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.