Through-Wall Sensing With Multifrequency Microwave Radiometry: A Proof-of-Concept Demonstration

A proof-of-concept demonstration of through-wall sensing with microwave radiometry is described. A multifrequency microwave radiometer with 37 channels from 2.1 to 17.35 GHz was used in two experiments to observe objects through a cinder block wall of approximately 20-cm thickness. Measured data show the clear ability of the radiometer to detect thermal contrasts on the interior of the wall. A discussion of the basic physical processes involved in the measurement is provided. When compared with active systems, microwave radiometry for through-wall sensing faces significant challenges, including limitations in ranging, horizontal resolution, and corruption by radio-frequency interference, but also provides complementary capabilities, particularly with regard to thermal information. Further consideration of microwave radiometry appears warranted for applications where thermal information is of interest.