A Phaseless Inverse Source Method (PISM) Based on Near-Field Scanning for Radiation Diagnosis and Prediction of PCBs

In this article, we present an efficient phaseless inverse source method (PISM) to reconstruct equivalent sources on a printed circuit board (PCB) using magnitude-only single-plane near-field scanning. The equivalent source distribution reconstructed by the conventional source reconstruction method requires accurate near-field magnitude and phase information, but phase measurement is difficult in many cases due to inaccuracy and complexity. In order to describe the inverse problem between phaseless fields and radiation sources, a nonlinear cost function based on surface integral equations is established. The cost function of the PISM is rapidly minimized by an iterative optimization and regularization technique for nonlinear ill-posed systems. The proposed method gives the characterization of PCBs both for diagnostic tasks of radiation sources and the near-field radiation behavior prediction when the phase information is missing. It also shows excellent robustness in tackling with various near-field data and noises. Both numerical examples and laboratory experiments are given to verify the effectiveness of the proposed method.