Transmission Characteristics of Ridge Waveguide Loaded with Left-Handed Materials

Abstract

This paper presents a numerical study of the electromagnetic wave propagation in a double ridge waveguide, loaded with left-handed materials (LHM). The LHM is defined phenomenologically by assigning to it a negative permittivity and negative permeability simultaneously. Transmission characteristics such as cutoff wavelength, single-mode bandwidth, dispersion and field patterns have been investigated by edge-based finite element method. The results are compared to those with air- and dielectric-loaded ridge waveguide. It was found that the LHM-loaded ridge waveguide can greatly increase the cutoff wavelength with the disadvantage of a dramatic reduction in the single-mode bandwidth. The behavior of the dispersion curve of LHM-loaded ridge waveguide is similar to the cases of waveguide loaded with air or dielectric, except for a significant improvement of the propagation constant. The boundary conditions at the interface between the air and the LHM have been well illustrated and the antiparallel wave vector in LHM were obtained by considering the field patterns. The unusual behaviors of the LHM-loaded ridge waveguide provides the potential opportunities to design novel microwave and millimeter devices.