Advanced Trends in Wireless Communications

Physical limitations on wireless communication channels impose huge challenges to reliable communication. Bandwidth limitations, propagation loss, noise and interference make the wireless channel a narrow pipe that does not readily accommodate rapid flow of data. Thus, researches aim to design systems that are suitable to operate in such channels, in order to have high performance quality of service. Also, the mobility of the communication systems requires further investigations to reduce the complexity and the power consumption of the receiver. This book aims to provide highlights of the current research in the field of wireless communications. The subjects discussed are very valuable to communication researchers rather than researchers in the wireless related areas. The book chapters cover a wide range of wireless communication topics

Solid State Circuits Technologies

The evolution of solid-state circuit technology has a long history within a relatively short period of time. This technology has lead to the modern information society that connects us and tools, a large market, and many types of products and applications. The solid-state circuit technology continuously evolves via breakthroughs and improvements every year. This book is devoted to review and present novel approaches for some of the main issues involved in this exciting and vigorous technology. The book is composed of 22 chapters, written by authors coming from 30 different institutions located in 12 different countries throughout the Americas, Asia and Europe. Thus, reflecting the wide international contribution to the book. The broad range of subjects presented in the book offers a general overview of the main issues in modern solid-state circuit technology. Furthermore, the book offers an in depth analysis on specific subjects for specialists. We believe the book is of great scientific and educational value for many readers. I am profoundly indebted to the support provided by all of those involved in the work. First and foremost I would like to acknowledge and thank the authors who worked hard and generously agreed to share their results and knowledge. Second I would like to express my gratitude to the Intech team that invited me to edit the book and give me their full support and a fruitful experience while working together to combine this book

Microelectromechanical Systems and Devices

The advances of microelectromechanical systems (MEMS) and devices have been instrumental in the demonstration of new devices and applications, and even in the creation of new fields of research and development: bioMEMS, actuators, microfluidic devices, RF and optical MEMS. Experience indicates a need for MEMS book covering these materials as well as the most important process steps in bulk micro-machining and modeling. We are very pleased to present this book that contains 18 chapters, written by the experts in the field of MEMS. These chapters are groups into four broad sections of BioMEMS Devices, MEMS characterization and micromachining, RF and Optical MEMS, and MEMS based Actuators. The book starts with the emerging field of bioMEMS, including MEMS coil for retinal prostheses, DNA extraction by micro/bio-fluidics devices and acoustic biosensors. MEMS characterization, micromachining, macromodels, RF and Optical MEMS switches are discussed in next sections. The book concludes with the emphasis on MEMS based actuators

Laminat-Basierte Integrationsplattformen für Millimeterwellen-RoF-Photodioden-Module

This thesis investigates the potential offered by cost-effective printed circuit technology (PCT) for the packaging of mm-wave photodiode (PD) modules, as an alternative to the commonly used integration approaches based on thin/ thick-films or co-fired ceramics. We will therefore analyze the limitations imposed by this technology, focusing on the loss mechanisms and the theoretical frequency limits due to the material properties of the laminates and the RF circuitry concepts, as well as limitations imposed by the resolution and tolerances achievable in the printed circuit board (PCB) manufacturing processes. For the RF circuitry design, we will investigate characteristics and performances of traditional planar transmission lines (PTL), in particular microstrips and grounded coplanar waveguides (GCPW), and innovative substrate integrated waveguides (SIW). We will show that via holes play a fundamental role in the RF circuitry design, as they ultimately decide the highest possible frequency, independently of other parameters like conductor and dielectric loss, or etching inaccuracies. In fact, it is found that they are vital to guarantee a correct functioning of both GCPW and SIW, by avoiding board resonances and interferences between different lines. We will show that the current PCB via-hole technology allows the development of circuits working up to at least the upper limit of the W-band. As conventional microstrips are subject to higher radiation in the mm-wave region, GCPWs will be preferred for practical applications, also by virtue of their other practical advantages, such as easily accessible ground planes, increased design freedom, and extended impedance range. We will thus introduce the first concept of mm-wave PD modules with rectangular waveguide (WR) output for E-band Radio-over-Fiber (RoF) applications based on PCT integration boards. A particular feature of the proposed integration approach, is that a photonic transmitter can conveniently be assembled without any mechanical modifications of the WR, using standard off-the-shelf WR components, therefore simplifying the assembly process and reducing the cost of the module. We will also show that the availability of laminates with low moisture absorption as dielectric carrier furthermore opens up the possibility to develop quasi-hermetic packages without the need of dedicated radomes to seal the WR opening. The developed PD module will be used in mm-wave RoF demonstrators in order to prove the suitability of our approach for the development of commercial communication systems: We will be able to show a successful, error-free, 1-Gb/s, wireless connectivity in the 70-GHz communication band, with a power penalty limited to 1.5 dB. We will also present several additional prototypes, which include dedicated, on-board, biasing circuits, to allow integration of in-house-developed PDs and commercial amplifiers, and other solutions to reduce the loss of the signal power. In order to overcome the shortcomings of microstrips and GCPWs, such as unwanted radiation and increased power dissipation due to high current densities, we will then introduce for the first time the PCB SIW in the packaging of mm-wave photonic transmitters. The properties and advantages of this innovative transmission line in terms of low loss and high integration will be investigated and assessed, showing that its unique configuration allows a superior control of radiation and interferences, and drastically reduces losses. This suggests its use in all mm-wave systems where long on-board interconnects are required. A new integration approach for the development of quasi-hermetic PD modules with in-package antennas based on PCB SIW will thus be presented, focusing in particular on non-directive data distribution systems. It will be shown that compact, low-loss, and quasi-hermetic packaging solutions can conveniently be designed making use of the PCB SIW. We will furthermore introduce innovative GCPW-to-SIW transitions necessary for the integration of PDs on SIW platforms. Theoretically predicted performances will be compared with experimentally determined performances for a specifically optimized 60-GHz band GCPW-to-SIW transition. Also, the design and optimization of mm-wave antennas for indoor 60 GHz RoF systems will be presented, testing their performance against PCB manufacture inaccuracies. Finally, we will show an example of a fully characterized integration platform for PD modules, confirming the suitability of PCB SIW for the development of future, low-loss, and cost-effective photonic RoF transmitters.Diese Arbeit untersucht das Potenzial kostengünstige Leiterplattentechnik (PCT) für das Packaging von Millimeter-Wellen-Photodioden (PD) als Alternative zu den üblicherweise verwendeten Dünn-/ Dickschicht-Substraten oder co-fired Keramiken einzusetzen. Zunächst werden die physikalischen Grenzen dieser PCT-Technologie hinsichtlich eines Einsatzes bei höchsten Frequenzen untersucht. Die materialbedingten Verlustwinkel im Millimeter-Wellen-Bereich aber auch Abstrahlverluste im Zusammenhang mit verschiedenen planaren Schaltungs¬konzepten werden sowohl theoretisch als auch experimentell untersucht. Zum Einsatz kommen hierbei neben konventionellen planaren Übertragungsleitungen (PTL), wie Mikrostreifen und Grounded-Coplanar-Waveguides (GCPW), auch innovative Substrat-Integrierte-Wellenleiter (SIW). Weiterhin wird der Einfluss prozessbedingter Parameter, wie die minimal erreichbare Strukturgröße sowie Fertigungs¬toleranzen, auf das Hochfrequenzverhalten analysiert. Die Arbeit wird zeigen, dass Durchkontaktierungen (engl. Via Holes) eine fundamentale Rolle spielen. Unabhängig von anderen Einflussgrößen wie den dielektrischen Verlusten, den Abstrahlverlusten oder Fertigungstoleranzen begrenzt die minimal erreichbare Strukturgröße der Vias das Hochfrequenz¬verhalten der PCT-Technologie. Es wird theoretisch und experimentell nachgewiesen, dass die Vias für GCPW und SIW auf PCT-Technologie erforderlich sind, um geringe Ausbreitungsverluste zu gewährleisten, sowie um Resonanzen im Übertragungsverhalten und elektrischen Überkoppeln zwischen benachbarten Leitungen zu unterdrücken. Die Arbeit zeigt, dass die aktuelle PCB-Technologie die Entwicklung von planaren Hochfrequenz-Schaltungen erlaubt, die bis zur oberen Grenze des W-Bands (ca. 110 GHz) anwendbar sind. Da Mikrostreifenleitungen bekanntermaßen erhöhte Abstrahlverluste im Millimeterwellen-Bereich aufweisen, werden für technologische Realisierungen GCPWs vorgezogen. GCPW bieten gegenüber Mikrostreifenleitungen auch weitere Vorteile, wie leicht zugängliche Erdungsebenen, eine erhöhte Gestaltungsfreiheit und einen deutlich erweiterten Abstimmbereich der Leitungs-Impedanz. Basierend auf der PCT-Technologie und einer planaren GCPW-Schaltung wird im Folgenden ein neuartiger Ansatz für die Anbindung von hochfrequenten InP-basierten Photodioden-Chips an einen Rechteckhohlleiter entwickelt. Ein besonderes Merkmal des in dieser Arbeit vorgeschlagenen Integrationsansatzes besteht darin, dass sich das Photodioden-Modul ohne eine mechanische Modifikation des Hohlleiters realisieren lässt, was hinsichtlich Montageprozess und -kosten einen deutlichen Vorteil darstellt. Die Arbeit zeigt auch, dass die Verwendung von Laminaten mit geringer Feuchtigkeitsaufnahme weiterhin die Möglichkeit eröffnet, quasi-hermetische Module ohne die sonst erforderlichen Radome zu realisieren. Da eine wesentliche Anwendung für solche hochfrequenten Photodioden-Module im Bereich der Funkkommunikation und speziell für die Entwicklung von Punkt-zu-Punkt-Funkverbindungen im E-Band (60-90 GHz) liegt, konzentriert sich diese Arbeit auf die Entwicklung einer PCT-Integrationstechnologie für E-Band-Photodioden-Module mit WR-12 Hohlleiter. Die Arbeit beschreibt das Design und die Herstellung der GCPW-PCT-Schaltung. Die theoretisch simulierten Streuparameter der GCPW-PCT-Schaltung werden mit experimentellen Werten verglichen, bevor im Anschluss näher auf die erfolgreiche technologische Realisierung eines Prototyp-Photodioden-Moduls mit WR-12-Hohlleiterausgang eingegangen wird. Die Funktionalität des entwickelten PD-Moduls wird durch Einsatz in einer 70-GHz-Funkstrecke nachgewiesen. Es gelingt die Funkübertragung eines 1-Gbit/s-Datensignals im regulierten 70-GHz-Frequenzbereich (71-76 GHz). Die Arbeit zeigt im Anschluss weitere Prototypen, welche die Integration von hausintern entwickelten Photodioden und kommerziellen RF-Verstärkern erlauben, sowie Lösungen zur Reduzierung des Signalleistungsverlusts. Obwohl die verwendeten GCPW im Vergleich zu Mikrostreifenleitungen geringere Abstrahlverluste aufweisen, kommt es bei hohen Frequenzen doch zu einer unerwünschten Dämpfung durch Strahlungs- und ohmsche Verluste aufgrund der hohen Stromdichten in der GCPW-Schaltung. Zur weiteren Reduzierung dieser Verluste werden in dieser Arbeit daher erstmalig SIW-PCB-Schaltungen für die Integration von Millimeterwellen-Photodioden vorgeschlagen und entwickelt. Die Vorteile dieser innovativen Leitungsstruktur hinsichtlich der elektrischen Dämpfung im Millimeterwellen-Bereich werden theoretisch und experimentell untersucht. Es kann gezeigt werden, dass die SIW-PCT gegenüber den GCPW-PCT signifikant geringere Verluste aufweisen, was insbesondere für den Einsatz in planaren Hochfrequenz-Schaltungen mit vergleichsweise langen Verbindungsleitungen vorteilhaft ist. Die Arbeit präsentiert eine neue Integrationstechnologie auf Basis planarer SIW-PCB-Schaltungen für quasi-hermetische PD-Module mit In-Package-Antennen. Es werden kompakte, verlustarme und quasi-hermetische SIW-basierte Lösungen für 60-GHz-PD-Module hergestellt und experimentell untersucht. Abschließend wird die Eignung der SIW-PCB-Technologie für die Entwicklung zukünftiger, verlustarmer und kostengünstiger photonischer Millimeter-Wellen-Funktransmitter diskutiert

Photodetectors

In this book some recent advances in development of photodetectors and photodetection systems for specific applications are included. In the first section of the book nine different types of photodetectors and their characteristics are presented. Next, some theoretical aspects and simulations are discussed. The last eight chapters are devoted to the development of photodetection systems for imaging, particle size analysis, transfers of time, measurement of vibrations, magnetic field, polarization of light, and particle energy. The book is addressed to students, engineers, and researchers working in the field of photonics and advanced technologies

Desenho de antenas para sensores passivos em materiais não convencionais

Doutoramento em Engenharia EletrotécnicaMotivado pela larga expansão dos sistemas RFID e com o desenvolvimento do conceito de Internet das Coisas, a evolução no desenho e métodos de produção de antenas em suportes de materiais alternativos tem tido uma exploração intensiva nos últimos anos. Isto permitiu, não só o desenvolvimento de produtos no campo da interação homem-máquina, mas também tornar estes produtos mais pequenos e leves. A procura de novas técnicas e métodos para produzir eletrónica impressa e antenas em materiais alternativos e, portanto, uma porta aberta para o aparecimento de novas tecnologias. Isto aplica-se especialmente no mercado dos sensores, onde o peso, o tamanho, o consumo energético, e a adaptabilidade a diversos ambientes, têm grande relevância. Esta tese foca-se no desenvolvimento de antenas com suporte em materiais não convenvionais, como os já testados papel e têxteis, mas também na exploração de outros, desconhecidos do ponto de vista eléctrico, como a cortiça e polímeros biodegradáveis usados em impressão 3D. Estes materiais são portanto usados como substrato, ou material de suporte, para diversas antenas e, como tal, as propriedades electromagnéticas destes materiais têm de ser determinadas. Assim, e apresentado neste documento uma revisão de métodos de caracterização de materiais, bem como a proposta de um método baseado em linhas de trasmissão impressas, e a respectiva caracterização electromagnética de diversos materiais. Além disso, são propostos desenhos de antenas para diversos cenários e aplicações utilizando os materiais anteriormente mencionados. Com esta tese concluiu-se que a utilização de materiais alternativos e hoje uma realidade e os resultados obtidos são muito encorajodares para o desenvolvimento de um conjunto de sensores para aplicações RFID com uma grande capacidade de integração.The advancement of the design and fabrication of antennas using textiles or paper as substrates has rapidly grown motivated by the boom of RFID systems and the developing concept of the Internet of Things. These advancements have allowed, not only the development of products for manmachine interaction, but also to make these products smaller and lighter. The search for new techniques and methods to produce printed electronics and antennas in alternative materials is therefore an open door for new technologies to emerge. Especially in the sensors market, where weight, size, power consumption and the adaptability to the target application, are of great importance. This thesis focuses on the development of antenna design approaches with alternative materials, such as the already tested paper and textiles, but also others relatively unknown, such as cork and biodegradable polymers used in 3D printing. These materials are applied to act as substrates, or support structures for the antennas. Therefore, their electromagnetic properties need to be determined. Due to that, a review of electromagnetic characterization methods, as well as the proposal of a custom method based on printed transmission lines, is presented in this document. Besides, several antenna designs, for di erent application scenarios, using the previously mentioned materials, are proposed. With this thesis it was proved that it is possible to develop passive sensors in di erent alternative materials for RFID applications and others, which shows great promise in the use of these materials to achieve higher integration in sensing and identi cation applications