A Microwave Interferometer for Wide-Band Measurements of Complex Transmission Coefficients

A wide-band (8.2-12 GHz) microwave interferometer was developed to measure the complex transmission coefficient of samples inserted in a waveguide system. Amplitude A and phase shift ¿ of a signal are presented either as A sin ¿, A cos ¿ versus frequency, or in polar coordinate form Aei¿ as frequency is swept. The attenuation range of measurement is 0-50 dB; phase shifts between n·2¿ and (n + 1)·2¿ are given as ¿ - n·2¿ (n = 0, 1, 2,···). The unique feature of this system is its ability to measure broad frequency bands in a simple way. The system was tested with components with known characteristics and used to measure transmission of a sheet of water.