Time domain analysis of pulse-excited reflector antennas-UAT approach

Time domain versions of asymptotic high-frequency domain methods of reflector antenna analysis have recently been developed and applied to obtain their transient response. These include the time-domain uniform geometrical theory of diffraction (TD-UTD) (see Rousseau, P.R. and Pathak, P.H., 1995) and the time-domain physical optics (TDPO) (see Sun, E.Y. and Rusch, W.V.T., 1994). This implementation, together with the development of time-domain equivalent edge current (TD-EEC) corrections to TDPO, has been compared within the framework of reflector antennas illuminated by a pulsed source (see Rego, C.G. and Hasselmann, F.J.V., Proceedings of IEEE Antennas and Propagation Society International Symposium, p.2046-9, 2000). A time domain version of the uniform asymptotic theory of diffraction (TD-UAT) is introduced following an analytical transformation of its well known frequency domain counterpart. The TD-UAT is implemented to perform the calculation of the field scattered by a hyperbolic reflector illuminated by a spherical with a double-Gaussian pulse temporal behavior and its applicability is validated through comparison with results obtained from a reference solution consisting of a Fourier inversion of a frequency-domain method of moments (MoM) formulation. The applicability of the TD-UAT formulation to the analysis of a pulse-excited reflector antenna, illuminated by fields with a rapid spatial variation near its rim, is also ascertained by composing its implementation with those from TD-UTD with slope diffraction terms and from TDPO with TD-EEC corrections.