Electromagnetic Field Transformations of Near-Field Data Without Global Reference for Magnitude and Phase

Some innovative near-field antenna measurement setups, e.g., UAV-based, have limited capabilites for providing a phase and magnitude reference to the receiver. Phaseless antenna measurements have always been an important topic for such scenarios, but they often suffer from the unreliability of nonconvex phase retrieval algorithms, necessity of extremely accurate magnitude measurements and strong oversampling requirements. A similar problem arises if the measured magnitudes are impaired, i.e., if the global magnitude reference is unreliable for instance due to drift. We present a linearized method to reconstruct the phases for measurements without a global phase reference as well as an inherently linear method to reconstruct the magnitudes for measurements without a global magnitude reference. The underlying assumption is that a drift in either the phase or the magnitude occurs during the field measurement. With the reconstructed, thus, fully consistent observation vector, standard electromagnetic field transformations are possible and yield accurate and reliable results.