Tunable Wideband Graphene based Filters in THz Band

In this paper, a procedure for analyzing and designing of tunable wideband band-pass and band-stop graphene based filters in the terahertz band is proposed. These planar wideband plasmonic filters are unique in their kind. With this procedure, it is possible to design filters with the desired functional characteristics in the form of the similar quarter-wavelength resonance stubs. The discontinuity of the open stub used for this type of filter is investigated and the required length of compensation is obtained.   Also, in order to analyze the designed filters, Transfer Matrix method is used based on transmission line model of structure. An example of wideband band-pass and band-stop filters are designed and analyzed according to the mentioned process. The obtained frequency response for bandpass and bandstop filters shows fractional bandwidth of 30% and 32% respectively including desired band-edge transition, attenuation level and group delay. The results of full-wave simulation also confirm analytical results. These types of filters due to the compact structure and simple design are suitable candidate for using in all-integrated wideband planar circuits of terahertz systems.