Preliminary Cold Test of a Terahertz Band Sheet Beam Travelling Wave Tube

Abstract

In this paper, the preliminary cold test of a high frequency system composed of two identical input / output couplers and a 90-period double-staggered grating waveguide is presented. A HFS without dielectric attenuators was machined by nano-CNC machining. The vector network analyzer measured results showed that the transmission coefficient $S_{21}$ and port reflection $S_{11}$ were better than −8.0 dB and −15.0 dB in the bandwidth of ∼47.2 GHz (241.4-288.6 GHz), respectively. The measured results were indicative of satisfactory machining accuracy and surface roughness and verified the adopted manufacturing technique.