A heterodyne circuit for measuring the spectral characteristics of Ka-band nanosecond high power microwave pulses

A circuit was constructed based on a heterodyne receiver to measure the spectral characteristics of Ka-band high-power nanosecond microwave pulses. The circuit included a receiving antenna, three input waveguide directional couplers with different coupling coefficients, a variable waveguide attenuator, two coaxial-to-waveguide adapters, a microwave cable, an additional directional waveguide coupler, as well as a heterodyne receiver consisting of an electrically controlled electronic attenuator, a mixer and a local oscillator combined in one unit. The developed circuit was intended to measure the spectral characteristics of high-power nanosecond microwave pulses in the range of 35.7-37 GHz.