Field distribution and dispersion characteristics of a coaxial oversized slow wave structure with deep corrugation operating on high-order mode

Compared with the traditional slow wave structure (SWS) with a fundamental mode, the oversized SWS with deep corrugation operating in a high-order mode has a higher power handling capacity and lower beam density. However, for the new structures, the traditional Floquet harmonic expansion method is not applicable in analyzing the dispersion characteristics of the slow wave structure. In this paper, we present a new analysis method based on the mode matching method, which is suitable for the arbitrary depth of corrugation of SWS. Besides, as the field matches at the corrugated surface of inner and outer conductors, the method is applicable whether the conductors are corrugated or uniform. The method is validated by software simulation. The calculation results of the software verify the correctness of the theory and show that the theoretical calculation is more convenient. By the method we present, the dispersion characteristics, field distribution, and coupling impedance are theoretically derived and analyzed.