Searched for: subject%3A%22Geometrical%255C+optics%22
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Zhang, H. (author)
In recent decades, dielectric lens antennas have been more and more adopted and developed for sensing and imaging applications at sub-millimeter (sub-mm) wavelengths because they can achieve high gain while keeping their physical size and weight acceptable at these wavelengths. More recently, as low-loss and low-cost lens materials have become...
doctoral thesis 2024
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Hu, Weiya (author), Coco Martin, C.M. (author), Cavallo, D. (author)
A semi-analytical method is presented for the design of gradient index (GRIN) flat lenses. Closed-form expressions are derived to define the refractive index distribution of the lens, for several cases: collimating lenses with on-axis feed, collimating lenses with off-axis feed, lenses converting spherical wavefronts with different...
journal article 2024
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Konijnenberg, A.P. (author), Adam, A.J.L. (author), Urbach, Paul (author)
This book treats optics at the level of students in the later stage of their bachelor or the beginning of their master. It is assumed that the student is familiar with Maxwell’s equations. Although the book takes account of the fact that optics is part of electromagnetism, special emphasis is put on the usefulness of approximate models of optics...
book 2024
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Mavropoulou, Alexandra (author)
In the framework of this MSc thesis, the analysis and design guidelines for part of the quasi-optical system of a proposed astronomical instrument, called TIFUUN, are presented. The TIFUUN instrument is an imaging spectrometer, planned to be placed in the ASTE telescope to perform ground-based astronomical observations in the mm-submm wavelength...
master thesis 2023
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Gottmer, Leila (author)
In this thesis, an efficient optimization method is described for synthesizing lens antennas fabricated in low permittivity plastic materials to achieve wide scanning performances. The method is based on an antenna in reception representation. The optimized parameters are the location and orientation of the antenna feeder, lens angular region...
master thesis 2022
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Nair, Ashwita (author)
Lens array architectures are being developed for high frequency applications such as phased arrays for 5G point-to-point communications, Fly’s Eye lens arrays for wideband wireless communications and scanning phased arrays at sub-millimeter wavelengths. Each of these applications employ different feed configurations, lens geometries and require...
master thesis 2021
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Konijnenberg, A.P. (author), Adam, A.J.L. (author), Urbach, Paul (author)
This book treats optics at the level of students in the later stage of their bachelor or the beginning of their master. It is assumed that the student is familiar with Maxwell’s equations. Although the book takes account of the fact that optics is part of electromagnetism, special emphasis is put on the usefulness of approximate models of optics...
book 2021
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Dabironezare, Shahab Oddin (author)
doctoral thesis 2020
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Dabironezare, Shahab Oddin (author), Carluccio, G. (author), Freni, Angelo (author), Neto, A. (author), Llombart, Nuria (author)
Future sub millimeter imagers are being developed with large focal plane arrays (FPAs) of lenses to increase the field of view (FoV) and the imaging speed. A full-wave electromagnetic analysis of such arrays is numerically cumbersome and time-consuming. This article presents a spectral technique based on Fourier optics combined with...
journal article 2020
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Zhang, Huasheng (author)
In this work, a MATLAB based graphical user interface (GUI) tool is built to analyze Quasi-optical (QO) systems in reception with the Fourier Optics (FO) and Geometrical Optics (GO) methods. Five canonical QO components are discussed, namely parabolic reflectors, elliptical lenses, hemispherical lenses, hyperbolic lenses, and elliptical mirrors....
master thesis 2018
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Mout, B.M. (author), Wick, Michael (author), Bociort, F. (author), Petschulat, Joerg (author), Urbach, Paul (author)
We study a simulation method that uses the Wigner distribution function to incorporate wave optical effects in an established framework based on geometrical optics, i.e., a ray tracing engine. We use the method to calculate point spread functions and show that it is accurate for paraxial systems but produces unphysical results in the presence...
journal article 2018
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Santbergen, R. (author), Meguro, Tomomi (author), Suezaki, Takashi (author), Koizumi, Gensuke (author), Yamamoto, Kenji (author), Zeman, M. (author)
We present a new version of our optical model for solar cell simulation: GenPro4. Its working principles are briefly explained. The model is suitable for quickly and accurately simulating a wide range of wafer-based and thin-film solar cells. Especially adjusting layer thicknesses to match the currents in multijunction devices can be done...
journal article 2017
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Strauch, M. (author), Shao, Y. (author), Bociort, F. (author), Urbach, Paul (author)
The increased usage of liquid lenses motivates us to investigate surface waves on the liquid's surface. During fast focal switching, the surface waves decrease the imaging quality. We propose a model that describes the surface modes appearing on a liquid lens and predicts the resonance frequencies. The effects of those surface modes on a...
journal article 2017
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Mata Pavia, J. (author), Wolf, M. (author), Charbon, E. (author)
Single-photon avalanche diode (SPAD) imagers typically have a relatively low fil factor, i.e. a low proportion of the pixel’s surface is light sensitive, due to in-pixel circuitry. We present a microlens array fabricated on a 128x128 single-photon avalanche diode (SPAD) imager to enhance its sensitivity. The benefit and limitations of these...
journal article 2014
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Sluijter, M. (author)
When the optical behavior of light in a medium depends on the direction in which light is traveling, the medium is called optically anisotropic. Light is an electromagnetic wave and in this thesis, we discuss the electromagnetic theory on optical anisotropy. We do this with the assumption that the wavelength of light approaches zero. The field...
doctoral thesis 2010
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Van Turnhout, M. (author), Bociort, F. (author)
In lens design, damped least-squares methods are typically used to find the nearest local minimum to a starting configuration in the merit function landscape. In this paper, we explore the use of such a method for a purpose that goes beyond local optimization. The merit function barrier, which separates an unsatisfactory solution from a...
journal article 2009
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Sluijter, M. (author), De Boer, D.K.G. (author), Urbach, H.P. (author), Strömer, J. (author), Cennini, G. (author)
conference paper 2009
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Van Turnhout, M. (author), Bociort, F. (author)
Many optical design programs use various forms of the damped least-squares method for local optimization. In this paper, we show that damped least-squares algorithms, with maximized computational speed, can create sensitivity with respect to changes in initial conditions. In such cases, starting points, which are very close to each other, lead...
journal article 2009
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Grabarnik, S. (author), Emadi, A. (author), Wu, H. (author), De Graaf, G. (author), Wolffenbuttel, R.F. (author)
A concept for a highly miniaturized spectrometer featuring a two-component design is presented. The first component is a planar chip that integrates an input slit and aberration-correcting diffraction grating with an image sensor and is fabricated using microelectromechanical systems (MEMS) technologies. Due to the fabrication in a simple MEMS...
journal article 2008
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Bociort, F. (author), Andersen, T.B. (author), Beckmann, L.H.J.F. (author)
We extend the method for the automatic computation of high-order optical aberration coefficients to include (1) a finite object distance and (2) an infinite entrance pupil position (telecentricity in object space). We present coefficients of the power series expansion of the transverse aberration vector with respect to the normalized aperture...
journal article 2008
Searched for: subject%3A%22Geometrical%255C+optics%22
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