Optical Methods for the Measurement of Complex Dielectric and Magnetic Constants at Centimeter and Millimeter Wavelengths

A method is described which permits the determination of the complex dielectric constant, epsilon* = epsilon_ok_e(l-j tan delta_e), and the complex permeability, µ* = µ_ok_m (l-j tan delta_m), using free space transmission and reflection from a plane sheet of the sample dielectric. The procedure represents an extension of that used at optical frequencies. Differences arise however, due to the fact that the assumptions of k_m = 1 and tan delta_m = 0, which are made in the optical theory, are not always valid at millimeter wavelengths.