SU1525640A1 - Apparatus for calibrating electric field pulse transducers - Google Patents

Abstract

The invention relates to a measurement technique, namely, devices for calibrating sensors for measuring pulsed electromagnetic fields inside non-uniform metallic screens. The purpose of the invention is to improve the calibration accuracy and reduce the energy loss of the internal electric fields of aperiodic electromagnetic pulses. This is achieved by using a uniform two-electrode line with a transverse dimension A, determined from the relation A = 1.25 ^{. C.} Τ _f , where C is the velocity of propagation of an electromagnetic wave in the medium surrounding the line

Τ _f is the front duration of the aperiodic electromagnetic pulse and the symmetrical arrangement between the line electrodes and the sensor of two conducting plates parallel to the electric and magnetic field vectors and having the same size and geometric shape that coincides with the shape of the hole in the screen under study. The device contains a capacitor drive 1, a switch 2, resistors 3 and 4, electrodes 5 and 6, a calibrated sensor 7, conductive plates 8. 1 sludge.

Description

(61) 8753Й

(21) A36it038 / 2it-2i

(22) 01/15/88

() 30.11,89, Byul, f kk.

(71) Kharkiv Polytechnic Institute. V.I. Lenin

(72) A.Ye.Vyvolokin, V.P.Datsenko, V.V.Kn zev and G., F.Neskorodov (53) 621.317. (088.8)

(56) USSR Author's Certificate No. 87531 4, cl. G 01 R 33/00, 1980.

(DEVICE FOR CALIBRATION OF SENSORS OF PULSE ELECTRIC FIELD

(57) The invention relates to a measurement technique, namely, devices for calibrating sensors for measuring pulsed electromagnetic fields inside non-uniform metallic screens. The goal of the acquisition is to increase calibration accuracy and reduce energy loss.

internal electric fields of aperiodic electromagnetic pulses. This is achieved by using a uniform two-electrode line with a transverse dimension, a, determined from the ratio, 25 C t cp, where C is the speed of propagation of an electromagnetic wave in the medium surrounding the line; cf is the duration of the front of the aperiodic electromagnetic pulse, and the symmetrical arrangement between the line electrodes and the sensor of two conducting plates parallel to the electric and magnetic field vectors and having the same size and geometric shape that coincides with the shape of the hole in the screen under study. The device contains a capacitor drive 1, a switch 2, resistors 3 and i, electrodes 5 and 6, a calibrated sensor 7, conductive plates 8. 1 sludge.

but

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I3 15256 about

The invention relates to a measurement technique, namely, devices for calibrating sensors for measuring pulsed fields inside non-uniform metal en: wounds.

The purpose of the invention is to increase the accuracy of calibration and reduce losses.

energy of the internal electric field; aperiodic electromagnetic

ten

and

| pulses.

The drawing shows the proposed device ..

The goal is achieved barely- 5

D

signs: transverse size

a homogeneous two-electrode line is associated with the front duration of an aperiodic electromagnetic pulse with the following ratio a, 25 Ci bop, where C is the velocity of propagation of the electromagnetic wave in this H (j) medium; between the electrodes of the line sensor symmetrically arranged conductive plates, for example, medlej they are located so that the vectors

electric and magnetic fields are parallel to the plane of the plates; plates have the same size and geometric shape; plate form. coincides with the shape of the holes in the research screens.

I Select parameter a, i. The distance between line elements is made from the following considerations. The two-electrode line for an electromagnetic field is a wave structure which, with the least attenuation, passes only the fundamental harmonic -: a frequency. F. The calibrator is designed /: | FOR calibration of the pulse field sensors, and the aperiodic pulse has (infinite frequency spectrum. There is a connection of the effective frequency f with; | 1 the front length of the aperiodic pulse oe., Which causes the choice of i.e. with minimal energy loss.

In the proposed device, a homogeneous two-electrode line in cross section is a rectangle with a distance between the elements of the line, (impudent a. Critical wavelength, E, hence the frequency, are related to size a by the ratio:

,: f.i ... c. (one)

2

For an aperiodic pulse, the frequency relationship with the pulse front duration is as follows:

f - 2i

m

(2)

five

0

0

five

0

35

40

45

50

From formulas (1) and (2), it is easy to obtain a relationship between the dimensions of the line and the duration of the pulse front.

a, 25 CZ,, (3) where C is the speed of propagation of a wave in a given medium (in our case, air), therefore 1 / -JEp7 l).

Conductive plates located between the electrodes of the line have a geometrical shape and dimensions identical to the shape and dimensions of the hole in the body of the metal screen,

The device for calibrating the pulsed electric field sensors contains a capacitor drive 1 connected in series with the switch 2, which is connected to the connection point of the resistors 3 and connected to the discontinuity of the electrode 5. Condenser

1 is also connected to electrode 6. Between electrodes 5 and 6 at a point diametrically opposite to switch 2, there is a calibrated sensor 7, conductive plates 8, for example copper, of the same geometric dimensions and shape, coinciding with the shape of holes in the right and left of the sensor screen under study.

The drawing also indicates: E, H are the electric and magnetic field vectors; I is the traveling wave current; R is the radius of the ring; if is the azimuth angle of the observation point; 1 linear sensor size; and - the transverse size of the two-electrode line.

The device works as follows.

At the moment, a capacitor drive 1, charged up to a voltage Ug, is connected via switch 2 to the connection point of resistors 3 and 4. At this moment, along the electrodes 5 and 6 of the uniform line from the switch

2, sensor 7 begins to propagate two identical waves. If the resistance Z of each resistor is 3

55 and + is equal to the wave resistance of the line, then the amplitude of the current of these waves is 1

In Uo / 2 Z. Electric fields are equal and magnetic

 oh oh

and equally

the sex is equal and opposite. After time t, where C is the speed of propagation of electromagnetic waves in the line, both waves reach the plates 8, distort and come to the sensor 7. The distribution of the field on the plates is such that it completely simulates the passage of the field through the hole in the metal screen with the hole whose plane is normally located to the F vectors, which is consistent with the Babinet principle applied to the electromagnetic field. Their superposition leads to the addition of electric fields and the subtraction of magnetic fields.

Thus, for the sensor 7, the effect of the field H is reduced to zero. If the sensor 7. has a linear dimension 1 in the direction of the wave propagation (along the line), it is during the left and right half of the sensor that the parasitic signal appears

Claims (1)

Invention Formula ten A device for calibrating pulsed electric field sensors according to the author. St. No. 87531, characterized in that, in order to improve calibration accuracy and reduce energy loss, additionally introduced conductive plates are arranged symmetrically between the line electrodes and the sensor, the planes of which are parallel to the 20 vectors of electric and magnetic fields, are made equal in size and geometric shape, and the transverse dimension is related to the duration of the aperiodic front ka 7 is exposed to several 25 pulses by the ratio, 25 C tj, pensirovannye magnetic fields against where C is the speed of propagation opposite sign that may cause an electromagnetic wave in a given environment. However, due to the finite steepness of the leading front, the magnitude of these fields is significantly lower than the amplitude value of the traveling wave. Invention Formula ten 15 20