System-on-Chip Microwave Radiometer for Thermal Remote Sensing and its Application to the Forest Fire Detection

This research activity focuses on the opportunities offered bythe latest advances in silicon technologies for realizing systemon-chip microwave radiometer. Such a highly integrated, lowcost,radiometer chip could be applied to the environmentalremote sensing and, in particular, to the forest fire detection.The feasibility study is carried-out in two steps. First, a proof ofthe concept is given by means of a discrete-componentradiometer operating at 12.65 GHz. This radiometer exploitsTV-SAT components such as low-noise down-converter and dishantenna. On-field measurements shows a radiometric contrast(increase of the antenna noise temperature due to the fire withrespect to the background) of about 8 K for a wooden fire of0.38 m2 placed 30 m away from the antenna. Then, a single-chip13 GHz radiometer has been designed exploiting a CMOS 90 nmstandard process. The sensor is based on a direct-conversionarchitecture with integrated LNA, Gilbert’s cell mixer and PLLfrequency synthesizer. The IF chain includes an active (gm-C)low-pass filter and a CMOS square-law detector. The circuitsimulations show a total receiver gain of 72 dB, an equivalentinput noise temperature of 105 K and an IF bandwidth of100 MHz.