Sensitivity analysis of a double corrugated waveguide slow wave structure for a 151 - 161.5 GHz TWT

TWTs at D-band (141 – 174.5 GHz) are the most promising solution to provide high transmission power for enabling long range wireless links with high capacity at sub-THz frequency. A D-band TWT was designed in the 151-161.5 GHz frequency band with about 10 W output power. The double corrugated waveguide is adopted as slow wave structure (SWS) for the relatively easy fabrication and alignment in comparison to other SWSs typically used at sub-THz frequency. Due to the short wavelength at D-band, the fabrication requires high precision computerised numerically controlled (CNC) milling machining and tight tolerance control. The sensitivity analysis of performance as a function of the dimensions of a device is an important method to predict in advance how the performance of the device is affected by geometry variations, and also to ascertain the required level of fabrication accuracy to meet the specifications. The sensitivity analysis is also useful to define the best initial dimensions for further optimization. This paper discusses the sensitivity analysis applied to the double corrugated waveguide (DCW) to be used in a 151-161.5 GHz TWT. A broad range of parameters are considered demonstrating the importance of fabrication accuracy and the eventual correction options for a correct functioning. The impact of fillets in the DCW pillars is also evaluated to eventually ease the fabrication requirement

Design and fabrication of a D-band traveling wave tube for millimeter wave communications

The design and fabrication aspects of a novel D-band (141 GHz-148.5 GHz) Traveling Wave Tube (TWT) for enabling the first point to multipoint front end at D-band, objective of European Commission H2020 ULTRAWAVE is presented. The ULTRAWAVE system will provide unprecedented wireless area capacity over wide area sectors, with radius up to 500 - 600 m for the future 5G high density small cell deployment. The design and fabrication processes adopted for the TWT are focused to find new low cost solutions for TWTs at millimetre waves to satisfy the requirements of the wireless market. The proposed TWT will provide more than 10 W saturated output power for achieving more than 100 Gb/s/km2 of area capacity over 600 meters radius wide angle sector, with 99.99% availability in ITU zone K

Design of Slow Wave Structure for G-band TWT for High Data Rate Links

The need of high data rate can be satisfied only by wide frequency bands in the millimetre wave region. This paper presents the design of a G-band (215 – 250 GHz) Traveling Wave Tube with 40 dB gain for wireless communications, based on the double corrugated waveguide. The structure of the TWT is based on a single section, instead of the typical configuration of two sections with a sever used at microwave frequency. This is possible due to the high losses at those frequency that permit a stable behaviour. This paper reports both cold and hot simulations

Design of D-band Double Corrugated Waveguide TWT for Wireless Communications

The European Commission Horizon 2020 ULTRAWAVE, “Ultra capacity wireless layer beyond 100 GHz based on millimeter wave Traveling Wave Tubes”, aims to exploit portions of two frequency bands in the millimetre wave spectrum, the D-band (141 – 148.5 GHz) and the G-band (275 – 305 GHz) for creating a very high capacity layer. Due to the high atmosphere and rain attenuation, high transmission power is needed to provide a useful transmission range. Traveling Wave Tubes are the only devices that can provide the multi-Watt transmission power above 100 GHz. In this paper, the design of the Double Corrugated Waveguide (DCW), as slow wave structure, for a novel D-band TWT, for wireless communications, will be described

Development of a D-band Traveling Wave Tube for high data rate wireless links

biquitous wireless distribution of multi- gigabit per second data rate for enabling new 5G and 6G paradigms can be only achieved by exploiting the wide fre- quency 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 waveg- uide as slow wave structure and a new electron gun, both devised 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

Long-range millimetre wave wireless links enabled by travelling wave tubes and resonant tunnelling diodes

High data rate wireless links are an affordable and easily deployable solution to replace or complement fibre. The wide frequency band available at millimetre waves above 100 GHz can support multi-gigabit per second data rate. However, the high attenuation due to rain and humidity poses a substantial obstacle to long-range links. This study describes a wireless system being developed for point-to-point links at D-band (DLINK), above 150 GHz, to enable a full fibre-on-air link with more than 1 km range and unprecedented data rate up to 45 Gb/s. The upper end of the D-band spectrum is used (151.5–174.8 GHz) in full frequency division duplex transmission. The DLINK system consists of a transmitter using a directly modulated resonant tunnelling diode oscillator powered by novel travelling wave tubes. The performance and the small footprint of the front end will make the DLINK system highly competitive to the point-to-point links presently available in the market at frequencies below 100 GHz. The innovative approach and the design are oriented to large-scale productions to satisfy the high data traffic demand of the new 5G infrastructure

Long range millimeter wave wireless links enabled by traveling wave tubes and resonant tunnelling diodes

This paper describes a new project to realize a high data rate point to point wireless system above 150 GHz. The upper end of the D-band spectrum is used (151 -174 GHz) for full duplex transmission. The aims it to enable a full fiber on air with more than 1 km range to provide up to 45 Gb/s data rate. The system consists in a transmitter using a directly modulated Resonant Tunnelling Diode (RTD) oscillator and powered by novel traveling wave tubes (TWT)

D-band point to multi-point deployment with G-band transport

The first Point to MultiPoint wireless system at D-band has been designed and is in advanced development. The European Commission H2020 ULTRAWAVE "Ultra capacity wireless layer beyond 100 GHz based on millimeter wave Traveling Wave Tubes"project aims to respond to the demand of high capacity at level of tens of Gigabit per second, in urban areas, where fiber backhaul is not economically viable and high density small cell architectures are deployed. A transmission hub powered by a novel D-band TWTs will feed a number of terminals arbitrarily allocated in the corresponding area sector. This paper illustrates the main characteristics, advantages and networking aspects and provide a summary of the latest results of the ULTRAWAVE project

Toward the first D-band Point to multipoint wireless system field test

The European Commission Horizon 2020 ULTRAWAVE “Ultra capacity wireless layer beyond 100 GHz based on millimeter waves” is in the final stage of development. The first ever field test of a D-band point to multipoint wireless system will be performed in a real environment. The ULTRAWAVE wireless system comprises a D-band Transmission Hub to produce a 30 degree sector with 600 m radius with multi gigabit per second data rate and a number of compact D-band terminals. The terminals will be distributed at different distances from the transmission hub to recreate real deployment condition. The paper describes the latest update on the development of the ULTRAWAVE systems and the field test set up