A Uniform Asymptotic Analysis for Transient Scattered Fields by a Cylindrically Curved Open Surface with Varying Radius of Curvature

The time-domain uniform asymptotic solution (TD-UAS) for the transient scattered field excited by the high-frequency (HF) pulse wave incident on a cylindrically curved open surface with a varying radius of curvature is presented in this paper. The TD-UAS, effective in the transition regions including the geometrical boundaries RB and SB, is constructed by the geometrical rays, the surface diffracted rays, the lowest order adiabatic whispering gallery mode radiation fields, and the combination of these pulse waves. The TD-UAS has an advantage that the total solution can be obtained from the summation of the individual solution which can easily be interpreted physically. We have confirmed the accuracy and the validity of the TD-UAS by comparing with the reference solution calculated from the combination of the method of moment (MoM) and the fast Fourier transform (FFT) code and with the reference solution obtained from the combination of the frequency-domain UAS and the FFT code.