Radio Frequency (RF) Modeling of Layered Composite Dielectric Building Materials

This SBIR Phase I project proposes to develop a system that will permit reliable RF detection of humans visually obscured behind non-homogeneous walls. It aims at accurate EM modeling of walls over the upper band of the UHF frequency range. The EM modeling results will then be used to devise algorithms to mitigate the wall dispersive effects that tend to obscure the EM signature of persons standing, sitting or kneeling behind the walls. Towards this end, recent advances in time-reversal, singularity expansion method (SEM), and statistical mutual information are considered as potential and viable solutions to unmask the human RF signature behind attenuative walls and walls with enclosed air gaps. The proposed research is hybrid between electromagnetic modeling and signal processing. Similarities and divergence measures are applied to signal returns for wall classifications. Transmitted pulse shaping and reshaping as well as linear processing of received signals are proposed to mitigate the wall effects and reveal human presence. Wideband beamforming implemented by an antenna transmit-receive array is used to provide three-dimensional imaging and to allow surveillance operations from desirable standoff distances. The proposed efforts involve verification of theoretical and computer simulation findings through experimentations and real data collection.