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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Compact Helical Antenna for Smart Implant Applications

Karnaushenko, Dmitriy D. 06 December 2017 (has links) (PDF)
Medical devices have made a big step forward in the past decades. One of the most noticeable medical events of the twenties century was the development of long-lasting, wireless electronic implants such as identification tags, pacemakers and neuronal stimulators. These devices were only made possible after the development of small scale radio frequency electronics. Small radio electronic circuits provided a way to operate in both transmission and reception mode allowing an implant to communicate with an external world from inside a living organism. Bidirectional communication is a vital feature that has been increasingly implemented in similar systems to continuously record biological parameters, to remotely configure the implant, or to wirelessly stimulate internal organs. Further miniaturisation of implantable devices to make the operation of the device more comfortable for the patient requires rethinking of the whole radio system concept making it both power efficient and of high performance. Nowadays, high data throughput, large bandwidth, and long term operation requires new radio systems to operate at UHF (ultra-high frequency) bands as this is the most suitable for implantable applications. For instance, the MICS (Medical Implant Communication System) band was introduced for the communication with implantable devices. However, this band could only enable communication at low data rates. This was acceptable for the transmission of telemetry data such as heart beat rate, respiratory and temperature with sub Mbps rates. Novel developments such as neuronal and prosthetic implants require significantly higher data rates more than 10 Mbps that can be achieved with large bandwidth communicating systems operating at higher frequencies in a GHz range. Higher operating frequency would also resolve a strong issue of MICS devices, namely the scale of implants defined by dimensions of antennas used at this band. Operation at 2.4 GHz ISM band was recognized to be the most adequate as it has a moderate absorption in the human body providing a compromise between an antenna/implant scale and a total power efficiency of the communicating system. This thesis addresses a key challenge of implantable radio communicating systems namely an efficient and small scale antenna design which allows a high yield fabrication in a microelectronic fashion. It was demonstrated that a helical antenna design allows the designer to precisely tune the operating frequency, input impedance, and bandwidth by changing the geometry of a self-assembled 3D structure defined by an initial 2D planar layout. Novel stimuli responsive materials were synthesized, and the rolled-up technology was explored for fabrication of 5.5-mm-long helical antenna arrays operating in ISM bands at 5.8 and 2.4 GHz. Characterization and various applications of the fabricated antennas are successfully demonstrated in the thesis.
2

Optimierung des Innovations- und Entwicklungsprozesses von biomedizintechnischen Geräten

Busch, Erik 08 April 2022 (has links)
Objective: Cardiovascular diseases are the leading cause of death. The gold standard for their diagnosis and treatment are angiographic procedures. Clinicians rely on dedicated and specialized equipment for these interventions, e.g. angiography systems. The speed of the associated development is important as better technology enables progress in treatment methods and clinical outcomes. The goal of this article is to show how to optimize the innovation and development process such that it takes minimal time. Methods: 672 data sets on 302 topics were collected over 47 months during a long-term observation of the innovation and development process of angiographic systems. The total data collected is equivalent to efforts worth 30 man-years. This input was used to calculate key process parameters, analyse key process roles, evaluate the use of problem-solving methods and identify key technologies. We also developed a process model comprising the primary innovation sources, important input providers and key processes. This model is characterized by a continuous loop for the innovation and development process. Results: The conducted literature research identifies this closed loop process model as being unique in comparison to the well-established models proposed by Brockhoff, Cooper, Crawford, Durfee, Ebert, Eppinger, Hughes, Pleschak, Thom, Ulrich, Vahs and Witt. According to the best knowledge of the authors no comparable data collection has been performed and presented anywhere else yet. When analysing our 672 data sets, we found that the median process time ( in this data pool (n=672) was to be 10 weeks (p<0,05). The median number of task owners (xPA) per task across all topics was 2. Our data revealed that the number of task owners had a direct impact on the process time. For data sets with up to eight task owners the relationship between process time and task owners can be described as tPd=3.6*xPA^1.4. The median time of owning a topic was determined for Sales (7 weeks), Service (11 weeks), Customer Relationship Management (6 weeks), Product Lifecycle Management (10 weeks) and Research & Development (11 weeks). Main input providers were Sales (53%) and customers (28%). Sales (42%) and PLM (37%) are significant connectors. Problem solvers are PLM (35%), CRM (27%) and R&D (27%). The problem-solving methods were analysed and it was found that clarification (77%) as well as dialog and variation method (both 50%) were used most often. We found that changes to the application software (33%), mechanics, device interfaces and user interface (all 21%) are the four out of six components that were involved in most often. In the analysed datasets a potential of an up to 20% shorter process time was identified. Conclusion: This article proposes a new model for the innovation and development process. Based on our data, we recommend to apply a continuous loop process in the context of innovation and development of medical devices. Our results can, for example, be used for Activity Based Costing Approach or be applied to bring new or upgraded angiography systems faster to market benefitting patient outcome due to improved diagnosis and treatment of cardiovascular diseases.
3

Compact Helical Antenna for Smart Implant Applications

Karnaushenko, Dmitriy D. 19 October 2017 (has links)
Medical devices have made a big step forward in the past decades. One of the most noticeable medical events of the twenties century was the development of long-lasting, wireless electronic implants such as identification tags, pacemakers and neuronal stimulators. These devices were only made possible after the development of small scale radio frequency electronics. Small radio electronic circuits provided a way to operate in both transmission and reception mode allowing an implant to communicate with an external world from inside a living organism. Bidirectional communication is a vital feature that has been increasingly implemented in similar systems to continuously record biological parameters, to remotely configure the implant, or to wirelessly stimulate internal organs. Further miniaturisation of implantable devices to make the operation of the device more comfortable for the patient requires rethinking of the whole radio system concept making it both power efficient and of high performance. Nowadays, high data throughput, large bandwidth, and long term operation requires new radio systems to operate at UHF (ultra-high frequency) bands as this is the most suitable for implantable applications. For instance, the MICS (Medical Implant Communication System) band was introduced for the communication with implantable devices. However, this band could only enable communication at low data rates. This was acceptable for the transmission of telemetry data such as heart beat rate, respiratory and temperature with sub Mbps rates. Novel developments such as neuronal and prosthetic implants require significantly higher data rates more than 10 Mbps that can be achieved with large bandwidth communicating systems operating at higher frequencies in a GHz range. Higher operating frequency would also resolve a strong issue of MICS devices, namely the scale of implants defined by dimensions of antennas used at this band. Operation at 2.4 GHz ISM band was recognized to be the most adequate as it has a moderate absorption in the human body providing a compromise between an antenna/implant scale and a total power efficiency of the communicating system. This thesis addresses a key challenge of implantable radio communicating systems namely an efficient and small scale antenna design which allows a high yield fabrication in a microelectronic fashion. It was demonstrated that a helical antenna design allows the designer to precisely tune the operating frequency, input impedance, and bandwidth by changing the geometry of a self-assembled 3D structure defined by an initial 2D planar layout. Novel stimuli responsive materials were synthesized, and the rolled-up technology was explored for fabrication of 5.5-mm-long helical antenna arrays operating in ISM bands at 5.8 and 2.4 GHz. Characterization and various applications of the fabricated antennas are successfully demonstrated in the thesis.

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