Development of aD-Band Traveling Wave Tube for High Data-Rate Wireless Links

Abstract

Ubiquitous wireless distribution of multigigabit per second data rate for enabling new 5G and 6G paradigms can be only achieved by exploiting the wide frequency bands available in the sub-THz spectrum (90 -305 GHz). The high total attenuation at sub-THz, in particular due to rain and humidity, poses a substantial challenge to achieve long links, not yet resolved due to the lack of sources with adequate transmission power. Sub-THz traveling wave tubes are emerging as key components to ensure high signal to noise ratio over a large coverage area or for long distance. This paper will describe the design and fabrication of a novel TWT for enabling point to multipoint wireless distribution at D-band (141 -148.5 GHz). To be suitable for the wireless market, TWTs need to be low cost and of easy manufacture for large scale production. The proposed D-band TWT uses a double corrugated waveguide as slow wave structure and a new electron gun, both designed for easy assembly and low fabrication cost. The paper describes the design process, the development of the parts of the TWT and the first prototype assembly.

Sub-THz X-Haul Architecture with Ultra Capacity Wireless Distribution and Transport

“…In the frame of the European Commission Horizon 2020 ULTRAWAVE "Ultra capacity wireless layer beyond 100 GHz based on millimeter wave Traveling Wave Tubes" [6] a network with wireless distribution at D-band (141 -148.5 GHz) and transport G-band (275 -305 GHz) was proposed [10]. The novelty of the approach is the use of novel sub-THz traveling wave tubes [11] as power amplifiers to provide more than one order of magnitude power than SSPAs at the same frequency. In particular, a TWT with 10 -12 W output power (SSPAs are limited to about 200 mW) in the 141 -148.5 , GHz band and a TWT with 1 -2 W output power (SSPAs are limited to about 20 mW) in the 275 -305 GHz band have been designed and are in advanced fabrication stage [11].…”

“…The novelty of the approach is the use of novel sub-THz traveling wave tubes [11] as power amplifiers to provide more than one order of magnitude power than SSPAs at the same frequency. In particular, a TWT with 10 -12 W output power (SSPAs are limited to about 200 mW) in the 141 -148.5 , GHz band and a TWT with 1 -2 W output power (SSPAs are limited to about 20 mW) in the 275 -305 GHz band have been designed and are in advanced fabrication stage [11]. To note that sub-THz TWTs are state of the art devices with substantial fabrication challenges, but very promising for the high power at sub-THz frequency.…”

D-Band Medium Power Traveling Wave Tube

“…The design of the D-band SWS was focussed to achieve the wider frequency band, possibly to use the same SWS to cover wide portion of the D-band for different TWTs. The double corrugated waveguide (DCW) single cell has similar dimensions reported in [7]. The DCW was simulated with 108 periods and input and output couplers.…”

Backward-Wave Oscillation Suppression in Folded Waveguide Traveling-Wave Tube With Metamaterial Absorber

“…Traveling-Wave Tubes (TWT) possess the merits of high power and wide bandwidth, making them an ideal amplifier at mmW band. Corrugated Waveguide (CWG) [8], Sine Waveguide (SWG) [9], Staggered Double Vane (SDV) [10], Microstrip Meander-Line (MML) [11] with sheet beam and Folded Waveguide (FWG) [12], and Double Corrugated Waveguide (DCW) [13] with pencil beam are the most common Slow Wave Structures (SWSs) for TWT in the mmW band. Although SWSs with sheet electron beams might provide higher power and gain, the sheet-beam TWTs can only operate in pulse mode for the time being, due to the poor beam transmission [14,15].…”