Frequency-Independent Scattering From a Flat Strip With ${\rm TE}_{z}$-Polarized Fields

The surface current for scattering from a PEC strip naturally decomposes into three slowly varying functions modulating rapidly oscillating phase factors. We exploit this structure to derive a numerical solution that is error-controllable and exhibits a bounded error over the full range of frequencies. Frequency independence is obtained by expanding the current in terms of slowly-varying amplitude functions, stretching coordinates in the boundary layer, and employing a frequency-independent quadrature rule. Though the total current solution is always well-defined, unique, minimally-varying amplitude functions may also be found by using the minimum norm concept.