Lumped-element loaded metamaterial structure

The effect of lumped elements on the performance of lumped element loaded high impedance surfaces (HIS) is considered. Two HIS configurations are employed. The first contains passive capacitors and the second contains varactor diodes. Experimental results, obtained in a rectangular waveguide simulator setup demonstrate the change in the operating frequency of the HIS as the lumped element capacitance varies. Significant HIS absorption is also shown and its dependence on lumped element resistance, capacitance and substrate thickness is examined numerically