A truncation criterion in planar near field techniques

In this paper, the planar near field measurement techniques are addressed. The physical implementation of the near-field technique necessitates the use of a truncated observation domain. This truncation will cause an error in the calculated far-field pattern whose magnitude depends on the relative energy of the fields neglected outside the measurement plane. Accordingly, a new truncation criterion is proposed. This criterion has been compared to the valid angle one. The main advantage of the proposed approach respect to the other is the capability to estimate the truncation error in terms of observation domain extension. This allow to obtain a more accurate estimation of observation domain extension guaranteeing a measurement truncation error lower than a fixed value. In fact, the valid angle criterion always overestimates the observation domain extension respect to the proposed approach.