Fast analysis over a wide band using Chebyshev approximation with Clenshaw-Lord approximation

Pade-Chebyshev approximation with Clenshaw-Lord type approximation is presented for wide-band analysis with method of moments (MoM). The surface currents can be expanded in a Chebyshev series. To improve bandwidth and accuracy of the expected results, a rational function is obtained from Chebyshev series with Clenshaw-Lord type approximation. Also, Chebyshev polynomials such as first, third, and fourth kinds are used to express the singular points in the graph. To validate the proposed method, radar cross section (RCS) of numerical examples such as perfect electric conductor (PEC) sphere, plate, and periodic structure are obtained. The Pade-Chebyshev approximation with Clenshaw-Lord type approximation agreed well with the exact solution.