Efficient linear analysis of coupled-cavity traveling-wave tubes using minimum number of dispersion frequency points

Coupled-cavity traveling-wave tubes (CCTWTs) are high-power amplifiers operating in the microwave and millimeter-wave regions of the spectrum, utilizing beam-wave coupling within an electromagnetic slow-wave structure (SWS). The linear (small-signal) analysis of these amplifiers is a crucial initial step in their electromagnetic design. This paper presents and evaluates a method for analyzing these structures in the linear regime using only three frequency points from the SWS. The results obtained from this method are compared with full-wave particle-in-cell simulations, demonstrating satisfactory agreement. This approach offers a rapid analysis method for examining CCTWTs in the linear state, eliminating the need for lumped circuit modeling and detailed knowledge of the SWS dispersion characteristics.