Network reciprocity in modeling and analysis of phased array antennas

This paper addresses aspects of network reciprocity in the modeling and analysis of phased array antennas. As is well known, transformations of the network terminal quantities, voltages and currents, or incident and reflected waves, via any real orthogonal transformation preserves both the respective power relations and the formal reciprocity symmetry of the corresponding impedance or normalized scattering matrix. In contrast, a general unitary transformation does not necessarily preserve the reciprocity symmetry of the impedance or normalized scattering matrices.