A Thermal Noise Measurement System for Noise Temperature Standards in $W$ -Band

A W-band waveguide noise measurement system has been developed for noise temperature (NT) standards. The system consists of two standard noise sources and a waveguide radiometer. A horn-type cryogenic noise source operating at the liquid nitrogen temperature and an ambient temperature termination have been employed as standard noise sources. To measure noise power radiated from the noise sources including a device under test, a total-power waveguide radiometer has been constructed and its performance has been evaluated. Measured NT of a commercial waveguide noise source is presented with the measurement uncertainty of 0.10-0.13 dB (k=2) in W-band.