Les travaux présentés dans ce mémoire s'inscrivent dans la thématique de la transmission d'énergie sans fil, appliquée à l'alimentation à distance de capteurs, de réseaux de capteurs et d'actionneurs à faible consommation. Cette étude porte sur la conception, la caractérisation, et la mesure d'un circuit Rectenna (Rectifying antenna) à double polarisation circulaire à 2.45 GHz, compact et à rendement de conversion RF-DC optimisé. Un outil d'analyse globale basé sur la méthode itérative a été développé et exploité pour valider la faisabilité de cette analyse. La diode Schottky a été modélisée en utilisant une impédance de surface. La rectenna à double polarisation circulaire, réalisée en technologie micro-ruban, a été validée expérimentalement. Elle est caractérisée par la rejection de la 2ème harmonique et une possibilité de recevoir les deux sens de polarisation LHCP et RHCP par l'intermédiaire de 2 accès. Le rendement mesuré avec une densité de puissance de 0.525 mW/cm² est de l'ordre de 63%, tandis que la tension DC obtenue aux bornes d'une charge optimale de 1.6 kohm est de 2.82 V / The work presented in this thesis is within the subject of wireless power transmission, power applied to the remote sensors, networks of sensors and actuators with low power consumption. This study focuses on the design, characterization, and measurement of a rectenna circuit (rectifying antenna) with dual circular polarization at 2.45 GHz, and optimisation of the conversion efficiency. A global analysis tool, based on the iterative method was developed and used to validate the feasibility of this concept by this method. The Schottky diode was modeled using surface impedance. The dual circular polarization rectenna with microstrip technology has been optimized and characterized experimentally operating at 2.45 GHz. It includes the property of harmonic rejections. Two accesses can receive either direction LHCP or RHCP sense. The conversion efficiency of 63% has been measured with a power density of 0.525 mW/cm². A DC voltage of 2.82V was measured across an optimum load of 1.6 kohm

Un des défis majeurs de l’Internet des Objets et, plus généralement, des tous les réseaux de capteurs sans fils, c’est l’alimentation de chaque nœud connecté. La solution la plus commune est d’équiper chaque dispositif d’une batterie mais cela introduit plusieurs contraintes, qui mettent en question la faisabilité de cette approche sur le long terme (durée de vie limité, couts de gestion élevé, empreinte écologique).Cette thèse développe une possible solution basée sur la transmission sans-fils de l’énergie. Un récupérateur d’énergie RF, composé d’une antenne, un redresseur haute-fréquence et un convertisseur élévateur, est présenté. Ce système permet de récupérer les ondes électromagnétiques et de produire une tension continue en sortie, qui peut être utilisé pour alimenter des microcontrôleurs ou des capteurs. L’absence d’une batterie interne augmente la flexibilité globale, surtout pour les situations où le remplacement n’est pas possible (ex. dispositifs implantés, nombre élevé de nœuds, milieux dangereux). Une étude approfondie sur les redresseur intégrés ultra-haute-fréquence de type Schottky et MOS a été mené ; plusieurs topologies ont été analysées et optimisées. De plus, l’utilisation d’un convertisseur élévateur a été envisagée, dans le but d’accroitre la tension en sortie ; une première version discrète et puis une plus compacte version intégrée, ont été abordées et testées. Ces développements ont permis d’aboutir à un récupérateur complet, potentiellement capable d’alimenter un microcontrôleur du commerce. / One of the challenges of the Internet of Things and, more in general, of every wireless sensor network is to provide electrical power to every single one of its smart nodes. A typical solution uses batteries but various major concerns reduce the long-term feasibility of this approach (limited lifetime, maintenance and replacement costs, and environmental footprint).This thesis develops a possible solution based on the wireless transmission of power. A complete RF harvester composed of an antenna, a UHF rectifier and a step-up voltage converter is presented. This system captures electromagnetic waves and converts them to a stable DC voltage to supply power to common logic circuits like microcontrollers and sensors. The lack of an internal battery provides an extended flexibility, especially when its replacement is not a viable option (ex. implanted devices, large number of nodes, dangerous environments, etc.). An in-depth study of integrated Schottky and CMOS UHF rectifiers is carried out; various topologies and optimizations are analyzed. Moreover, the use of an additional step-up converter is proposed in order to increase the system output voltage; an early discrete implementation and a final, more compact, integrated version are discussed and tested. These developments lead to a complete system capable of potentially powering an application with an off-the-shelf microcontroller.

Les systèmes électroniques sont au cœur de notre vie quotidienne, ils sont intégrés dans la plupart des objets que nous utilisons chaque jour, et dans des secteurs clés comme l’aéronautique, l’automobile, le spatial, l’électronique grand public... Les techniques d’alimentation classiques (pile ou batterie) restent difficiles à envisager dans certaines applications car, elles sont limitées en autonomie, elles nécessitent des remplacements périodiques et leur recyclage est coûteux. Afin de détourner ces contraintes, le concept de la transmission d’énergie sans fil se présente comme une alternative aux systèmes d’alimentation classiques. La récupération d'énergie électromagnétique a beaucoup attiré l'attention puisque la puissance RF est largement diffusée à partir de nombreuses ressources électromagnétiques fiables. De plus, les circuits électroniques et notamment microondes deviennent de plus en plus rapides à cause des fréquences de travail de plus en plus élevées. L’analyse fréquentielle seule ne peut répondre à un certain nombre d’interrogations dans ces circuits. Une analyse purement temporelle devient nécessaire pour résoudre et répondre à toutes les problématiques. Parmi les problèmes posés dans les circuits microondes, on s’intéresse à deux approches totalement complémentaires:• L’Intégrité du Signal qui représente le dysfonctionnement des circuits du à la distorsion des signaux. • La Compatibilité ElectroMagnétique qui est le résultat de l’encombrement des composants électroniques dans les circuits. La première approche se base sur les modèles de composants et peut prédire parfaitement la qualité des signaux pendant le placement et le routage des cartes électroniques. En revanche, il sera très difficile de mettre en évidence les causes du comportement anormal du circuit en question. La deuxième approche complémentaire de la première, et qui est l’analyse par la compatibilité électromagnétique permettra de couvrir les causes du problème tels que diaphonie (Cross Talk), rayonnement et susceptibilité des systèmes dans le but de corriger le circuit pour qu’il fonctionne correctement.La méthode de travail adoptée dans cette thèse consiste dans un premier temps à identifier les différents problèmes. Ensuite proposer des solutions via des codes de calcul existants (FDTD, FEM, MoM…) et qu’on pourra développer (2D) ou bien via des logiciels adaptés tels que Spice, Matlab, EMPro, ADS…..etc. / Electronic systems are integrated into most objects that we use every day, also in different key sectors such as, automotive, railway, spacial, defense and consumer electronics... Conventional feeding techniques remain difficult to envisage in certain applications because they are limited in their autonomy energy, and they require periodic replacements and their recycling is expensive. In this mind, the wireless power transfer is a very interesting solution, less expensive and aesthetic. This solution needs to pick up the RF power transmitted through the free space by a Rectenna and convert it to a DC voltage, to feed one or several wireless devices or to increase the operating life of batteries.The high operating frequencies makes the microwave circuits faster. Frequency analysis can’t answer a number of questions in these circuits. The introduction of the temporal analysis becomes necessary to solve and answer all the problems encountered. In fact, we are interested in two complementary approaches:• Signal integrity, which represents the malfunction of the circuits due to the distortion of the signals• ElectroMagnetic Compatibility, which is the result of the congestion of the electronic components in the circuits.• The first approach is based on component models and can perfectly predict signal quality during placement and routing of electronic boards. On the other hand, it will be difficult to highlight the causes of the abnormal behavior of the circuit. The second approach, is complementary of the first one, which is the analysis by the electromagnetic compatibility, who will allow to cover the causes of the problems such as cross talk, radiation and defined the susceptibility of this systems to work correctly.The working method adopted in this thesis consists in first identifying the various problems. Then propose solutions via existing calculation codes (FDTD, FEM, MoM ...) who can be developed or via the software such as Spice, Matlab, EMPro, ADS …Key words: Wireless power transfer, UWB systems, numerical methods, Rectenna systems, RF/DC converter, EMC analysis.

Transparent UWB antennas have been the focus of this PhD research. The use of transparent UWB antennas for stealth and energy harvesting has been the underlying applications that have given impetus to this research. Such transparent antennas being built on materials that are discreet, flexible, conformal, conductive and having the ability to provide good antenna performance on glass to serve as the ‘last mile’ link in subsequent generation communications after 4G have been the basis for this contention. UWB in this regard is able to provide the transmission and reception of high data rates and fast video transmission that is an elementary demand of even a 4G wireless communications system. The integration of UWB antennas with photovoltaic to provide integral energy harvesting solutions that will further enhance the value of the UWB system in terms of cost effectiveness and performance are thus the basis of this work. This work hence starts with the study of a transparent conductive oxide polymer, AgHT and its properties, and culminates in the development of a transparent UWB antenna, which can be integrated with photovoltaic for window glass applications on homes and buildings. Other applications such transparent antennas can find use for like on-body wireless communications in healthcare monitoring was also analysed and presented. The radar absorbing material (RAM) property of the AgHT was investigated and highlighted using CST simulation software, as no measurement facilities were available. The transparent UWB antenna in lieu of the inherent absorbent property of the AgHT material is thus able to exhibit stealth characteristics, a feature that would be much desired in military communications. Introduction of a novel method of connecting the co-axial connector to the feed of the antenna to improve gain and efficiency of transparent polymer based antennas and the development of a UWB antenna that maintains its Omni-directional characteristic instead of becoming directional on an amorphous silicon solar cell are presented as some of the contributions for this research work. Some preliminary analysis on the impact of glass on UWB antennas for video transmission and how to improve transmission is presented. The ability of the conductive part of the antenna radiator to be used as a RF and microwave harvester and how it can further add value to a transparent UWB antenna is presented by way of experimental data. Finally yet importantly, this thesis presents some insight into how transparent antennas may be used in Green Technology Buildings to provide an integrated solution for both wireless communications and energy harvesting as part of the future work. Improvement to the aesthetics of the external appearance of residential buildings through the integration of transparent satellite dish onto solar panels on rooftops is also discussed and illustrated as part of this future work.

There are various situations in which electrical energy is desired but cannot by conveniently supplied. Since the days of Hienrich Hertz and Nikola Tesla, scientists have tried to solve this problem using different methods of wireless power transfer. Today, wireless power transfer has only been commercially demonstrated at small distances through use of induction. This thesis demonstrated the transfer of wireless power at relatively large distances through radio frequencies in the development of a prototype for a commercial product - a wireless household lamp.

Kyoto University (京都大学) / 0048 / 新制・課程博士 / 博士(工学) / 甲第18992号 / 工博第4034号 / 新制||工||1621 / 31943 / 京都大学大学院工学研究科電気工学専攻 / (主査)教授 篠原 真毅, 教授 和田 修己, 教授 山川 宏 / 学位規則第4条第1項該当

The wireless transfer of power is the enabling technology for realizing a true internet-of-things. Broad sensor networks capable of monitoring environmental pollutants, health-related biological data, and building utility usage are just a small fraction of the myriad of applications which are part of an ever evolving ubiquitous lifestyle. Realizing these systems requires a means of powering their electronics sans batteries. Removing the batteries from the billions or trillions of these envisioned devices not only reduces their size and lowers their cost, but also avoids an ecological catastrophe. Increasing the efficiency of microwave-to-DC power conversion in energy-harvesting circuits extends the range and reliability of passive sensor networks. Multi-frequency waveforms are one technique that assists in overcoming the energy-harvesting circuit diode voltage threshold which limit the energy-conversion efficiency at low RF input powers typically encountered by sensors at the fringe of their coverage area. This thesis discusses a systematic optimization approach to the design of energy-conversion circuits along with multi-frequency waveform excitation. Using this methodology, a low-power 5.8 GHz rectenna showed an output power improvement of over 20 dB at -20 dBm input power using a 3-POW (power-optimized waveform) compared to continuous waveforms (CW). The resultant efficiency is the highest reported efficiency for low-power 5.8 GHz energy harvesters. Additionally, new theoretical models help to predict the maximum possible range of the next generation of passive electronics based upon trends in the semiconductor industry. These models predict improvements in diode turn-on power of over 20 dB using modern Schottky diodes. This improvement in turn-on power includes an improvement in output power of hundreds of dB when compared to CW.

The great innovations of the last century have ushered continuous progress in many areas of technology, especially in the form of miniaturization of electronic circuits. This progress shows a trend towards consistent decreases in power requirements due to miniaturization. According to the ITRS and industry leaders, such as Intel, the challenge of managing and providing power efficiency still persist as scaling down of devices continues. A variety of power sources can be used in order to provide power to low power applications. Few of these sources have favorable characteristics and can be designed to deliver maximum power such as the novel mini notched turbine used as a source in this work. The MiNT is a novel device that can be used as a feasible energy source when integrated into a system and evaluated for power delivery as investigated in this work. As part of this system, a maximum power point tracking system provides an applicable solution for capturing enhanced power delivery for an energy harvesting system. However, power efficiency and physical size are adversely affected by the characteristics and environment of many energy harvesting systems and must also be addressed. To address these issues, an analysis of mini notched turbine, a RF rectenna, and an enhanced maximum power point tracking system is presented and verified using simulations and measurements. Furthermore, mini notched energy harvesting system, RF rectenna energy harvesting system, and enhanced maximum power point tracking system are developed and experimental data analyzed. The enhanced maximum power point tracking system uses a resistor emulation technique and particle swarm optimization (PSO) to improve the power efficiency and reduce the physical size. This new innovative design improves the efficiency of optimized power management circuitry up to 7% compared to conventional power management circuits over a wide range of input power and range of emulated resistances, allowing more power to be harvested from small energy harvesting sources and delivering it to the load such as smart sensors. In addition, this is the first IC design to be implemented and tested for the patented mini notched turbine (MiNT) energy harvesting device. Another advantage of the enhanced power management system designed in this work is that the proposed approach can be utilized for extremely small energy sources and because of that the proposed work is valid for low emulated resistances. and systems with low load resistance Overall, through the successful completion of this work, various energy harvesting systems can have the ability to provide enhanced power management as the IC industry continues to progress toward miniaturization of devices and systems.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第18992号 / 工博第4034号 / 新制||工||1621(附属図書館) / 31943 / 京都大学大学院工学研究科電気工学専攻 / (主査)教授 篠原 真毅, 教授 和田 修己, 教授 山川 宏 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

No description available.