Antenna-coupled infrared detectors

Abstract

A theoretical study has been made of the use of antennas to couple radiation to infrared detectors. It is shown in general that for any detector characterized by a specific detectivity D, noise‐equivalent power (NEP) can be reduced until the background blackbody fluctuation limit is reached. The reduction in NEP is expected to be on the order of b/λ, where b² is the area of the detector. In the case of far‐infrared bolometers away from the blackbody limit, significant reductions of NEP appear to be possible. Alternatively the antenna may be used to increase the temperature at which the bolometer can be operated or to reduce its response time. The possible use of antennas with various other infrared detectors is also considered, and some criteria for suitability are described.