The present disclosure relates to an apparatus and method for synthetically making an ultra-wide imaging bandwidth in millimeter-wave frequencies, resulting in improved image resolutions to values previously unattained. The synthetic approach sums up a number of available sub-bands (channels) to build an unavailable ultra-wideband system. Each channel contains an antenna unit which is optimized for operation within that specific sub-band. The number and position of the channels can be adjusted to cover any frequency range as required for the specific application.