Simulation Environment for an Open-Ended Coaxial Probe and Visualisation of Permittivity Measurements

This thesis work focuses on the development of reference data and visualization software to implement a user friendly probe to image the electrical parameters (i.e., permittivity) of biological materials, such as the skin. The reference data is used for the creation of a lookup table that can be used to quickly derive the relative permittivity of a material from the probe measurements. It was found that the reference data provided for the lookup table resulted in reliable derivation of relative permittivity. A second task described in this report is the design and implementation of a graphical user interface which displays measured relative permittivity values. This user interface should be capable of interacting with the measuring equipment and positioning system to acquire data and corresponding positions. The user interface is capable of presenting these in a visual format by showing 2D and 3D plots of the values and the locations at which they were measured. The underlying design pattern is explained. The user interface, written in MATLAB, is fully Object Oriented and uses the Model-View-Controller paradigm. The permittivity values can be viewed at different frequencies and a choice to view the magnitude, the real part or the imaginary part of the permittivity can be made. A modular approach has made the user interface well extendible."Electrical Engineering, Mathematics and Computer ScienceMicroelectronicsElectrical EngineeringEE3L1

Road Surface Conditions Identification via H α A Decomposition and Its Application to mm-Wave Automotive Radar

A novel approach based on the entropy-alpha-anisotropy decomposition, also known as the $H\alpha A$ decomposition, for the recognition of road surface conditions using automotive radar is presented. To apply the $H\alpha A$ decomposition to automotive radar data, a dedicated signal processing pipeline has been developed. To investigate its effectiveness, fully polarimetric measurements of surface scattering were performed in lab conditions as well as outdoors on actual road surface material under various conditions. A high-level analysis using the Euclidean distances between cluster centroids and the standard deviations of the $H$ , $\alpha$ , and $A$ features is performed, and it is shown that the proposed pipeline can provide an opportunity for classification of road surfaces, leading to enhanced road safety. Finally, the effect of neglecting the cross-polar components of the fully polarimetric measurements is considered. It is shown that in this case, the $A$ feature cannot be used anymore. Despite this, the $H$ and $\alpha$ features can still be used and several road surface conditions can still be distinguished from each other at the cost of less separation between the classes, thus leading to a trade-off between classification accuracy and radar system cost/complexity.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Microwave Sensing, Signals & System

Convergence of Scattering Parameters and HαA-Features of Road Surfaces

The convergence of polarimetric scattering parameters and H, α and A features of road surfaces under various conditions is analysed. It is shown that the number of radar measurements used for surface classification can be traded off with accuracy of the estimation of the mean value and covariance of S-parameters and H, α and A features. Furthermore, it is shown that the H, α and A features converge at the same rate, independent of antenna orientation angles or considered road surface conditions.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Microwave Sensing, Signals & System

Dynamic Road Surface Signatures in Automotive Scenarios

A method to compute road surface signatures in the automotive scenario is presented. This method is subsequently applied to a rough asphalt surface without undulations. It is shown that, due to the observation geometry, the road surface signature experiences significant spreading along the Doppler-axis, resulting in a distinct range-Doppler map that could be used for classification purposes. This was also confirmed with an experimental recording from a car driving around the university campus. The variation of Doppler-shift and incident angle within a range bin and over a coherent processing interval is also evaluated.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work publicMicrowave Sensing, Signals & System

Statistical Polarimetric RCS Model of an Asphalt Road Surface for mm-Wave Automotive Radar

A method for extracting fully polarimetric statistical properties of road surface radar cross sections is presented. This method is subsequently applied to extract radar cross section information from an asphalt road surface. Furthermore, an approach is introduced to synthesise the scattered signal of road surface returns as measured by a radar. The extracted statistical properties of asphalt are subsequently used in this synthesis procedure, and excellent agreement with the experimental measurement results is demonstrated.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Microwave Sensing, Signals & System

Effect of a nanoparticle on the optical properties of a photonic crystal cavity: Theory and experiment

Single quantum emitters can be coupled to photonic crystal (PC) cavities by placing their host nanoparticles into the cavity field. We describe fabrication, characterization, and tuning of gallium-phosphide PC cavities that resonate in the visible, and simulations and measurements of the effect of a nanoparticle on the optical properties of these cavities. Simulations show that introducing a 50 nm (100 nm) sized nanoparticle into S1 and L3-type cavities, with original quality factors of 18·10^3 and 73·10^3, respectively, reduces the quality factor by <10% (?50%). Furthermore, simulations indicate that an emitter embedded in a 50 nm (100 nm) sized nanoparticle can be coupled 3.5 (9) times more effectively to an S1 cavity than to an L3 cavity. We employ a nanopositioning technique to position individual, 50 nm sized nanocrystals into S1 cavities, and find that the quality factors are reduced by a factor of 0.9±0.1 from the original values of order 10^3.QN/Quantum NanoscienceApplied Science

Surface PEG Grafting Density Determines Magnetic Relaxation Properties of Gd-Loaded Porous Nanoparticles for MR Imaging Applications

Surface PEGylation of nanoparticles designed for biomedical applications is a common and straightforward way to stabilize the materials for in vivo administration and to increase their circulation time. This strategy becomes less trivial when MRI active porous nanomaterials are concerned as their function relies on water/proton-exchange between the pores and bulk water. Here we present a comprehensive study on the effects of PEGylation on the relaxometric properties of nanozeolite LTL (dimensions of 20 × 40 nm) ion-exchanged with paramagnetic GdIII ions. We evidence that as long as the surface grafting density of the PEG chains does not exceed the “mushroom” regime (conjugation of up to 6.2 wt % of PEG), Gd-LTL retains a remarkable longitudinal relaxivity (38 s–1 mM–1 at 7 T and 25 °C) as well as the pH-dependence of the longitudinal and transverse relaxation times. At higher PEG content, the more compact PEG layer (brush regime) limits proton/water diffusion and exchange between the interior of LTL and the bulk, with detrimental consequences on relaxivity. Furthermore, PEGylation of Gd-LTL dramatically decreases the leakage of toxic GdIII ions in biological media and in the presence of competing anions, which together with minimal cytotoxicity renders these materials promising probes for MRI applications.BT/Biocatalysi