Near-field analysis of spherical loop arrays

In a recent paper (see ibid., vol.42, p473-7, April 1994), the authors presented the development of an algorithm for the reconstruction of element currents of a spherical loop array given the far-field pattern data in an azimuthal plane, and demonstrated the validity of the method with several computational examples. In this letter, it is shown that the same algorithm can be applied to the reconstruction of the spherical loop-array currents from the near-field data by application of spherical wave expansion of the electric field integral of the array. The main feature of the reconstruction algorithm is that the array currents are obtained recursively through the solution of a triangular equation set.