A passive millimeter wave imaging system that includes at least one millimeter wave frequency scanning antenna and multiple beam formers collecting narrow beams of millimeter wave radiation from a two-dimensional field of view. The collected radiation is amplified and separated into bins corresponding to various vertical and horizontal beam orientations. In a preferred embodiment each beam formers include one phase processor with 232 inputs and 192 outputs that feed into 192 frequency processors. In another preferred embodiment each beam formers include one phase processor with 232 inputs and 72 outputs that feed into only 24 frequency processors. In this second embodiment 26 3×1 PIN diode switches sequentially switch one of three phase processor outputs into a frequency processor. As in the first embodiment two dimensional images of a target are obtained by the simultaneous detection of signal power within each beam and converting it into pixel intensity level. This embodiment is a lower cost and lower weight unit but operates at a rate of 10 frames per second with some reduction in the horizontal field of view.