Electromagnetic analysis of the main and higher modes on the onion-like carbon tubes

The electric and magnetic field distributions as well as the dispersion characteristics of open cylindrical tube (hollow-core) waveguides are analysed in this work. The analysed waveguides are made of an onion-like carbon (OLC) material. The solution of the boundary problem was fulfilled by the partial area method. It was discovered the very complicated dependencies of the phase and attenuation constants on the waveguide radii. Such dependencies arise because the OLC material is the highly dispersive and absorbing one. The fundamental and four higher modes can propagate in our investigated waveguides. We have analysed the high-frequency cut-off frequency of modes that is dependent on the tube waveguide external radius. The certain electromagnetic (EM) mode can propagate only on the frequencies lower than the mentioned cut-off frequency. For this reason, this cut-off frequency has an important use in practical applications. We presented here the EM field distributions of modes. We discovered that it is possible to reach the one-mode regime of OLC tube waveguide at the certain external radius. The fundamental and first higher modes’ EM energy is concentrated in the OLC material between the internal and external surfaces of the waveguide.