Abstract:Waveguides that afford unidirectional electromagnetic-wave propagation are highly desirable for application in splitters, switches, and isolators. In this context, ferrimagnetic materials exhibiting remanence can be used to achieve unidirectional electromagnetic-field propagation in the form of magnetoplasmons in the subwavelength regime. This study investigates the magnetoplasmon properties and guided modes in a hollow cylindrical waveguide made of materials that exhibit remanence. Pattern analysis and numerical simulations are used to demonstrate that dispersion relationships and electromagnetic-field distribution are strongly affected by the operating frequency and physical dimensions of the structure. In addition, the existence of two different operational modes is proved, namely bulk and surface modes. By adjusting the operating frequency and reducing the inner diameter of the hollow cylinder, the bulk mode can be suppressed so as to only retain the surface mode, which enables unidirectional magnetoplasmon propagation in the cylindrical waveguide. Moreover, the unidirectional surface mode is robust to backscattering due to surface roughness and defects, which makes it very useful for application in broadband splitters, subwavelength-size isolators, and ?eld-enhancement devices.