Methods of Experimental Measurement of Scattering and Transmission Parameters in Microwave Frequency Bands

This paper discusses modern available techniques for the experimental measurement of the scattering and transmission parameters of microwave devices. Peculiarities of microwave frequency bands require application of specific approaches, which significantly differ from the low-frequency methods utilized in the classical circuit theory. The wavelength at microwave frequencies becomes value of the order of physical dimensions of radio engineering devices. Additional phase delays cannot be taken into account by the classical circuit theory. Concept of concentrated at conductors currents and voltages between conductors lose their sense at microwaves. Consequently, several new specific measurement methods become widespread for the analysis of multipole devices of microwave frequency bands. In this investigation we consider and demonstrate measurement setups for the experimental investigations of transmission parameters by the substitution technique. Besides, measurements of reflection coefficients, which are diagonal elements of the scattering matrix, are discussed. We present the measuring waveguide line and illustrate its application for the estimation of VSWR. Second part of the paper is dedicated to automated measurement setups based on scalar network analyzers and waveguide directional couplers.