Combining the fast irregular antenna field transformation algorithm with asymptotic high frequency methods

The fast irregular antenna field transformation algorithm (FIAFTA) is extended by the asymptotic high frequency methods geometrical optics (GO) and the uniform geometrical theory of diffraction (UTD) to consider the effect of electrically large scattering objects in near-field antenna measurement setups. The extension is realized by decomposing the measurement setup into two domains: The first domain is covered by accurate plane wave expansion based field transformation principles and contains the unknown equivalent sources of the AUT and the observation points. In the second domain, electrically large components are located whose effect on the measurement is considered using ray optical concepts. This hybrid method allows to reduce the number of inverse problem unknowns and the number of near-field samples. It can also be used to compensate the influence of reflections caused by electrically large and well known scattering objects. Numerical examples show the applicability and effectiveness of the approach.