Design of a coaxial coupler for an E-band Helix Traveling-wave Tube

The performance of coupling system directly affects the bandwidth, power level and the efficiency of traveling-wave tube (TWT), so it is significant to match coupler structure and helix properly. In this paper, a coaxial coupler with matching cylinder for an E-band helix TWT is proposed. It is suitable for the case where there is a large characteristic impedance contrast between helix and the coax...