A wirelessly-powered sensor platform using a novel textile antenna

This thesis describes the design and analysis of a novel wideband circularly-polarized textile antenna to power up a wearable wirelessly-powered sensor system operating in the 2.45 GHz ISM band (2.4-2.5 GHz) and the building of the whole system. The system is constructed using off-the-shelf components and it is shown that the wirelessly-powered sensor system is able to operate when just a few mW are transmitted from a base station at a distance over a metre. Initially, standard linearly-polarized patch antennas are used for power transmission. However, the antennas have to be aligned perfectly for the best efficiency. Subsequently, a circularly-polarized antenna is proposed for enhanced wireless-power transfer due to the freedom of orientation. A wide-slot antenna without a ground plane has been chosen for its simplicity and wide impedance band. The geometry is firstly optimized for wide impedance and 3-dB axial ratio bandwidth on FR-4. The experimental and simulation results have been studied to analyse the characteristics of such an antenna. The wideband circularly-polarized antenna is then constructed using a conductive textile and re-optimized for on-body applications. With a simple antenna geometry and only a single layer of conductive textile layer, the axial ratio and impedance bandwidths are wide enough to cover the whole 2.45 GHz ISM band with plenty of margin and are significantly wider than any other on-body circularly-polarized textile patch antennas which have been reported. The characteristics of this wideband circularly-polarized antenna under different conditions on the human body have been measured and then connected to the wirelessly-powered sensor system to demonstrate the effectiveness of power transfer to the human body

Microwave Devices for Wearable Sensors and IoT

The Internet of Things (IoT) paradigm is currently highly demanded in multiple scenarios and in particular plays an important role in solving medical-related challenges. RF and microwave technologies, coupled with wireless energy transfer, are interesting candidates because of their inherent contactless spectrometric capabilities and for the wireless transmission of sensing data. This article reviews some recent achievements in the field of wearable sensors, highlighting the benefits that these solutions introduce in operative contexts, such as indoor localization and microwave sensing. Wireless power transfer is an essential requirement to be fulfilled to allow these sensors to be not only wearable but also compact and lightweight while avoiding bulky batteries. Flexible materials and 3D printing polymers, as well as daily garments, are widely exploited within the presented solutions, allowing comfort and wearability without renouncing the robustness and reliability of the built-in wearable sensor

Integrated on-chip gallium arsenide schottky diode and antenna for application in proximity communication system

The objective of this research is to investigate the possibility of direct integration between III–V based materials of Schottky diode and planar antenna without any insertion of the matching circuit by applying direct connection through Coplanar Waveguide (CPW) structure. Gallium Arsenide (GaAs) and integrated onchip Schottky diode and antenna are considered as the promising material and device structure, to achieve such purposes. This kind of device structure should be able to function as wireless power supply as well as power detector. To achieve this objective, several basic components were studied. Firstly, the design, fabrication and characterization of individual Schottky diode and planar antenna were conducted in order to understand both Direct Current (DC) and Radio Frequency (RF) characteristics. RF signals were well detected and rectified by the fabricated Schottky diodes with the cut-off frequency of up to several tens GHz, and a stable DC output voltage was generated. The RF characteristics of planar dipole and meander antenna as a function of antenna dimension were investigated. Good return loss was obtained at the resonant frequency of the antenna. From the direct injection experiment, the conversion efficiency up to 80 % of 1 GHz signal to the diode was achieved. Then, the integrated device was evaluated by transmitting RF signal from a different planar antenna and also using a horn antenna placed at a certain distance. The irradiated signal was successfully received by the planar antenna and rectified by the integrated diode. The rectification achieved was due to enough power received by the antenna to turn on the diode (Schottky barrier height = 0.381 eV- Cr/Au metallization, turn on voltage = 0.8 V). The output voltage of several volts (V) was generated at the load which was connected in parallel to the diode. A maximum output voltage of around 0.6 V and 130 mV were generated at the load resistance for frequency of 2 GHz and 7 GHz, respectively. A closed-form equation for the conversion efficiency of the Schottky diode has been derived to analyse the diode for the high frequency rectenna. The measured results were in good agreement with calculated results with small discrepancy between them due to resistance blow up effect, effect of non-linear junction capacitance, effect of the finite forward voltage drop and the breakdown voltage of the diode. From these presented results, the proposed on-chip AlGaAs/GaAs HEMT Schottky diode and antenna seems to be a promising candidate to be used for application in proximity communication system as a wireless low power source as well as a highly sensitive RF detector device

High Data-Rate, Battery-Free, Active Millimeter-Wave Identification Technologies for Future Integrated Sensing, Tracking, and Communication Systems-On-Chip

RÉSUMÉ Pour de nombreuses applications allant de la sécurité, le contrôle d'accès, la surveillance et la gestion de la chaîne d'approvisionnement aux applications biomédicales et d'imagerie parmi tant d'autres, l'identification par radiofréquence (RFID) a énormément influencé notre quotidien. Jusqu'à présent, cette technologie émergente a été la plupart du temps conçue et développé dans les basses fréquences (en dessous de 3 GHz). D’une part, pour des applications où de courte distances (quelques centimètres) et à faible taux de communications de données sont suffisantes (même préférables dans certains cas), la technologie RFID à couplage inductif qui fonctionne à basse fréquences (LF) ou à haute fréquences (HF) fonctionne très bien et elle est largement utilisée dans de nombreuses applications commerciales. D'autre part, afin d’augmenter la distance de communication (quelques mètres), le débit de données de communication, et ainsi minimiser la taille du tag, la technologie RFID fonctionnant dans la bande d’ultra-haute fréquence (UHF) et aux fréquences micro-ondes (par exemple, 2.4 GHz) a récemment attiré beaucoup d'attention dans le milieu de la recherche et le développement. Cependant, dans ces bandes de fréquences, une bande passante disponible restreinte avec la taille du tag assez large (principalement dominée par la taille d'antenne et de la batterie dans le cas d'un tag actif) sont les principaux facteurs qui ont toujours limité l'évolution de la technologie RFID actuelle. En effet, propulser la technologie RFID dans la bande de fréquences à ondes millimétriques briserait les barrières actuelles de la technologie RFID. La technologie d’identification aux fréquences à ondes millimétriques (MMID) offre plus de bande passante, et permet également la miniaturisation de la taille du tag, car à ces bandes de fréquences, la longueur d’onde est de l’ordre de quelques millimètres, une taille comparable à la taille d’un circuit intégré. L'antenne peut donc être soit intégré sur la même puce (antenne sur puce) ou soit encapsulé dans le même boitier que le circuit intégré. En dotant le tag la capacité de récolter sans fil son énergie à partir d'un signal aux fréquences à ondes millimétriques provenant du lecteur, lui fournissant ainsi l'autonomie énergétique (ainsi éliminant la nécessité d'une batterie et en même temps permettant la miniaturisation du tag), il devient alors possible d'intégrer entièrement tout le tag MMID sur une seule puce y compris les antennes, ce qui aboutira à la mise au point d’une nouvelle technologie miniature (μRFID) fonctionnant à la bande de fréquences à ondes millimétriques.----------ABSTRACT For countless applications ranging from security, access control, monitoring, and supply chain management to biomedical and imaging applications among many others, radio frequency identification (RFID) technology has tremendously impacted our daily life. So far, this ever-needed and emerging technology has been mostly designed and developed at low RF frequencies (below 3-GHz). For many practical applications where short-range (few centimeters) and low data-rate communications are sufficient and in some cases even preferable, inductively coupled RFID systems that operate over either low-frequency (LF) or high-frequency (HF) bands have performed quite well and have been widely used for practical and commercial applications. On the other hand, in the quest for a longer communication range (few meters), relatively high data-rate and smaller antenna size RFID systems operating over ultra-high frequency (UHF) and microwave frequency bands (e.g., 2.4-GHz) have recently attracted much attention in the research and development community. However, over these RF bands, a restricted available bandwidth together with an undesired tag size (mainly dominated by its off-chip antenna size and battery in the case of active tag) are the main factors that have been limiting the evolution of today’s RFID technology. Indeed, propelling RFID technology into millimeter-wave frequencies opens up new applications that cannot be made possible today.Millimeter-wave identification (MMID) technology is set out to exploit significantly larger bandwidth and smaller antenna size. Over these frequency bands, an effective wavelength is in the order of a few millimeters, hence close to a typical semiconductor (CMOS) die size. The antenna, therefore, may either be integrated on the same chip (antenna-on-chip – AoC) or embedded in the related package (antenna-in-package – AiP). In addition, by equipping the tag with the capability to wirelessly harvest its energy from an incoming millimeter-wave signal, thereby providing energy autonomy without the need of a battery and at the same time allowing miniaturization, it becomes possible to integrate the entire MMID tag circuitry on a single chip. Furthermore, the timely MMID concept is fully compatible with upcoming and future applications of millimeter-wave technology in wireless communications which are being discussed and developed worldwide in research and development communities, such as the internet of things (IoT), 5G, autonomous mobility, μSmart sensors, automotive RADAR technologies, etc

Antenna and rectifier designs for miniaturized radio frequency energy scavenging systems

With ample radio transmitters scattered throughout urban landscape, RF energy scavenging emerges as a promising approach to extract energy from propagating radio waves in the ambient environment to continuously charge low power electronics. With the ability of generating power from RF energy, the need for batteries could be eliminated. The effective distance of a RF energy scavenging system is highly dependent on its conversion efficiency. This results in significant limitations on the mobility and space requirement of conventional RF energy scavenging systems as they operate only in presence of physically large antennas and conversion circuits to achieve acceptable efficiency. This thesis presents a number of novel design strategies in the antenna and rectifier designs for miniaturized RF energy scavenging system. In the first stage, different energy scavenging systems including solar energy scavenging system, thermoelectric energy scavenging system, wind energy scavenging system, kinetic energy scavenging system, radio frequency energy scavenging system and hybrid energy scavenging system are investigated with regard to their principle and performance. Compared with the other systems, RF energy scavenging system has its advantages on system size and power density with relatively stable energy source. For a typical RF energy scavenging system, antenna and rectifier (AC-DC convertor) are the two essential components to extract RF energy and convert to usable electricity. As the antenna occupies most of the area in the RF energy scavenging system, reduction in antenna size is necessary in order to design a miniaturized system. Several antennas with different characteristics are proposed in the second stage. Firstly, ultra-wideband microstrip antennas printed on a thin substrate with a thickness of 0.2 mm are designed for both half-wave and full-wave wideband RF energy scavenging. Ambient RF power is distributed over a wide range of frequency bands. A wideband RF energy scavenging system can extract power from different frequencies to maximize the input power, hence, generating sufficient output power for charging devices. Wideband operation with 4 GHz bandwidth is obtained by the proposed microstrip antenna. Secondly, multi-band planar inverted-F antennas with low profile are proposed for frequency bands of GSM 900, DCS 1800 and Wi-Fi 2.4 GHz, which are the three most promising frequency bands for RF energy scavenging. Compared with previous designs, the triple band antenna has smaller dimensions with higher antenna gain. Thirdly, a novel miniature inverted-F antenna without empty space covering Wi-Fi 2.4 GHz frequency band is presented dedicated for indoor RF energy scavenging. The antenna has dimensions of only 10 × 5 × 3.5 mm3 with appreciable efficiency across the operating frequency range. In the final stage, a passive CMOS charge pump rectifier in 0.35 μm CMOS technology is proposed for AC to DC conversion. Bootstrapping capacitors are employed to reduce the effective threshold voltage drop of the selected MOS transistors. Transistor sizes are optimized to be 200/0.5 μm. The proposed rectifier achieves improvements in both power conversion efficiency and voltage conversion efficiency compared with conventional designs. The design strategies proposed in this thesis contribute towards the realization of miniaturized RF energy scavenging systems

Miniaturized Microwave Devices and Antennas for Wearable, Implantable and Wireless Applications

This thesis presents a number of microwave devices and antennas that maintain high operational efficiency and are compact in size at the same time. One goal of this thesis is to address several miniaturization challenges of antennas and microwave components by using the theoretical principles of metamaterials, Metasurface coupling resonators and stacked radiators, in combination with the elementary antenna and transmission line theory. While innovating novel solutions, standards and specifications of next generation wireless and bio-medical applications were considered to ensure advancement in the respective scientific fields. Compact reconfigurable phase-shifter and a microwave cross-over based on negative-refractive-index transmission-line (NRI-TL) materialist unit cells is presented. A Metasurface based wearable sensor architecture is proposed, containing an electromagnetic band-gap (EBG) structure backed monopole antenna for off-body communication and a fork shaped antenna for efficient radiation towards the human body. A fully parametrized solution for an implantable antenna is proposed using metallic coated stacked substrate layers. Challenges and possible solutions for off-body, on-body, through-body and across-body communication have been investigated with an aid of computationally extensive simulations and experimental verification. Next, miniaturization and implementation of a UWB antenna along with an analytical model to predict the resonance is presented. Lastly, several miniaturized rectifiers designed specifically for efficient wireless power transfer are proposed, experimentally verified, and discussed. The study answered several research questions of applied electromagnetic in the field of bio-medicine and wireless communication.Comment: A thesis submitted for the degree of Ph

Düşük güçte çalışan sensörler i̇çi̇n bi̇r radyo frekansı enerji̇ hasatlayıcı devre tasarımı ve geli̇şti̇ri̇lmesi̇

This thesis presents a systematic design and implementation of a rectenna. As a beginning, a receiving antenna is proposed. In the design of the receiving antenna, a fractal topology is utilized to widen the antenna bandwidth. Moreover, a rectifier circuit with a proposed dualband matching technique is realized to aggregate the DC power. Ultimately, the broadband fractal antenna and the proposed dual-band rectifier circuit have been assembled to realize the rectenna. In addition, a simple RF spectrum study and a field measurement are conducted to obtain a better understanding of the available electric field density in the Middle East Technical University–Northern Cyprus Campus. Finally, the energy harvesting capability of the proposed rectenna has been verified in both controlled environment (laboratory) and ambient. As a result of the laboratory measurements, the proposed rectenna yields the highest RF-toDC conversion efficiency of 51.9% when the total power density of the two tone signal is 11.1 µW/cm2 . As a result of the ambient measurements, the proposed rectenna features an openvoltage in the range of 195–417 mV in the ambient when the highest electric field densities are 4.137 V/m and 1.818 V/m from the standards of GSM-900 and 3G (UMTS), respectivelyBu tez, bir dogrultucu antenin sistematik tasarımını ve uygunlamasını sunmaktadır. İlk olarak, alıcı antenin bant genişligini arttırmak için fraktal topoloji ile tasarımına yer verilir. Bunun yanında, önerilen çift bantlı empedans uyumlaştırma özelligine sahip bir doğrultucu devresinin tasarımı ele alınır. Son olarak, geniş bantlı alıcı anten ile önerilen dogrultucu devre enerji hasatlayıcı devreyi gerçekleştirmek için birleştirilir. Bunlara ek olarak, Orta Dogu Teknik Üniversitesi Kuzey Kıbrıs Kampüsü’ndeki mevcut elektriksel alan yogunluğunun belirlen mesi için yapılan ölçümler ve sonuçları sunulur. Önerilen dogrultucu anten hem laboratu varda hem de dış ortamda bulunan RF sinyalleri ile test edilir. Laboratuvar ölçümlerinin sonucunda, dogrultucu antenin, iki ton RF sinyalinden gelen ve toplam güç yoğunluğunun 11.1 µW/cm2 oldugu bir test düzeneğinde, sağlayabildiği en yüksek dönüşüm verimliliği % 51.9 olarak kaydedilmiştir. Dış ortamdaki ölçümler sonucunda, dogrultucu antenin elektriksel alan yogunluklarının 4.137 V /m ile 1.818 V/m arasında degiştiği bir dış ortamda, 195 mV ile 417 mV arasında degişen yüksüz çıkış voltajı sağladığı kaydedilmiştir.M.S. - Master of Scienc

Antenna Designs for 5G/IoT and Space Applications

This book is intended to shed some light on recent advances in antenna design for these new emerging applications and identify further research areas in this exciting field of communications technologies. Considering the specificity of the operational environment, e.g., huge distance, moving support (satellite), huge temperature drift, small dimension with respect to the distance, etc, antennas, are the fundamental device allowing to maintain a constant interoperability between ground station and satellite, or different satellites. High gain, stable (in temperature, and time) performances, long lifecycle are some of the requirements that necessitates special attention with respect to standard designs. The chapters of this book discuss various aspects of the above-mentioned list presenting the view of the authors. Some of the contributors are working strictly in the field (space), so they have a very targeted view on the subjects, while others with a more academic background, proposes futuristic solutions. We hope that interested reader, will find a fertile source of information, that combined with their interest/background will allow efficiently exploiting the combination of these two perspectives

Recent Advances in Antenna Design for 5G Heterogeneous Networks

The aim of this book is to highlight up to date exploited technologies and approaches in terms of antenna designs and requirements. In this regard, this book targets a broad range of subjects, including the microstrip antenna and the dipole and printed monopole antenna. The varieties of antenna designs, along with several different approaches to improve their overall performance, have given this book a great value, in which makes this book is deemed as a good reference for practicing engineers and under/postgraduate students working in this field. The key technology trends in antenna design as part of the mobile communication evolution have mainly focused on multiband, wideband, and MIMO antennas, and all have been clearly presented, studied and implemented within this book. The forthcoming 5G systems consider a truly mobile multimedia platform that constitutes a converged networking arena that not only includes legacy heterogeneous mobile networks but advanced radio interfaces and the possibility to operate at mm wave frequencies to capitalize on the large swathes of available bandwidth. This provides the impetus for a new breed of antenna design that, in principle, should be multimode in nature, energy efficient, and, above all, able to operate at the mm wave band, placing new design drivers on the antenna design. Thus, this book proposes to investigate advanced 5G antennas for heterogeneous applications that can operate in the range of 5G spectrums and to meet the essential requirements of 5G systems such as low latency, large bandwidth, and high gains and efficiencies

Applications of Additive Manufacturing Technologies to Ambient Energy Harvesters for Microwave and Millimeter-Wave Autonomous Wireless Sensing Networks and 3D Packaging Integration

The objectives of my researches are developing new RF and mm-wave energy harvester topologies and realizing them with new additive manufacturing fabrication processes. The proposed energy harvester topologies are utilized to achieve energy-autonomous wireless sensing networks for 5G communication and IoT solutions. The developed additive manufacturing fabrication process is adopted to realize not only energy harvesters but also mm-wave IC packaging process. Ambient energy harvesting techniques collect ambient energy such as solar, RF, heat, and vibration and convert them into DC power sources to support the energy requirement of electronics. Since the energy is provided autonomously and constantly, maintenance or replacement for the batteries inside wireless electronics is not necessary resulting in enormous cost reduction. The researches of energy harvester focus on three categories, new topologies to enhance the performances, increased harvested power levels, and applied energy harvester to find new killer applications. This work proposes new designs and improvements in all three categories. Various proof-of-concept backscattered sensing systems with integrated RF energy harvesters for 5G and IoT applications are demonstrated. In this research, high-efficiency and broadband rectifiers are proposed to support high-performance rectifications as well as increase harvested energy. New topologies to utilize both DC and harmonics are demonstrated to increase the reading range of on-body wireless sensing networks. Furthermore, energy-autonomous microfluidic sensing systems are demonstrated to unleash the potential of microfluidic applications. 5G energy harvester is proposed and integrated inside the multi-layered additive manufacturing IC packages to achieve fully-functional SiP modules. While determining the fabrication methods, low-cost, fast-prototyping, and scalable methods with great material and structural flexibilities are preferable, and thus, additive manufacturing technologies including inkjet printing, 3D printing, and glass semi-additive patterning process are adopted. This research utilizes inkjet-printed masks, substrates, and metal traces to simplify the conventional fabrication process. The new low-loss inkjet-printable ink is developed to push the additive manufacturing technologies to mm-wave ranges. The flexible 3D-printed materials are characterized and used for wearable sensor designs, microfluidic channels, and flexible packaging topologies. The 3D features are included inside the IC packages to achieve high-performance multi-layer packaging structures with shorter lengths, lower loss, and smaller parasitics. The high-precision glass semi-additive patterning process is used to realized AiP and SiP designs with great performances. Furthermore, through combining inkjet and 3D printing, this work proposes a fast, cost-effective, scalable, and environmentally-friendly fabrication process for various high-performance and compact antenna designs, microwave/mm-wave components, microfluidic channels, RF energy harvesters, and SiP designs. In summary, this work utilizes additive manufacturing processes to realize various innovative topologies of energy harvesters to harvest more power and achieve higher rectification efficiency with smaller sizes. Additive manufacturing processes and energy harvesting techniques are also used to demonstrate new applications including the first on-body long-range sensing network, the first energy-autonomous long-range microfluidic sensing system, and the first fully-functional energy-autonomous 5G SiP module design. The proposed topologies are suitable for smart cities, smart skin, and IoT applications.Ph.D