An efficient computation of transient scattering by a perfectly conducting cylinder

The real axis integration technique is developed to compute the oscillatory infinite spectral integrals occurring in transient scattering by a perfect electrically conducting cylinder excited by a magnetic line source. Davidenko´s (1953) method is used to evaluate efficiently the complex azimuthal wavenumbers, namely, the complex zeros of the Hankel function in the order plane. The computed results of the transient Green´s function compare very well with those obtained by the wavefront approximation at early time, and by the singularity expansion method at late time. The real axis integration method can be used to compute the transient response for all time