Investation on Broad Bandwidth and High Power Terahertz Traveling Wave Tube Based on Mulit-Mode and High-Mode Beam Wave Interaction

Due to the scientific potentials of terahertz spectrum and prospect applications in spectroscopy, imaging and communication etc., the development of broadband and high power terahertz coherent radiation source has become extremely urgent nowadays. Based on the planar electron beam and new-type planar miniaturization staggered double vane (SDV) slow wave structure (SWS), the exploration on the multi-mode and high-mode beam wave interaction system can significantly broaden the bandwidth and increase the output power for such travelling wave tube (TWT) in terahertz band. Thus, this paper has focused on the development of the multi-mode and high-mode SDV-TWT with their frequency structures and beam wave interaction systems for the periodic SDV-SWS, exploring the high frequency characteristics of multi-mode and high-mode transmission dispersion, high coupling impedance, mode convert, broadband matching of input and output coupling system as well as the high power window. we proposed the SDV-SWS vacuum electron devices for TWT to produce several kilo-watts peak power at 0.1THz and above several hundred-watts at 0.22THz, with the 3dB bandwidth about 30- 70GHz using two-mode beam-wave interactions. Also, the output characteristics of mode TM
31
SDV-TWT at 340GHz is designed, a maximum output power of 40W near the center frequency with the gain of 36dB and a 3dB bandwidth of 38GHz is achieved. The works will lay a good foundation for the development of broad bandwidth and high output power terahertz coherent radiation sources, and for the expanding of higher terahertz frequency band and planar micro-nano integration of multiple devices in the future.