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- Llombart, Nuria (author), Hegmann, Frank (author), Song, Ho Jin (author) contribution to periodical 2024
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Neto, A. (author), Llombart, Nuria (author), Freni, Angelo (author)In the circuit theory, the Norton and Thevenin equivalent generators are tools that simplify the solutions of networks involving passive or active components. They have been extensively used in the frequency domain to describe time-harmonic sources. A time-stepped evolution is instead typically used to include transient sources. As a...journal article 2023
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Fiorellini Bernardis, A. (author), Sberna, P.M. (author), Bueno Lopez, J. (author), Zhang, H. (author), Llombart, Nuria (author), Neto, A. (author)Drude's description of the response of low-temperature gallium arsenide to optical pulse excitation is used to evaluate the components of a time-domain Norton equivalent circuit of a photoconductive antenna (PCA) source. The saturation of the terahertz (THz) radiated power occurring at large optical excitation levels was previously associated...journal article 2023
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Zhang, H. (author), Dabironezare, Shahab Oddin (author), Baselmans, J.J.A. (author), Llombart, Nuria (author)Large format focal plane arrays (FPAs) of dielectric lenses are promising candidates for wide field-of-view submillimeter imagers. In this work, we optimize the scanning gain of such imagers via shaping lens surfaces. We develop an optimization procedure using a field correlation technique between the fields generated by a reflector on the...journal article 2023
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Bueno Lopez, J. (author), Sberna, P.M. (author), Fiorellini Bernardis, A. (author), Zhang, H. (author), Neto, A. (author), Llombart, Nuria (author)State-of-the-art THz pulsed commercial systems operating over large bandwidth suffer from high dispersion or low radiation efficiency due to the poor coupling between the transmitter and receiver photoconductive antennas (PCAs). In this work, we present the fabrication and characterization of a leaky-lens PCA that has the potential to solve...journal article 2023
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Hoogelander, M. (author), van Berkel, S.L. (author), Malotaux, E.S. (author), Alonso Del Pino, M. (author), Cavallo, D. (author), Spirito, M. (author), Llombart, Nuria (author)This article presents the development of a focal plane array (FPA) for terahertz imaging applications with a near diffraction-limited resolution achieved through a very tight sampling of the focal plane. The antenna array is integrated with direct detectors in a 22-nm CMOS technology and operates from 200 to 600 GHz. The tight sampling of the...journal article 2023
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van Rooijen, N. (author), Alonso Del Pino, M. (author), Bueno Lopez, J. (author), Spirito, M. (author), Llombart, Nuria (author)This contribution presents the development of an electrically small lens antenna using an artificially loaded thermoplastic at 140-170GHz. We will present the on-going development of the Fly’s Eye front end antenna concept that was presented in [1]. The antenna is composed on a dual plastic lens, a core lens and a shell lens, fed by a double...conference paper 2023
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Hoogelander, M. (author), van Dijk, R. (author), Alonso Del Pino, M. (author), Spirito, M. (author), Llombart, Nuria (author)The design of a focal plane array (FPA) for imaging at sub-mm wavelengths generally is a trade-off between resolution and sensitivity. For maximum angular resolution, minimal spacing between FPA elements is desired, which leads to increased losses due to spillover and mutual coupling and therefore deteriorates the imaging sensitivity. This work...conference paper 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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Berkel, S. L. van (author), Maestrini, A. (author), Jung-Kubiak, C. (author), Bosma, S. (author), Alonso Del Pino, M. (author), Hayton, D. (author), Kooi, Jacob (author), Siles, J. V. (author), Llombart, Nuria (author), Mehdi, I. (author), Chattopadhyay, G. (author)Terahertz heterodyne spectrometer instruments have been traditionally limited to a single pixel or a handful of pixels due to integration and assembly constraints and a limited availability of local oscillator (LO) power. As a solution we propose a novel silicon-micromachined planar and modular packaging strategy, that will allow for a dense...conference paper 2023
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Hoogelander, M. (author), Alonso Del Pino, M. (author), Llombart, Nuria (author), Spirito, M. (author)The continuous advancements in the coverage and sensitivity of terahertz direct-detector imagers places increasing constraints on the test benches needed for characterization. Already, relative differences on the order of a few decibels are observed between simulated and measured performance in the state-of-the-art literature. This...conference paper 2023
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Zhang, H. (author), Bueno Lopez, J. (author), Sberna, P.M. (author), Llombart, Nuria (author), Neto, A. (author)Photoconductive antennas (PCAs) are promising candidates for sensing and imaging systems. We have investigated their properties under pulsed laser illumination both in transmission and reception. First, a transmitting PCA has been characterized including a power measurement. Then, a Quasi-Optical (QO) link between a transmitter and a receiver...conference paper 2023
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Huiskes, M.D. (author), Bueno Lopez, J. (author), Llombart, Nuria (author), Neto, A. (author)Photoconductive antennas (PCAs) are used for imaging and sensing applications because of their ability to radiate short pulses with large bandwidths in the THz regime. The characterization of PCAs has previously been done using a time-domain Norton equivalent circuit. Thanks to a recent contribution, the size of the excited photoconductive area...conference paper 2023
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Zhang, H. (author), Dabironezare, Shahab Oddin (author), Llombart, Nuria (author)Lens based focal plane arrays (FPAs) with thousand elements are promising candidates for wide scanning sub-millimeter security imaging systems. To analyze such arrays, a field correlation approach is employed to design an FPA of quartz lenses coupled to a reflector. We consider quartz as the lens material due to its lower cost compared to...conference paper 2023
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- Llombart, Nuria (author) contribution to periodical 2023
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Pascual Laguna, A. (author), Cavallo, D. (author), Baselmans, J.J.A. (author), Llombart, Nuria (author)This communication proposes a broadband and efficient integrated focal plane array solution based on a near-field focused connected array of slots. The focused aperture provides: 1) broadband and highly efficient illumination of the quasi-optical system and 2) scanning capabilities within a focusing system. The connected array antenna in turn...journal article 2022
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Llombart, Nuria (author), Dabironezare, Shahab Oddin (author)This article presents a feasibility study of single feed per beam quasi-optical (QO) antennas for enabling incoherent multiple-input multiple-output (MIMO) array front-end architectures at 270 GHz. The objective is to reach ultrafast and radiated energy efficient point-to-point (PtP) wireless links by exploiting the multimode capacity of...journal article 2022
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Hu, Yong (author), Baggio, Mariangela (author), Dabironezare, Shahab Oddin (author), Tamminen, Aleksi (author), Toy, Brandon (author), Ala-laurinaho, Juha (author), Brown, Elliot (author), Llombart, Nuria (author), Deng, Sophie X. (author), Wallace, Vincent (author), Taylor, Zachary D. (author)A system concept for online alignment verification of millimeter-wave, corneal reflectometry is presented. The system utilizes beam scanning to generate magnitude-only reflectivity maps of the cornea at 650 GHz and compares these images to a precomputed/measured template map to confirm/reject sufficient alignment. A system utilizing five off...journal article 2022
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Baselmans, J.J.A. (author), Karatsu, K. (author), Llombart, Nuria (author), Rybak, M. (author), Bueno Lopez, J. (author), Buijtendorp, B.T. (author), Dabironezare, Shahab Oddin (author), Hähnle, S.A. (author), Pascual Laguna, A. (author), Thoen, David (author), Yates, S.J.C. (author), Endo, A. (author)Integrated superconducting spectrometer (ISS) technology will enable ultra-wideband, integral-field spectroscopy for (sub)millimeter-wave astronomy, in particular, for uncovering the dust-obscured cosmic star formation and galaxy evolution over cosmic time. Here, we present the development of DESHIMA 2.0, an ISS for ultra-wideband...journal article 2022
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Baselmans, J.J.A. (author), Facchin, F. (author), Pascual Laguna, A. (author), Bueno, J. (author), Thoen, David (author), Murugesan, V. (author), Llombart, Nuria (author), de Visser, P.J. (author)Aims. Future actively cooled space-borne observatories for the far-infrared, loosely defined as a 1-10 THz band, can potentially reach a sensitivity limited only by background radiation from the Universe. This will result in an increase in observing speed of many orders of magnitude. A spectroscopic instrument on such an observatory requires...journal article 2022