Diss. / Cover title. From Amer. journ. of sci., v. xix, Feb., 1905.

Reproduction de : Thèse de doctorat : Génie électrique : Toulouse, INPT : 2007. / Titre provenant de l'écran-titre. Bibliogr. 52 réf.

Thesis (M.S.)--University of Missouri-Columbia, 2008. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on August 13, 2009) Includes bibliographical references.

An inductance can be simulated for microelectronics applications using semiconductor elements (e.g., the "inductance diode"), using circuits containing amplifiers, or using gyrators. The last two methods are considered in this thesis. Several "amplifier methods" have appeared in the literature; these methods are classified into integrating- or differentiatiiig-type circuits, and a differentiating-type circuit is proposed which is believed to be new. Gyrator realization methods are tabulated and compared. An "active gyrator" ("AG") is proposed as a circuit element (it has unequal gyration resistances). The AG behaves much like a gyrator; it can be used to simulate inductance, and an analysis shows that it can be used to make isolators and circulators with a power gain. Methods of realizing an AG with amplifiers are investigated, and an analysis leads to seven 2-amplifier circuits. One of these AG circuits appears "best" for inductance simulation, and this one is investigated experimentally using a transistor circuit. An extensive bibliography of the inductance simulation and gyrator literature is presented. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

As the demand for portable electronic devices increase, the need to replace off-chip discrete devices with on-chip devices is imperative. Inductors are one such passive device that is widely used in low noise amplifiers, oscillators, etc. Current on-chip spiral inductors suffer from large parasitics and area for a meager value of inductance and quality factor. The need to overcome these issues has led to the development inductors with new geometries housing magnetic cores that show an enhanced inductance compared to the air core coil. In this thesis, we discuss the design of a three-dimensional spiral inductor with a Co-Fe nanoparticle core that will be fabricated as per the process rules set by VT MT SPL. The changes in the value of the inductance, resistance, quality factor and parasitics are studied for varying number of turns of the coil, thickness of the coil, spacing between turns and different materials used as the coil. An optimum design incorporating the least parasitics and reasonable inductance is proposed. / Master of Science

La prochaine génération d’instruments pour l'observation de la polarisation du fond diffus cosmologique est particulièrement exigeante en termes de nombre de détecteurs, de qualité de la mesure et d'efficacité de remplissage du plan focal. De plus, pour détecter les modes-B de polarisation provenant de l’inflation, il faut observer le ciel avec plusieurs bandes de fréquence afin de soustraire les avant-plans. Dans ce contexte, les détecteurs à inductance cinétique (KIDs) représentent une technologie très prometteuse en raison de leur grand facteur de multiplexage et de leur facilité de réalisation, tandis que le couplage avec une antenne peut fournir des solutions multi-bandes et double-polarisation dans un design compacte. Les KIDs à éléments localisés (LEKID) couplé à une antenne développé dans cette thèse sont sensibles à la polarisation avec deux sous-bandes à 140 GHz et 160 GHz chacune avec une bande passante de 10%. L'architecture proposée utilise une antenne à fente excitée par une ligne microruban et deux filtres passe-bande vers deux résonateurs. Ces derniers sont couplés capacitivement avec l'antenne et comprennent une ligne microruban en Aluminium comme absorbeur. Cette architecture est particulièrement simple à fabriquer, sans via et ne nécessite que de deux niveaux de métallisation. La transition ne nécessite aucun dépôt de diélectrique au-dessus du résonateur, évitant ainsi les limitations de toute source de bruit due au substrat non-monocristallin (TLS). En outre, la même technique de couplage peut être appliquée à de nombreux types d'antennes excitées par une ligne microruban, ce qui permet de s'adapter aux filtres passe-bande. / Next generation telescopes for observing the Cosmic Microwave Background are demanding in terms of number of detectors and focal plane area filling efficiency. Moreover, foreground reduction in B-Mode polarimetry requires sky observation with multiple frequency bands. In this context KIDs are promising technology because of their large multiplexing rate, while antenna coupling can provide multi-band and dual-polarization solutions in compact design. The proposed polarization sensitive antenna-coupled LEKID is operating at 140 GHz and 160 GHz with a bandwidth of almost 10% for each sub-band. The design involves a microstrip excited slot antenna and two open-stub band-pass filters to direct the signal toward two resonators. These are lumped elements capacitively coupled to the antenna and include an Aluminium strip as absorber. The architecture proposed is particularly simple to fabricate, via-less and only involves two metallization levels. The transition doesn't require any dielectric deposition above the resonator, thus preventing limitations from any source of noise due to non-monocrystalline substrate (TLS). Furthermore, the same coupling technique can be applied to many types of microstrip excited antennas, which allow to accommodate band-pass filters.

Over the recent years many people have been trying to reduce the size and weight of magnetic components and thus the overall system [ 19 ]. One attempt at this is to increase the switching frequency of the system. However, this attempt has its limitations due to increased device switching losses. Device limitations usually confine this frequency to lower value than is desired. An effective approach, reducing the size and weight is to use the planar magnetics for possible integration with the power circuit and thus eliminating the associated interconnections. Planar magnetics uses the printed circuit board as the windings. This will allow the magnetic component to be implemented into the circuit. The integration of the magnetic components and power circuit will decrease the number of connections, reduce the height, and ensure the parasitic repeatability. Having external connections can cause problems in the system. In this case the system must carry a large amount of current. The connections can cause heating from resistance and inductance of the connection. The planar approach also will decrease the height of the system. This is because the planar magnetic cores have a higher surface area with a decreased height. This can reduce the height of the system by 25 %- 50 % [ 19 ]. The parasitic repeatability is also a very important factor. In many cases the typology relies on the parasitic elements for energy storage. Since, the parasitic elements are mainly a result from the geometry of the system; and the planar system has the windings made from the printed circuit board, the parasitic elements will be very consistent through the manufacturing process. For topologies that rely on the parasitic elements for soft switching, the planar design can incorporate parasitic elements with the leakage components for the soft-switching requirement. This thesis redefines the conventional term of leakage inductance as the sum of a set of lumped parasitic inductances and the transformer leakage inductance for the integrated planar magnetics and inverter power circuitry. For the conventional non-integrated transformer, either planar or non-planar, the leakage inductance is defined between two terminals of the transformer. However, for the integrated planar magnetics, the new lumped parasitic and leakage inductance should include the inverter switch and dc bus interconnections. The transformer was first designed using a closed-form solution for a known geometry with different copper thickness. The calculated leakage inductance was then verified with finite element analysis and the impedance analyzer measurement. It was found that the theoretical calculation and the finite element analysis results agreed very well, but the measurement was more than one order of magnitude higher. This prompted the study of interconnect parasitics. With geometrical structure and proper termination and lumping, a set of parasitic inductances were defined, and the results were verified with measurements of both impedance analyzer and phase-shifted modulated full-bridge inverter testing. In addition to parasitic inductance analysis, the flux distribution and associated thermal performance of the planar structure were also studied with finite element analysis. The resulting plots of flux distribution and temperature profile indicate the key locations of mechanical mounting and heat sinking. Overall the thesis covers essential design considerations in electrical, mechanical, and thermal aspects for the planar magnetics integration. / Master of Science

Thèse de doctorat : Génie électrique : Nancy 1 : 2009. / Titre provenant de l'écran-titre.

No description available.

A microfluidic-based inductance sensor operating at 1.5 GHz is presented that can detect single 4.5 μm superparamagnetic particles flowing in a microfluidic channel. The particles are detected as they pass over a micron-sized planar gold loop electrode, with a maximum signal-to-noise ratio of 26.3 dB for an 80 μm/s flow rate; the magnetic beads are simultaneously observed with microscope images. The sensor consists of a coupled-line resonator and microwave interferometric system coupled to the loop electrode that is integrated within a polydimethylsiloxane-on-glass microfluidic chip assembly. A time-averaged inductance change caused by a single particle is related to the real part of its magnetic Clausius-Mossotti factor. The effective real part of the magnetic permeability for a particular particle is estimated to be 1.13 at 1.5 GHz. The sensor detects magnetic particles in flow and does not require an external biasing magnetic field, which distinguishes it from other magnetic microparticle sensors.