Development of a high average power W-band TWT

A first-unit full-gain W-Band folded-waveguide TWT has been rebuilt and is scheduled for hot test. This light-weight integral pole piece TWT is expected to achieve high average power by utilizing multiple L-3 proprietary features: a PPM-type, folded-waveguide circuit that has close-proximity copper-block heat-sinks [1]; a broadband block-type RF window that demonstrated 1500 watts of average-power transmission with a 33% bandwidth match at Ka- band [1]; a tetrode gun that provides high-PRF modulation to diode-gun-quality electron beams [2] [3]; and voided iron parts that permit pole pieces with thicknesses that exceed an RF period to supply focusing fields with lambdaP/L values around 10 for 4-kilowatt beams [4].