APPLICATION OF THE INTEGRAL EQUATION-ASYMPTOTIC PHASE METHOD TO 2-DIMENSIONAL SCATTERING

A hybrid procedure called the integral equation-asymptotic phase (IE-A P) method is investigated for scattering from perfectly conducting cyl inders 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 residua l function that can be represented by a coarse density of unknowns. In the present investigation, the current density appearing within the c ombined-field integral equation is replaced by the product of a rapidl y varying phase function obtained from the physical optics current and a residual function. The resulting equation is discretized by the met hod of moments, using subsectional quadratic polynomial basis function s 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 th e computed current density, even for scatterers with corners.