Two analytic frequency dependent current density approximations for TE scattering from a conducting strip grating

Two analytic frequency dependent current density approximations are presented for TE mode incidence on a conducting strip grating. The current densities are assumed to have both a spatial and a frequency dependence. The first is based upon using the classic edge mode approximation. The second is derived from applying conformal mapping methods and invoking Babinet´s theorem. The solutions are compared to the moment method solution. The resultant reflection coefficients are found to be good approximations at all frequencies for narrow strips and at moderately low frequencies for arbitrary strip widths. Although the solutions are not as accurate as a moment method solution at all frequencies, they are computationally faster and provide analytic expressions that demonstrate the relationship between grating dimensions and performance