Design and test of an E-band CW space TWT

This paper presents a design and experimental study of an E-band continuous wave (CW) space traveling wave tube (TWT) with overall efficiency of over 37% using multistage depressed collectors (MDC) at 71–76 GHz. The folded waveguide (FWG) and phase velocity tapering circuit are used to achieve the electronic efficiency of over 7.8%. A prototype tube has been fabricated and tested with beam voltage of 14.7 kV and beam current of 74 mA. The testing results show that the TWT has achieved over 85W output power and above 39.5 dB gain within a bandwidth of 5GHz, with a maximum saturated output power of 100.7W, a corresponding gain of 43 dB and overall efficiency of 46%.