A Chamfered-shaped Microstrip Meander Line Slow-wave Structure for D-band Traveling-wave Tube

A novel chamfered-shaped microstrip meander-line slow-wave structure is proposed for D-band traveling-wave tube to decrease the reflection and improve the transmission. The slow-wave electromagnetic characteristics and the beam-wave interaction of this structure are carried out. The high-frequency characteristics show that the interaction impedance of chamfered-shaped MML is larger than that of N-shaped MML and U-shaped MML near the center frequency of 140GHz. The transmission characteristics show that the transmission loss of chamfered-shaped microstrip meander line slow-wave structure is reduced by 0.5dB for 20 periods compared with the N-shaped microstrip meander line slow-wave structure. The simulation results show that TWT with the novel SWS can generate hundreds of watts in the frequency range of 130-150GHz, and the average output power is 578 watts with the corresponding gain of 27.62dB.