The open rectangular grating with step-loaded slow-wave structure (SWS), a type of all-metal SWS for high power wide band mm-wave wave traveling wave tubes (TWT) is presented in this paper. By using the jumping conditions at the interface of two neighboring steps and single-mode approximation (SMA) field matching theory, the dispersion equation and coupling impedance of this SWS were obtained. Then the obtained complex dispersion equation was numerically calculated, and the slow-wave characteristics of the fundamental wave of this structure were discussed. Moreover, the calculation results by our theory were accordant with the simulation data obtained by the 3-D electromagnetic simulation software HFSS, The numerical calculation results show that the dispersion characteristics and coupling impedance are notably improved by loading the steps. And the working bandwidth may be the widest when the thickness of the step is about equal to the thickness of the groove depth. The proper design parameters can be optimized to meet the needs of high frequency characteristics with wide bandwidth and high output power. The present study will be useful for further research and design of this kind of high frequency system.
"Analysis of Step-Loaded Open Rectangular Grating Slow-Wave Structures for mm
-Wave Traveling-Wave Tubes," Progress In Electromagnetics Research M,
Vol. 45, 27-34, 2016. doi:10.2528/PIERM15100801
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