Shielding Effectiveness of Board Level Shields with Absorbing Materials


A method is proposed to extend the shielding effectiveness (SE) of board level shields (BLSs) with absorbing material. Resonances of the metallic shield reduce the electromagnetic interference (EMI) suppression and limit the working frequency range to the fundamental resonant frequency. Two strategies of the absorbing material placement are developed to improve the SE and extend the working frequency of a BLS by inserting the absorbing material over the emission source. At low frequencies (below 10 GHz), a large amount of absorber material is needed to effectively reduce the quality factor of the low-order resonances. At high frequencies (above 10 GHz), a much smaller amount of absorber is required to achieve similar effect. At least 15 dB shielding effectiveness is achieved in the frequency range up to 32 GHz, extending from the fundamental resonant frequency of the BLS cavity (about 5 GHz).

Meeting Name

2019 IEEE International Symposium on Electromagnetic Compatibility, Signal and Power Integrity, EMC+SIPI 2019 (2019: Jul. 22-26, New Orleans, LA)


Electrical and Computer Engineering

Research Center/Lab(s)

Electromagnetic Compatibility (EMC) Laboratory


This material is based upon work supported by the National Science Foundation (NSF) under Grants IIP-1440110.

Keywords and Phrases

Absorbing Material; Board Level Shield; Cavity; EMI; Shielding Effectiveness

International Standard Book Number (ISBN)


Document Type

Article - Conference proceedings

Document Version


File Type





© 2019 Institute of Electrical and Electronics Engineers (IEEE), All rights reserved.

Publication Date

01 Jul 2019