The research of an open-styled dielectric-lined azimuthally periodic circular waveguide for TWT

An open-styled dielectric-lined azimuthally periodic circular waveguide (ODLAP-CW) which is a modified form of a dielectric-lined azimuthally periodic circular waveguide (DLAP-CW) is proposed in this paper. Here, the metal shell in the DLAP-CW is replaced by absorbing materials in the improved structure. The improved structure can effectively eliminate the mode competition in the beam-wave interaction with only slight influence on the dispersion characteristics. As a result, the interaction efficiency and the stability of the TWT based on such a structure can be expected to be greatly improved.