ACCURATE EVALUATION OF THE CONDUCTOR LOSS IN RECTANGULAR MICROSTRIP PATCH REFLECTARRAYS

In the moment method solution of the integral equations for currents of a rectangular microstrip patch reflectarray, the Leontovich boundary condition is employed to determine the conductor loss. If the basis functions contain edge conditions that approach infinity, the moment matrix elements will have diverging integrals in the Galerkin technique. In this paper, we present a criterion to stop the evaluation of these integrals at a distance before the edge, thereby avoiding the divergence problem. The stopping distance derived here is found to work for a range of values of permittivity, loss tangent, and thickness of the substrate, polarization, angles of incidence of the plane wave source, and also for superstrates. Our computed results are in good agreement with measured results and those computed by HFSS.