Student Poster Session

Millimeter wave security sensors play an important role in the fight against terrorism. Combining two modes – active and passive – into a single pactive sensor shows potential to reduce ambiguity in the detection of concealed items. The ability to measure the properties of such items would enhance the capability of pactive sensors to classify them. This work proposes a new technique to extract the thickness and complex permittivity of a concealed (embedded) dielectric under planar, multi-layer dielectric assumptions using pactive sensors. The technique is experimentally verified with a K-band (18-26 GHz) pactive sensor and a five-layer dielectric stack backed by a simplified human body phantom (warm water). The proposed technique shows less than 5% error in the extracted properties. Compared to other dielectric characterization approaches, this technique works even for normal incidence angles.