Contents I. Introduction
Near field (NF) scanning of integrated circuit [1], antenna [2], and module [3] is popular in recent years due to the potential application of NF to far-field transformation [4], [5] for low-cost electromagnetic (EM) interference (EMI) [6] and EM emission evaluation. In order to realize the NF to far-field transformation, the source reconstruction algorithm is essential to find the equivalent source to represent the emission radiation device. Based on the EM NF scanning data, there are mainly the following two models to derive the equivalent EMI sources: 1) the magnetic and/or electric currents model [7], [8], [9], [10], [11]; 2) the electric and/or magnetic infinitesimal dipoles model [1], [12], [13]. The equivalent current model finds the equivalent current by solving a set of equivalent regularly shaped space boundary integral equations [7], [8], with which the actual boundary-value problems are simplified. In the source reconstruction of antenna [14], [15] and IC [16], the dipole model is an effective and common method. The NF EM field is supposed to be contributed by a linear superposition of the radiation of dipoles (based on the conceptually clear dipole radiation formulas), and the dipoles model is simple to build the linear relation matrix between dipoles. It is worth noting that both methods are essentially the same and differ only in their choice of basis functions.
