COMESA: concurrent measurements of the elements of the scattering matrix

Up to now, the full scattering matrix of a radar target can only be measured with a sequence of pulses where, in each pulse, a different sub-set of the scattering matrix is measured. In best case, a dual polarized receiver is used and two pulses are needed to measure the full scattering matrix. Although for many applications this works fine, it has inherent limitations. For a correct measurement of the scattering matrix, all elements should be measured simultaneously. To do this, a method must be used to isolate the transmitted and received signals corresponding to the different scattering elements. This can be done using so-called orthogonal signals. In this paper, a first experiment is described showing the possibilities of orthogonal signals based on the FM-CW radar principle. The experimental set-up as well as the results are described in detail. Also a block scheme of a radar system using the principle based upon the use of orthogonal FM-CW signals is described. This new radar is called COMESA.