A E-Band Broadband 100-W Continuous-Wave Traveling-Wave Tube With Novel Slow Wave Circuit

A broadband E-band continuous-wave (CW) 100-W traveling-wave tube (TWT) is developed to meet the requirements of radar and electronic warfare systems. The following methods are adopted in this E-band CW TWT to expand the operation bandwidth, improve the gain flatness, and increase the output power: flat dispersion curves and high coupling impedance by adopting a new type slow wave structure of nonconcentric serpentine waveguide circuit with variable narrow edges (NSWC), improved output power in the high-frequency end by using the positive and negative phase velocity jump technology, high electron beam transmission by a dual-anode long-range electron gun, and minimized reflection within the widest possible frequency band by sapphire box windows with linear double gradient transition waveguides. The first prototype tube has been assembled and tested. Within 8-GHz operation bandwidth of 80–88 GHz, this TWT provides the saturated output power of more than 112.9 W and −1-dB compression point powers of more than 81.44 W. The saturated gain and the small signal gains are higher than 32.37 dB with fluctuations less than 2.23 and 34.92 dB with fluctuations less than 4.96 dB, respectively. Compared with other existing CW TWTs in E-band, this TWT has a wider operating bandwidth, higher linear output power, and better gain flatness.