This project deals with calculation parts of complex permittivity varnish samples which is filled by nanoparticles of metal oxides. Opening of this project deals with theory of dielectric and effects in dielectric, theory of compounds and expressions in composite systems. Following topic is theory of nanoparticles and nanotechnologies and summarize adjusted results about this branch of knowledge. In practical part of work is include method which was use to make varnish samples filled by nanoparticles, prepare to measurement methods and whole results of measurement. In the end of work is analysis influence of filler particles each filler types to dielectric material and results verified mixture mathematical expressions.

The aim of this dissertation is to get to know metodology and construction of suitable electrical insertion in measurement of energy consumed by discharge. These findings will serve to scale dependings of output to frequence for surface and voluminous dielektric barrier discharge in synthetic dry air and determination of effect of humidity in air on electric characteristics of discharge.

The bachelor thesis submitted deals with properties of electro-insulating lacquer hardenable by ultraviolent radiation and temperature. Within the theoretical part a summary of electro-insulating lacquers used in electrotechnics has been elaborated. Chemical changes that take place in this material group have been described during hardening process. A method of dielectric relaxation spectroscopy specifically focused on mathematic and physical description of polarisation and conductive mechanisms taking place in the structure of the given material has been closely studied. In the experimental part a workplace for hardening and long-term exposition of lacquered samples during simultaneous effect of various climatic elements has been designed and built. The selected electric and mechanical properties have been monitored on three sets of experimental samples prepared by means of different methodical procedures. The results gained have been mathematically evaluated and physically interpreted in term of methodical procedure of hardening and different temperature of measurement.

This thesis deals with problems of electrical insulation materials based on epoxy composites used in the electronics industry. This thesis is divided into theoretical part focused on composite materials, their technological processing and diagnostics. It also describes dielectric materials, their properties and events taking place in their structure. The experimental section describes the measurement of electrical properties of samples of electrical insulating materials with different types of fillers.

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Harmonic distorted voltage waveforms can lead to excessive heat in the insulation of electrical equipment. The prospectively increasing number of power electronic devices in electrical grids requires the careful examination of the conse- quences of harmonics, which are introduced due to the operating principle of the semiconductor switches. Investigations of the thermal breakdown of solid dielectrics that may occur as a consequence of harmonic distortion on the voltage waveform of electrical grids are presented in this contribution. A thermo-electrical multi-frequency model allows the calculation of the overtemperature in the material. The calculations are confirmed by breakdown experiments of phenolic paper and epoxy resin. Generally, the additional dielectric losses due to the harmonic voltage distortion increase the possibility of exceeding the thermal equilibrium. However, modern insulation materials like the investigated epoxy resin have very low loss factors which is favourable for good thermal performance even with severely distorted voltages.

Entirely soft robots with animal-like behavior and integrated artificial nervous systems will open up totally new perspectives and applications. To produce them we must integrate control and actuation in the same soft structure. Soft actuators (e.g. pneumatic, and hydraulic) exist but electronics are hard and stiff and remotely located. We present novel soft, electronicsfree dielectric elastomer oscillators, able to drive bioinspired robots. As a demonstrator we present a robot that mimics the crawling motion of the caterpillar, with integrated artificial nervous system, soft actuators and without any conventional stiff electronic parts. Supplied with an external DC voltage, the robot autonomously generates all signals necessary to drive its dielectric elastomer actuators, and translates an in-plane electromechanical oscillation into a crawling locomotion movement. Thereby, all functional and supporting parts are made of polymer materials and carbon. Besides the basic design of this first electronic-free, biomimetic robot we present prospects to control the general behavior of such robots. The absence of conventional stiff electronics and the exclusive use of polymeric materials will provide a large step towards real animal-like robots, compliant human machine interfaces and a new class of distributed, neuron-like internal control for robotic systems.

With increasing frequency up to the THz frequency range and the desire to optimize performance of modern applications, precise knowledge of the dielectric material parameters of a substrate being used in a planar application is crucial: High performance of the desired device or circuit can often be achieved only by properly designing it, using specific values for the material properties. Especially the integration of planar devices for very broadband applications at high frequencies often demands specific dielectric properties such as a low permittivity, dispersion and loss, assuring a predictable performance over a broad frequency range. Therefore, material characterization at these frequencies is of interest to the developing THz community, although not a lot of methods suitable in terms of frequency range and measurement setup exist yet. In this work, a comprehensive method for dielectric material parameter determination from S-Parameter measurements of unloaded and loaded planar transmission lines up to THz frequencies is developed. A measurement setup and methodology based on wafer prober measurements is established, which allows for characterization of planar substrates and bulk material samples alike. In comparison with most existing methods, no specialized measurement cell or cumbersome micro-machining of material samples is necessary. The required theory is developed, including a discussion of effective parameter extraction methods from measurement, identification of and correction for undesired transmission line effects such as higher order modes, internal inductance and surface roughness, as well as mapping and modelling procedures based on physical permittivity models and electromagnetic simulations. Due to the general approach and modular structure of the developed method, new models to cover additional aspects or enhance its performance even further are easily implementable. Measurement results from 100 MHz to 500 GHz for planar substrates and from 100 MHz to 220 GHz for bulk material samples emphasize the general applicability of the developed method. It is inherently broadband, while the upper frequency limit is only subject to the fabrication capabilities of modern planar technology (i.e. minimum planar dimensions of transmission lines and height of substrate) and thus is easily extendable to higher frequencies. Furthermore, the developed method is not bound to a specific measurement setup and applicable with other measurement setups as well, as is exemplary presented for a free-space setup using antennas, enabling measurement of large, flat material samples not fitting on the wafer prober. Several substrate and bulk material samples covering a wide range of permittivities and material classes are characterized and compared with reference values from literature and own comparison measurements. The uncertainties for both planar substrate as well as bulk material sample measurements are estimated with a single-digit percentage. For all measurements, the order of magnitude of the dielectric loss tangent can be determined, while the lower resolution boundary for bulk material sample measurements is estimated to 0.01. Concerning measurements in the wafer prober environment, fixture-related issues are a main cause of measurement uncertainty. This topic is discussed as well as the design of on-wafer probe pads and custom calibration standards required for broadband operation at THz frequencies. / Mit zunehmender Erschließung des THz-Frequenzbereichs und der zugehörigen Optimierung moderner Anwendungen ist eine genaue Kenntnis der dielektrischen Materialparameter verwendeter planarer Substrate unabdingbar: Eine hohe Performance angestrebter Bauteile oder Schaltungen kann nur durch einen präzisen Entwurf sichergestellt werden, wofür spezifische Werte für die Materialeigenschaften bekannt sein müssen. Insbesondere die Integration planarer Bauelemente für sehr breitbandige Anwendungen bei hohen Frequenzen bedingt spezifische dielektrische Materialeigenschaften, wie bspw. geringe Permittivität, Dispersion und Verluste, sodass eine vorhersagbare Performance über einen breiten Frequenzbereich sichergestellt werden kann. Materialcharakterisierung bei diesen Frequenzen ist folglich von Interesse für die sich entwickelnde THz-Forschungslandschaft, wenngleich derzeit kaum Verfahren existieren, die geeignet in Bezug auf den Frequenzbereich oder Messaufbau sind. Im Rahmen dieser Arbeit wird ein umfassendes Verfahren zur Bestimmung der dielektrischen Materialparameter aus S-Parameter-Messungen unbelasteter und belasteter planarer Leitungen bis in den THz-Bereich entwickelt. Ein Messaufbau mitsamt Messmethodik basierend auf Wafer Prober-Messungen wird entworfen, welcher die Charakterisierung von planaren Substraten und losen Materialproben ermöglicht. Im Vergleich zu existierenden Verfahren ist weder eine spezielle Messzelle noch eine umständliche Mikrobearbeitung der Materialproben notwendig. Die Entwicklung der hierfür notwendigen Theorie beinhaltet eine Diskussion von Methoden zur Extraktion effektiver Parameter aus Messungen, die Identifikation und Korrektur unerwünschter Leitungseffekte wie bspw. höherer Moden, interner Induktivität und Oberflächenrauhigkeit sowie Zuordnungs- und Modellierungsverfahren basierend auf physikalischen Permittivitätsmodellen und elektromagnetischen Simulationen. Durch den allgemeinen, modularen Ansatz des entwickelten Verfahrens lassen sich neue Modelle zur Berücksichtigung zusätzlicher Effekte oder weiteren Verbesserung der Performance einfach einarbeiten. Messergebnisse von 100 MHz bis 500 GHz für planare Substrate und von 100 MHz bis 220 GHz für lose Materialproben unterstreichen die allgemeine Anwendbarkeit des entwickelten Verfahrens. Es ist inhärent breitbandig, wobei eine obere Frequenzgrenze nur durch die Fertigungstoleranzen moderner planarer Technologien gegeben ist (minimale Leitungsdimensionen und Substrathöhe), sodass es einfach zu höheren Frequenzen hin erweiterbar ist. Weiterhin ist das entwickelte Verfahren nicht an einen bestimmten Messaufbau gebunden und auch mit weiteren Aufbauten anwendbar, wie beispielhaft an einem Freiraum-Aufbau mit Antennen präsentiert wird. Eine Vielzahl planarer Substrate und loser Materialproben, die ein weites Spektrum an Permittivitäten und Materialklassen abdecken, werden charakterisiert und mit Referenzdaten aus der Literatur sowie eigenen Messungen verglichen. Die Messunsicherheiten der Permittivitätsmessungen werden im einstelligen Prozentbereich abgeschätzt und der dielektrische Verlustwinkel kann in seiner Größenordnung bestimmt werden. Aufbaubezogene Einflüsse als eine Hauptursache für Messunsicherheiten am Wafer Prober werden adressiert, ebenso wie der Entwurf von On-Wafer Probe Pads und selbsterstellter Kalibrierstandards, die notwendig sind für den Einsatz bei THz-Frequenzen.

Blue phase liquid crystals (BPLCs) have a delicate lattice structure existing between chiral nematic and isotropic phases, with a stable temperature range of about 2 K. But due to short coherent length, these self-assembled nano-structured BPLCs have a fast response time. In the past three decades, the application of BPLC has been rather limited because of its narrow temperature range. In 2002, Kikuchi et al. developed a polymer stabilization method to extend the blue-phase temperature range to more than 60 K. This opens a new gateway for display and photonic applications. In this dissertation, I investigate the material properties of polymer-stabilized BPLCs. According the Gerber’s model, the Kerr constant of a BPLC is linearly proportional to the dielectric anisotropy of the LC host. Therefore, in the frequency domain, the relaxation of the Kerr constant follows the same trend as the dielectric relaxation of the host LC. I have carried out experiments to validate the theoretical predictions, and proposed a model called extended Cole-Cole model to describe the relaxation of the Kerr constant. On the other hand, because of the linear relationship, the Kerr constant should have the same sign as the dielectric anisotropy of the LC host; that is, a positive or negative Kerr constant results from positive (∆ε > 0) or negative host LCs (∆ε < 0), respectively. BPLCs with a positive Kerr constant have been studied extensively, but there has been no study on negative ∆ε polymer-stabilized BPLCs. Therefore, I have prepared a BPLC mixture using a negative ∆ε LC host and investigated its electro-optic properties. I have demonstrated that indeed the induced birefringence and Kerr constant are of negative sign. Due to the fast response time of BPLCs, color sequential display is made possible without color breakup. By removing the spatial color filters, the optical efficiency and resolution density are both tripled. With other advantages such as alignment free and wide viewing angle, polymer-stabilized BPLC is emerging as a promising candidate for next-generation displays. However, the optical efficiency of the BPLC cell is relatively low and the operating voltage is quite high using conventional in-plane-switching electrodes. I have proposed several device structures for improving the optical efficiency of transmissive BPLC cells. Significant improvement in transmittance is achieved by using enhanced protrusion electrodes, and a 100% transmittance is achievable using complementary enhanced protrusion electrode structure. For a conventional transmissive blue phase LCD, although it has superb performances indoor, when exposed to strong sunlight the displayed images could be washed out, leading to a degraded contrast ratio and readability. To overcome the sunlight readability problem, a common approach is to adaptively boost the backlight intensity, but the tradeoff is in the increased power consumption. Here, I have proposed a transflective blue phase LCD where the backlight is turned on in dark surroundings while ambient light is used to illuminate the displayed images in bright surroundings. Therefore, a good contrast ratio is preserved even for a strong ambient. I have proposed two transflective blue phase LCD structures, both of which have single cell gap, single gamma driving, reasonably wide view angle, low power consumption, and high optical efficiency. Among all the 3D technologies, integral imaging is an attractive approach due to its high efficiency and real image depth. However, the optimum observation distance should be adjusted as the displayed image depth changes. This requires a fast focal length change of an adaptive lens array. BPLC adaptive lenses are a good candidate because of their intrinsic fast response time. I have proposed several BPLC lens structures which are polarization independent and exhibit a parabolic phase profile in addition to fast response time. To meet the low power consumption requirement set by Energy Star, high optical efficiency is among the top lists of next-generation LCDs. In this dissertation, I have demonstrated some new device structures for improving the optical efficiency of a polymerstabilized BPLC transmissive display and proposed sunlight readable transflective blue-phase LCDs by utilizing ambient light to reduce the power consumption. Moreover, we have proposed several blue-phase LC adaptive lenses for high efficiency 3D displays.

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