Exploring scattering in a cylindrical duct containing plasma, vacuum, and dielectric media

This study investigates the propagation of electromagnetic waves in a perfectly electric conducting cylindrical waveguide with a central chamber filled with cold plasma embedded in vacuum which is covered by dielectric layer in conducting cylinder. The mathematical modeling formulates a boundary value problem which is solved by using the mode-matching technique to analyze the scattering characteristics. This technique relies on the projection of solution on orthogonal bases. The development and application of orthogonality relations are useful to convert the differential system into linear algebraic systems, truncated and inverted for the solution. The validity of the truncated solution is confirmed by verifying the matching conditions, which demonstrate the perfect alignment of electric and magnetic fields at the two interfaces. The investigation focuses on the power flux in different regions of the waveguide, considering both transparency and non-transparency regimes. Computational results demonstrate energy propagation versus the properties of the medium and geometrical parameters of configuration. It is found that the plasma radius alterations do not significantly affect transmission, but influence the number of cut-on modes. In the transparency regime, one cut-on mode, consistently, exists across all chamber regions. In the non-transparency regime, the plasma region has no cut-on mode while the vacuum and dielectric regions exhibit one cut-on mode.