Miniaturized Polarization Insensitive Metamaterial Absorber Applied on EMI Suppression

This paper presents the analysis and design of a miniaturized polarization insensitive metamaterial absorber (MMA) for suppression of the electromagnetic interference (EMI) at microwave frequency range. The proposed MMA consists of a periodic array of double split ring structures printed on an FR4 substrate with a thickness of 0.07 λ
₀
. The simulated results derived from CST indicate that the absorption ratio of the MMA is over 90% with a wide frequency range from 8.3 GHz to 11.3 GHz for a normal incident electromagnetic (EM) wave. To understand the EM wave absorption mechanism, an equivalent circuit model of the MMA unit cell is constructed to investigate the absorbing characteristics, and the electric field and surface current distributions are analyzed at absorption peaks.. Both equivalent circuit model (ECM) and measured results show good agreement. What's more, the measurement data shows that the radiated electric field of the patch antenna at 1 meter is significantly reduced at 10 GHz while loading with the MMA. A maximum suppression of 18 dBμν/m is achieved at 10 GHz. As the proposed absorber possesses good ability on electromagnetic radiation absorption, it could be well applied on printed circuit board (PCB) level EMI suppression.