1. A radar screening system for detecting an object in a region of interest comprising: at least one radar array, said at least one radar array including: a plurality of transmitter elements that transmit a plurality of differently coded signals toward the object, the coded signals having at least a first polarization; and a plurality of receiver elements that receive a plurality of coded return signals reflected from the object, the coded return signals having at least a second polarization orthogonal to the first polarization; and at least one processor coupled to the plurality of transmitter elements and the plurality of receiver elements, said at least one processor being adapted to: decode the plurality of coded return signals reflected from the object; extract from the decoded plurality of coded return signals a multiplicity of captured signals for each transmitter to receiver path; align the multiplicity of captured signals to be substantially time and phase coincident for each voxel in a region of interest; sum the aligned captured signals for each voxel in the region of interest; calculate at least a cross-polar value at each voxel; and identify a voxel as from an object of interest if an indicator calculated using at least the cross-polar value exceeds a threshold.