Projects

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An adequate analysis and simulation of the signal and EMC behavior of electronic assembly and connection structures requires an electrodynamic description with the means of numerical simulation. The treatment of practical structures with commercially available field calculation simulations is often relatively complex and impractical, especially for broadband analyses. A much more efficient and flexible description is offered by a network model with constant parameters, which maps the gate behavior of any linear, passive structure with regard to its high-frequency behavior. This enables seamless integration into a realistic system simulation with linear/non-linear components. In the network modeling of structures that exhibit significant radiation losses, the methods developed to date reach their limits. This also applies to internal material losses, which must be modeled in their specific frequency behavior. For this purpose, extended theoretical approaches based on an integral equation formulation are to be developed and tested on practical examples.
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The modeling of electronic structures within conductive housings is of increasing importance with regard to the analysis of signal and EMC behaviour. Due to the relatively high signal frequencies and frequency bandwidths, the excitation of resonant cavity modes leads to more intensive coupling within the system. The treatment of practical structures with commercially available software tools is often relatively complex and impractical, especially for broadband analyses. In practice, appropriate network models are required to carry out simulations in the frequency and time domain in an efficient manner. For this purpose, starting from an electromagnetic modal analysis, canonical equivalent circuit diagrams are set up for a freely definable number of arbitrarily arranged gates. To validate the model, test arrangements are set up and measured with a vector network analyzer in a large frequency range.
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The signal and EMC analysis of electronic systems requires an electrodynamic description with the means of numerical simulation. Especially for electronic circuits on assemblies, a direct treatment with conventional simulation tools is extremely impractical, not only because of the geometric complexity including extreme scale differences, but also because of the extensive interaction of passive and active or linear/non-linear elements. For the modal network synthesis method developed at the chair, the efficiency of the underlying field integral equation approach is to be significantly increased by a problem-adapted formulation in order to enable practical use. For this purpose, corresponding dyadic Green's functions of the stratified medium are to be used. The general mathematically complex solutions are to be reduced to the approximations sufficient for the required accuracy. The theoretical models are to be flanked by high-frequency measurements.
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An adequate analysis and simulation of the signal and EMC behavior of electronic assembly and connection structures requires an electrodynamic description with the means of numerical simulation. The treatment of practical structures with commercially available field calculation simulations is often relatively complex and impractical, especially for broadband analyses. A much more efficient and flexible description is offered by a network model with constant parameters, which maps the gate behavior of any linear, passive structure with regard to its high-frequency behavior. This enables seamless integration into a realistic system simulation with linear/non-linear components. Based on an integral equation formulation, the previously developed approach is to be extended with regard to losses, including electromagnetic radiation, and numerical efficiency is to be increased.
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When it comes to network modeling of structures that exhibit significant radiation losses, the methods developed to date reach their limits. This also applies to internal material losses, which must be represented in their specific frequency behavior. For this purpose, extended theoretical approaches need to be developed and tested using practical examples.
This text was translated with DeepL

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The modeling of electronic structures within conductive housings is of increasing importance with regard to the analysis of signal and EMC behaviour. Due to the relatively high signal frequencies and frequency bandwidths, the excitation of resonant cavity modes leads to more intensive coupling within the system. The treatment of practical structures with commercially available software tools is often relatively complex and impractical, especially for broadband analyses. In practice, appropriate network models are required to carry out simulations in the frequency and time domain in an efficient manner. For this purpose, starting from an electromagnetic modal analysis, canonical equivalent circuit diagrams are set up for a freely definable number of arbitrarily arranged gates. To validate the model, test arrangements are set up and measured with a vector network analyzer in a large frequency range.
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Feasibility study for numerical modeling and simulation of electromagnetic susceptibility of highly integrated audiological systems. Simplified modeling approaches for passive structures and active/passive elements. Methods for effective identification of critical coupling structures. Analysis and evaluation methods with regard to relevant test criteria.
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Feasibility study for numerical modeling and simulation of via transitions in multilayer printed circuit boards with differential signal transmission. Testing of parameter studies to optimize the signal transmission properties depending on geometric and material parameters.
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Investigation and electromagnetic simulation of audiological systems. Preparation of suitable feasibility studies on computational models at circuit board level and analysis of a radio transmission system. Development of methods to optimize radiation characteristics and efficiency.
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When it comes to network modeling of structures that exhibit significant radiation losses, the methods developed to date reach their limits. This also applies to internal material losses, which must be represented in their specific frequency behavior. For this purpose, extended theoretical approaches need to be developed and tested using practical examples.
This text was translated with DeepL

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Investigation and electromagnetic simulation of audiological systems. Creation of suitable calculation models at circuit board level to analyze a radio transmission system. Development of methods to optimize radiation characteristics and efficiency.
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Investigation and electromagnetic simulation of audiological systems. Creation of suitable calculation models at circuit board level to analyze a radio transmission system. Development of methods to optimize radiation characteristics and efficiency.
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Theoretical and experimental research on macromodeling of cable structures. The focus is on the modeling of homogeneous connection structures for the purpose of system simulation with regard to functionality (supply and signal integrity), as well as electromagnetic compatibility (irradiation and radiation problems).
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Theoretical and practical investigations into field coupling between electronic systems located in the electromagnetic near field. Mathematical description of the coupling as a function of frequency, geometry and distance. Formulation of worst-case estimates and validation using 3D full-wave simulations.
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Study on EMC analysis of audiological systems. Identification of coupling paths and quantification of interference based on calculation models at PCB level. Evaluation of remedial measures and optimization.
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The interference of electronic systems is usually investigated in the far field of a transmitting antenna as part of standardized test procedures. In practice, however, the distances between the interference source and sink can be so small that far-field conditions cannot be assumed. The coupling between a resonant radiator and a transmission line is investigated theoretically and practically as a model arrangement. Corresponding deviations in the interference effect of near fields in contrast to an influence under far-field conditions are to be investigated and evaluated with regard to the interpretation of practical tests.
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Study on the EMC analysis of audiological systems. Identification of coupling paths and quantification of interference based on calculation models at PCB level. Evaluation of remedial measures and optimization.
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Investigation and electromagnetic simulation of audiological systems. Creation of suitable calculation models at circuit board level to analyze a radio transmission system. Development of methods to optimize radiation characteristics and efficiency.
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Development and validation of semiconductor models for the EMC simulation of power electronic components of automotive electronics on the basis of a simple behavior and coupling description.
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For the EMC simulation of filter measures, the automotive industry requires models for inductive components that adequately reflect the frequency behavior of the ferrite material, including losses. In applications with a direct current component, such as electric vehicles, the influence of bias is also important. An extraction method for the complex permeability of the ferrite material on the basis of measured impedance curves is to be developed and tested.
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Investigation and electromagnetic simulation of audiological systems. Creation of suitable calculation models at circuit board level to analyze a radio transmission system. Development of computational models for realistic simulation of radiation characteristics and efficiency.
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Development of efficient high-frequency models for capacitors and resistors in EMC filters for automotive applications. Metrological validation through corresponding S-parameter measurements with vector network analyzer. Implementation of numerical simulations for selected configurations.
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On the basis of an integral equation formulation, methods for creating equivalent circuit diagrams are to be tested and further developed. Effective ways of reducing the computational effort are to be developed. The range of application of approximate solutions is to be examined and evaluated in detail using exact numerical reference simulations.
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Investigation and electromagnetic simulation of interference phenomena in audiological systems. Creation of suitable computational models at circuit board level for the purpose of carrying out analyses with regard to the effectiveness of design measures for interference suppression. Development of methods for the automated creation of partial models.
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Low signal levels and supply voltages in combination with increasing integration and processing speeds are responsible for the electromagnetic susceptibility of electronic systems. In conventional immunity tests, the test object is exposed to the far field of an antenna or examined within a TEM cell. However, if interference occurs, identifying the responsible coupling paths or locating the sensitive areas can often prove difficult, which can make it difficult to eliminate the causes. A possible alternative or supplement to the usual test procedures is a near-field immunity test, in which entire assemblies down to individual integrated circuits (ICs) can be examined using a small field probe. An automated measuring station with a scanner to guide the field probe makes it possible to test the PCB surface with millimeter precision. An additional advantage of the method is that high field strengths can be generated with relatively low signal power. In order to be able to carry out systematic investigations on a quantitative basis, it is essential to calibrate the measuring system with regard to the frequency-dependent field amplitudes generated. In particular, the RF modeling of the probes and the coupling process or the selective analysis of E- and H-field influence with corresponding field probes on selected test objects are the subject of the research project..
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In view of increasing processing speeds in electronic systems, necessary connection structures between modules, heat sinks, etc. are often the cause of signal impairments and unwanted electromagnetic radiation. Appropriate models are to be developed to describe the EMC behavior of typical connection structures.
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Conducting computational studies on the noise sensitivity of hearing aids using computer simulations. Investigation of measures to improve the signal-to-noise ratio using realistic models. Quantitative evaluation of noise suppression measures.
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Im Zusammenhang mit der Funkenerosion (EDM) wird untersucht, welche veränderten Plasmakanalstrukturen in gasförmigen Arbeitsmedien auftreten. Schwerpunkte sind die Splittung des Plasmakanals, seine radiale Ausdehnung und die energetische Verteilung bezüglich der Plasmaflußpunkte.

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Investigation of the direct radiation of EC motors. A suitable radiation model is to be developed and verified on the basis of measurement results. Important parameters influencing the level of interference radiation are to be determined. Computer models are to be developed for practical analysis.
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Analyse elektrischer Entladungen in Arbeitsspalten kleiner 100 µm mit flüssigen Arbeitsmedien.
Untersuchung spezieller Zündmechanismen durch Variation der Arbeitsflüssigkeit und von Additiven.
Messung kurzzeitphysikalischer Effekte zur Beschreibung der Zündmechanismen, Modellbildung und Simulation des elektrischen Durchschalgs bei verschiedenen Spaltkonditionen mit ANSYS, ANSYS-Simulation thermisch beeinflusster Zonen.

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Niedrige Signalpegel und Versorgungsspannungen in Kombination mit zunehmender Integration und steigenden Verarbeitungsgeschwindigkeiten sind für die elektromagnetische Störempfindlichkeit elektronischer Systeme verantwortlich. Bei herkömmlichen Störfestigkeitsuntersuchungen wird das Testobjekt dem Fernfeld einer Antenne ausgesetzt oder innerhalb einer TEM-Zelle untersucht. Bei Auftreten von Störungen kann allerdings die Identifikation der verantwortlichen Koppelpfade bzw. die Lokalisierung der empfindlichen Bereiche sich oft als nicht einfach erweisen, was die Behebung der Ursachen erschweren kann. Als mögliche Alternative oder Ergänzung zu den üblichen Testverfahren bietet sich eine Nahfeld-Immunitätsprüfung an, bei der mittels einer kleinen Feldsonde ganze Baugruppen bis hin zu einzelnen integrierten Schaltkreisen (ICs) untersucht werden können. Ein automatisierter Messplatz mit einem Scanner zur Führung der Feldsonde bietet dabei die Möglichkeit, die Leiterplattenoberfläche millimetergenau zu prüfen. Ein zusätzlicher Vorteil des Verfahrens ist, dass mit relativ geringen Signalleistungen hohe Feldstärken erzeugt werden können. Um systematische Untersuchungen auf quantitativer Basis durchführen zu können, ist eine Kalibrierung des Meßsystems hinsichtlich der erzeugten frequenzabhängigen Feldamplituden unumgänglich. Speziell die HF-Modellierung der Sonden und des Einkoppelvorganges bzw. die selektive Analyse von E- und H-Feldbeeinflussung mit entsprechenden Feldsonden an ausgewählten Testobjekten sind Gegenstand des Forschungsprojektes.

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Der technische Fortschritt in der Leistungselektronik ist geprägt von steigenden Schaltfrequenzen, Flankensteilheiten der Ströme und Spannungen und zunehmenden Packungsdichten. Gleichzeitig aber ist die Gewährleistung der elektromagnetischen Verträglichkeit (EMV) hinsichtlich der CE-Zertifizierung für den Betrieb und die Vermarktung eines elektronischen Systems erforderlich. Das Schaltungsdesign und die EMVAnalyse sind als Teil der Produktentwicklung rechnergestützt und finden bei immer höheren Frequenzen statt. Dazu durchgeführte Computersimulationen erfordern aber nicht nur exakte Modelle für die passive Verbindungsstruktur einer Schaltung, sondern nunmehr genauere und effiziente Modelle der Halbleiterbauelemente.
Durch Anwendung einer hierarchisch strukturierten, auf Makromodellen aufbauenden Modellierung, sollen genaue Simulationsmodelle von Halbleitern und komplexen leistungselektronischen Baugruppen entwickelt werden, die zudem auch parasitäre Effekte wie die Streuadmittanz zur Kühlkörperfläche nachbilden. Die den Makromodellen inhärenten Eigenschaften wie ausreichende Genauigkeit bei geringer Komplexität, Flexibilität usw. kommen dabei zu tragen. Dadurch wird eine EMV-gerechte Schaltungsentwicklung bzw. Analyse mit sinnvollem Rechen- und Zeitaufwand überhaupt erst möglich.

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wird der Einfluss der geometrischen und elektrotechnischen Prozessparameter sowie der Einfluss des Werkstoffes auf die Schweißnahtgüte untersucht und eine Optimierung der Schweißnahtgüte durch Anpassung der Prozessparameter durchgeführt. Ergänzend wird das FE-Modell weiterentwickelt, um die Modellierung zu optimieren.

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Für die Micro System Technology (MST) steigt steig die Anzahl der Anwendungen, die eine Bearbeitung mit hoher Präzision und kleinen Abmessungen verlangt. Die Elektrochemische Bearbeitung (ECM) entwickelte sich in den letzten Jahren, insbesondere die gepulste ECM-Technology (PECM). Im Projekt werden die zwei Techniken der PECM (konventionelle gepulste ECM) und die µ-PECM (Wirkung der Doppleschichtumladung) darauf hin untersucht, auch bei Mikrodetailbearbeitungen eine hohe Effizienz und Präzision zu erreichen. Das Arbeitsgebiet umfasst dabei die Prozessenergiequellen, die Prozesssteuerungen, die Halterungs- und Führungssysteme, die Elektrolyte und die Anbindung An CAD/CAM.

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ufbau spezieller Messzellen zur Analyse des Durchbruchverhaltens von Kohlenwasserstoffen bei Spaltweiten von 5 bis 100 µm. Neben der Analyse der Strom- und Spannungsverläufe von Einzelentladungen und Entladungsfolgen werden Hochgeschwindigkeitsaufnahmen (Belichtungsdauern < 100 ns) vorgenommen, die Rückschlüsse auf die Entstehung und Ausbreitung des Plasmakanals und der Gasblase einer Funkenentladung zu lassen. Im Speziellen wird das Basis-Dielektrikum mit ausgewählten Additiven versetzt, um das Durchbruchverhalten für Folgeentladungen zu verbessern.

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Das Magnetimpulsschweißen stellt für eine Vielzahl von Anwendungen eine fertigungstechnische Altertnative für das Fügen dar. Dabei wird ein Werkstück unter Anwendung von Wirkenergie derart beschleunigt, dass bei der anschließenden Kollision mit dem fügepartner eine stoffschlüssige Verbindung auch ohne zusätzliche Wärmezufuhr realisiert wird. Im Gegensatz zum Schmelzschweißen können auch unterschiedliche metallische Werkstoffe wie Aluminium mit Stahl oder Kupfer mit Messing miteinander verschweißt werden

Mit dem Ziel der Prozessparameteroptimierung wird während des Forschungsvorhabens das Magentimpulsschweißen modelliert und analysiert. Dazu wird der Einfluss der geometrischen und elektrotechnischen Prozessparameter sowie des Werkstoffes auf die Schweißgüte untersucht und eine Optimierung der Schweißgüte durch Anpassung der Prozessparameter durchgeführt. Mit Hilfe der Finite Elemente Methode wird erstmals ein Simulationsmodell zur Bestimmung der Prozessparameter beim Magnetimpulsschweißen geschaffen

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Gegenstand ist die Analyse der Störempfindlichkeit eines komplexen elektronischen Systems gegenüber äußeren elektromagnetischen Feldern. Dazu werden mit dem Mitteln der elektromagnetischen Feldberechnung numerische Simulationen durchgeführt und hinsichtlich des Einflusses verschiedener Parameter ausgewertet.

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Berechnung dreidimensionaler elektrischer Strömungsfelder idealisierter Mehr-Elektrodenanordnungen mit dem Ziel, den elektrochemischen Abtrag bei Verwendung nichtpassivierender und passivierender Elektrolyte zu ermitteln

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