Design and Development of High-Power Interdigital Coupled-Cavity Slow Wave Structure for Ka-Band TWT

A design and development of a high-power interdigital coupled-cavity slow wave structure (ID-CC-SWS), operating at Ka-band is presented in the present work. The design is carried out using commercially available 3-D electromagnetic simulation code CST-Studio for RF parameters, such as dispersion, interaction impedance, VSWR characteristics, and RF loss. A typical Ka-band structure is fabricated and experiment is carried out to measure these parameters. The simulated and experimental results are compared, which shows close agreement. The measured RF loss is considered for beam–wave interaction analysis. The beam–wave interaction analysis of a two section ID-CC-SWS is carried out using particle-in cell (PIC) for the beam voltage of 20.5 kV and beam current of 500 mA. The analysis predicts an RF output power of 650 W for 1-GHz bandwidth.