Application of the integral equation-asymptotic phase method to two-dimensional scattering

A hybrid-procedure called the integral equation-asymptotic phase (IE-AP) method is investigated for scattering from perfectly conducting cylinders of arbitrary cross-section shape. The IE-AP approach employs an asymptotic solution to predict the relatively rapid phase dependence of the unknown current distribution, to leave a slowly varying residual function that can be represented by a coarse density of unknowns. In the present investigation, the current density appearing within the combined-field integral equation is replaced by the product of a rapidly varying phase function obtained from the physical optics current and a residual function. The resulting equation is discretized by the method of moments, using subsectional quadratic polynomial basis functions defined on curved cells to represent the residual function. Results show that the required density of unknowns can often be as few as one per wavelength on average without a significant loss of accuracy in the computed current density, even for scatterers with corners.>