Experimental Investigation of an Ultrawide Bandwidth $W$ -Band Pulsed Traveling- Wave Tube With Microfabricated Folded-Waveguide Circuits

The W-band pulsed traveling-wave tubes (TWTs) are known to play a crucial role in the high-resolution radars due to their wide bandwidth and high output power. This paper presents some experimental results of an ultrawide bandwidth W-band pulsed TWT with folded-waveguide circuits fabricated by ultraviolet lithography, electroplating, and molding. A prototype tube has been tested, showing a gain of over 30 dB from 94 to 110 GHz and saturated output power of over 100 W from 94 to 101.8 GHz, with an electronic efficiency of 2.86%-4.08%. Limited by the drive power, the prototype's unsaturation output power is over 60 W from 101.8 to 110 GHz.