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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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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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Alonso Del Pino, M. (author), Bosma, S. (author), Jung-Kubiak, C. (author), Bueno, J. (author), Chattopadhyay, G. (author), Llombart, Nuria (author)In this paper, we present a quasi-optical power distribution architecture based on the use of an integrated lens antenna that generates a uniform aperture field distribution. By using such distribution in combination with an integrated lens array, an efficient and scalable quasi-optical power distribution can be achieved at THz frequencies....conference paper 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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- Dabironezare, Shahab Oddin (author) doctoral thesis 2020
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Gandini, E. (author), Tamminen, Aleksi (author), Luukanen, Arttu (author), Llombart, Nuria (author)A wide field of view (FOV) inversely magnified dual-lens system for submillimeter wavelength imagers is presented in this paper. The antenna is designed for near-field focusing, at a range of 2.1 m from the primary aperture and to work in the frequency range from 200 to 600 GHz. The half-power beamwidth (HPBW) is 0.27° (1 cm in the image...journal article 2018
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Gandini, E. (author), Svedin, Jan (author), Bryllert, Thomas (author), Llombart, Nuria (author)In this paper, the practical tradeoffs for designing submillimeter wavelength imagers based on optomechanical systems combined with focal plane arrays (FPAs) are presented. The architecture of these systems differs for operation at short and long ranges. General formulas to derive the effective field of view of diffraction limited quasi...journal article 2017
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Meskers, A.J.H. (author), Spronck, J.W. (author), Munnig Schmidt, R.H. (author)The use of optical fibers presents several advantages with respect to free-space optical transport regarding sourcefrequency delivery to individual heterodyne interferometers. Unfortunately, fiber delivery to individual coaxial heterodyne interferometers leads to an increase of (periodic) nonlinearity in the measurement, because transporting...journal article 2014
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HesamMahmoudiNezhad, N.H.M.N. (author)The goal of this project is to investigate the performance of the Genetic Algorithms (GA) and the influence of their parameters on optical system optimization. We have developed our own code on optical system optimization using the MatLab GA module to accomplish this task. To evaluate the optical part of our code we checked the outcomes of each...master thesis 2014
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Meskers, A.J.H. (author), Spronck, J.W. (author), Munnig Schmidt, R.H. (author)Periodic nonlinearity (PNL) in displacement interferometers is a systematic error source that limits measurement accuracy. The PNL of coaxial heterodyne interferometers is highly influenced by the polarization state and orientation of the source frequencies. In this Letter, we investigate this error source and discuss two interferometer designs,...journal article 2014
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Bociort, F. (author), van Grol, P. (author)Understanding the structure of the design space in optical system optimization is difficult, because common human intuition fails when it encounters the challenge of high dimensionality, resulting from the many optimization parameters of lens systems. However, a deep mathematical idea, that critical points structure the properties of the space...conference paper 2012
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Ellis, J.D. (author), Meskers, A.J.H. (author), Spronck, J.W. (author), Munnig Schmidt, R.H. (author)Displacement interferometry is widely used for accurately characterizing nanometer and subnanometer displacements in many applications. In many modern systems, fiber delivery is desired to limit optical alignment and remove heat sources from the system, but fiber delivery can exacerbate common interferometric measurement problems, such as...journal article 2011
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Bociort, F. (author), Van Grol, P. (author)In this paper we describe new properties of the design landscape that could lead in the future to a new way to determine good starting points for subsequent local optimization. While in optimization the focus is usually only on local minima, here we show that points selected in the vicinity of other types of critical points (i.e. points where...conference paper 2010
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Bociort, F. (author)The presence of many local minima in the merit function landscape is perhaps the most difficult challenge in lens design. We present a simplified mathematical model that illustrates why the number of local minima increases rapidly with each additional lens added to the imaging system. Comparisons with results obtained with lens design software...conference paper 2010
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Bociort, F. (author), Van Grol, P. (author)In this paper we describe new properties of the design landscape that could lead in the future to a new way to determine good starting points for subsequent local optimization. While in optimization the focus is usually only on local minima, here we show that points selected in the vicinity of other types of critical points (i.e. points where...conference paper 2010
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Sluijter, M. (author), Xu, M. (author), Urbach, H.P. (author), De Boer, D.K.G. (author)We study the applicability of geometrical optics to inhomogeneous dielectric nongyrotropic optically anisotropic media typically found in in-plane liquid-crystal configurations with refractive indices no=1.5 and ne=1.7. To this end, we compare the results of advanced ray- and wave-optics simulations of the propagation of an incident plane wave...journal article 2010
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Sluijter, M. (author), Herzog, A. (author), De Boer, D.K.G. (author), Krijn, M.P.C.M. (author), Urbach, P.H. (author)For the first time, to our knowledge, we report ray-tracing simulations of an advanced liquid-crystal gradientindex lens structure for application in switchable two-dimensional/three-dimensional (3D) autostereoscopic displays. We present ray-tracing simulations of the angular-dependent lens action. From the results we conclude that the lens...journal article 2009
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Van Grol, P. (author), Bociort, F. (author), Van Turnhout, M. (author)Contrary to the frequent tacit assumption that the local minima of a merit function are points scattered more or less randomly over the design landscape, we have found that, at least for simple imaging systems (doublets with three and triplets with five variables) all design shapes we have observed thus far form a strictly ordered set of points,...conference paper 2009
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- Bociort, F. (author), Van Turnhout, M. (author) journal article 2009
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