Comparison between Two Phase-retrieval Methods for Electromagnetic Source Mod- Eling

Phase-retrieval from measured phaseless field data is of interest for various applications including electromagnetic dosimetry, electromagnetic compatibility investigations, near-field to far-field transformations and antenna diagnostics. In this study two phaseretrieval methods, namely the adjoint field method and the phase angle gradient method, are compared using 3D numerical test cases. The methods were previously presented by us, but the adjoint field method was at that time only implemented in 2D. In this study the adjoint field method has been extended to 3D, which makes it possible to test the method for more realistic test cases and to compare it with the phase angle gradient method. The results show that the phase angle gradient method is able to retrieve the phase with better accuracy than the adjoint field method. Moreover it gives results that agree well with correct phase. The phase angle gradient method was also tested with measured magnetic field. The obtained phase angles on a measurement plane in front of the source gave calculated field amplitudes that agree well with measured field.