Passive millimetre wave imaging and absorption from exhaust gases

Passive millimetre wave imaging systems have been developed and their applications investigated at DERA Malvern for several years. In this paper the applications of passive millimetre wave imaging for the detection of exhaust gases is investigated. In principle, this is feasible over the whole of the millimetre wave band. DERA has developed the world's first mechanically scanning real-time passive millimetre wave imager for the Ka band, the lower frequency end of the millimetre wave band. Currently at W-band, DERA is developing a real time imager using MMIC electronics to build the compact focal plane receiver array. Recent developments in MMIC technologies are beginning to make possible development of real time passive millimetre wave imaging systems at the still higher frequencies of the F- and D-bands.