Finite scattering matrix for an infinite antenna array

A finite scattering matrix, S, for a plane-wave excited infinite array is developed for the purpose of relating a number of array and active-element properties. The size of S depends on the polarization in space, the grating lobe locations, and the propagating modes in the feed. Array properties such as scattering on receive, transmission amplitude and phase, surface-wave propagation, phase and amplitude of the active-element pattern, etc., are described by this matrix. For the lossless array, the unitary conditions on S further relate the array properties. Some of the results are illustrated by the exact S matrix for an infinite TEM parallel-plate array. The active element characteristics, and the occurrence of surface-wave-type mutual admittances, are discussed in terms of S.