  In this work, a physical and geometrical optics based single-frequency
imaging scheme is proposed for personal screening systems using multiple
reconfigurable reflectarrays. This scheme is able to not only reconstruct
profiles of potential threat objects on human body, but also identify their
materials in terms of their complex relative permittivities. Both simulation
and experiment are carried out to detect dielectric objects at a microwave
frequency of 24.16 GHz. The object profiles and complex relative permittivities
are obtained with both high accuracy and computational efficiency, which show
great potentials for security imaging where inspection of human body for threat
materials, such as narcotics, explosives, and other types of contraband, is
very common.
