Reconfigurable WLAN notch for UWB filters

This paper presents the design and results of an ultra-wideband (3.1-10.6 GHz) filter with a reconfigurable WLAN notch at 5.8 GHz. Reconfigurability has been achieved by the implementation of Graphene based switching elements. The switches are in OFF state when Graphene is unbiased at a chemical potential of μ_c = 0.0eV and are in ON state when Graphene is biased at a chemical potential of μ_c = 1.0eV. The simulation and measurement results of the filter when the Graphene switches are OFF show an entire bandpass response from 3.1 GHz to 10.6 GHz and with low insertion loss. When the Graphene switches are ON, the simulation result shows that a sharp rejection of the WLAN band at 5.8 GHz is achieved, with a very low passband insertion loss. The obtained results of both states, i.e. switches OFF and switches ON, are as desired. An additional filter, implemented with PIN diodes as the switching elements, is also designed and measured. Upon comparison, the obtained results of PIN diodes in OFF and ON states match those of the Graphene switches in OFF and ON states.