Shielding effectiveness of artificial magnetic screens in the VHF band

Performance of artificial planar screens composed of small magnetic elements are investigated through equivalent circuit models and a full-wave approach involving a periodic method-of-moments formulation. The conventional split-ring resonator screen is first studied and next the geometry of the single inclusion is modified in order to reduce the operating frequency of the screen. It is shown how the proposed spiral-resonator screen can operate in the VHF band and that a careful numerical analysis needs to be carried out to accurately predict the selective properties of the screen. Different commercial full-wave software are also used and their limits in the modeling of such microstructured materials are pointed out.