An instrument for the measurement of surface impedance at microwave frequencies

Abstract

A theory is given of an instrument for the measurement of surface impedance at microwave frequencies.Two prototype instruments—one for 6 Gc/s and one for 34 Gc/s—are described, and the measurement procedure is explained. Basically the surface impedance (Zs = Rs + jXs) is deduced from the resonant conditions of the cavity operated simultaneously in H01- and E11-modes. In particular, the cavity bandwidth is a measure of the surface resistance Rs, and the surface reactance, Xs, is deducible from the separation between the H01 and E11 responses.As an illustration of the use of the instruments a number of experimental results are cited.