Design of An Asymmetric Multistage Depressed Collector for terahertz TWTs

For the purpose of improving the whole efficiency of terahertz traveling wave tubes (TWT), multistage depressed collector is widely used during the design phase. It is tough to collect all the wasted electrons which undergo the beam wave interaction thus generating secondary electron emission in MDC. Emission will increase the back-streaming current that would damage the slow wave structure, effecting the whole microwave tube. In order to tackle this problem, an asymmetric model is proposed in this paper through detailed analysis of the spent beam. According to the simulation results, this asymmetric MDC maintains lower electron streaming backward while keeping high recovery efficiency which shed some light to the researchers.