1. A broad-band millimeter wave imaging system, useful for producing images of metal and non-metal objects such as guns, knives and explosives hidden under clothing, comprising: A) a linear array of radiation collectors, B) a cylindrical antenna for focusing millimeter wave radiation from a substantially one dimensional section of a target region onto said a linear array of radiation collectors, C) an array of millimeter wave amplifiers for amplifying millimeter wave radiation collected at each radiation collector to produce a set of amplified millimeter wave signals. D) a millimeter wave beam forming lens defining an input side and an output side for focusing at its output side amplified millimeter wave radiation received at its input side, E) a plurality of input ports located along the input side of said beam forming lens. F) an array of focusing delay lines in communication with said array of amplifiers and the plurality of input ports along the input side of said beam forming lens for delaying each amplified millimeter wave signal by a time interval such that millimeter wave radiation from a point near the center of said target region arrives at each of the input ports at about the same time, G) an array of detectors located at said output side of said millimeter wave lens for collecting millimeter waves focused by said lens to produce a one-dimensional image of a portion of the target region, H) a scanning means for scanning the antenna to produce a two-dimensional image of the target region and I) a monitor for displaying said two-dimensional image of said target region.