Trådlös energiskörd möjliggör förmågan att skörda energi från elektromagnetisk strålning. Med de senaste framstegen inom trådlös kommunikationsteknik och med tillgången till energieffektiva sensorer, så har radiofrekvensenergiskördning potential till att bli en självförsörjande sensorbaserad plattform. Detta examensarbete undersöker möjligheten att använda radiofrekventa energiskördare som en autonom sensorbaserad plattform. Genom att skapa en sensornod för radiofrekvensenergiskördning, syftar denna avhandling till att undersöka möjliga begränsningar och framsteg som behövs för att göra sådana plattformar möjliga för allmänt bruk. Målet med sensornoden är att simulera en potentiell tillämpning som använder energiskördare som energikälla och backscattering som ett kommunikationsmedium. Ambient backscattering-kommunikation är en trådlös kommunikationsteknik som uppnår energieffektiv kommunikation genom att reflektera energi från omgivande elektromagnetiska källor. Följande avhandling har framgångsrikt utvecklat en prototyp som skördar energi så låg som -10 dBm med 3% verkningsgrad. Trots den låga effektiviteten kan det föreslagna systemet skörda tillräckligt med energi vid -10 dBm för att mäta, konvertera och överföra temperaturdata inom en rimlig tidsram. Den lägsta energiförbrukningen för sensornoden mäts till sex mikrojoule, detta påvisar energieffektiviteten hos dagens mikrokontroller och sensorer. Utöver de utförda labbmätningarna har det utvecklade systemet även testats i en elektromagnetisk kompatibilitetskammare för att validera resultaten. Denna avhandling drar slutsatsen om att radiofrekvent energiskörd är möjlig under kontrollerade förhållanden. Eftersom variationer i ineffekt kan resultera i att energiskördarens prestanda varierar, så bör fler studier undersöka möjligheten till att implementera automatiska impedanstuners. Sådana tuners kommer att möjliggöra optimerad prestanda för ett bredare spektrum av drifteffekter och därmed förbättra prestandan för allmänt bruk. / Wireless energy harvesting is the process of capturing electromagnetic energy into usable direct current. With recent advancements in wireless communication technology and the availability of power-efficient sensors and microcontrollers, radio frequency energy harvesting has the potential to become a viable self-sustaining sensor-based platform. This thesis investigates the possibility of utilizing radio frequency energy harvesters as an autonomous sensor-based platform. By creating a radio frequency energy harvesting sensor node, this thesis aims to investigate possible limitations and advancements needed to make such platforms viable for general usage. The goal of the sensor node is to simulate a potential application that utilizes energy harvesters as an energy source and backscattering as a communication medium. Ambient backscattering communication is a wireless communication technique that achieves energy-efficient communication by reflecting energy from ambient electromagnetic sources. The following thesis has successfully developed a prototype that harvests radio frequency energy as low as -10 dBm with 3\% efficiency. Despite the low efficiency, the proposed system can harvest enough energy at -10 dBm to sense, convert and transmit temperature data every 2 seconds. The lowest energy consumption of the sensor node is measured to be six microjoules of energy, demonstrating the energy efficiency of ’todays microcontrollers and sensors. In addition to the performed lab measurements, the developed system has also been tested in a state-of-the-art electromagnetic compatibility chamber to validate the results. This thesis can conclude that radio frequency energy harvesting is possible under controlled conditions. As variations in input power can result in the varying performance of the energy harvester, future studies are needed to investigate the possibility of implementing automatic impedance tuners. Such tuners will allow for optimized performance for a wider range of operating powers hence improving the performance for general usage.

The development and implementation of silicon carbine (SiC) devices is steadily increasing facilitating the electrification of aircrafts. In this thesis, a printed circuit board (PCB) based heavy copper busbar design and verification are introduced for a SiC based 250 kW multiphase drive system operated at 40,000 ft. Finite-element analysis (FEA) simulation studies of the PCB busbar are conducted to optimize the electric field intensity. Busbar modeling technic is also discussed to derive the current distribution and extract the loss. The measured partial discharge inception voltage (PDIV), switching transients and converter-level validations are provided for insulation, thermal and commutation loop verifications. As the part of the inverter system, the integrated gate driver is designed with SPI communication to drive the wide bandgap SiC power modules. With feature of drain-to-source current sensing feature, the gate driver could also provide over-current protection to fast-switching SiC power modules. The converter level verification is performed under single, dual, and quadruple three-phase inverter system for aviation motor drive to evaluate the overall performance of the powertrain converter. The outcomes of this research contribute to the advancement of electric aircraft technology by leveraging the benefits of SiC devices and optimizing busbar design, providing valuable insights and guidelines for engineers and researchers involved in the development and optimization of power electronic systems for all-electric aircraft applications. / Master of Science / This research focuses on the design and verification of PCB (Printed Circuit Board) busbars for a multiphase SiC-based all-electric aircraft powertrain converter. Silicon Carbide (SiC) devices, known for their high efficiency and fast-switching capabilities, are used in the converter to enhance its performance. The goal is to develop an optimized busbar design that ensures efficient power distribution and minimizes energy losses in this advanced aviation powertrain system. The study explores different aspects of busbar insulation design and analyzes busbar current distribution and loss extraction using simulation and modeling techniques. Additionally, gate driver design and communication network are investigated to drive and protect the wide bandgap SiC devices and to ensure the overall performance of the powertrain converter. The converter level verification is also performed under single, dual, and quadruple three-phase inverter system for aviation motor drive. The findings of this research contribute to the advancement of electric aircraft technology, utilizing SiC devices and optimized busbar design, and provide valuable insights for engineers and researchers working on power electronic systems for electric aircraft applications.

The scope of this work is the development of a 60 GHz flexible transceiver frontend by adopting an economic prototyping approach. Such a platform can validate the proposed protocols for the 60 GHz band in a real wireless environment, especially the physical layer security concept. The development course uses the hybrid architecture with off-the-shelf components and custom-designed RF chain blocks on printed circuit technology. Challenge in this approach is the coarse resolution of the selected manufacturing technology and higher process tolerance. This work extends the state-of-the-art by proposing etching-resilient RF chain blocks on wide bandwidths. It presents the design validation of each block and performance analysis for various manufacturing conditions. The study also reviews and proposes a high-frequency interconnect model for bondwires, vital in a frontend design. Parasitics' compensation of the interconnects at millimeter-wave operation is proposed, compatible with printed circuit technology. The 60 GHz frontend is realized by packaging the designed RF blocks and off-the-shelf components with optimized and characterized high-frequency interconnects. The frontend, equipped with a tailor-made antenna duplexer, is reconfigurable for frequency, power, and modulation scheme. The developed frontend is characterized for local oscillator, transmitter, and receiver operations. The adaptability of the frontend allows it to be used as an agent in a heterogeneous network. Two units of the developed frontends are used in a network for frequency domain channel sounding. The antenna duplexer ensures channel reciprocity in bidirectional sounding campaigns. Matched two-way channel response is achieved in various indoor environments, which endorses the frontend for channel reciprocity key generation. Finally, the frontend units are successfully deployed in a physical layer security demonstrator.:Abstract Chapter1: Introduction Chapter 2: Fundamentals and state-of-the-art Chapter 3: The design Chapter 4: Integration and characterization Chapter 5: Application example: Channel sounder Chapter 6: Summary and future work Appendices Bibliography

Polychlorinated biphenyls (PCBs) and their metabolic derivatives are ubiquitous environmental contaminants. These compounds are of concern because of their persistence and bioaccumulation in nature. PCBs and the hydroxylated metabolites have shown endocrine-disrupting activity. A method of detection in surface water samples is important to identify and quantify the environmental contamination. In this research we have attempted to develop a method of detection. Six representative polychloromethoxybiphenyls (PCMBs) were prepared. The corresponding polychlorobiphenylols, hydroxylated PCB metabolites (OH-PCBs), were prepared from the PCMBs. A method coupling solid phase extraction with liquid chromatography, on-line electrospray ionization, and mass spectrometry (SPE-LC/ESI/MS) was developed for detection of the OH-PCBs in distilled and surface water samples.

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