TIME-DOMAIN UNIFORM GEOMETRICAL-THEORY OF DIFFRACTION FOR A CURVED WEDGE

A time-domain version of the uniform geometrical theory of diffraction (TD-UTD) is developed to describe, in closed form, the transient elec tromagnetic scattering from a perfectly conducting, arbitrarily curved wedge excited by a general time impulsive astigmatic wavefront. This TD-UTD impulse response is obtained by a Fourier inversion of the corr esponding frequency domain UTD solution. An analytic signal representa tion of the transient fields is used because it provides a very simple procedure to avoid the difficulties that result when inverting freque ncy domain UTD fields associated with rays that traverse line or smoot h caustics. The TD-UTD response to a more general transient wave excit ation of the wedge may be found via convolution. A very useful represe ntation for modeling a general pulsed astigmatic wave excitation is al so developed which, in particular, allows its convolution with the TD- UTD impulse response to be done in closed form. Some numerical example s illustrating the utility of these developments are presented.