Electromagnetic radiation sensor for e.g. mm waveband at 30 to 300 GHz - has dielectric support body with metal antenna in close proximity so that resonance is dependent on dielectric properties of body

摘要

The sensor has an antenna (141) of metal strip on a high resistivity semiconductor substrate, and one or more mixer diodes (43A to D) integrated in the substrate material and connecting adjacent antenna limbs (141A & B; 141B & C; 141C & D; 141D & A). The antenna may be a single dipole or may consist of a pair of crossed dipoles. For a crossed dipole antenna, one antenna limb (141D) is split along its length to enable extraction of the mixed signal this is developed across the split portions (155, 157). Antennae (141), as above, may be assembled in close-packed array, and the substrate material shaped to converge radiation onto these antennae.