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Ganeshpure, D.A. (author)The integration of wind and solar energy through power electronic converters has introduced new challenges to High Voltage (HV) equipment in the electrical power system. Switchgear, cables, and transformers are now subject to higher dV/dt stress and complex wave shapes due to solid-state switching. This poses a threat to the reliability of the...doctoral thesis 2024
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Coco Martin, C.M. (author), Hu, Weiya (author), Cavallo, D. (author)This work aims to provide guidelines on the design of wideband flat lenses based on artificial dielectric layers (ADLs). Planar lenses based on metasurfaces are typically narrowband, due to the phase wrapping over the period of 2\pi that is strongly frequency-dependent. On the contrary, true-time-delay (TTD) planar lenses, which do not resort...journal article 2024
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Wang, C. (author), Liu, M. (author), Bannenberg, L.J. (author), Zhao, C. (author), Thijs, M.A. (author), Boshuizen, B. (author), Ganapathy, S. (author), Wagemaker, M. (author)Lithium metal with its high theoretical capacity and low negative potential is considered one of the most important candidates to raise the energy density of all-solid-state batteries. However, lithium filament growth and its induced solid electrolyte decomposition pose severe challenges to realize a long cycle life. Here, dendrite growth in...journal article 2024
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Ozzola, R. (author), Neto, A. (author), Imberg, Ulrik (author), Cavallo, D. (author)We present a dual-polarized connected array of slots with an artificial dielectric layer (ADL) radome for mobile communication applications operating in the sub-6 GHz and the upper 6 GHz bands of 5G. The radiating slots are combined with two interchangeable ADL radomes with different thicknesses, targeting the bands 6-8 and 2-8 GHz,...journal article 2024
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Chang, J. (author), Ji, W. (author), Yao, X. (author), van Run, A.J. (author), Groeblacher, S. (author)Highly ambitious initiatives aspire to propel a miniature spacecraft to a neighboring star within a human generation, leveraging the radiation pressure of lasers for propulsion. One major challenge for this enormous feat is to build a meter-scale, ultralow mass lightsail with broadband reflectivity. In this work, we present the design and...journal article 2024
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Hadjigeorgiou, Georgios (author)This thesis research focuses on MRI technology and more specifically the evaluation of the generalized signal model (full-wave signal). The research aims to investigate how dielectric properties influence the magnetic fields in MRI scans, by using a more complex signal model that takes into account scattered fields caused by dielectric...master thesis 2023
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Hu, Weiya (author)Flat lens antennas are convenient solutions to realize highly directive antennas for millimeter wave and terahertz frequencies. Unlike the traditional three-dimensional bulky lens antennas, flat lenses are compact, low profile, and planar structures that can be manufactured with standard multi-layer technology, e.g. printed circuit board (PCB)...master thesis 2023
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Ganesan, Shruthi (author)The urgent need to decrease greenhouse gas emissions and enable clean energy transition has driven the power industry to seek compact and eco-friendly solutions for power transmission. Gas Insulated Switchgear has been a key technology in this regard, using Sulphur Hexafluoride gas as an insulating medium. However, is a potent greenhouse gas...master thesis 2023
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Anand Nair, Keshav (author)The mm-wave operational band (24-30 GHz) is becoming increasingly important for various practical applications. However, at such high frequencies, the issue of propagation losses arises, emphasizing the necessity for these systems to achieve high radiation efficiency. Dielectric Resonator Antennas (DRA) are promising candidates to replace...master thesis 2023
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Dekker, Jeroen (author)In this thesis new dielectric metasurfaces in immersion were explored with a periodic distribution of unit cells with multiple silicon cylinder structures on a reflective gold slab with a fused quartz spacer in between. These new metasurfaces were designed with 60 nm and 130 nm gaps in order to improve manufacturability and enable larger...master thesis 2023
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Mathew, P. (author), Ghaffarian Niasar, M. (author), Vaessen, P.T.M. (author)Penetration of power electronics in the grid has produced a new species of stresses, characterized by fast-rising pulsed waveforms with microsecond rise times repeating at several tens of kilohertz. Analyzing their impact on existing and future insulation systems requires pulse modulators, most often with pulse transformers (PTs), to perform...journal article 2023
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Zhang, Y. (author), Mo, J. (author), Vollebregt, S. (author), Zhang, Kouchi (author), May, Alexander (author), Erlbacher, Tobias (author)The 4H-silicon carbide (SiC) exhibits excellent material characteristics, particularly in high-temperature, high-power, high-frequency applications. However, the reliability of SiC-based devices operating in harsh environments is a critical concern. While time-dependent dielectric breakdown (TDDB) in conventional SiC devices has been extensively...conference paper 2023
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Cavallo, D. (author)Artificial Dielectric Layers (ADLs) have recently been exploited to improve the radiation and impedance performance of integrated antennas at millimeter wave (mmWave) and terahertz (THz) frequencies. The ADLs are composed by layers of sub-wavelength periodic metal patches that can be arranged within a host medium to synthesize an equivalent...conference paper 2023
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Hehenberger, S.P. (author), Caizzone, Stefano (author), Thurner, Stefan (author), Yarovoy, Alexander (author)Additive manufactured structured dielectrics with engineered permittivity tensors are promising tools for novel microwave components and are drawing increasing attention from researchers. However, design modeling and experimental verification of anisotropic materials are challenging and have not yet been thoroughly explored in the literature. In...conference paper 2023
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Ganeshpure, D.A. (author), Soeiro, Thiago B. (author), Gagic, Mladen (author), Ghaffarian Niasar, M. (author), Bauer, P. (author), Vaessen, P.T.M. (author)To test high-voltage (HV) equipment with increasingly complex transients obtained from various power system studies, this article demonstrates a hardware implementation of a medium-voltage (MV) submodule (SM) to be used in a modular multilevel converter (MMC)-based HV arbitrary wave shape generator (AWG). The MV SM is scalable with its own...journal article 2023
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Brink, Wyger M. (author), Remis, R.F. (author), Webb, A. (author)Purpose: High permittivity dielectric pads are known to be effective for tailoring the RF field and improving image quality in high field MRI. Despite a number of studies reporting benign specific absorption rate (SAR) effects, their “universal” safety remains an open concern. In this work, we evaluate the impact of the insulation material in...journal article 2023
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Hehenberger, Simon P. (author), Caizzone, Stefano (author), Thurner, Stefan (author), Yarovoy, Alexander (author)Frequency-dependent dielectric properties of 3-D-printed structured dielectrics (dielectric crystals) with engineered effective permittivity for micro-and mmWave applications are studied. Different modeling and measurement techniques for broadband dielectric properties of such 3-D-printed crystals are reviewed, their tradeoffs discussed, and...journal article 2023
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Klein, Julian (author), Pingault, B.J. (author), Florian, Matthias (author), Heißenbüttel, Marie Christin (author), Steinhoff, Alexander (author), Song, Zhigang (author), Torres, Kierstin (author), Dirnberger, Florian (author), Curtis, Jonathan B. (author)Correlated quantum phenomena in one-dimensional (1D) systems that exhibit competing electronic and magnetic order are of strong interest for the study of fundamental interactions and excitations, such as Tomonaga-Luttinger liquids and topological orders and defects with properties completely different from the quasiparticles expected in their...journal article 2023
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Hehenberger, S.P. (author), Caizzone, Stefano (author), Yarovoy, Alexander (author)The utilization of additive manufacturing (AM) to engineer the permittivity profile of dielectric resonator antennas (DRAs) is considered. For the first time, the capabilities of AM are exploited to create continuously swept permittivity profiles and applied to cylindrical DRAs. The spatial variant lattices (SVL) synthesis algorithm is...journal article 2023
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van Schelven, R.M. (author), Syed, Waqas (author), Carluccio, G. (author), Doris, Kostas (author), de Graauw, Anton (author), Neto, A. (author), Cavallo, D. (author)In this work, we investigate antenna architectures to implement dual-mode operation in phased array designs. Planar slot antenna elements are used in array configuration, in combination with artificial dielectrics layers (ADLs) located in the close proximity of the array, to achieve pattern shaping. The artificial dielectric superstrate...journal article 2023