Reconfigurable and Tunable Iris Filter Based on Plasma Technology

This paper presents a novel tunable and reconfigurable bandpass iris filter integrated within a standard rectangular waveguide, utilizing plasma technology. The proposed filter employs plasma slabs to create iris structures that enable dynamic control over the center frequency and bandwidth of the filter. When the plasma slabs are inactive, the filter behaves as a conventional waveguide, while activation allows for tuning the characteristics of the filter by adjusting the excitation current applied to the plasma tubes. In the following, commercially available cylindrical plasma tubes are utilized to develop plasma slabs for practical implementation. Numerical simulations demonstrate the effectiveness of this approach, revealing a tunability of approximately $5 \%(0.06 \mathrm{GHz}$ around a center frequency of 1.2 GHz) with return losses exceeding 10 dB and insertion losses maintained below 0.6 dB. The results of this study highlight the feasibility and potential of plasma-based reconfigurable filters in advancing next-generation RF and microwave systems. Index Plasma-based filter, tunable filter, bandpass iris filter, reconfigurable filter.