Approximate calculation of time-domain effective height for aperture antennas

The time-domain (TD) effective height is a space-time vector operator recently introduced to describe the performance of ultrawide-band antennas. Since generally obtained by measurements or intensive numerical modeling, it is represented through a large set of data not very suitable to the evaluation of the whole TD link. For the particular class of aperture-radiating antennas of separable shapes, such as slot, open-ended waveguides and horns, this paper proposes a systematic TD processing of the aperture field, involving model-based deconvolution and parameter estimation, at the purpose of an efficient calculation and a more manageable representation of the effective height. Following the idea at the base of modal near to far field transformation, as previously presented by the authors, the processing of the aperture impulse response is here addressed with a particular care to the fast varying early transient. The corresponding time-dependent Radon transforms are then approximated by semi-analytical formulas whose accuracy is discussed as for the aperture size and frequency limits. The proposed methods, which are much faster than the conventional approach, are demonstrated by some examples.