Airflow perforations in shielding enclosures can act as apertures facilitating the coupling from internal sources to external electromagnetic interference (EMI). This EMI radiation for single- and dual-screen configurations was studied herein experimentally and with finite-difference time-domain (FDTD) modeling. A general EMI reduction of more than 20 dB was achieved for dual-perforated screens spaced 1 cm apart when compared to EMI for a single perforated screen. However, in the dual-screen case, the space between the screens can act as a thin cavity, which, in turn, can lead to significant radiation at distinct angles. Damping the resonances by loading the space between the screens with lossy material mitigates this problem and achieves more than 20-dB reduction over a single screen.


Electrical and Computer Engineering

Research Center/Lab(s)

Electromagnetic Compatibility (EMC) Laboratory

Keywords and Phrases

1 cm; EM Coupling; EMI Radiation; EMI Reduction; FDTD Modeling; Absorbing Media; Airflow Aperture Arrays; Airflow Perforations; Dual-Perforated Screens; Electromagnetic Coupling; Electromagnetic Interference; Electromagnetic Shielding; Finite Difference Time-Domain Analysis; Finite-Difference Time Domain; Internal Sources Coupling; Lossy Material; Packaging; Resonance; Resonance Damping; Shielding Enclosures; Single-Screen Configuration; Thin Cavity; Electromagnetic Wave Interference; Finite Difference Method; Mathematical Models; Time Domain Analysis; Electromagnetic Compatibility

International Standard Serial Number (ISSN)

0018-9375; 1558-187X

Document Type

Article - Journal

Document Version

Final Version

File Type





© 2000 Institute of Electrical and Electronics Engineers (IEEE), All rights reserved.

Publication Date

01 May 2000