A 3mm band IF-switch Radiometer was proposed in this paper. On the basis of
discussing the theory and circuit structure features, the performance of e
xperimental prototype was presented. The research and experiment result sho
ws that not only its stability is better than that of total power radiomete
r, but also its cost and size are just similar as the latter. In the absenc
e of 3mm band switch it can surely meet the needs of practical use.