A study on helix pitch tolerance impact on TWT small-signal gain

Traveling-wave tubes (TWTs) consist of several sections with different helix pitch to provide the required small-signal gain. An extensive study aiming to improve the comprehension of the effect of the helix pitch manufacturing tolerances on the TWT small-signal gain has been completed. The obtained results demonstrate the relevant impact on the TWT small-signal gain when the helix pitch deviates from its nominal value and allow devising a tuning procedure for the realized tubes.

I. Introduction

Helix traveling-wave tubes (TWTs) still represent a key device in high data rate telecommunication systems and in satellite transmitters, where high output power (up to hundreds of watts) in a large instantaneous bandwidth is required [1], [2]. Further, the merging of TWTs with solid-state technology in the microwave power module (MPM) permits the realization of low weight, low noise, high power, and high reliability amplifier devices [3].