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Fire detection by low-cost microwave radiometric sensors

This paper discuss the possibility to detect a fire exploiting microwave radiometric sensors. In particular the experiences carried-out at the University of Duisburg-Essen, Germany and at the University of Perugia, Italy, are described. At the University of Duisburg-Essen a multi-frequency radiometer, capable of full 2-40 GHz coverage, has been developed. This sensor has been used to characterize the microwave emission of fire as a function of shape and of burning materials. In addition, the response of this microwave radiometer has been compared with those of standard (i.e. CO and CO2) fire sensors. At the University of Perugia, instead, a portable 12.65 GHz radiometric sensor has been developed. This frequency has been chosen in such a way as to balance a good obstacle penetration capability with a reasonable antenna size. To keep low the radiometer cost, commercial TV-SAT components have been adopted along with a noise-adding (switch-less) calibration architecture. Such a sensor is able to detect small fires (filling factor below 1%) while being characterized by a component cost less than $1800.