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

Aktive Frequenzvervielfacher zur Signalerzeugung im Millimeter- und Submillimeterwellen Frequenzbereich

Die in dieser Arbeit entwickelte Schaltungstopologie zur Frequenzvervielfachung erreicht Bandbreiten komplexer und balancierter Vervielfacher mit nur vier Transistoren. Als Einzelschaltung erreicht sie die höchsten relativen Bandbreiten aktiver Vervielfacher über 110 GHz. Weiter werden Kaskadierungstechniken gezeigt, die einen Verachtfacher mit einer Bandbreite von 220 bis 320 GHz ermöglichen. Erstmals erzeugt ein hier entwickelter aktiver Frequenzversechsfacher Frequenzen bis zu 670 GHz

Aktive Frequenzvervielfacher zur Signalerzeugung im Millimeter- und Submillimeterwellen Frequenzbereich

In this work a new transistor topology for frequency multiplication is developed, achieving relative bandwidths of complex and balanced structures with only four transistors. It enables the highest bandwidth in active multiplication beyond 110 GHz. Cascading techniques are shown enabling a cascaded frequency multiplier by eight with a frequency range of 220 to 320 GHz. For the first time an active frequency multiplier by six reaches output frequencies up to 670 GHz

Next-generation IoT devices: sustainable eco-friendly manufacturing, energy harvesting, and wireless connectivity

This invited paper presents potential solutions for tackling some of the main underlying challenges toward developing sustainable Internet-of-things (IoT) devices with a focus on eco-friendly manufacturing, sustainable powering, and wireless connectivity for next-generation IoT devices. The diverse applications of IoT systems, such as smart cities, wearable devices, self-driving cars, and industrial automation, are driving up the number of IoT systems at an unprecedented rate. In recent years, the rapidly-increasing number of IoT devices and the diverse application-specific system requirements have resulted in a paradigm shift in manufacturing processes, powering methods, and wireless connectivity solutions. The traditional cloud-centering IoT systems are moving toward distributed intelligence schemes that impose strict requirements on IoT devices, e.g., operating range, latency, and reliability. In this article, we provide an overview of hardware-related research trends and application use cases of emerging IoT systems and highlight the enabling technologies of next-generation IoT. We review eco-friendly manufacturing for next-generation IoT devices, present alternative biodegradable and eco-friendly options to replace existing materials, and discuss sustainable powering IoT devices by exploiting energy harvesting and wireless power transfer. Finally, we present (ultra-)low-power wireless connectivity solutions that meet the stringent energy efficiency and data rate requirements of future IoT systems that are compatible with a batteryless operation

Enhancing Digital Controllability in Wideband RF Transceiver Front-Ends for FTTx Applications

Enhancing the digital controllability of wideband RF transceiver front-ends helps in widening the range of operating conditions and applications in which such systems can be employed. Technology limitations and design challenges often constrain the extensive adoption of digital controllability in RF front-ends. This work focuses on three major aspects associated with the design and implementation of a digitally controllable RF transceiver front-end for enhanced digital control. Firstly, the influence of the choice of semiconductor technology for a system-on-chip integration of digital gain control circuits are investigated. The digital control of gain is achieved by utilizing step attenuators that consist of cascaded switched attenuation stages. A design methodology is presented to evaluate the influence of the chosen technology on the performance of the three conventionally used switched attenuator topologies for desired attenuation levels, and the constraints that the technology suitable for high amplification places on the attenuator performance are examined. Secondly, a novel approach to the integrated implementation of gain slope equalization is presented, and the suitability of the proposed approach for integration within the RF front-end is verified. Thirdly, a sensitivity-aware implementation of a peak power detector is presented. The increased employment of digital gain control also increases the requirements on the sensitivity of the power detector employed for adaptive power and gain control. The design, implementation, and measurement results of a state-of-the-art wideband power detector with high sensitivity and large dynamic range are presented. The design is optimized to provide a large offset cancellation range, and the influence of offset cancellation circuits on the sensitivity of the power detector is studied. Moreover, design considerations for high sensitivity performance of the power detector are investigated, and the noise contributions from individual sub-circuits are evaluated. Finally, a wideband RF transceiver front-end is realized using a commercially available SiGe BiCMOS technology to demonstrate the enhancements in the digital controllability of the system. The RF front-end has a bandwidth of 500 MHz to 2.5 GHz, an input dynamic range of 20 dB, a digital gain control range larger than 30 dB, a digital gain slope equalization range from 1.49 dB/GHz to 3.78 dB/GHz, and employs a power detector with a sensitivity of -56 dBm and dynamic range of 64 dB. The digital control in the RF front-end is implemented using an on-chip serial-parallel-interface (SPI) that is controlled by an external micro-controller. A prototype implementation of the RF front-end system is presented as part of an RFIC intended for use in optical transceiver modules for fiber-to-the-x applications

Millimeter-wave and terahertz optical heterodyne photonic integrated circuits for high data rate wireless communications

The data rate of wireless communications systems has been increasing because of the new applications that today’s society are applying. The prospective data rate for wireless communications in the marketplace will be 100 Gbps within 10 years. Therefore, to enable such data rates the use of millimetre and terahertz (THz) waves, whose frequencies range from 100 GHz to 1 THz, for broadband wireless communications is very suitable and efficient. At frequencies above 100 GHz, GaAs and InP based devices and integrated circuits (ICs) have been key players in THz communications research, because of high cut-off and maximum frequencies of transistors. In fact, the photonics-based transmitter has become more effective to achieve higher data rates of over 20 Gbps. This could be realized thanks to the availability of telecom-based high-frequency components such as lasers, modulators and photodiodes (O-E converters). The use of optical fiber cables enables us to distribute high-frequency RF signals over long distances, and makes the size of transmitter frontends compact and light. Regarding the photonics-based receiver, photodiode is the photonic component best suited to be a signal downconverter. It is used an enveloped detector, so an easy modulation format such as on-off keying shifting (OOK) can be used to recover the transmitted data. Most common optical continuous wave (CW) signal generator is based on an optical heterodyning, using a dual-wavelength optical source. In this technique, two optical wavelengths λ1 and λ2 are mixed on a photodiode or a photoconductor to generate an electrical beat note with its frequency being determined by the difference of the two optical wavelengths. There are different solutions to implement the dual wavelength source. The most straightforward source involves combining the light from two independent different single-frequency semiconductor lasers. The most straightforward approach to implement these signal generation schemes is to assemble the required discrete components. However, the optical fiber connections that are required introduce many problems, including path length variations due to thermal variations. A novel approach, that is becoming readily available nowadays, is to use photonic integration techniques. Photonic integration allows placing all of the required components onto a single chip. This has several advantages, starting from eliminating fiber coupling losses among the different components. Besides, a reduced size of the components gives a result a cost-effective solution.Programa Oficial de Doctorado en Ingeniería Eléctrica, Electrónica y AutomáticaPresidente: Tadao Nagatsuma.- Secretario: Horacio Lamela Rivera.- Vocal: Íñigo Molina Fernánde

Breitbandige Frequenzweichen für die Parallelisierung von Millimeterwellen-Messtechnik

In dieser Arbeit wird der neuartige Einsatz von breitbandigen kontinuierlichen Frequenzweichen für die Parallelisierung von Millimeterwellen-On-Wafer-Messtechnik vorgestellt. Die Frequenzweichen können in On-Wafer-Messspitzen integriert werden, um so den parallelen Einsatz von Messtechnik für unterschiedliche Frequenzbereiche zu ermöglichen. Ziel ist die nachhaltige und kostengünstige Erweiterung bestehender On-Wafer-Messtechnik zum Erfassen eines größeren Frequenzbereiches bei einmaliger Kontaktierung des Messobjektes, ohne dabei die On-Wafer-Messspitzen und die sensible Messtechnik für unterschiedliche Frequenzbänder austauschen, warm laufen lassen und erneut kalibrieren zu müssen. Anhand skalierter Prototypen wird eine modellbasierte Methode für den Entwurf breitbandiger kontinuierlicher Frequenzweichen mit Stepped-Impedance-Tiefpassfiltern und Bandpassfiltern aus gekoppelten Leitungsresonatoren im Detail beschrieben. Das methodische Vorgehen mit Modellierungen der Filterstrukturen ermöglicht einen effizienten Entwurf und die Optimierung breitbandiger kontinuierlicher Frequenzweichen mit einer Vielzahl an einstellbaren Parametern, bei der Optimierungen in elektromagnetischen Feldsimulationen nicht mehr zielführend sind. Die benötigte Anzahl elektromagnetischer Feldsimulationen kann mit den einfachen Berechnungen der Filtermodelle erheblich reduziert werden, was den gesamten Entwurfsprozess verkürzt und zielgerichtet strukturiert. Als Schlüsselkomponente der entworfenen Diplexer wird eine neuartige T-Verzweigung vorgestellt, deren Geometrie eigens zur Verschaltung der verwendeten Filter optimiert ist. Mit der neuartigen Struktur ist es möglich, alle relevanten Kenngrößen der T-Verzweigung so einzustellen, dass die komplementären Filter optimal aufeinander angepasst werden können. Dünnschicht-Polyimidplatinen und filigran gefräste Gehäuse mit $\mu$m-Präzision ermöglichen die erstmalige Realisierung von breitbandigen kontinuierlichen Frequenzweichen für den mmW-Frequenzbereich DC - 110 GHz - 170 GHz und erweitern damit den aktuellen Stand der Forschung hin zu höheren Frequenzen. Die realisierten Diplexer werden mit 3 Tor Streuparametermessungen bis 170 GHz charakterisiert. Auftretende Fertigungstoleranzen werden durch sorgfältige Analyse der gefertigten Leiterplatten-Nutzen und individuelle Anpassung der Gehäusestrukturen teilweise ausgeglichen und in umfassenden Toleranzanalysen ausführlich untersucht

Hybride Beamformingsysteme niedriger Komplexität für den Mobilfunk

Ein wichtiger Baustein zur Steigerung der spektralen Effizienz von drahtlosen Funkkommunikationsnetzwerken stellt der Einsatz von Mehrantennensystemen im Zentimeter- und Millimeterwellenfrequenzbereich dar. Wie diese Mehrantennensysteme mit einem möglichst geringen Hardwareaufwand in Form von hybriden Beamformingsystemen realisiert werden können ist Thema dieser Arbeit

Hybride Beamformingsysteme niedriger Komplexität für den Mobilfunk

An important method to increase the spectral efficiency of wireless radio communication networks is the use of multiple-input multiple-output communication systems operating in the centimetre and millimetre wave region. How these multiple-input multiple-output communication systems can be realised with as little hardware effort as possible using hybrid beamforming architectures is the subject of this work