Radiation Diagnosis of PCBs and ICs Using Array Probes and Phaseless Inverse Source Method With a Joint Regularization

In this article, we present a new diagnostic technique for printed circuit boards (PCBs) and integrated circuits (ICs). This technique consists of an array-probe scanning system and the phaseless inverse source method with a joint regularization. Different from the single probe scanning system, a ground plane for array probes is applied to protect the RF transmission path from interference by other radiation in the array probes scanning system. In order to consider the influence of both PCB ground and array probes ground on electromagnetic near-field distributions, we use the method of moments to solve the surface integral equations in the forward problem. In the inverse problem, we establish a nonlinear cost function between the magnitude-only fields and equivalent sources. Because of the ill-posedness of the inverse problem, an efficient iterative method with a joint regularization framework is applied to reconstruct the equivalent sources on the source plane above the PCB ground. Different levels of noise are added to the simulated data to validate the algorithm. Laboratory experiments and numerical examples show the effectiveness of the proposed method.