Inclined Bar in a Rectangular Waveguide as a Position-Controllable Fano-Resonance Stop-Band Component

The resonance behavior of an inclined metallic wire, bar, or strip placed inside a rectangular waveguide is investigated. The structure acts as a stop-band component exhibiting asymmetric reflection and transmission spectra characteristic of Fano resonances. By varying the inclination angle of the conductor, the resonant frequency can be continuously tuned across nearly the entire single-mode frequency band of a rectangular waveguide. Numerical analysis is performed using the mode-matching technique combined with generalized scattering matrices and a stepped approximation for modeling the inclined element. The proposed configuration offers simplicity and robustness compared to previously studied designs of a wire with a step. Furthermore, inspired by plasma-based reflective elements, we propose replacing the metallic conductor with a plasma column, enabling dynamic electronic control of the resonance and reconfigurable filtering functionality.