Personnel and mail screening with millimeter waves

The detection and interdiction of biological and chemical warfare agents at point-of-entry military, government, and civilian facilities remains a high priority for security personnel. Commercial personnel and mail screening technologies for these harmful agents are still being developed and improved upon to meet all security client requirements. Millimeter-wave holographic imaging technology developed at the Pacific Northwest National Laboratory is an ideal sensor to interrogate objects concealed behind low dielectric barriers such as paper, cardboard, and clothing. It uses harmless millimeter waves to illuminate the object or person under surveillance. The waves penetrate through the low dielectric barrier and either reflects off or pass through the hidden object, depending on its material dielectric properties. The reflected signals are digitized and sent to high-speed computers to form high-resolution, three-dimensional (3-D) images. Feasibility imaging studies have been conducted to determine whether simulated biological or chemical agents concealed in mail packages or under clothing could be detected using holographic radar imaging techniques. The results of this study will be presented in this paper.