Optimization of Source Modeling From Phaseless Near-Field Scanning Based on SVD-Defined Eigenmodes

Abstract

This article proposes a procedure for reconstructing dipole moment models from magnitude-only near-field scanned magnetic fields. Preprocessing uses a finite-impulse response filter to deblur the 2-D divergence of the magnetic fields to locate the dipoles. The procedure defines the modes of the dipole distribution using singular value decomposition. Based on mode decomposition, the modal coefficients are optimized through a pattern search algorithm to obtain the dipole moments. Compared with existing methods, this method reconstructs better phase information in high-noise situations. Using mode decomposition circumvents the problem of a limited number of dipoles that can be solved by existing optimization methods. Real experiments using high-resolution near-field scanned data show that the main emission sources of individual traces inside an integrated circuit (IC) chip can be distinguished through the proposed procedure.