Homodyne Phase Sensitive Sub-Millimetrewave Transmission Measurements

A novel measurement setup for transmission measurements using a homodyne receiver is presented. The measurement principle is basically usable at any frequency from microwaves to light. However, it is especially interesting in the sub-millimetre wavelength range where tunable frequency stabilised sources are expensive, as it only uses a single source with low frequency stability requirements. Sinusoidal phase modulation and digital processing of the acquired signal are key to the measurement principle.