Wave propagation in pyrolytic-graphite slow-wave circuits

The possibility of using an anisotropic resistive material to simulate sheath-type microwave slow-wave structures is investigated experimentally. The specific anisotropic material considered in the present study is pyrolytic graphite which has an anisotropic electrical conductivity. A sheath model of the Karp line is simulated by replacing wires and slots by a sheet of pyrolytic graphite. The mode of propagation in this waveguide structure is measured and compared with the theory. The Karp-line mode with a relatively high attenuation is found to be present in this structure.