Designing of new active frequency selective surface for HPM protection

Conventional active frequency selective surfaces (AFSS) are designed with a DC biasing circuit to apply DC biasing voltage across active components. An innovative method to design AFSS is proposed in this paper to use an induced voltage across both ends of the surface loading components as the biasing signal to control FSS´s transmission properties. The result from simulation proved that, a pass band exists on the AFSS at 3.5GHz when it is exposed to an electric field at a smaller intensity; at the electric field intensity (EFI) over 70 V/m, the insertion loss of the electromagnetic wave (EMW) increases at 3.5 GHz; in the case that the incident microwave´s field intensity reaches 5000 V/m, the insertion loss is over 20 dB. This interesting phenomenon make the new AFSS has the ability of HPM protection, which mean that a pass band exists when EFI is weak enough, along with increasing incident field intensity, the pass-band finally turns into a stop-band because of the break though of the diodes.