Modeling Electromagnetic Field Coupling Through Apertures for Radio-Frequency Interference Applications


Electromagnetic field coupling between a digital platform and a radio-frequency antenna through an aperture represents one of the typical coupling paths responsible for radio-frequency interference (RFI) issues in mixed-signal systems. Conventional approaches of modeling radiation through an aperture and evaluating the shielding effectiveness of a metallic enclosure with apertures for classic electromagnetic interference (EMI) applications are not sufficient to handle modern RFI challenges. This paper discusses a segmentation method, together with impedance network representation, employed to divide the enclosure EMI problem into exterior and interior problems. With a port definition based on the vector roof-top basis function, the impedance network for the exterior domain was rigorously formulated using a method of moments solution for mixed potential integral equations. The impedance network for the interior domain was computed using the cavity method based on the analytical formula of 3-D Green's functions in a rectangular cavity. Connecting a pair of impedance networks yielded the overall impedance relationship between the interior port and the exterior port. Ewald's transform was used to accelerate the computation of Green's functions in a cavity with metallic walls, which yielded fast convergence of the series summation in Green's functions. Good agreement with a commercial full-wave tool validated the proposed approach.


Electrical and Computer Engineering

Research Center/Lab(s)

Center for High Performance Computing Research

Second Research Center/Lab

Electromagnetic Compatibility (EMC) Laboratory

Keywords and Phrases

Digital radio; Electric signal systems; Electromagnetic fields; Electromagnetic pulse; Enclosures; Green's function; Integral equations; Method of moments; Microstrip devices; Partial discharges; Radiation shielding; Radio interference; Radio waves; Signal interference; Signal systems; Electromagnetic field coupling; Metallic enclosure; Method of moments (MOM); Mixed potential integral equations; Radio frequency interference; Segmentation methods; Electromagnetic shielding; Ewald's transform; impedance network

International Standard Serial Number (ISSN)


Document Type

Article - Journal

Document Version


File Type





© 2015 Institute of Electrical and Electronics Engineers (IEEE), All rights reserved.

Publication Date

01 Oct 2015