Spoof surface plasmon polaritons based tunable band notch filter for terahertz and microwave

A novel tunable band notch filter which consists of a coplanar waveguide and a corrugated metallic strip with horn shaped arms is presented for terahertz (THz) and microwave applications. The corrugated metallic strip with horn shaped arms offer more attenuation to EM wave than the corrugated metallic strip with conventional rectangular arms as the horn shape provides more area for the efficient trapping of the spoof surface plasmon polaritons (SSPPs), which results in the reduction of the overall size of the filter. The effect of the single defect and multiple defects at various locations are studied and analyzed in the THz and microwave region, using full wave numerical simulator CST. The study shows that the desired center frequency of the band stop and attenuation could be achieved by adjusting the position of the defects and their physical dimensions. The attenuation level and tuning frequency range is more for the proposed filter in comparison to the filter based on the corrugated metallic strip with conventional rectangular shaped. The experimental verification of the proposed tunable band notch filter is carried out in the microwave frequency band by fabricating the scaled up version, and measuring the transmission coefficient data using the network analyzer.