Comparison Between Pierce Equivalent Circuit and Recent Discrete Model for Traveling-Wave Tubes

TL;DR

This paper compares a new discrete model for traveling-wave tubes with the traditional Pierce equivalent circuit, demonstrating that the discrete model closely matches Pierce's model with potential for higher accuracy.

Contribution

The paper introduces and validates a discrete model for traveling-wave tubes, showing its accuracy and advantages over the traditional Pierce model in small signal regimes.

Findings

Discrete model closely matches Pierce model in simulations

Small deviations occur at the edges of the amplification band

Discrete model potentially offers more accurate results

Abstract

To perform accurate numerical simulations of the traveling-wave tube in time domain, a new approach using field decomposition with large reduction of degrees-of-freedom has been proposed: the discrete model. To assess its validity, we compare it with the well-established Pierce equivalent circuit model in small signal regime. We also discuss associated beam, circuit-beam, and circuit impedances. We demonstrate analytically and with a numerical example that the newly developed discrete model is very close to the Pierce model. Interestingly, small deviations do exist at the edges of the amplification band. We speculate that the deviation from reality is on the Pierce model side, while the discrete model would be more accurate.