An imaging system includes a scanning reflector that sweeps through a periodic scan pattern to redirect millimeter wave energy from a target object to a detector. The imaging system may include one or more millimeter wave lenses that gather and focus the millimeter wave energy from the target object onto the reflector or the detector. The detector is super-cooled to increases sensitivity, so that the imaging system does not require an illumination source. For each location on the target object, the detector monitors the intensity of the millimeter wave energy and an electronic controller builds a memory map from the detector data. Because different materials block millimeter wave energy differently, the detector data, and thus the memory map corresponds to the structure of the target object. In one embodiment, the scanning reflector is a resonant scanner. The scanner may be a microelectromechanical (MEMs) or mesomechanical scanner.