Finite difference analysis of infinite arrays of two-dimensional microstrip structures

Infinite arrays of two-dimensional printed elements are analysed using the finite difference method. Grid models accounting for dielectric discontinuities and current continuity at rectangular junctions are developed. The procedure is used to study the behaviour of three configurations of planar strips over dielectric substrates in an infinite array environment. These configurations include the ´dipole´ element, the ´microstrip´ element and the ´microstrip´ element over an inhomogeneous substrate. For each configuration, calculated results are presented with special attention given to the correctness of antenna characteristics such as input impedance and scan performance. The results accurately predict antenna performance and comparison with published data confirms the method.