SU1597758A1 - Absorbing load of mcw-wattmeter - Google Patents

Abstract

This invention relates to a microwave technique. The purpose of the invention is to improve consistency. The absorbing load contains a segment of the waveguide 1, inside of which the absorbing film 2 and two dielectric inserts 4 are placed, separated by a gap. The absorbing film 2 contacts the surface of the dielectric liner 4 nearest to it. The thickness of the dielectric liners, the size of the gap and the surface resistance are chosen according to certain dependencies, which provides the best matching of the microwave wattmeter load.

Description

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This invention relates to microwave radio engineering and can be used in bolometric and calorimetric applications. Microwave wattmeter for precision measurement of low levels of microwave power in waveguide paths of rectangular cross section.

The purpose of the invention is to improve the consistency

The drawing shows the design of the absorbing load of the microwave power meter.

Absorbed and the load of the microwave wattmeter contains a waveguide section shortly closed at one end, an absorbing film 2, a shorting piston 3, two identical dielectric contributions 4, between which there is an air gap 5.

The principle of operation and matching of the microwave-wattmeter load is in the following.

The electromagnetic field of the incident wave is guided / hit on the absorbing film 2 by an electric current, which leads to heating of the film 2. As a result, its resistance changes, which is fixed by the indicator device

In addition to absorbing a larger fraction of the incident wave power, part of the power is carried away by the reflected wave. In order to achieve good matching in the frequency range of waveguide 1, the distance from film 2 to piston 3 should be on the order of al (where length; is the wave at the center frequency of the operating range), since then the minimum difference in the frequency range of conduction of short-setting piston 3 the plane of the absorbing film 2. However, a significant frequency dependence of the conductivity of the piston 3 does not allow for good agreement

throughout the frequency range of the waveguide. To match the film absorber in a wide frequency range, a matching transformer in the form of two identical

dielectric inserts 4, which fill the entire cross section of the waveguide 1. Between the dielectric inserts 4 there is an air gap 5, and one of these inserts closely

draws on the absorbing film 2. The presence of dielectric inputs in the structure leads to the appearance of additional reflected waves in the waveguide path, which are excited at the junction of lines with different wave resistances. The choice of thickness Lg. the contribution of the air gap and the width L of the air gap 5 can be achieved such phase relations between the waves reflected from

films 2 of the piston 3 and dielectric liners 4, in which mutual compensation of these waves is achieved. The surface impedance W is absorbed; the film 2 and the magnitude L n L are determined from the relations:

W Wn + 7,4e - 0,35-,

h cos cos Lg X (E :) arccos

sSElj-fe-l-I-tyM liig Jil 1;

L (1 + A) 1

L.A.

V,

L - arccos,. y,

de A, (R, - R |) y (1 + Rp / 2R; 9, 0.3h; R, K, o / h;

H / 10 /%;

h 1) 1,6 -;

.K, (, / (2) Ha / L) -1H; Kg / () H-IT; X () 0.62 + 0, Wj 240 - 260 OM, a is the waveguide width; A - wavelength in free space at the middle frequency of the working range;

 - relative dielectric constant of the material of the dielectric contributed 4.

Claims (1)

Invention Formula The absorbing load of the microwave wattmeter containing a waveguide section, short-circuited at one end, in which the absorbing pedestal is placed, which overlaps the cross-section of the waveguide section, which is different. so that, with the aim of improving -, - matching /, inside a segment of the wave of an ode, between the absorbing film and the short-circuited end of the wave-: water there are two dielectric ones. 51597758 the liner whose dimensions correspond to another, with the surface of the cross section being the impedance W of the absorbing film, the thickness of the waveguide, and the absorbing film placed on the surface of the dielectric liner closest to the closed loop of the waveguide, b, and the gap L are determined from the ratios + 7.4 - 0.35e. W- Wo suspended with clearance I., 2Kg arccos L, jjS. arccos (f-) where A, (R, - R |) / 4RjRg; X - (1 + R) / 2Rf; et 0.3h R, K, o / h; R Kffl / Kg; . h (21Га / Л) 1.6 K, o () -1i Compiled by R. Kuznetsova Editor N. Yatsola Tehred M. DidykKorrektor I. Kuska Order 3050 Circulation 548 VNIIPI State Committee for Inventions and Discoveries at the State Committee on Science and Technology of the USSR 113035, Moscow, Zh-35, Raushsk nab. 4/5 Production and publishing plant Patent, Uzhgorod, st. Gagarin, 10.1 to another, with the surface impedance W of the absorbing film, on dielectric inputs b and gap size L, are determined from the ratios + 7.4 - 0.35e. W- Wo 2 iL Oj: -4 l lM6 i sill il (1 + A) if- 1 five R | (2 (ha // 1). E; X () 0.62 + 0, W 240 - 260 OM: a is the width of the waveguide section; d - wavelength in free space; on the middle frequency of the working range; - the dielectric constant of the dielectric material is embedded. Subscription