Research on the transmissivity of some clothing materials at millimeter-wave band

The passive millimeter-wave (PMMW) imaging technology used for the detection of contraband concealed on personnel has been extensively studied, due to the fact that millimeter-wave (MMW) can readily penetrate clothing materials and the passive operation mode doesn't present a safety hazard to the persons who are under inspection. However, the research on the transmission property of clothing materials covered on contraband has received relatively little attention, although it also plays an important role in design and fabrication of the whole imaging system. This paper focuses on the problem of measuring the transmissivity of some clothing materials with different thickness. These measurements are carried out in a RF anechoic chamber, based on the analysis to radiation characteristics of contraband carried on personnel. In addition, the theoretical model of the radiometric temperature contrast between human body and contraband at MMW band is also described in detail. Ultimately, the measurement results of some clothing materials are presented and analyzed.