New frontiers in microwave metamaterials : magnetic-free non-reciprocal devices based on angular-momentum-biasing and negative-index metawaveguides

In this work, metamaterial concepts are applied to improve the design and realization of microwave components of a new generation. Conventional radiation sources, despite the mature and efficient development over the past century, maintain fundamental limitations. Slow-wave structures, such as backward-wave oscillators and traveling-wave tubes, function on the order of several operational wavelengths, leading to bulky architectures. Cherenkov radiation-based detectors are constrained to forward propagation, where the detection or diagnostic scheme may be damaged by energetic particles. Metamaterial concepts, specifically negative-index structures, provide new opportunities for these applications. In this context, we developed a detailed design of a negative-index metamaterial conducive to microwave generation. We experimentally validated a negative-index waveguide based on patterned plates of complementary split ring resonators. The design is conducive to interaction between particles and waves; it maintains a scalable negative-index band along with a longitudinal electric field component for particle interaction. The sub-wavelength resonant nature of the metamaterial allows for a compact design. In a different field of research, there is also significant need to squeeze the dimensions of microwave components. We have developed magnet-less, non-reciprocal, microwave circulators based on angular-momentum-biasing, which allow the realization of non-reciprocal devices that do not require magnets, and therefore lead to cheaper, lighter and significantly smaller devices. Angular-momentum-biasing, theoretically proposed recently in our research group, effectively mimics the collective alignment of electron spins seen in a ferromagnetic medium under a magnetic bias. Through spatiotemporal modulation, one can generate electrical rotation, leading to strong nonreciprocal response without magnetism. We have experimentally proven the theory on lumped element circulators and proposed transmission-line variations, providing over 50 dB of isolation in a range of frequency bands. This method provides efficient, easily tunable, fully integrable, compact devices that may revolutionize the future of integrated components. We have developed rigorous design principles that not only provide guidance for designs based on desired performance metrics, but also proves the passive nature of the concept. Furthermore, we have crafted mechanisms to enhance the bandwidth performance and improve linearity.Electrical and Computer Engineerin

Miniaturised and reconfigurable planar filters for ultra-wideband applications

An increasing demand for electromagnetic spectrum has resulted from the emergence of feature-rich and faster throughputs wireless applications. This necessitates the developments of dynamic reconfigurable or multifunctional systems to better exploit the existing spectrum. Future wireless devices will be expected to communicate over several bands with various other devices in order to fine tune the services they provide to the user. Each band may require a separate RF transceiver and such modern wireless multi-band multi-mode communication systems call for high performance, highly integrated compact modules. Since the Federal Communications Commission (FCC) released the unlicensed frequency band 3.1-10.6 GHz for ultra-wideband (UWB) commercial communications, the development race for commercialising UWB technology has seen a dramatic increase around the world. The aim of this research is to develop reconfigurable planar microwave filters for ultrawideband applications. The project investigates some key design issues of reconfigurable filters, which are being observed constantly in the latest development and realisation of microwave filters. Both analytical and numerical methods are performed to construct a realistic and functional design. Two different types of frequency reconfigurability are investigated in this thesis: discrete (e.g. PIN diode, Optical switch) and continuous (e.g. varactor diode). Using the equivalent circuits and considering the direct coupled filter structure in most cases, several topologies with attractive features are developed for future communication systems. The proposed works may be broadly categorised into three sections as follows. The first section explores a square ring shape close loop resonator along with an opencircuited stub in the symmetry plane. To realise a reconfigurable frequency states within the same spectrum, an innovative approach is developed for this case. An optical or photoconductive switch, comprised of a silicon die activated using near infrared light is investigated as a substitute of PIN diode and performances are evaluated to compare the feasibilities. In addition, a in-band interference rejection technique via externally coupled Tshape resonator is shown. However, it is observed that both structures achieve significant size reductions by utilising the inner part of the resonators. To improve the filter selectivity, a convenient design approach generating a pair of transmission zeros between both passband edges and a single zero in the stop band for harmonic suppression is discussed in the second section. Moreover, the development of notched rejection bands are studied and several novel methods to create a single and multiple notched bands employing the square ring shape structure are proposed. On inspection, it is found that the notch structure can be implemented without deteriorating the filter performances. The discussions are supplemented with detailed design examples which are accompanied by theoretical, simulated and experimental results in order to illustrate the filter development process and showcase practical filter performance. The third section reveals a novel highly compact planar dual-mode resonator with sharp rejections characteristics for UWB applications. A bandwidth reconfiguring technique is demonstrated by splitting its even-mode resonance. Filter structure with the dual-mode resonator is shown to have a relatively wide tuning range, significantly low insertion loss and a constant selectivity along with frequency variations in comparison to similar published works. Finally, the earlier dual-mode structure are modified to realise a dual wideband behaviour. A detail analysis with comprehensive design procedures is outlined and a solution for controlling the frequency bandwidths independently according to the application interest is provided. In line with the previous section, experimental verification is presented to support and supplement the discussions

Advances in Filter Miniaturization and Design/Analysis of RF MEMS Tunable Filters

The main purpose of this dissertation was to address key issues in the design and analysis of RF/microwave filters for wireless applications. Since RF/microwave filters are one of the bulkiest parts of communication systems, their miniaturization is one of the most important technological challenges for the development of compact transceivers. In this work, novel miniaturization techniques were investigated for single-band, dual-band, ultra-wideband and tunable bandpass filters. In single-band filters, the use of cross-shaped fractals in half-mode substrate-integrated-waveguide bandpass filters resulted in a 37 percent size reduction. A compact bandpass filter that occupies an area of 0.315 mm2 is implemented in 90-nm CMOS technology for 20 GHz applications. For dual-band filters, using half-mode substrate-integrated-waveguides resulted in a filter that is six times smaller than its full-mode counterpart. For ultra-wideband filters, using slow-wave capacitively-loaded coplanar-waveguides resulted in a filter with improved stopband performance and frequency notch, while being 25 percent smaller in size. A major part of this work also dealt with the concept of 'hybrid' RF MEMS tunable filters where packaged, off-the-shelf RF MEMS switches were used to implement high-performance tunable filters using substrate-integrated-waveguide technology. These 'hybrid' filters are very easily fabricated compared to current state-of-the-art RF MEMS tunable filters because they do not require a clean-room facility. Both the full-mode and half-mode substrate-integrated waveguide tunable filters reported in this work have the best Q-factors (93 - 132 and 75 - 140, respectively) compared to any 'hybrid' RF MEMS tunable filter reported in current literature. Also, the half-mode substrate-integrated waveguide tunable filter is 2.5 times smaller than its full-mode counterpart while having similar performance. This dissertation also presented detailed analytical and simulation-based studies of nonlinear noise phenomena induced by Brownian motion in all-pole RF MEMS tunable filters. Two independent mathematical methods are proposed to calculate phase noise in RF MEMS tunable filters: (1) pole-perturbation approach, and (2) admittance-approach. These methods are compared to each other and to harmonic balance noise simulations using the CAD-model of the RF MEMS switch. To account for the switch nonlinearity in the mathematical methods, a nonlinear nodal analysis technique for tunable filters is also presented. In summary, it is shown that output signal-to-noise ratio degradation due to Brownian motion is maximum for low fractional bandwidth, high order and high quality factor RF MEMS tunable filters. Finally, a self-sustained microwave platform to detect the dielectric constant of organic liquids is presented in this dissertation. The main idea is to use a voltage- controlled negative-resistance oscillator whose frequency of oscillation varies according to the organic liquid under test. To make the system self-sustained, the oscillator is embedded in a frequency synthesizer system, which is then digitally interfaced to a computer for calculation of dielectric constant. Such a system has potential uses in a variety of applications in medicine, agriculture and pharmaceuticals

A built-in self-test technique for high speed analog-to-digital converters

Fundação para a Ciência e a Tecnologia (FCT) - PhD grant (SFRH/BD/62568/2009

NASA Thesaurus. Volume 2: Access vocabulary

The NASA Thesaurus -- Volume 2, Access Vocabulary -- contains an alphabetical listing of all Thesaurus terms (postable and nonpostable) and permutations of all multiword and pseudo-multiword terms. Also included are Other Words (non-Thesaurus terms) consisting of abbreviations, chemical symbols, etc. The permutations and Other Words provide 'access' to the appropriate postable entries in the Thesaurus

Active Backscattering Positioning System Using Innovative Harmonic Oscillator Tags for Future Internet of Things: Theory and Experiments

RÉSUMÉ D'ici 2020, l'Internet des objets (IoT) permettra probablement de créer 25 milliards d'objets connectés, 44 ZB de données et de débloquer 11 000 milliards de dollars d’opportunités commerciales. Par conséquent, ce sujet a suscité d’énormes intérêts de recherche dans le monde académique entier. L'une des technologies clés pour l'IoT concerne le positionnement physique intérieur précis. Le principal objectif dans ce domaine est le développement d'un système de positionnement intérieur avec une grande précision, une haute résolution, un fonctionnement à plusieurs cibles, un faible coût, un faible encombrement et une faible consommation d'énergie. Le système de positionnement intérieur conventionnel basé sur les technologies de Wi-Fi ou d'identification par radiofréquence (RFID) ne peut répondre à ces exigences. Principalement parce que leur appareil et leur signal ne sont pas conçus spécialement pour atteindre les objectifs visés. Les chercheurs ont découvert qu'en mettant en oeuvre de différents types de modulation sur les étiquettes, le radar à onde continue (CW) et ses dérivés deviennent des solutions prometteuses. Les activités de recherche présentées dans cette thèse sont menées dans le but de développer des systèmes de positionnement en intérieur bidimensionnel (2-D) à plusieurs cibles basées sur des étiquettes actives à rétrodiffusion harmonique avec une technique à onde continue modulée en fréquence (FMCW). Les contributions de cette thèse peuvent être résumées comme suit: Tout d'abord, la conception d'un circuit actif harmonique, plus spécifiquement une classe d'oscillateurs harmoniques innovants utilisée comme composant central des étiquettes actives dans notre système, implique une méthodologie de conception de signal de grande taille et des installations de caractérisation. L’analyseur de réseau à grand signal (LSNA) est un instrument émergent basé sur les fondements théoriques du cadre de distorsion polyharmonique (PHD). Bien qu'ils soient disponibles dans le commerce depuis 2008, des organismes de normalisation et de recherche tels que l’Institut national des normes et de la technologie (NIST) des États-Unis travaillent toujours à la mise au point d'un standard largement reconnu permettant d'évaluer et de comparer leurs performances. Dans ce travail, un artefact de génération multi-harmonique pour la vérification LSNA est développé. C'est un dispositif actif capable de générer les 5 premières harmoniques d'un signal d'entrée avec une réponse ultra-stables en amplitude et en phase, quelle que soit la variation de l'impédance de la charge.----------ABSTRACT By 2020, the internet of things (IoT) will probably enable 25 billion connected objects, create 44 ZB data and unlock 11 trillion US dollar business opportunities. Therefore, this topic has been attracting tremendous research interests in the entire academic world. One of the key enabling technologies for IoT is concerned with accurate indoor physical positioning. The development of such an indoor positioning system with high accuracy, high resolution, multitarget operation, low cost, small footprint, and low power consumption is the major objective in this area. The conventional indoor positioning system based on WiFi or radiofrequency identification (RFID) technology cannot fulfill these requirements mainly because their device and signal are not purposely designed for achieving the targeted goals. Researchers have found that by implementing different types of modulation on the tags, continuous-wave (CW) radar and its derivatives become promising solutions. The research activities presented in this Ph.D. thesis are carried out towards the goal of developing multitarget two-dimensional (2-D) indoor positioning systems based on harmonic backscattering active tags together with a frequency-modulated continuous-wave (FMCW) technique. Research contributions of this thesis can be summarized as follows: First of all, the design of a harmonic active circuit, more specifically, a class of innovative harmonic oscillators used as the core component of active tags in our system, involves a large signal design methodology and characterization facilities. The large signal network analyzer (LSNA) is an emerging instrument based on the theoretical foundation for the Poly-Harmonic Distortion (PHD) framework. Although they have been commercially available since 2008, standard and research organizations such as the National Institute of Standards and Technology (NIST) of the US are still working towards a widely-recognized standard to evaluate and cross-reference their performances. In this work, a multi-harmonic generation artifact for LSNA verification is developed. It is an active device that can generate the first 5 harmonics of an input signal with ultra-stable amplitude and phase response regardless of the load impedance variation

Advanced deep space communication systems study Final report

Deep space communication system requirements for period 1970 to 198

Development of superconducting thin film travelling wave parametric amplifiers

Ultra low-noise amplification is crucial for various fundamental physics platforms, including microwave/mm/sub-mm astronomy, dark matter search experiments, neutrino mass experiments, and qubit readout. Superconducting kinetic inductance travelling-wave parametric amplifiers (KITWPAs) are a recent development in amplifier technology, which are able to achieve high gain over broad bandwidth by efficiently transferring power from a strong ‘pump’ wave to a detected weak ‘signal’ wave via the wave mixing mechanisms in a non-linear medium comprising a high kinetic inductance wire. They have been experimentally verified to achieve high gain over broad bandwidth and quantum-limited noise performance with negligible heat dissipation, making them a natural successor to the current generation of semiconductor-based high electron mobility transistor (HEMT) amplifiers, which are the current standard in low-noise amplification. The elimination of the resonant architecture associated with earlier parametric amplifiers removes the narrow-band restrictions on these KITWPAs, which combined with their low heat dissipation and power requirements makes them readily scalable to arrays for large pixel count applications, such as the readout of astronomical detector arrays or qubit arrays. This thesis focuses on the development of microwave KITWPAs in the frequency range of 2-18 GHz, made from titanium nitride (TiN) superconducting transmission lines, a material chosen as it displays many of the desired characteristics for KITWPA operation, namely high resistivity, high kinetic inductance, and mechanical robustness, as well as being a commonly used material in the field of microwave kinetic inductance detectors (MKIDs). The choice in material and topology for a KITWPA device, however, is not typically discussed in the literature, hence to understand the design considerations for a KITWPA device, we commence an investigation into KITWPA material and topology choice. Based on this analysis, we present an optimised TiN KITWPA design, which was designed using a commercial 3-D electromagnetic simulator (HFSS) and a complementary python package (SuperTWPA). Although measurements of our KITWPA devices revealed unexpected losses, we were able to achieve a peak averaged gain of 5 dB with a bandwidth of ∼ 3 − 13 GHz when operating in a three-wave mixing (3WM) mode, making this, to the best of our knowledge, the first broadband gain measurement of a TiN KITWPA reported in the literature. The behaviour of the TiN film additionally points to physics beyond standard BCS theory, which could form the basis of future analysis of the microphysics of the material. We conclude our experimental work with a number of design improvements, which we believe could ultimately lead to a high-gain TiN KITWPA device. At time of writing this thesis, KITWPAs are yet to be widely used in large-scale experiments due to a number of operational obstacles. We, therefore, conclude this thesis with a number of design concepts that could provide solutions to these operational obstacles, beginning with a dual-pump KITWPA to provide wideband amplification at millimetre (mm) frequencies, before introducing a balanced KITWPA concept; a novel parallel TWPA architecture, which we demonstrate to be able solve the signal-idler contamination problem in KITWPAs and to simplify the pump injection and cancellation schemes, paving the way for the widespread operation of KITWPAs in ultra-sensitive experimental setups

NASA thesaurus. Volume 2: Access vocabulary

The Access Vocabulary, which is essentially a permuted index, provides access to any word or number in authorized postable and nonpostable terms. Additional entries include postable and nonpostable terms, other word entries, and pseudo-multiword terms that are permutations of words that contain words within words. The Access Vocabulary contains 40,738 entries that give increased access to the hierarchies in Volume 1 - Hierarchical Listing