Tunable Rectangular Waveguide Bandpass Filter Based on Plasma Technology

This paper presents a novel tunable bandpass filter that exploits plasma conductors within a standard hollow waveguide framework. The operational principle of the filter leverages the reconfigurability of plasma and its tunable properties, allowing dynamic control over the lower frequency boundary. Through the adjustment of plasma frequency, the filter demonstrates remarkable adaptability, shifting the lower cutoff frequency within a range from 1.66 GHz to 1.75 GHz while maintaining a nearly fixed upper cutoff frequency at approximately 2 GHz. Additionally, the paper includes a parametric analysis that investigates the influence of post dimensions on filter performance. This analysis underscores the significance of initial post dimensions in shaping the bandwidth of the filter. Findings affirm the feasibility of this innovative filter concept.