in the wire on the other opposite side. As a result, no reception (E)mα＝0)。
As the direction of the electromagnetic wave approaches the plane of the toroidal coil, the path difference of the electromagnetic wave to the opposite plumb side of the coil increases as well, when
Figure BDA00037721180700000510
And
Figure BDA00037721180700000511
and increases to a maximum value. In this case, the mutual cancellation of the electromotive forces in the loop coil with respect to the conductor is almost completely eliminated, so that the maximum amplitude of the resulting electromotive force is:
Figure BDA00037721180700000512
changing the electromotive force and the electric field strength in the toroidal coil into effective values, we obtain:
Figure BDA00037721180700000513
with the known formula for the electromotive force in the receiving antenna: eα＝EghλBy contrast, it can be concluded that the effective height of the loop-shaped receive antenna is equal to:
Figure BDA0003772118070000061
the application of magnetic antennas is generally embodied in the use for making measurements of magnetic field strength. If the induced voltages of the two orthogonal loop antennas are taken as a ratio, the azimuth angle theta of the incident electromagnetic wave can be obtained as follows:
Figure BDA0003772118070000062
UEWand UNSRepresenting induced voltages on two orthogonal antennas, respectively.
(2) Establishing a magnetic antenna signal processing circuit based on the basic receiving theory of the magnetic antenna in the step (1) and an equivalent circuit thereof; the method specifically comprises the following steps:
the signal processing circuit is generally composed of an amplifier, a filter, and a linearization processing circuit. The magnetic antenna signal processing circuit used in the experiment is composed of four parts, namely a differential amplifying circuit, a two-stage amplifying circuit, a low-pass filter and a follower. The coupled antenna signal is converted into a voltage signal after being sampled by a resistor R and a capacitor C, and then the signal is amplified by an amplifier. After the signal is amplified by the first stage, the signal does not reach the magnitude that can be recognized and analyzed by the back-end equipment, so that further amplification of the signal is required.
As shown in fig. 6, IC1 is the main body of the differential amplifier, and the inverting input and non-inverting input of the integrated operational amplifier bear the two input voltages flowing through the load resistors, respectively. After this, the inverting input is again connected back to the output resistor via the feedback resistor. In order to ensure the resistance balance between the two inputs of the operational amplifier, the feedback resistance and the ground resistance are generally required to be small in order to avoid and reduce the common mode rejection ratio. If the values of the feedback resistance and the grounding resistance are reduced, the common mode rejection ratio can be improved, and the resistance of the two input ends to the ground is kept balanced.
IC2 is a secondary amplifier, and the preceding stage circuit and the following stage circuit may be directly coupled to each other in order to amplify the ac signal and the slowly varying signal and to achieve circuit integration. The front-stage circuit needs to select a low-power-consumption and low-noise sound tube, and the static working point needs to be adjusted to be as small as possible, so that the noise characteristic is easy to improve. Generally, the noise of the whole secondary amplifying circuit is determined by the noise in the front of the circuit. The low-pass filter mainly functions to combine the integrated operational amplifier with a circuit formed by a resistor R and a capacitor C to form an active low-pass filter with high voltage and strong load capacity, and is used for controlling the frequency band of an input electromagnetic signal.
IC3 is a voltage follower having the capability of reducing the output resistance of the preceding follower and the capability of increasing the input resistance of the following follower. After the four parts, the magnetic signals collected by the antenna are converted into voltage signals and accurately recorded. It should be noted that each stage of circuit connection is an impedance matching problem, and the signal source should be kept to the maximum extent.
(3) Establishing an experimental magnetic field under the environment of simulating thunder and lightning electromagnetic waves; the method specifically comprises the following steps: firstly, simulating a magnetic field in a thunder and lightning electromagnetic wave environment, and building a Helmholtz circular coil test bed. The Helmholtz ring coil is composed of two coils with the same diameter, the coils are coaxially and parallelly placed, and the distance between the two coils is much smaller than the half-diameter of each coil. Its magnetic field features that in the range of two coils, the magnetic field has high uniformity and can be approximated to a constant magnetic field in a certain region.
The Helmholtz toroid is shown in FIG. 7, where a is the radius of the toroid, h is the distance between the two toroids, and r is the distance between the two toroids<In the region a, the magnetic field generated by the coil 1 is set as B(1)The magnetic field generated by the coil 2 is B(2)The axial component of the resultant magnetic field of coils 1, 2 is, depending on the additive properties of the magnetic field, that
Figure BDA0003772118070000071
Wherein L isnRepresents the nth order magnetic field coefficient of a single toroid, β = h/a.
The central magnetic field is:
Figure BDA0003772118070000072
uniformity degree:
Figure BDA0003772118070000073
wherein mu0＝4π×10-7And I is the current of the Helmholtz circular ring coil.
When the two identical and parallel coaxial current-carrying coils of the helmholtz toroid are energized with currents in the same direction, the total magnetic field of the two current-carrying coils is uniform over a large range near the midpoint of the coaxial axis when the distance between the two coils is equal to the radius of the coils. The distance between the Helmholtz ring coils is 27.5cm according to the medium voltage data of the signal channel,
Figure BDA0003772118070000074
two stools with the same height are used for placing two current-carrying coils of Helmholtz circular coils on the same straight line, and then ferrite wound with a plurality of turns of small circular coils is placedThe magnetic rod antenna is suspended at the coaxial midpoint of the Helmholtz toroid, so that it is placed in a standard uniform magnetic field.
Secondly, based on the Helmholtz circular coil test bed, secondly, a signal source is connected with a resistance box in series, then a magnetic antenna is connected with a capacitor in series, the two ends of the adjustable capacitor are connected with the resistance box in parallel, and then the closed circuit is connected into a magnetic antenna signal processing circuit. The electric capacity can select for use two 100 pF's electric capacity to establish ties at first in with whole access circuit, establish ties and later can obtain a 50 pF's electric capacity from this, later replaces from low to high according to the capacitance value in proper order. The positive pole of the magnetic antenna signal processing circuit is connected with a direct current stabilized voltage power supply and a signal source generator, and the negative pole of the magnetic antenna signal processing circuit is connected with an oscilloscope, and the oscilloscope processes, outputs and displays the final signal.
(4) Testing influences caused by different parameters based on a magnetic antenna coupling lightning electromagnetic wave system, and processing obtained data and analyzing a frequency response curve; the method comprises the following specific steps: the frequency response curve of the magnetic antenna refers to the difference of the processing capacity of the magnetic antenna on signals with different frequencies, and different sampling parameters also have certain influence on the capacity of the magnetic antenna for coupling and receiving lightning electromagnetic waves, so that the influence of the frequency response curve of the magnetic antenna on the selection of different sampling parameters needs to be researched. Generally, if the static operating point Q is set high, the output tends to enter the saturation region, and the output waveform appears to clip; if the static operating point Q point is set to be lower, the output can easily enter a cut-off region, the output waveform can be capped, and the topping phenomenon can occur. Both up-clipping and down-clipping cause distortion in the output waveform.
(4.1) analysis of test oscillogram:
as shown in fig. 8, when the input voltage of the signal source Vpp is 1V and the frequency is 1kHz, in the case that the resistance is 10 Ω and the capacitance is 100pF, the oscilloscope outputs a signal channel CH1 with an amplitude of 1V and a signal channel CH2 with an amplitude of 3.6V, and the waveform appears normal because the peak voltage of 3.6V of the channel CH2 is much smaller than the peak-to-peak value of the critical voltage of waveform distortion 20.50V.
When the amplitude Vpp of the input voltage of the signal source is 7V and the frequency is 1kHz, the oscilloscope outputs the signal channel CH1 with the amplitude of 6.250V and the signal channel CH2 with the amplitude of 21.25V under the conditions that the resistance is 10 Ω and the capacitance is 100pF, and the waveform is distorted because the peak voltage 21.25V of the channel CH2 is greater than the critical voltage of the waveform distortion, the phenomena of top clipping and bottom clipping occur.
(4.2) during normal waveform, analyzing the measurement results of different sampling parameters:
(1) selecting magnetic antenna frequency response values with the same resistance and different capacitances when the voltage is 1 Vpp;
when the input voltage value of the signal source is 1Vpp, the resistance is set to 10 Ω, and the capacitance and the frequency are changed, so that a first group of frequency loudness test results can be obtained. The same can be obtained for the measurement results of four other sets of parameter values with the resistances of 20 omega, 30 omega, 40 omega and 50 omega. As shown in FIG. 9, the general rule trend of the frequency response curve of the five groups of resistance values is that the low frequency part (100 Hz-1 kHz) rises greatly, the curve becomes flat and straight at the inflection point of 1kHz and keeps a maximum value unchanged, and the curve begins to show a descending trend until the frequency increases to 200 kHz.
The relationship between the maximum values of the frequency response curves of different capacitance values can be clearly seen in the frequency band of the part where the curve enters the gentle straight line, and the maximum values can be seen in table 1.
TABLE 1 maximum value of frequency response curve of magnetic antenna with same resistance and different capacitance in 1Vpp
Frequency response value (V/nT) U/B(50pF) U/B(100pF) U/B(1000pF) U/B(0.01μF)
U/B(10Ω) 0.063 0.065 0.068 0.070
U/B(20Ω) 0.120 0.120 0.130 0.130
U/B(30Ω) 0.160 0.170 0.180 0.185
U/B(40Ω) 0.200 0.230 0.240 0.250
U/B(50Ω) 0.250 0.280 0.300 0.300
(2) Selecting magnetic antenna frequency response values with the same capacitance and different resistances when the voltage is 1 Vpp;
when the input voltage of the signal source is 1Vpp, the capacitors are set to 50pF, 100pF, 1000pF and 0.01 μ F, and four sets of measurements are obtained by changing the resistance and frequency. As shown in fig. 10, the frequency response curves of 50pF, 100pF, 1000pF and 0.01 μ F all have a general trend of greatly increasing at a frequency of 100Hz to 1kHz, and with 1kHz as an inflection point, the curve abruptly increases to a relatively flat state, and finally shows a descending trend in a frequency band of 200kHz to 500 kHz.
According to the measurement results, the change rule of the frequency response curve of the magnetic antenna under the two conditions is that the curve in the low frequency band at the early stage linearly increases along with the increase of the frequency, the frequency band is relatively gentle in the range of 1kHz to 300kHz, and the curve is in a descending state after 300 kHz. The method can accurately reflect the variation trend that the magnitudes of the lightning electromagnetic waves and the lightning current and the ratio of the voltage to the magnetic induction intensity change along with the change of the frequency under the selection and combination of different parameters, and has guiding significance for the research on the characteristics of coupling and receiving the lightning electromagnetic waves of the magnetic antenna and the improvement of the detection precision of the magnetic antenna.

Claims (6)

1. A method for coupling thunder electromagnetic wave signals based on a magnetic antenna is characterized by comprising the following steps:
(1) Establishing a magnetic antenna equivalent circuit model according to a basic receiving theory of the magnetic antenna;
(2) Establishing a magnetic antenna signal processing circuit based on the magnetic antenna equivalent circuit model;
(3) Simulating a thunder and lightning electromagnetic environment generated by a lightning channel by building a Helmholtz ring coil test bed to generate a uniform magnetic field;
(4) The method comprises the steps of testing influences caused by different parameters based on a magnetic antenna coupling lightning electromagnetic wave system, processing obtained data and analyzing a frequency response curve.
2. The method for coupling the lightning electromagnetic wave signal based on the magnetic antenna according to the claim 1, wherein the step (1) is specifically as follows:
(1.1) surface area of Loop antenna AL；BNIs a planar normal phase magnetic field component of a loop antenna；RLIs C, C0、R0Resistance values after parallel connection; l is the inductance of the loop antenna; the relationship expression among the parameters is derived from the circuit principle:
Figure FDA0003772118060000011
in the formula of U0Representing the load resistance R0Output voltages at both terminals;
(1.2) in the simplest case, the loop antenna is a rectangular planar coil coaxial with the axis of rotation OO and coincident with the axis of symmetry of the loop; assuming that the loop antenna is located on a vertical plane and has a vertically polarized wave passing through it with its propagation direction on a horizontal plane at an angle of v to the loop coil plane; since it is a vertically polarized wave, electromotive forces are induced only on the plumb wires α σ and δ τ of the ring; the electromagnetic wave first reaches the wire δ τ and induces an electromotive force therein:
eθz＝Em sinωt
when the annular coil has N turns, the electromotive force induced on the N leads is as follows:
Figure FDA0003772118060000012
in the formula, EmIs the amplitude of the electric field strength.
3. The method for coupling the lightning electromagnetic wave signal based on the magnetic antenna according to the claim 1, wherein the step (3) is specifically as follows:
a is the radius of the Helmholtz ring, h is the distance between the two rings, r<In the region a, the magnetic field generated by the coil 1 is set as B(1)The magnetic field generated by the coil 2 is B(2)According to the additive property of the magnetic field, the axial component of the combined magnetic field of the coil 1 and the coil 2 is:
Figure FDA0003772118060000013
wherein L isnRepresents the nth order magnetic field coefficient of a single toroid, β = h/a;
the central magnetic field is:
Figure FDA0003772118060000014
wherein mu0＝4π×10-7And I is the current of the Helmholtz ring coil.
4. A system for coupling thunder electromagnetic wave signals based on a magnetic antenna, the system can realize a method for coupling thunder electromagnetic wave signals based on a magnetic antenna according to any one of claims 1-3, and is characterized by comprising a thunder electromagnetic field receiving system and a magnetic antenna signal processing circuit, the thunder electromagnetic field receiving system is used for receiving, storing and outputting electromagnetic wave signals and data thereof, and the magnetic antenna signal processing circuit is used for modulating electromagnetic wave signals in a magnetic antenna equivalent circuit.
5. A computer storage medium having a computer program stored thereon, the computer program, when being executed by a processor, implementing a method of coupling lightning electromagnetic wave signals based on a magnetic antenna according to any of claims 1-3.
6. A computer arrangement comprising a memory, a processor and a computer program stored on the memory and executable on the processor, characterized in that the processor implements a method of coupling lightning electromagnetic wave signals based on a magnetic antenna according to any of claims 1-3 when executing the computer program.
CN202210905174.7A 2022-07-29 2022-07-29 Method and system for coupling thunder and lightning electromagnetic wave signals based on magnetic antenna Pending CN115267355A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116299111A (en) * 2022-12-02 2023-06-23 中国气象局气象探测中心 Lightning positioning instrument detection fault diagnosis instrument
CN117890846A (en) * 2024-03-13 2024-04-16 南京信息工程大学 Signal simulator for lightning data acquisition

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116299111A (en) * 2022-12-02 2023-06-23 中国气象局气象探测中心 Lightning positioning instrument detection fault diagnosis instrument
CN116299111B (en) * 2022-12-02 2023-09-19 中国气象局气象探测中心 Lightning positioning instrument detection fault diagnosis instrument
CN117890846A (en) * 2024-03-13 2024-04-16 南京信息工程大学 Signal simulator for lightning data acquisition

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