Long-Wave Infrared (LWIR) Polarimetric and Radiometric Analysis for a Variety of Thermal and Electromagnetic Suppressing Materials

This technical report examines the polarimetric and radiometric properties of novel textile materials designed to suppress either thermal emission typically radiated by warm objects or attenuated stray electromagnetic EM fields that may damage electrical equipment, i.e., electromagnetic interference EMI shielding materials. Nine materials were examined 3 forms of aluminum-coated heat-shield fabric, 2 samples of a nickel-Kevlar material, 2 samples of a silver-copper coated polyester material, and 2 weaves of a carbon-based textile material. Various-sized swaths of each material were placed on a temperature-controlled, black anodized-aluminum plate that was capable of tilting from 0 to 90 , where the angle is defined by the surface normal and the line of sight LOS of the sensor. Test-plate surface temperatures were intentionally kept moderate and ranged from 50 to 60 C. Calibrated radiometric and polarimetric images were recorded at various orientations over a 5-day period in which the following parameters were measured for each material the raw radiometric emission, S0 wsr-cm2 the percentage of overall thermal radiance that was suppressed the normalized Stokes parameters S1 and S2 and the degree of linear polarization DoLP. All parameters were determined in the long-wave infrared LWIR spectral region defined as 7.5 11.1 m.