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PublicationThermo-mechanical-optical coupling within a digital twin development for automotive LiDAR( 2021)In the current work, the steps of the development of a Reduced Complexity Model (RCM) of a Light Detection and Ranging (LiDAR) system and the requirements for the preparation of a Digital Twin (DT) from such system are discussed. Preliminary thermal and optical simulations are presented, along with different concepts for cooling of the system. Additionally, the current barrier of coupling of the thermo-mechanical simulations produced in Ansys Mechanical and optical simulations done by Zemax OpticStudio is discussed.
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PublicationGenerative Machine Learning for Resource-Aware 5G and IoT SystemsExtrapolations predict that the sheer number of Internet-of-Things (IoT) devices will exceed 40 billion in the next five years. Hand-crafting specialized energy models and monitoring sub-systems for each type of device is error prone, costly, and sometimes infeasible. In order to detect abnormal or faulty behavior as well as inefficient resource usage autonomously, it is of tremendous importance to endow upcoming IoT and 5G devices with sufficient intelligence to deduce an energy model from their own resource usage data. Such models can in-turn be applied to predict upcoming resource consumption and to detect system behavior that deviates from normal states. To this end, we investigate a special class of undirected probabilistic graphical model, the so-called integer Markov random fields (IntMRF). On the one hand, this model learns a full generative probability distribution over all possible states of the system-allowing us to predict system states and to measure the probability of observed states. On the other hand, IntMRFs are themselves designed to consume as less resources as possible-e.g., faithful modelling of systems with an exponentially large number of states, by using only 8-bit unsigned integer arithmetic and less than 16KB memory. We explain how IntMRFs can be applied to model the resource consumption and the system behavior of an IoT device and a 5G core network component, both under various workloads. Our results suggest, that the machine learning model can represent important characteristics of our two test systems and deliver reasonable predictions of the power consumption.
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PublicationPlattformkonzept zum Aufbau von hochintegrierten Multisensorknoten( 2019)Diese Veröffentlichung stellt das Konzept und die dazugehörige Packaginglösung einer universellen IoT Sensorplattformmit einer System-on-Chip (SoC) Familie als zentrale Steuer- und Recheneinheit vor. Die Plattform besteht aus 4 Ebenen, die angefangen vom hochintegrierten SoC, über die Montagemöglichkeit von gehäusten wie auch ungehäusten Sensoren bis hin zum System Board, was die üblichsten drahtgebundenen und drahtlosen Schnittstellen zur Verfügung stellt. Das Layout zur Sensormontage kann auf individuelle Kundenwünsche angepasst werden, um so spezielle Anforderungen an die Messaufgabe zu ermöglichen. Die Kerntechnologie des Packages besteht aus einem Moldpackage in Fan-Out Technologiemit unterseitiger Umverdrahtung des SoC zu den Balling Pads und Durchführungen zur oberseitigen Umverdrahtungfür die Montage der Sensoren.
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PublicationHBM and ASIC silicon interposer( 2019)The presented project shows the realization and selected analyses results of the first stage of a passive interposer chip for high performance data transfer between processor and memory dies, a 2D HBM (high bandwidth memory) interposer. The realized interposer chip can carry 8 HBM dies with each having 10'000 connections and one ASIC die with 80'000connections. A complex design was reduced from 5 to 3 levels of redistribution layers, which significantly saves manufacturing costs. By using line/space dimensions of 4 mm a mask aligner could be utilized for exposure. Therefore big interposer dies of 44 mm by 44 mm can be produced using relatively simple lithography technology at high per wafer yield. All technology is demonstrated on 300 mm silicon wafers.
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PublicationVery-Thin System-in-Package Technology for Structural Analysis( 2019)The integration of very-thin electronic systems will enable new application fields like structural analysis of components used in aviation, windmills or other critical applications. Presented are two integration options, by using flexible substrates or a RDLFirst packaging approach suitable for multiple device assembly. The RDLFirst is very thin and the flip-chip devices can be thinned also, so that the overall system gets very thin. One main difference to flexible substrate is the possible line space, which is in the region of 100um for flexible substrates and down to some um for RDLFirst.
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PublicationFunctional integration - structure-integrated wireless sensor technology targeting smart mechanical engineering applications( 2018)Functional integration on the micro/nano scales enables smart functionalities in mechanical engineering systems. Here, exemplarily shown for a ball screw drive, a structure-integrated wireless sensor technology is implemented into a manufacturing system for advanced process control and status monitoring - even at machine components being not yet accessible or difficult to access. This includes also a miniaturized, networked and energy-efficient information and communication technology (ICT) integrated into the machine.
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PublicationEnergy harvesting and conversion - applications of piezoelectric transformer and transducer MEMS( 2018)A systematic investigation of the feasibility to integrate complete piezo-based power supply on silicon was done. Up to now, fully integrated off-line power supplies on chip are available as products for below 1 Watts. Higher power levels up to 10 Watts and more are strongly desired for many miniaturized applications as Off-Line LED light sources, integrated power supplies for communication devices as iPhone, portable devices for medical applications, portable beamers an others. The integration of high-efficient power supplies based on magnetic transformers (PT) including galvanic isolation is limited due to the physics of electromagnetism. Piezoelectric transformers can be integrated as MEMS when PZT material is applied on silicon to a height of several Micrometers to form an oscillating device which will be processed after micro-bonding in an etching process. Although power density of discrete PT is already high, it can be increased by a factor of 100 to 1000 in integrated devices on silicon taking advantage of uniform crystal structure of sputtering process and improved heat removal through silicon. Serial piezo-transformer-strings allow for high isolating voltage up to 4 kV and provide efficiency up to 95% or more, but unfortunately on the cost of significant large chip area. However, piezoelectric transformers will gain higher acceptance in power converters if a magnetic-field-free environment is requested as for magnetic resonance tomography. Promising piezoelectric applications can be found for transformer-transducer units to harvest ultrasonic energy, preferably in medical therapy-diagnosis applications, but further, in industrial autonomous sensor supplies with avoidance of electromagnetic disturbance. Piezoelectric energy harvesting becomes attractive using ultrasonic energy harvester MEMS with wide range frequency excitation using permanent magnet cantilever construction. Ultrasonic MEMS loudspeakers are miniaturized alternatives to traditional magnetic devices. The advantage of piezoelectric MEMS applications will result in an extreme miniaturization compared to conventional power conversion by magnetic or electrostatic solutions. High reliability including intelligent integrated functions in some cases may improve the practicability of piezoelectric MEMS.
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PublicationAdaptive camouflage panel in the visible spectral range( 2018)In this work an adaptive panel in the visible spectral range is presented. Principal possibilities and basic aspects of adaptive camouflage in the VIS are considered and some details are discussed. The panel consists of modular tiles, each containing several high power four-color-LEDs controlled by a microcontroller and high current power supply and each tile designed to operate autonomously. To control the color and the intensity several color sensors were integrated into the system. The purpose of the panel is to take on a uniform color to best match its appearance to a given reference color, where both the panel and the reference color are subject to the same environmental conditions. The panel was not designed, however, to produce different camouflage patterns. The tiles on the surface were covered by a dark plastic plate in order to provide dark and saturated colors and to guarantee a dark appearance in the passive state of the system. As was to be expected, extreme situations like high ambient brightness and direct solar illumination turned out to be particularly challenging. Substantial tests and some modifications were performed to achieve a satisfactorily uniform color reproduction of a given reference color. Physical measurements as well as observer tests have been performed to demonstrate the capability of the adaptive system.
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PublicationMiniaturization of power converters by piezoelectric transformers - chances and challenges( 2017)A systematic approach of the feasibility to integrate complete piezo-based power supply on silicon is the focus of research activities within Fraunhofer EAS, ISIT an IZM. Up to now, fully integrated off-line power supplies on chip are available for below 1 Watts, e.g. from Texas Instruments. Higher power levels up to 10 Watts and more are strongly desired for many miniaturized applications as Off-Line LED light sources, integrated power supplies for communication devices as iPhone, portable devices for medical applications, portable beamers an others. The integration of high-efficient power supplies based on magnetic transformers (PT) including galvanic isolation is limited due to the physics of electromagnetism. Piezoelectric transformers can be integrated when PZT material is applied on silicon to a height of several Micrometers to form an oscillating device which will be processed after micro-bonding in an etching process. Although power density of discrete PT is already high, it can be increased by a factor of 100 to 1000 in integrated devices on silicon taking advantage of uniform crystal structure of sputtering process and improved heat removal through silicon. The driving topology can be formed by high-voltage Mosfets or multi-level low-voltage Mosfet topology based on SOI or GaN on Si and integrated micro-inductors in the future. Serial piezo-transformer-strings allow for high isolating voltage up to 4 kV and provide efficiency up to 95% or more. Synchronous rectifying devices can be formed by low-voltage Mosfets at the output stage of the power supply. The advantage will be an extreme miniaturization compared to discrete power supplies, reduction of blocking capacitors by interleaving techniques, and thus, high reliability including intelligent integrated functions as stabilization circuits, sensors or control.
