The use of impedance standards in free space reflection coefficient measurements

Author

Smith, F.C. ; Chambers, Barry ; Bennett, J.C.

Author_Institution

Sheffield Univ., UK

fYear

1992

fDate

33750

Firstpage

42491

Lastpage

42494

Abstract

The standards used in free space reflection coefficient (S₁₁) measurements are examined. As with all standards, the response of a free space impedance standard has to be calculable. The impedance standards discussed use transmission line analogy (TLA) techniques to determine their reflection coefficient. However, the TLA can only derive approximate values of reflectivity; to calculate a more accurate value of a standard´s reflectivity a model has been developed, based on the Geometric Theory of Diffraction (GTD), which calculates the reflection coefficient of a standard so as to include the effects of finite sample size and arbitrary illumination. Some preliminary results from the GTD model are presented

Keywords

electric impedance measurement; electromagnetic wave diffraction; electromagnetic wave reflection; measurement standards; microwave reflectometry; transmission line theory; GTD model; Geometric Theory of Diffraction; arbitrary illumination; finite sample size; free space measurements; free space reflection coefficient; impedance standards; radar absorbing material; reflection coefficient measurements; transmission line analogy;

fLanguage

English

Publisher

iet

Conference_Titel

Low Profile Absorbers and Scatterers, IEE Colloquium on

Conference_Location

London

Type

conf

Filename

168443