A revisit to the “Rigorous study of propagation in metallic circular waveguide filled with anisotropic metamaterial”

Abstract Sakli et al. previously studied the propagation characteristics of wave modes in a metallic circular waveguide filled with anisotropic metamaterial [ Int. J. Microw. Wirel. Technol. 9 , 805–813 (2017)]. They derived and analyzed the wave equation and dispersion relations for TE z and TM z modes (i.e., TE and TM waves related to the z -axis) within the waveguide. However, they did not verify whether the system actually supports these TE z and TM z waves. This work aims to investigate that issue. Our findings indicate that, in general, a metallic circular waveguide filled with anisotropic metamaterial cannot support the propagation of TE z and TM z waves. Consequently, the results presented by Sakli et al. are incorrect.