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van Katwijk, Alexander J. (author), Coco Martin, C.M. (author), Toso, Giovanni (author), Cavallo, D. (author)The characteristic cross-polarization (X-pol) of wide angle impedance matching (WAIM) structures is investigated. The study considers an ideal linearly polarized current sheet in the presence of various dielectric and artificial dielectric superstrates, analyzed using transmission line models representing the stratified media. The main...journal article 2024
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Simader, Thomas (author)Ground penetrating radar (GPR) data has proven to be a powerful tool for non-invasively estimating the electrical properties of the shallow subsurface. Petrophysical relationships allow them to be converted into hydrological parameters such as soil water content (SWC) and porosity. In the presence of thin layers, complex wave phenomena can occur...master thesis 2023
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Remmerswaal, Evan (author)Objective: This work focuses on the feasibility of using Electrical Impedance Spectroscopy (EIS) to differentiate between cancerous and healthy tissues in real-time alongside the GI tract. This is to see whether it is possible to support surgeons when taking biopsies, or to see if it is possible to make biopsies obsolete with EIS. Methods: The...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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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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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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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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Vlachogiannakis, G. (author)Abundant research reported in the literature has indicated that broadband dielectric spectroscopy (BDS), i.e., the measurement of material permittivity versus frequency, can serve a broad range of applications, including, but not limited to, biomedical, food, automotive, and agricultural industries. Adopting this technique in real-life...doctoral thesis 2022
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Leijsen, R.L. (author), Brink-van Caspel, W.M. (author), At Van Den Berg, Cornelis (author), Webb, A. (author), Remis, R.F. (author)Electrical properties tomography (EPT) is an imaging method that uses a magnetic resonance (MR) system to non-invasively determine the spatial distribution of the conductivity and permittivity of the imaged object. This manuscript starts by providing clear definitions about the data required for, and acquired in, EPT, followed by comprehensively...journal article 2021
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van der Lingen, Elke (author)Due to the earth’s population growth and the increased living age of a person, more and more people could deal with medical problems. Early detection of health related problems in both healthy and people with medical problems, will catch problems early and prevent the need for more costly procedures. One of these medical problems is concerning...master thesis 2020
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Adla, Soham (author), Rai, Neeraj Kumar (author), Karumanchi, Sri Harsha (author), Tripathi, Shivam (author), Disse, Markus (author), Pande, S. (author)Soil volumetric water content (VWC) is a vital parameter to understand several ecohydrological and environmental processes. Its cost-effective measurement can potentially drive various technological tools to promote data-driven sustainable agriculture through supplemental irrigation solutions, the lack of which has contributed to severe...journal article 2020
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van Gemert, J.H.F. (author)This dissertation describes how to design dielectric pads that can be used to increase image quality in Magnetic Resonance Imaging, and how to accelerate image reconstruction times using a preconditioner.<br/><br/>Image quality is limited by the signal to noise ratio of a scan. This ratio is increased for higher static magnetic field strengths...doctoral thesis 2019
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van Gemert, J.H.F. (author), Brink, Wyger M. (author), Remis, R.F. (author), Webb, A. (author)PURPOSE: One of the main concerns in fetal MRI is the radiofrequency power that is absorbed both by the mother and the fetus. Passive shimming using high permittivity materials in the form of "dielectric pads" has previously been shown to increase the formula presented efficiency and homogeneity in different applications, while reducing the...journal article 2019
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Leijsen, R.L. (author), van den Berg, Cornelis (author), Webb, A. (author), Remis, R.F. (author), Mandija, Stefano (author)Magnetic resonance electrical properties tomography (MR-EPT) is a technique used to estimate the conductivity and permittivity of tissues from MR measurements of the transmit magnetic field. Different reconstruction methods are available; however, all these methods present several limitations, which hamper the clinical applicability. Standard...journal article 2019
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van Gemert, J.H.F. (author), Brink, Wyger (author), Webb, A. (author), Remis, R.F. (author)Purpose: High-permittivity materials in the form of flexible “dielectric pads” have proved very useful for addressing RF inhomogeneities in high field MRI systems. Finding the optimal design of such pads is, however, a tedious task, reducing the impact of this technique. We present an easy-to-use software tool which allows researchers and...journal article 2019
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van Gemert, J.H.F. (author), Brink, W.M. (author), Webb, A. (author), Remis, R.F. (author)Inhomogeneities in the transmit radio frequency magnetic field ( {\text{B}}-{1}^{+} ) reduce the quality of magnetic resonance (MR) images. This quality can be improved by using high-permittivity pads that tailor the {\text{B}}-{1}^{+} fields. The design of an optimal pad is application-specific and not straightforward and would therefore...journal article 2018
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Vlachogiannakis, G. (author), Pertijs, M.A.P. (author), Spirito, M. (author), de Vreede, L.C.N. (author)A compact sensing pixel for the determination of the localized complex permittivity at microwave frequencies is proposed. Implemented in the 40-nm CMOS, the architecture comprises a square patch, interfaced to the material-under-test sample, that provides permittivity-dependent admittance. The patch admittance is read out by embedding the patch...journal article 2018
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Hu, Z. (author), Vlachogiannakis, G. (author), Pertijs, M.A.P. (author), de Vreede, L.C.N. (author), Spirito, M. (author)A 0.14-μ m CMOS 2-D permittivity imaging matrix prototype operating at microwave frequencies is presented. It comprises 25 permittivity-sensing pixels, each consisting of a sensing patch connected to a dedicated RF bridge. A trans-conduct-ance stage converts the imbalance voltage to a current signal, subsequently down-converted to an...conference paper 2018
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Marx, Philipp (author), Wanner, Andrea (author), Zhang, Zucong (author), Jin, H. (author), Tsekmes, I.A. (author), Smit, J.J. (author), Kern, Wolfgang (author), Wiesbrock, Frank (author)Five types of nanofillers, namely, silica, surface-silylated silica, alumina, surface-silylated alumina, and boron nitride, were tested in this study. Nanocomposites composed of an epoxy/amine resin and one of the five types of nanoparticles were tested as dielectrics with a focus on (i) the surface functionalization of the nanoparticles and (ii...contribution to periodical 2017
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Cavallo, Daniele (author), Cantika Felita, Cantika (author)We present an analysis of artificial dielectric layers (ADLs), when a lateral shift between layers is present. The alternate lateral displacement of the layers is an important parameter to engineer the desired effective electromagnetic properties of the ADL material. More specifically, much higher equivalent dielectric constants can be...conference paper 2017
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