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

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 because of rain and humidity, poses a substantial challenge to achieve long links, not yet resolved because of the lack of amplifiers with adequate transmission power. Sub-THz traveling wave tubes (TWTs) are emerging as key components to ensure high signal-to-noise ratio over a large coverage area or for long distance. This article 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 easily manufacturable 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. This article describes the design process, the development of the parts of the TWT, and the first prototype assembly.