Accurate tape analysis of the attenuator-coated helical slow-wave structure

The tape-helix model is used to analyze the helical slow-wave structure considering the helix turns to be effectively shorted by the resistive attenuator coating on dielectric helix-support rods. An effective surface resistivity is calculated based on the resistive coating on discrete support rods. The results of the analysis are validated against reported experimental results in the special case of no attenuator coating. The attenuation constant and the phase propagation constant as well as the interaction impedance of the structure obtained by the present analysis in the tape model are compared with those obtained by the sheath-helix model reported elsewhere. The dependence of the attenuation constant, the phase propagation constant, and the interaction impedance on the effective surface resistivity is accurately predicted by our tape-helix model.