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Asian Journal of Physics Vol. 33, Nos 9 & 10 (2024) 541-561

Sub-terahertz high-power microfabricated folded-waveguide traveling-wave tubes: needs and challenges in realization

Anurag Srivastava and Subrata Kumar Datta
Microwave Tubes Research & Development Centre, DRDO, Bangalore-560 013, India
This paper is dedicated to Dr Shrinivas Joshi

In recent years, folded-waveguide traveling-wave tubes (FWTWTs) have attracted much attention in sub-THz frequency band due to their potential applications in civilian and defence systems. High power and broadband sub-THz sources are required mainly for high resolution radar, secured communication, security sensing and imaging applications. A single FWTWT device provides a figure of merit of ‘power-bandwidth product’ ranging in the regime of 300-3000 W-GHz in the sub-THz band (0.09-0.3 THz) against that of about 2-20 W-GHz obtainable from the present day solid-state technology. Moreover, a folded-waveguide structure is microfabrication compatible and provides high gain and quite broad frequency bandwidth. These advantage led a surge of experimentation in the sub-THz high-power TWT sources using folded-waveguide slow-wave structure (SWS). This review paper briefly presents the need for high-power TWT sources at sub-THz frequency band. A review of state-of-the-art experimentally reported FWTWT sources and solid-state sources at W-band, D-band, and G-band is presented. Criticalities in the realisation of typical sub-assemblies of the sub-THz high power FWTWT, like, folded-waveguide interaction structure, electron beam optics module (EBOM), and broadband pillbox window assembly for the input and output couplers are also highlighted. © Anita Publications. All rights reserved.
Doi: 10.54955/AJP.33.9-10.2024.541-561
Keywords: Sub-Terahertz (STHz), Traveling-wave tube (TWT), Folded-waveguide (FW), Electron beam optics module (EBOM), Slow-wave structure (SWS), Pill-box window (PBW), Magnetic focussing structure.

Peer Review Information
Method: Single- anonymous; Screened for Plagiarism? Yes
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