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Actuated Dielectric-Lossy Screen for Dynamically Suppressing Electromagnetic Interference

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journal contribution
posted on 09.11.2020, 06:06 by Andrew D. M. Charles, Andrew N. Rider, Sonya A. Brown, Chun H. Wang
Existing methods for electromagnetic interference suppression typically employ attaching absorbers to the external surface of a structure at a fixed distance. In this work, we present a dynamically tunable, electromagnetic interference suppression technique using a multifunctional nanocomposite that offers a wider bandwidth and exceptional absorption when compared to existing approaches. The nanocomposite, incorporating carbon nanotubes and carbonyl iron powder, provides multiple functions as a lossy dielectric screen for attenuating electromagnetic waves, supporting stress, and conducting heat to dynamically control the position and hence the resonant characteristics of the absorbing screen. The dielectric properties of the nanocomposite were optimized for a target operational frequency, enabling a large reduction in the total thickness when compared with conventional resistive screen absorbers. Tuning the resonance around the design frequency yielded a peak absorption of −40.9 dB and an effective −10 dB bandwidth of 7.4 GHz in the 2–18 GHz frequency range. The mechanical and electromagnetic properties of the nanocomposite were characterized and found to correlate well with numerical and analytical modeling. The multifunctional nanocomposite and complimentary tunable structure design provide opportunities for highly improved EMI suppression structures.