A broad-band millimeter wave imaging system with improved thermal resolution as compared to prior art devices. The system is useful for producing images of metal and non-metal objects such as guns, knives and explosives hidden under clothing. A cylindrical antenna focuses millimeter wave radiation from a substantially one dimensional section of a target region onto a linear array of radiation collectors. Radiation collected at each collector is amplified to produce a set of amplified millimeter wave signals and the amplified signals pass through focusing delay lines to a millimeter wave lens. Millimeter wave signals are collected at the output of the lens and the collected signals are monitored by an array of detectors. The combined effects of the delay lines and the lens produce a focus of the amplified millimeter wave radiation emitted and reflected from the one dimensional section of the target region. The array of millimeter wave detectors at the focus of the lens produces a one dimensional image of the one dimensional section of the target region. The antenna is scanned to produce a two dimensional image of the complete target region. The two dimensional image is displayed on a monitor screen. A full two-dimensional image of a human subject located at a stand-off distance of several meters (e.g., 7 meters) from the imager is acquired in few seconds time frame.