Investigation of W-band High Power TWT Amplifier with Broadband Output Window

In this paper, the planar three-beam is adopted to investigate the potential of high output power and broad bandwidth for W-band staggered double-vane slow wave structure (SDV-SWS) travelling wave tube (TWT). A simple input/output coupler is proposed for the three-beam SDV-SWS, which consists of non-taper structures for the TWT. The high frequency simulations are used to design SWS and broadband diamond output window. With the center frequency of 95 GHz, the high transmission frequency range of 80 GHz to 114 GHz can be achieved for the super bandwidth. The 3D PIC simulation for the W-band SDV-TWT combined with the broadband diamond output window are designed and optimized for its output characteristics with the sensitively and stability thoroughly. With the beam voltage of 22 kV and beam current of 3 x 0.15 A, the output power can be reached above 1000W within the frequency range of 89 GHz and 111 GHz. The highest output power is obtained at 108 GHz of 1141 W, with the gain of 43.5 dB, the efficiency of 11.5%, and 3 dB bandwidth of 28 GHz. Thus, the physical model designed in this paper can be used as the engineering prototype to develop the high power and broadband SDV-TWT in W-band in future.