The project deals with the design of a switch-mode power supply (SMPS) with a medium and high power output. The power supply uses multiphase control switching. Electric energy is converted through a series parallel LLC resonant circuit to reach the maximum efficiency with a small size and cost efficiency of the designed power supply. The semiconductor switches use ZVS (Zero Voltage Switching) on the primary side and ZCS (Zero Current Switching) on the secondary side of the converter. The design of the converter is based on the knowledge of the high power output converters (types of switching, art topologies) and resonant topologies (series resonant circuit – SRC, parallel resonant circuit – PRC and series parallel circuit –SPRC). The design of the converter was done theoreticaly and tested by using simulation program. The simulation and partial tests served to build prototype the Interleaves Converter (ILLC). The function of the converter was tested in laboratory. The laboratory results have been compared with the theoretical and the simulation results.

Nowadays the developments of power supplies in military, industrial or commercial applications are growing rapidly, not only to achieve the highest efficiency but also to focus on the size and weight minimization which are playing a major role in this area. Therefore, the research trends in dc-dc, ac-dc, dc-ac, ac-ac topologies are still continuously developing into the direction of new topologies, new control concepts, new materials and devices to achieve highest efficiency and smallest size. The cost per unit is also one of the most important points of power supplies. Also, with new control methods and new ways of manufacturing, for example, the cost per unit might be reduced. Also, a simplified control concept might help to avoid discrete circuits, especially, at low power levels. The last mentioned statement is demonstrated, for instance, by the concept of the Link-Switch of the company Power Integration where an extremely small number of components are necessary. With the target of minimization, this research work explores the possibility to replace conventional electromagnetic transformers considered as the most bulky devices in power supplies by piezoelectric transformers (PT) for innovative off-line power supplies. Several control methods for a load resonant converter focusing on class-E topology utilizing PT, were developed in order to investigate and to select an appropriate control method capable of improving the efficiency and reducing the size of the converter. Efficiency should be understood in this way as maximum reliability at minimum power losses. Different controllers were evaluated for optimizing the effect of disturbances of line and load variations. The ZVS condition for a wide input voltage range and a wide output load range can be achieved by a method called duty-cycle tracking. Further, with an improved design of the PT containing an auxiliary tap, the ZVS condition can be obtained by a method called turn-on synchronization. The controlled output voltage, current or power is achieved by a variable frequency control. Further, the dynamic modeling for open loop and closed loop of load resonant converters, focused on the class-E topology, was introduced. The transient behavior of the output voltage of the open loop against perturbations such as the input voltage change, the switching frequency change, and the output load change is treated by replacing the complete circuit of the class-E converter by simple equivalent circuit models. The results from the analysis of the open loop dynamic behavior are applied to modeling the closed loop class-E converter with several control methods. The methods of linearization for exact solution and heuristic approximation for the steady state analysis were purposed. These models of linearization were implemented with the controller in its topologies to investigate the sufficient accuracy of obtained results of the regulation. Besides, the linearization models were used to observe the stability condition of the proposed control loops. Finally, the evaluation of a well-known classical control such P, I, PI, PD, PID and a simplified controller for a fixed load application by matching an appropriate switching frequency according to the input voltage, into the load resonant converter, considering class-E topology, were presented. Also, the optimum design of the controller for a load resonant converter was discussed and derived. / Die Entwicklung von Stromversorgungen in militärischen, industriellen und kommerziellen Anwendungen nimmt bis heute tendenziell stark zu. Nicht nur zur Erzielung höchster Wirkungsgrade, sondern auch im Hinblick auf Baugrößen- und Gewichtsminimierung, welche eine vorrangige Rolle spielen, ist diese Tendenz zu verzeichnen. Diesbezüglich gehen die Forschungstrends bei DC-DC, AC-DC, DC-AC und AC-AC Topologien in Richtung neuer Topologien, neuer Regelungskonzepte, sowie neuer Materialien und Bauelemente, um den höchsten Wirkungsgrad bei kleinster Baugröße zu erreichen. Die Gerätekosten sind ebenso ein sehr wichtiger Punkt bei Stromversorgungen. Auch durch neue Regelungsmethoden und durch neue Herstellungsverfahren können die Gerätekosten beispielsweise reduziert werden. Ebenso kann ein vereinfachtes Regelungskonzept dazu verhelfen, dass diskrete Schaltungen, speziell im unteren Leistungsbereich, vermieden werden. Letzteres wird beispielsweise beim Konzept des Link-Switch der Firma Power Integration verdeutlicht, indem extern wenige Bauelemente benötigt werden. Mit dem Ziel der Miniaturisierung wird in dieser Forschungsarbeit die Möglichkeit untersucht, konventionelle elektromagnetische Transformatoren, welche in Stromversorgungen als besonders voluminös gelten, durch piezoelektrische Transformatoren (PT) bei der Herstellung innovativer Netzstromversorgungen zu ersetzen. Verschiedene Regelungsmethoden für Lastresonanzkonverter, mit dem Fokus auf eine Klasse- E-Topologie mit PT, wurden hierzu entwickelt. Dies hatte zum Ziel, ein geeignetes Regelungsverfahren zu erarbeiten und auszuwählen, welches eine verbesserte Effizienz bei reduzierter Konverter-Baugröße aufzuweisen hat. Effizienz soll hierbei verstanden werden als maximale Zuverlässigkeit bei minimalen Leistungsverlusten. Verschiedene Reglertypen wurden entworfen um die Effekte der Störungen durch Netzspannungs-und Lastvariationen regelungstechnisch zu optimieren. Die Nullspannungsschaltungsbedingung (ZVS-Bedingung) über einen weiten Bereich der Eingangspannung und einen weiten Lastbereich kann durch einen sogenannte Duty-Cycle-Nachführung mit der Frequenz erreicht werden. Weiterhin kann durch eine verbesserte Ausführung des PT auf Basis einer Hilfsanzapfung die ZVSBedingung durch eine sogenannte Einschaltsynchronisation erreicht werden. Geregelte Ausgangsspannung, Ausgangsstrom oder Ausgangsleistung werden über eine Frequenzstellung erreicht. Die dynamische Modellierung der offenen und geschlossenen Regelschleife eines Lastresonanzkonverters, wieder im Hinblick auf die Klasse-E, wird im weiteren vorgestellt. Das transiente Verhalten der Ausgangsspannung der offenen Regelschleife gegenüber Störungen durch Eingangsspannungsänderung, durch Schaltfrequenzänderung oder durch Ausgangslaständerung, wird durch den Ersatz der Klasse-E-Schaltung durch einfache Äquivalenzmodelle behandelt. Die Ergebnisse der Analyse des Verhaltens des offenenen Regelkreises werden verwendet, um den Klasse-E-Konverter mit geschlossener Regelschleife unter Verwendung verschiedener vorgestellter Regelungsmethoden zu modellieren. Methoden der Linearisierung für die exakte Lösung und für eine heuristische Approximation der statischen Analyse des eingeschwungenen Zustands werden vorgeschlagen. Diese Methoden der Linearisierung werden zusammen mit den Reglermodellen in deren jeweilige Topologie implementiert um die ausreichende Genauigkeit der erhaltenen Resultate des Regelungsverhaltens zu beurteilen. Weiterhin werden diese Linearisierungsmodelle dazu verwendet, die Stabilitätskriterien der vorgeschlagenen Regelschleife zu überwachen. Schlussendlich wird die Bestimmung der bekannten klassischen Regler (P, I, PI, PD, PID), sowie eines vereinfachten Konstantlaststellers durch geeignete Anpassung der Schaltfrequenz an die Eingangsspannung, für Lastresonanzkonverter, wieder mit Blick auf die Klasse-E, vorgestellt. Außerdem wird der optimierte Reglerentwurf für Lastresonanzkonverter diskutiert und abgeleitet.

This thesis deals with desing of serial resonant converter with regulation output voltage in full bridge configuration like alternative power switching converter with pulse width modulation. The thesis includes analysis of serial resonant converter, desing power transformer, driving circuits. The thesis concludes with the functional converter and complete technical documentation.

Nowadays the developments of power supplies in military, industrial or commercial applications are growing rapidly, not only to achieve the highest efficiency but also to focus on the size and weight minimization which are playing a major role in this area. Therefore, the research trends in dc-dc, ac-dc, dc-ac, ac-ac topologies are still continuously developing into the direction of new topologies, new control concepts, new materials and devices to achieve highest efficiency and smallest size. The cost per unit is also one of the most important points of power supplies. Also, with new control methods and new ways of manufacturing, for example, the cost per unit might be reduced. Also, a simplified control concept might help to avoid discrete circuits, especially, at low power levels. The last mentioned statement is demonstrated, for instance, by the concept of the Link-Switch of the company Power Integration where an extremely small number of components are necessary. With the target of minimization, this research work explores the possibility to replace conventional electromagnetic transformers considered as the most bulky devices in power supplies by piezoelectric transformers (PT) for innovative off-line power supplies. Several control methods for a load resonant converter focusing on class-E topology utilizing PT, were developed in order to investigate and to select an appropriate control method capable of improving the efficiency and reducing the size of the converter. Efficiency should be understood in this way as maximum reliability at minimum power losses. Different controllers were evaluated for optimizing the effect of disturbances of line and load variations. The ZVS condition for a wide input voltage range and a wide output load range can be achieved by a method called duty-cycle tracking. Further, with an improved design of the PT containing an auxiliary tap, the ZVS condition can be obtained by a method called turn-on synchronization. The controlled output voltage, current or power is achieved by a variable frequency control. Further, the dynamic modeling for open loop and closed loop of load resonant converters, focused on the class-E topology, was introduced. The transient behavior of the output voltage of the open loop against perturbations such as the input voltage change, the switching frequency change, and the output load change is treated by replacing the complete circuit of the class-E converter by simple equivalent circuit models. The results from the analysis of the open loop dynamic behavior are applied to modeling the closed loop class-E converter with several control methods. The methods of linearization for exact solution and heuristic approximation for the steady state analysis were purposed. These models of linearization were implemented with the controller in its topologies to investigate the sufficient accuracy of obtained results of the regulation. Besides, the linearization models were used to observe the stability condition of the proposed control loops. Finally, the evaluation of a well-known classical control such P, I, PI, PD, PID and a simplified controller for a fixed load application by matching an appropriate switching frequency according to the input voltage, into the load resonant converter, considering class-E topology, were presented. Also, the optimum design of the controller for a load resonant converter was discussed and derived. / Die Entwicklung von Stromversorgungen in militärischen, industriellen und kommerziellen Anwendungen nimmt bis heute tendenziell stark zu. Nicht nur zur Erzielung höchster Wirkungsgrade, sondern auch im Hinblick auf Baugrößen- und Gewichtsminimierung, welche eine vorrangige Rolle spielen, ist diese Tendenz zu verzeichnen. Diesbezüglich gehen die Forschungstrends bei DC-DC, AC-DC, DC-AC und AC-AC Topologien in Richtung neuer Topologien, neuer Regelungskonzepte, sowie neuer Materialien und Bauelemente, um den höchsten Wirkungsgrad bei kleinster Baugröße zu erreichen. Die Gerätekosten sind ebenso ein sehr wichtiger Punkt bei Stromversorgungen. Auch durch neue Regelungsmethoden und durch neue Herstellungsverfahren können die Gerätekosten beispielsweise reduziert werden. Ebenso kann ein vereinfachtes Regelungskonzept dazu verhelfen, dass diskrete Schaltungen, speziell im unteren Leistungsbereich, vermieden werden. Letzteres wird beispielsweise beim Konzept des Link-Switch der Firma Power Integration verdeutlicht, indem extern wenige Bauelemente benötigt werden. Mit dem Ziel der Miniaturisierung wird in dieser Forschungsarbeit die Möglichkeit untersucht, konventionelle elektromagnetische Transformatoren, welche in Stromversorgungen als besonders voluminös gelten, durch piezoelektrische Transformatoren (PT) bei der Herstellung innovativer Netzstromversorgungen zu ersetzen. Verschiedene Regelungsmethoden für Lastresonanzkonverter, mit dem Fokus auf eine Klasse- E-Topologie mit PT, wurden hierzu entwickelt. Dies hatte zum Ziel, ein geeignetes Regelungsverfahren zu erarbeiten und auszuwählen, welches eine verbesserte Effizienz bei reduzierter Konverter-Baugröße aufzuweisen hat. Effizienz soll hierbei verstanden werden als maximale Zuverlässigkeit bei minimalen Leistungsverlusten. Verschiedene Reglertypen wurden entworfen um die Effekte der Störungen durch Netzspannungs-und Lastvariationen regelungstechnisch zu optimieren. Die Nullspannungsschaltungsbedingung (ZVS-Bedingung) über einen weiten Bereich der Eingangspannung und einen weiten Lastbereich kann durch einen sogenannte Duty-Cycle-Nachführung mit der Frequenz erreicht werden. Weiterhin kann durch eine verbesserte Ausführung des PT auf Basis einer Hilfsanzapfung die ZVSBedingung durch eine sogenannte Einschaltsynchronisation erreicht werden. Geregelte Ausgangsspannung, Ausgangsstrom oder Ausgangsleistung werden über eine Frequenzstellung erreicht. Die dynamische Modellierung der offenen und geschlossenen Regelschleife eines Lastresonanzkonverters, wieder im Hinblick auf die Klasse-E, wird im weiteren vorgestellt. Das transiente Verhalten der Ausgangsspannung der offenen Regelschleife gegenüber Störungen durch Eingangsspannungsänderung, durch Schaltfrequenzänderung oder durch Ausgangslaständerung, wird durch den Ersatz der Klasse-E-Schaltung durch einfache Äquivalenzmodelle behandelt. Die Ergebnisse der Analyse des Verhaltens des offenenen Regelkreises werden verwendet, um den Klasse-E-Konverter mit geschlossener Regelschleife unter Verwendung verschiedener vorgestellter Regelungsmethoden zu modellieren. Methoden der Linearisierung für die exakte Lösung und für eine heuristische Approximation der statischen Analyse des eingeschwungenen Zustands werden vorgeschlagen. Diese Methoden der Linearisierung werden zusammen mit den Reglermodellen in deren jeweilige Topologie implementiert um die ausreichende Genauigkeit der erhaltenen Resultate des Regelungsverhaltens zu beurteilen. Weiterhin werden diese Linearisierungsmodelle dazu verwendet, die Stabilitätskriterien der vorgeschlagenen Regelschleife zu überwachen. Schlussendlich wird die Bestimmung der bekannten klassischen Regler (P, I, PI, PD, PID), sowie eines vereinfachten Konstantlaststellers durch geeignete Anpassung der Schaltfrequenz an die Eingangsspannung, für Lastresonanzkonverter, wieder mit Blick auf die Klasse-E, vorgestellt. Außerdem wird der optimierte Reglerentwurf für Lastresonanzkonverter diskutiert und abgeleitet.

High step-down dc/dc converters are widely adopted in a variety of areas such as industrial, automotive, and telecommunication. The 48 V power delivery system becomes increasingly popular for powering high-current and low-voltage chips. The Series-Capacitor Buck (SCB) converter doubles the duty ratio and equalizes the current between the two phases. Hard switching has hindered efforts to reduce volume via increased switching frequency, although a monolithically integrated SCB converter has boosted current density. A Series-Resonator Buck (SRB) converter is realized by adding a resonant tank in series with the series capacitor Cs. All switches turn on at zero-voltage (ZVOn), and the low-side switches turn off at zero-current (ZCOff). The design of the SRB converter includes characterizing the design variables' impacts on the converter performances and designing low-loss resonant components as the series resonator. The Series-Resonator Buck converter belongs to the class of quasi-resonant converters. Its resonant frequency is higher than the switching frequency, and its waveforms are quasi-sinusoidal. This work develops a steady-state model of the SRB converter to calculate voltage gain, component peak voltages, and resonant inductor peak current. Each switching cycle is modeled based on the concept of generalized state-space averaging. The soft-switching condition of the high-side switches is derived. The ZVS condition depends on the normalized control variable and the load condition. The gain equation models the load-dependent characteristic and the peak gain boundary. The theoretical peak voltage gain of the SRB converter is smaller than the maximum gain of the SCB converter. A smaller normalized load condition results in a larger peak voltage gain of the SRB converter. The large-signal model of the SRB converter characterizes the low-frequency behavior of the low-pass filters with the series capacitor and the high-frequency behavior of the resonant elements. A design recommendation of t_off f_r<0.5 is suggested to avoid the oscillation between the series capacitor Cs and the output inductors Lo. In other words, the off-duration of the low-side switches is less than half of 1/fr, and therefore the negative damping effect from the parallel resonant tank to the vCs response is reduced. The transfer functions of the SRB converter are presented and compared with those of the SCB converter. The series resonator brings in an extra damping effect to the response of output capacitor voltage. The understanding of the analytical relationships among the resonant tank energy, voltage gain, and component stresses was utilized to guide the converter design of the converter's parameters. A normalized load condition at √2 minimizes the stresses of the series resonator by balancing the peak energy in the resonant elements Lr and Cr. The f_s variation with voltage gain M is less than 10%. The non-resonant components C_s, L_oa, and L_ob are designed according to the specified switching ripples. The ac winding loss complicates the winding design of a resonant inductor. This work replaces the rectangular window with a rhombic window to reduce the eddy current loss caused by the fringing effect. The window ratio k_y is added as a design variable. The impacts of the design variables on the inductance, core loss, and winding loss are discussed. The air-gap length l_g is designed to control the inductance. A larger k_y design results in a short inductor length l_c and a smaller winding loss. The disadvantages include a smaller energy density design and a larger core loss due to the smaller cross-sectional area. In the design example presented in the thesis, the presence of the rhombic shape increases the gap-to-winding distance by two times, and also reduces the y-component of the magnetic field by a factor of two. The total inductor loss is reduced by 56% compared to a conventional design with a rectangular winding window while keeping the same inductance and the same inductor volume. This dissertation implements a resonator, replacing the series capacitor, in an SCB converter. The resultant SRB converter shows a 30% reduction in loss and a 50% increase in power density. The root cause of the divergence issue is identified by modeling the negative damping effect caused by resonant elements. The presented transient design guideline clears the barriers to closed-loop regulation and commercialization of the SRB converter. This work also reshapes winding windows from rectangle to rhombus which is a low-cost change that reduces magnetic loss by half. The theoretical analysis and design procedures are demonstrated in a 200 W prototype with 7% peak efficiency increase compared to the commonly used 30 W commercial SCB product. / Doctor of Philosophy / High step-down dc/dc converters are widely adopted in a variety of areas such as industrial, automotive, and telecommunication areas. The 48 V power delivery system becomes increasingly popular for powering high-current and low-voltage chips. The Series-Capacitor Buck (SCB) converter doubles the duty ratio and equalizes the current between the two phases. Hard switching has hindered efforts to reduce volume via increased switching frequency although a monolithically integrated SCB converter has boosted current density. A Series-Resonator Buck (SRB) converter is realized by adding a resonant tank in series with the series capacitor Cs. All switches turn on at zero-voltage (ZVOn), and the low-side switches turn off at zero-current (ZCOff). The challenges to designing the SRB converter include characterizing the design variables' impacts on the converter performances and designing low-loss resonant components as the series resonator. The resultant SRB converter shows a 30% reduction in loss and a 50% increase in power density. The root cause of the divergence issue is identified by modeling the negative damping effect caused by the resonant elements. The presented transient design guideline clears the barriers of closed-loop regulation and commercialization of the SRB converter. This work also reshapes winding windows from rectangle to rhombus, which is a low-cost change that reduces magnetic loss by half. The theoretical analysis and design procedures are demonstrated in a 200 W prototype with 7% peak efficiency increase compared to the commonly used 30 W commercial SCB product.

This research has its basis in developments within the field of inductive powering and wireless power transfer, WPT, and more specifically one the branch within this field, which is called magnetic resonance coupling. This principle enables efficient power transfer from a transmitting unit to a receiving unit at a distance of some times the unit diameter. The developments within magnetic resonant coupling are together with the possibilities and challenges of today’s smart textile industry the starting point to investigate a novel textile-based product concept for WPT by combining both technologies. Multiple textile samples, consisting of cotton and electrically conductive copper yarns, were produced by weaving technique, additional assembling of electronic components were performed manually and several measurements were carried out to investigate the sample characteristics and the sample performance in terms of power transfer. The produced samples showed to behave similarly to conventional inductors and were able to transfer power over some distance.

This thesis aims to bring an understanding to the silicon carbide (SiC) bipolar junction transistor (BJT). SiC power devices are superior to the silicon IGBT in several ways. They are for instance, able to operate with higher efficiency, at higher frequencies, and at higher junction temperatures. From a system point of view the SiC power device could decrease the cost and complexity of cooling, reduce the size and weight of the system, and enable the system to endure harsher environments. The three main SiC power device designs are discussed with a focus on the BJT. The SiC BJT is compared to the SiC junction field-effect transistor (JFET) and the metal-oxide semiconductor field-effect transistor (MOSFET). The potential of employing SiC power devices in applications, ranging from induction heating to high-voltage direct current (HVDC), is presented. The theory behind the state-of-the-art dual-source (2SRC) base driver that was presented by Rabkowski et al. a few years ago is described. This concept of proportional base drivers is introduced with a focus on the discretized proportional base drivers (DPBD). By implementing the DPBD concept and building a prototype it is shown that the steady-state consumption of the base driver can be reduced considerably.  The aspects of the reverse conduction of the SiC BJT are presented. It is shown to be of importance to consider the reduced voltage drop over the base-emitter junction. Last the impact of SiC unipolar and bipolar devices in series-resonant (SLR) converters is presented. Two full-bridges are designed and constructed, one with SiC MOSFETs utilizing the body diode for reverse conduction during the dead-time, and the second with SiC BJTs with anti-parallel SiC Schottky diodes. It is found that the SiC power devices, with their absence of tail current, are ideal devices to fully utilize the soft-switching properties that the SLR converters offer. The SiC MOSFET benefits from its possibility to utilize reverse conduction with a low voltage drop. It is also found that the size of capacitance of the snubbers can be reduced compare to state-of-the-art silicon technology. High switching frequencies of 200 kHz are possible while still keeping the losses low. A dead-time control strategy for each device is presented. The dual control (DuC) algorithm is tested with the SiC devices and compared to frequency modulation (FM). The analytical investigations presented in this thesis are confirmed by experimental results on several laboratory prototype converters. / <p>QC 20150529</p>

Dispositivos fotônicos têm estado continuamente no foco das pesquisas científicas, particularmente em aplicações para comunicações ópticas e sensoriamento. Por outro lado, as dimensões desses dispositivos são restringidas pelo limite de difração de Abbe. Esse limite tem se mostrado como o grande gargalo no desenvolvimento de novas tecnologias em microscopia óptica, litografia de projeção óptica, óptica integrada, e armazenamento óptico de dados, por limitar as dimensões e a capacidade de integração destes dispositivos. Felizmente, a \"plasmônica\" surgiu como um novo campo de estudo, possibilitando a superação dessa limitação por meio da propagação da luz em modos de plasmon-poláritons de superfície - SPP (Surface Plasmon Polariton). De maneira simplificada, SPPs são campos eletromagnéticos confinados em regiões menores que o comprimento de onda da luz. A geração de SPP ocorre por meio da excitação coletiva de elétrons na interface entre dois meios, metal-dielétrico, que se acoplam com a onda eletromagnética incidente. Pesquisadores logo perceberam que guias de onda baseados em SPP poderiam transportar a mesma banda de informação que um dispositivo fotônico convencional e serem tão localizados quanto dispositivos eletrônicos (elétrons têm maior capacidade de confinamento que fótons). Dessa maneira, alterando a estrutura da superfície de um metal, as propriedades dos SPPs - em particular sua interação com a luz - podem ser manipuladas, oferecendo potencial para o desenvolvimento de novos tipos de dispositivos fotônicos. Com isso, nanoestruturas capazes de guiar, dividir ou mesmo sintonizar a luz tornaram-se realidade. No presente trabalho, o fenômeno de geração de SPPs é estudado teoricamente e aplicado na modelagem de diversas estruturas de interesse científico e tecnológico, tais como filtros de cavidade ressonante e ressoadores em anel. O objetivo principal é a obtenção de estruturas capazes de filtrar ou sintonizar comprimentos de onda, minimizando as perdas ao máximo. Com isso, espera-se estender e explorar ainda mais o leque de possíveis aplicações. / Photonic devices have continuously been in the focus of scientific research, particularly for optical communications and sensing applications. On the other hand, the dimensions of these devices are well known to be limited by the Abbe\'s diffraction limit. This limit has been the major bottleneck in developing new technologies in optical microscopy, lithography projection optics, integrated optics, and optical data storage, as it limits the size and ability to integrate these devices. Fortunately, the field of \"Plasmonics\" has emerged and devices whose dimensions overcome the difraction limit have now become reality. This is possible with the propagation of light in the form of Surface Plasmon Polariton - SPP that, in a simplified way, is an electromagnetic field confined in regions smaller than the wavelength of light. SPP occurs via collective excitation of electrons at the interface between two media, metal-dielectric, as a result of the coupling with an incident electromagnetic wave. Researchers soon realized that waveguides based on SPP could carry the same band of information as that of a conventional photonic device and yet be as localized as electronic devices (electrons have a greater capacity for confinement than photons). Thus, changing the structure of the surface of a metal, the properties of SPPs - in particular its interaction with light - can be manipulated, offering potential for the development of new types of photonic devices. Thus, nanostructures capable of transferring, guiding, splitting, or even tuning the light have now become reality. In this work, the phenomenon of generation of SPPs is theoretically investigated and applied to various structures of scientific and technological interest, such as filters and cavity resonators. The main objective is to obtain structures that are able to filter or tune wavelengths, minimizing losses as much as possible. As a result, we expect to extend and explore even further the range of possible applications.

Die Lungen werden von einem oberflächenaktiven Gemisch, dem Surfactant ausgekleidet, das für die Regulation der Oberflächenspannung der Alveolen und die Immunabwehr der Lunge von Bedeutung ist. Bestandteile des Surfactants sind zu 90% Lipide und zu 10% vier durchalphabetisierte Surfactantproteine A bis D, von denen SP-A das mengenmäßig häufigste darstellt. Die Funktionen dieses Proteins liegen vermutlich in der Surfactanthomöostase und dabei im Phospholipid-Turnover der Hauptkomponente des Surfactants Dipalmitoylphosphatidylcholin (DPPC) und als Collektin in der Immunabwehr. In vitro ist die SP-A induzierte, calciumabhängige Liposomenaggregation eine charakteristische Eigenschaft des Proteins. In der vorliegenden Arbeit wurde die Wechselwirkung von SP-A mit Phospholipidliposomen mit der Resonant Mirror Spektroskopie und der Nah-Infrarot-Lichtstreuung untersucht. Durch den vergleichenden Einsatz der kinetischen Methoden ist es möglich, die Bindung von SP-A an Liposomen von der Aggregationsreaktion zu unterscheiden. Es konnte erstmals gezeigt werden, daß beide Reaktionen von mikromolaren Calciumkonzentrationen abhängig sind, die halbmaximale Reaktion erfolgt bei freien Calciumkonzentrationen < 20 µM. Die Ca2+-induzierte Interaktion zwischen SP-A und Liposomen zeigt eine hohe Kooperativität und ist durch Zugabe von Calciumchelatoren reversibel. Die Dissoziation der Liposomenbindung erfolgt schneller als der Zerfall der Aggregate (0,3 s vs. 30 s). Es sind zwei Konformationen des SP-A zu unterscheiden, eine lipidbindende Form in Gegenwart von Calcium und eine nichtbindende Form. Neben Calcium können auch mikromolare Strontium- und Bariumkonzentrationen die Konformationsänderung induzieren, Magnesium hingegen nicht. Die Liposomenbindung und nachfolgende Aggregation erfolgt bei SP-A von Rind, Ratte und Schaf in gleicher Weise in Abhängigkeit von mikromolaren Calciumkonzentrationen. Die Bindungseigenschaften des SP-A zeigen eine Abhängigkeit von der Art des verwendeten Phospholipids. Dabei zeigt sich eine "Affinität", im Sinne einer verstärkten Wechselwirkung mit DPPC, aber die postulierte Spezifität wurde in der kinetischen Analyse nicht bestätigt. SP-A interagiert bevorzugt mit Phospholipiden, die langkettige, gesättigte Fettsäureseitenketten besitzen (DPPC, Distearoylphosphatidylcholin), sowie mit Phosphatidylcholin und ähnlichen Kopfgruppen (Sphingomyelin, Phosphatidylinositol). Da neben den Kopfgruppen auch die Seitenketten bei der Erkennung durch das Protein bedeutsam sind, liegt nahe, daß die Packungsdichte der Lipidmoleküle in den Liposomen für die Interaktion wichtig ist. Die Ergebnisse werden als reversible, sequentielle Reaktionsfolge interpretiert: Diese ist ein Modell für die mögliche Wirkung von SP-A bei der Surfactanthomöostase, indem das Protein als Lipidtransporter zwischen alveolärer Hypophase und Typ-II-Pneumozyten funktioniert und erklärt, wie SP-A und Liposomen gemeinsam in die Zelle aufgenommen und auf unterschiedlichen Wegen wieder ausgeschleust werden könnten. / Surfactant protein A (SP-A) is crucial for lung function, including tubular myelin formation and lipid uptake by type II pneumocytes. Known properties of SP-A in vitro are ist Ca2+ dependent interaction with phospholipids and ist role in the aggregation of liposomes. To dissect and to analyze these processes, the SP-A was immobilized and liposome binding was measured by resonant mirror technique. Liposome aggregation was followed seperately by kinetic light scattering in suspensions. It was found that SP-A mediated binding and aggregation of liposomes depend on micromolar calcium concentrations in the range of < 20 µM, independent of the species (sheep, rat or cow) and of the phospholipid composition tested. The interaction between SP-A and liposomes shows cooperativity and reversibility. Liposomes dissociate from SP-A in < 0.3 s whereas disaggregation takes approx. 30 s. The interpretation of the results leads to a rapid and reversible reaction of three reactions: a cooperative Ca2+ dependent conformational change in SP-A, binding of Ca2+-bound SP-A to liposomes, and aggregation of the Ca2+/SP-A - bound liposomes. With palmitoyloleoylphosphatidylcholine (POPC), the complex formation proceeds two fold slower compared to DPPC, leading to a lower final equilibrium level of SP-A/lipid interaction. Regarding the phospholipid headgroups, phosphatidylinositol (PI) and sphingomyelin (SM) interact comparable to PC, whole less interaction is seen with phosphatidylethanolamine (PE) or phosphatidylserine (PS) or with phosphatidylglycerol (PG). Thus, both headgroup and fatty acid composition determine SP-A/phospholipid interaction. However, the protein has no high specificity, neither for the polar nor for the apolar moiety of phospholipids.

In this thesis, we present a new continuously variable high frequency standing wave oscillator and demonstrate its use in generating the phase locked clock signal of a digital IC. The ring based standing wave resonant oscillator is implemented with a plurality of wires connected in a mobius configuration, with a cross coupled inverter pair connected across the wires. The oscillation frequency can be modulated by coarse and fine tuning. Coarse modification is achieved by altering the number of wires in the ring that participate in the oscillation, by driving a digital word to a set of passgates which are connected to each wire in the ring. Fine tuning of the oscillation frequency is achieved by varying the body bias voltage of both the PMOS transistors in the cross coupled inverter pair which sustains the oscillations in the resonant ring. We validated our PLL design in a 90nm process technology. 3D parasitic RLCs for our oscillator ring were extracted with skin effect accounted for. Our PLL provides a frequency locking range from 6 GHz to 9 GHz, with a center frequency of 7.5 GHz. The oscillator alone consumes about 25 mW of power, and the complete PLL consumes a power of 28.5 mW. The observed jitter of the PLL is 2.56 percent. These numbers are significant improvements over the prior art in standing wave based PLLs.