Investigation of antenna pattern synthesis through higher order inverse equivalent current method

In the realm of near-field far-field (NF-FF) transformation and antenna diagnostic applications, the inverse equivalent current method (ECM) has gained popularity because of its versatile applicability to deal with arbitrary working domains and robust solution strategy where fast solvers are viable to gain memory and computation efficiencies. The unknown equivalent surface current densities in the governing integral equation for ECM are usually discretized with low order (LO) Rao-Wilton-Glisson (RWG) basis functions or even point based low order basis functions on the triangular surface elements. Higher order (HO) current modeling provides a mean for the higher solution accuracies as well as better computational efficiencies. Nearly-orthogonal hierarchical vector basis functions complete to full first order with respect to the curl space are therefore utilized for the discretization of inverse equivalent surface currents defined on flat triangular domains. Various numerical examples are presented and comparison is made with the results of LO discretization. Additionally, investigations have been carried out towards the possible applicability of ECM solver for customized radiation pattern antennas. Inverse ECM currents have been reconstructed for such radiated fields and preliminary discussion is made for their realization.