A coherent, solid state, 225 GHz receiver

A low noise, broadband, balanced mixer has been developed for use as a 225-GHz receiver. It utilizes a local oscillator (LO), whose frequency is nearly 1/4 the signal frequency, to mix the signal power to a low IF, which is then amplified. This same LO drives a similar mixer that is used to phase lock a 225-GHz transmitter. The use of a subharmonic mixer lowers LO cost, noise, and complexity, increases LO availability and reliability, and is compact and portable. Typical applications for this type of mixer include coherent receivers, passive imaging, multiple receiver systems, and broadband detection systems