A new approach is proposed for modeling electromagnetic emissions of a printed circuit board (PCB) based on amplitude-only near-field measurement data. Magnetic dipoles placed over the top layer of the PCB are introduced as the equivalent of actual radiated sources. A restarted optimization procedure based on a differential evolution algorithm is developed to determine the parameters of the dipoles (number, position, and moment components) via minimizing the difference between the measured magnetic near field and that radiated by the dipoles. These equivalent dipoles can be used to predict the radiated emissions of the PCB once being determined. The proposed approach does not need the phase of the measured near fields, and its computational complexity is very low. Numerical results are presented to demonstrate the validity and efficiency of the proposed approach.

An efficient hybrid analysis which hybridizes surface-wire integral equations (SWIE) with physical optics (PO) approximation is presented for wire antennas attached to an electrically large aircraft platform. In the analysis, the whole surface of the platform and antennas is divided into three regions, namely, the method of moments (MoM) region, the PO region and a region referred to as the joint PO-MoM (POM) region in this paper. The MoM region, generally, the smallest one among the three regions, includes wires, wire-surface junctions and a small part of the platform surface surrounding the junctions. A large part of the remaining platform surface forms the PO region with the rest being the POM region which is situated between the MoM and PO regions. The POM region is treated as a MoM region on the one hand so that the total MoM region is sufficiently large to well characterize the platform-attached antennas, whereas it is also regarded as a PO region on the other hand so that its interaction with the PO region needs not to be precisely considered so as to drastically reduce computational requirements.

An efficient method to extract equivalent radiated emission sources for printed circuit boards (PCBs) from near-field (NF) scanning data is presented. The equivalent sources are represented by elemental magnetic dipoles placed over a planar surface on the component side of a PCB. A global optimization procedure, based on the differential evolution algorithm, is used to determine the components of each dipole moment, by exploiting only the magnitude of the scanned NF data. The number and positions of the equivalent dipoles are predetermined by analyzing the scanning NF data, which is based on the NF radiation pattern of a single straight trace on a PCB. The effects of both of the spacing of the scanning points and the distance between the scanning and the reconstruction planes on the accuracy of the reconstructed results are studied. The proposed method is validated by the comparison of the reconstructed and full-wave results for PCBs with different types of traces.

A near-field scanning based equivalent dipole model is introduced to simplify the analysis of the emission from an electronic component at its nearby receivers. The model consists of a set of infinitesimal magnetic dipoles, with the number, position, and moment of the dipoles being unknowns. A nonlinear optimization problem in terms of the unknown parameters is established through minimizing the difference between the magnitude of magnetic fields obtained by near-field scanning and the radiation from the equivalent dipoles. The problem is difficult to solve as the number of dipoles is unknown. A differential evolution method based global optimization algorithm is proposed to solve the problem. A set of subproblems is first derived. It is then solved sequentially one after the other by using the proposed algorithm. A combination of the obtained solutions forms a solution of the original optimization problem. Numerical results are presented to demonstrate the validity and efficiency of the proposed algorithm.

A technique based on the surface integral equation is applied for the analysis of antenna radiation in the presence of an arbitrarily shaped dielectric radome terminated by a conducting surface. The equivalence principle is used to characterize the effect of the radome on the transmitted field in terms of equivalent surface electric and magnetic currents which radiate in an unbounded medium. A set of coupled integral equations involving these currents is obtained by using the boundary conditions on the tangential components of the total fields. The adaptive integral method is applied to solve the integral equations so that electrically large radomes can be analyzed. The radiation patterns of dipole arrays with dielectric radomes of superspheroidal shape are also presented.