Preliminary Study of a Terahertz TE20 Mode Input/Output Coupling Structure

Preliminary study of a TE20 input/output coupling structure for sheet electron beam traveling wave tubes is presented in this paper. A TE10-TE20 mode converter and a single branch waveguide coupler are used to realize the proposed design. Simulation results obtained by using the CST simulation software demonstrated that the port reflection and the transmission coefficient were respectively lower than - 15 dB and higher than - 1 dB in the frequency range of 241-298 GHz. The port isolation was lower than - 10 dB in the frequency range of 250-298 GHz.