An instrument for the measurement of surface impedance at microwave frequencies

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.