A Novel Background Calibration Technique for Microwave Radiometric Sensors in Indoor Applications

This letter presents a novel background calibration technique for microwave radiometers in indoor applications such as security sensing for static targets where unknown noise sources may add to background noise and degrade measurement accuracy. Such a background correction is important for absolute measurement of radiometric apparent temperature as opposed to relative measurement of contrast. The technique is validated by measuring the error in apparent temperature of hot water using a 23.55 GHz radiometer in an uncontrolled environment where the background noise is artificially increased using a diode-based noise source. The calibration technique reduced the prediction error introduced due to incorrect assumptions about the background by approximately 1 to 3 K.