Area and Power Efficient Ultra-Wideband Transmitter Based on Active Inductor

This paper presents the design of an impulse radio ultra-wideband (IR-UWB) transmitter for low-power, short-range, and high-data rate applications such as high density neural recording interfaces. The IR-UWB transmitter pulses are generated by modulating the output of a local oscillator. The large area requirement of the spiral inductor in a conventional on-chip LC tank is overcome by replacing it with an active inductor topology. The circuit has been fabricated in a UMC CMOS 180 nm technology, with a die area of 0.012 mm2. The temporal width of the output waveform is determined by a pulse generator based on logic gates. The measured pulse is compliant with Federal Communications Commission (FCC) power spectral density limits and within the frequency band of 3-6 GHz. For the minimum pulse duration of 1 ns, the energy consumption of the design is 20 pJ per bit, while transmitting at a 200 Mbps data rate with an amplitude of 130 mV

Compact and Efficient Millimetre-Wave Circuits for Wideband Applications

Radio systems, along with the ever increasing processing power provided by computer technology, have altered many aspects of our society over the last century. Various gadgets and integrated electronics are found everywhere nowadays; many of these were science-fiction only a few decades ago. Most apparent is perhaps your ``smart phone'', possibly kept within arm's reach wherever you go, that provides various services, news updates, and social networking via wireless communications systems. The frameworks of the fifth generation wireless system is currently being developed worldwide. Inclusion of millimetre-wave technology promise high-speed piconets, wireless back-haul on pencil-beam links, and further functionality such as high-resolution radar imaging. This thesis addresses the challenge to provide signals at carrier frequencies in the millimetre-wave spectrum, and compact integrated transmitter front-ends of sub-wavelength dimensions. A radio frequency pulse generator, i.e. a ``wavelet genarator'', circuit is implemented using diodes and transistors in III--V compound semiconductor technology. This simple but energy-efficient front-end circuit can be controlled on the time-scale of picoseconds. Transmission of wireless data is thereby achieved at high symbol-rates and low power consumption per bit. A compact antenna is integrated with the transmitter circuit, without any intermediate transmission line. The result is a physically small, single-chip, transmitter front-end that can output high equivalent isotropically radiated power. This element radiation characteristic is wide-beam and suitable for array implementations

Optical generation of mm-wave signals for use in broadband radio over fiber systems

In future cellular radio networks Radio over Fiber (RoF) is a very attractive technology to deliver microwave and millimeter-wave signals containing broad band multimedia services to numerous base stations of the network. The radio signals are placed on an optical carrier and distributed by means of an optical fiber network to the base stations (BS). In the BS the optical signals heterodyne in a photodiode to produce the radio signals which are then sent via a wireless link to the mobile units (MU). The optical fiber network provides high frequency, wideband, low loss and a means of signal distribution immune to electromagnetic interference. In this thesis, different methods of electrooptical upconversion were investigated. The generation of an optical double-sideband with suppressed carrier (DSB-SC) signal is a straightforward method due to the fact that only one optical modulator driven at half the millimeter-wave frequency is required. One or both sidebands were ASK-modulated with baseband data rates of up to 10 Gbps. Optical single sideband modulation proves to be dispersion resilient as error free transmission was demonstrated after 53 km of single mode fiber transmission for data rates up to 10 Gbps. Wireless links up to 7 m were also demonstrated, proving the feasibility of this approach for broadband wireless inhouse access systems.Für zukünftige zellulare Funknetze ist „Radio over Fiber (RoF)“ eine sehr attraktive Technologie, um breitbandige Multimedia-Dienste mit Mikro- und Millimeterwellen zu übertragen. Die Funksignale werden dabei auf eine optische Trägerwelle aufmoduliert und mittels eines optischen Fasernetzes zu den Basisstationen (BS) verteilt. In den BS erfolgt die Überlagung der optischen Signale durch eine Fotodiode, um die Funksignale zu erzeugen. Diese werden dann über eine drahtlose Verbindung zu den beweglichen Multimedia-Endgeräten geschickt. Vorteile des optischen Fasernetzes sind Breitbandigkeit, geringe Dämpfung und eine gegenüber elektromagnetischen Störungen immune Signalverteilung. In dieser Arbeit werden verschiedene Methoden der elektrooptischen Aufwärtskonversion erforscht und die wichtigsten Eigenschaften dieser untersucht. Die Erzeugung eines optischen Zweiseitenbandsignales mit unterdrücktem Träger (DSB-SC) ist eine einfache Methode, da nur ein optischer Modulator, betrieben mit der halben elektrischen Trägerfrequenz, benötigt wird. Eine oder beide Seitenbänder konnten mit Bitraten bis zu 10 Gbps amplitudenmoduliert werden. Optische Einseitenbandmodulation ist extrem tolerant bezüglich der chromatischen Dispersion der Faser, wie die fehlerfreie Übertragung nach 53 km Glasfaser beweist. Drahtlose Links bis zu 7 m wurden realisiert und zeigen die Möglichkeit dieser Verfahren für breitbandige drahtlose Inhouse-Zugangssysteme

Radio Communications

In the last decades the restless evolution of information and communication technologies (ICT) brought to a deep transformation of our habits. The growth of the Internet and the advances in hardware and software implementations modified our way to communicate and to share information. In this book, an overview of the major issues faced today by researchers in the field of radio communications is given through 35 high quality chapters written by specialists working in universities and research centers all over the world. Various aspects will be deeply discussed: channel modeling, beamforming, multiple antennas, cooperative networks, opportunistic scheduling, advanced admission control, handover management, systems performance assessment, routing issues in mobility conditions, localization, web security. Advanced techniques for the radio resource management will be discussed both in single and multiple radio technologies; either in infrastructure, mesh or ad hoc networks

Terahertz antenna design for future wireless communication

A Terahertz (THz) antenna with a size of a few micrometres cannot be accomplished by just reducing the extent of a traditional metallic antenna down to a couple of micrometres. This approach has several downsides. For example, the low mobility of electrons in nanoscale metallic structures would result in high channel attenuation. Thus, using traditional micrometre metallic antennas for THz wireless communication becomes unfeasible. The THz band refers to the electromagnetic spectrum between the microwave and infrared frequency bands, which is colloquially referred to as the band gap due to the lack of materials and technological advancements. As opposed to their visible-spectrum features, metals such as gold and silver, which typically exhibit surface plasmon polaritons (SPPs), have completely different THz physical properties. 2D materials, which typically refer to single-layer materials, have been the focal point of researchers since the advent of graphene. 2D materials, for example, graphene, perovskite, and MoS2 (TMDs), provide a ground-breaking stage to control the propagation, modulation, and detection of THz waves. Moreover, 2D materials can enable the propagation of SPP waves in the THz band. These materials offer a promise of a future technological revolution. Combined with other profound advantages in lightweight, mechanical flexibility, and environmental friendliness, 2D materials can be used to fabricate low-cost wearable devices. This study also reported CH3NH3PbI3 perovskite as a promising material for THz antennas for wearable applications. CH3NH3PbI3 has a high charge carrier mobility and diffusion length, indicating that this material is a potential candidate for antenna design. The attractive feature about perovskite, graphene and other 2D materials is the ultra-high specific surface areas that enable their energy band structures to be sensitive to external basing. In the literature, scientists have tested a wide range of nano-antenna designs using modelling and simulation approaches. Nano-antenna fabrication and measurement using 2D materials is still the missing piece in the THz band. The design, fabrication, and measurement of THz antennas based on 2D materials for wearable wireless communication is the primary goal of this PhD study, including designing, fabrication, and measurement. In this study, we have designed, fabricated, and measured five different designs using different materials in the THz band, which will pave the way for enabling future THz short-range wireless communication