Design and analysis of micro-machined folded waveguide slow-wave structure for 220 GHz application

Abstract

Folded waveguide is a promising structure for THz travelling wave tube (TWT) application. In this paper, a folded waveguide slow-wave structure of 220GHz TWT is designed and simulated using CST Microwave Studio and Particle Studio. Interaction impedance and dispersion relation vs. frequency are evaluated. The relationship between gain and parameters such as beam current, electron's emitting angle, energy spread, magnetic flux density and input power, are discussed. Simulations of a 60 periods folded waveguide circuit show that the gain is 17.4dB at 220GHz when the beam voltage is 18KV and beam current is 10mA.