A reflection method of measuring optical and electrical constants at ultra-high radio frequencies

Abstract

A source of ultra-high-frequency oscillations was coupled to a long antenna AB at a point O. By terminating one end B of the antenna with a reflecting surface of the substance under investigation, standing waves were produced between the reflector at B and the input at O. Resonance conditions along OB were detected by a thermojunction in the portion OA of the antenna and were controlled by altering the length OB. The phase change Φ produced on reflection was calculated from the difference in the resonant lengths OB with and without the reflecting termination. From the current distribution along OB, the amplitude reduction factor ρ was determined. The electrical and optical constants of the reflecting substance were then calculated from their known relationships to the Fresnel reflection coefficient ρejΦ.