Modal propagation characteristics of a W-type plasma loaded cardioid waveguide

A modal analysis for W-type plasma loaded cardioid waveguide is presented, which has three regions, viz. the core with higher index, the inner cladding with plasma, and outer cladding with air. The dispersion curves are obtained by considering both small and very high dielectric steps with various plasma frequencies. It is noted that, as the width of plasma layer is increased, the cutoff frequency also increases considerably in all considered cases. If we increase the refractive index of the core region keeping all other parameters fixed, the number of sustained guided modes increases, which indicates that the fields are tightly bounded. Further, the obtained results are also compared with those already reported for similar waveguides that provides some new insights into the propagation mechanisms. It is demonstrated that such plasma loaded cardioid waveguide exhibits some new parameters to control the propagation characteristics and can be operated in single mode at comparatively larger cutoff frequencies.