Nonredundant Representation of the Electromagnetic Fields Over a Cylinder with Application to the Near-Field Far-Field Transformation

An innovative sampling representation to efficiently reconstruct the electromagnetic field over a cylinder from a non-redundant and always finite number of samples is proposed. It is based on the recent results concerning the analytical properties of the fields radiated by finite sources and, in particular, on the proper choice of the phase factor extracted from the field expression and of the coordinates used to parameterize the cylinder. Such a sampling representation is properly employed to develop a fast and accurate near-field-far-field transformation technique with cylindrical scanning, which allows to evaluate the antenna far-field directly from the non-redundant near-field data without interpolating them. Accordingly, the measurement time is significantly reduced without losing the computational efficiency of the classical approach. Moreover, some numerical tests assessing the effectiveness and the stability of the above procedures are reported.