RU2022282C1 - Method of determination of parameters of open waveguide - Google Patents

Abstract

FIELD: radio measurement technology. SUBSTANCE: inhomogeneity is moved in lateral plane of waveguide from center in parallel to its wall and inhomogeneity position x₁ corresponding to absence of reflected signal is fixed. Then inhomogeneity is moved towards wall of waveguide and damping is determined by solving equation

Description

 The invention relates to a radio measurement technique.

 Closest to the proposed method is a method for determining the parameters of an open waveguide by perturbing the waveguide field by a pair of identical inhomogeneities located along the axis of the waveguide outside it, and longitudinally moving the inhomogeneities to obtain the minimum reflected signal. The disadvantage of this method is the high error in the determination of small attenuation.

 The aim of the invention is to improve the accuracy of determination of small attenuation.

+(1-

)e^-2α]} = e^-2α где N - отношение отраженных сигналов, фиксируемых при размещении неоднородности над стенкой и в центре волновода.This is achieved by the fact that the discontinuity is displaced in the transverse plane of the waveguide from the center parallel to its wall and the heterogeneity position X _{1 is} fixed, which corresponds to the absence of the reflected signal, the discontinuity is moved to the waveguide wall, and the attenuation is determined by solving the equation
cos {(x ₁ -0.5) arccos [

+ (1-

) e ^-2α ]} = e ^-2α where N is the ratio of the reflected signals recorded when the inhomogeneity is placed above the wall and in the center of the waveguide.

 Compared with the known method, the proposed method exhibits new properties, which include the possibility of determining small attenuation in the segment of the open waveguide between the inhomogeneities by comparing the reflected signals when one of the inhomogeneities moves in the transverse plane of the waveguide parallel to its wall, where there is a slight change in the field amplitude and, accordingly, the reflection coefficient .

 These properties are new, because in the prototype due to its inherent disadvantages, namely the lack of transverse movement of the heterogeneity and fixing the corresponding reflected signals, it is impossible to determine the attenuation with high accuracy.

 The method can be implemented using a device whose structural electrical diagram is shown in the drawing.

 The device contains a series-connected generator 1, a directional coupler of the reflected wave 2 and a segment of an H-shaped metal-dielectric waveguide 3 with the first and second capacitive probes 4 and 5, connected to the secondary channel of the coupler 2 in series with the detector 6 and indicator 7, while the first probe 4 can move in the transverse plane of the waveguide parallel to its wall, and the second probe 5 has the possibility of longitudinal movement.

 The method is as follows.

The signal from the generator 1 through the coupler 2 enters the waveguide 3 and is reflected in the planes of the probes 4 and 5. The signal at the detector 6 can be determined by the method of directed graphs and after tuning the probes 4 and 5 in the longitudinal direction has the form
E _g = E _g [S ₁₁ (x) -e ^-2α S ₂₂ ], (1) where α is the desired attenuation;
S ₁₁ (x) is the modulus of the reflection coefficient from the first probe 4;
E _g - signal generator;
S ₂₂ is the reflection coefficient modulus of the second probe 5.

- 0,5

, (2) где Е_ym - амплитуда поля в центре волновода 3;
а - поперечный размер волновода 3, вдоль которого осуществляются перемещения зонда 4;
E_ya= E_ym cos

- напряженность поля на стенке волновода 3, сигнал на индикаторе 7 с учетом квадратичности характеристики детектора 6 можно записать при размещении первого зонда 4 в центре волновода 3, над стенкой волновода 3 и в точке Х₁, фиксируемой по индикатору 7 в момент отсутствия отраженного сигнала соответственно:
U

= K_д(S₁₁-S₂₂e^-2α)² (3)
U

= K_д(S₁₁cos φ $\genfrac{}{}{0ex}{}{\text{n}}{\text{x}}$ -S₂₂e^-2α)² (4)
U

=0 = K

S₁₁cos

- 0,5

- S₂₂e

(5)
Тогда затухание можно определить из трансцендентного уравнения при условии идентичности конструкции зондов 4 и 5, т.е. S₁₁=S₂₂.Given the nature of the field distribution in the transverse plane of the waveguide 3,
E _y = E _ym cos

- 0.5

, (2) where Е _ym is the field amplitude in the center of waveguide 3;
a is the transverse dimension of the waveguide 3, along which the probe 4 moves;
E _ya = E _ym cos

- the field strength on the wall of the waveguide 3, the signal on the indicator 7 taking into account the quadratic characteristics of the detector 6 can be recorded when placing the first probe 4 in the center of the waveguide 3, above the waveguide 3 wall and at point X ₁ , fixed by indicator 7 in the absence of the reflected signal, respectively :
U

= K _d (S ₁₁ -S ₂₂ e ^-2α ) ² (3)
U

= K _d (S ₁₁ cos φ $\genfrac{}{}{0ex}{}{\text{n}}{\text{x}}$ -S ₂₂ e ^-2α ) ² (4)
U

= 0 = K

S ₁₁ cos

- 0.5

- S ₂₂ e

(5)
Then the attenuation can be determined from the transcendental equation provided that the design of the probes 4 and 5 is identical, i.e. S ₁₁ = S ₂₂ .

- 0,5

arccos

+(1-

)e

= e^-2α , (6) где N=

.cos

- 0.5

arccos

+ (1-

) e

= e ^-2α , (6) where N =

.

 Compared with the known, the proposed method improves the accuracy of determining small attenuation.

Claims (1)

THE METHOD FOR DETERMINING OPEN WAVEGUIDE PARAMETERS, which consists in perturbing the field with a pair of identical inhomogeneities located along the axis of the waveguide outside it, longitudinally moving the first inhomogeneity to obtain the minimum reflected signal, characterized in that, in order to increase the accuracy of determining small attenuations, the ratio N reflected is additionally measured signals when placing the second inhomogeneity over the waveguide wall at a distance x = 3/2 a and in its center x = a / 2, respectively, move the second inhomogeneity awn to obtain the minimum of the reflected signal in a transverse plane parallel to the waveguide wall, measure the distance to the inhomogeneity of the waveguide wall to the non-reflected signal, and α the attenuation is determined from the equation
cos {(x ₁ -0.5) arccos [

+ (1-

) e ^-2α ]} = e ^-2α ,
where a is the transverse dimension of the waveguide.

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