Excitation of Space Wave, Leaky Wave, and Creeping Waves in Cylindrical Media

The discrete and continuous spectrum in a cylindrical dielectric rod is rigorously characterized taking into account the TE–TM coupling and the longitudinal wavenumber for $\hat {z}$ -, $\hat {\rho }$ -, and $\hat {\phi }$ -directed sources. Pattern characteristics corresponding to space and leaky waves are investigated for all source-polarizations with variation in rod parameters. It is observed that the rod can function as a high-gain antenna and support proper and improper surface waves depending on rod-parameter values. The phase and attenuation characteristics of the axially propagating leaky waves are also investigated delineating the radiating and guided-wave regions of the rod. The beam scanning characteristics for the space and leaky waves with variation in rod parameters are also investigated. The complex azimuthal propagation characteristics of the creeping waves are examined to obtain an insight into propagation regions where such waves are strongly excited.