Inband scattering model for arrays with parallel feed networks

The computation of scattering from antennas is important in estimating their radar cross section (RCS). Traditionally the antenna scattered field has been decomposed into two components called the structural and antenna (radiation) modes. The antenna mode is determined completely by the radiation characteristics of the antenna, and vanishes when the antenna is conjugate matched to its radiation impedance. The structural mode contribution arises from currents induced on the antenna surfaces. For most antennas the two terms are not easily identifiable, in particular when the antenna is installed on a platform. The analysis presented is limited to the antenna mode, which is generally the dominant inband RCS contributor for a phased array.