Theoretical Research on a D-Band Traveling Wave Extended Interaction Amplifier

A traveling-wave, extended interaction amplifier is herein investigated for use in millimeter-wave and terahertz amplification sources. By placing engineered extended interaction cavities between the traveling wave structures, higher gain is obtained with a shorter high frequency circuit, compared with conventional traveling wave tubes architectures. The bandwidth of the device is significantly increased relative to extended interaction klystrons. A D-band beam wave interaction circuit of 26 mm long has been designed. Particle-in-cell simulations at 21.5-kV operating voltage, 0.3-A beam current, and 5-mW input power show that the maximum output power reaches 351 W, with a gain of 48.4 dB and 3-dB bandwidth of 1.42 GHz.