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van Schelven, R.M. (author), Syed, Waqas (author), Carluccio, G. (author), Doris, Kostas (author), de Graauw, Anton (author), Neto, A. (author), Cavallo, D. (author)In this work, we investigate antenna architectures to implement dual-mode operation in phased array designs. Planar slot antenna elements are used in array configuration, in combination with artificial dielectrics layers (ADLs) located in the close proximity of the array, to achieve pattern shaping. The artificial dielectric superstrate...journal article 2023
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Ozzola, R. (author), Cavallo, D. (author), Neto, A. (author)We present a study on beam coupling in radiating structures that support multiple simultaneous beams. The formation of multiple beams is relevant in modern wireless communication applications when diverse data streams can be sent from a single transmitter to users located in different directions. General expressions are provided that relate...journal article 2022
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Bosma, S. (author), Neto, A. (author), Llombart, Nuria (author)In this work, we show that the near field of leaky-wave resonant antennas (LWAs) radiating into a dense medium can be locally represented as a spherical wave in a certain solid angle around broadside using an accurate definition of the phase center. The near field in this solid angle can be efficiently evaluated through the integration of the...journal article 2022
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Hoogelander, M. (author), van Berkel, S.L. (author), Malotaux, E.S. (author), Alonso Del Pino, M. (author), Spirito, M. (author), Neto, A. (author), Cavallo, D. (author), Llombart, Nuria (author)In this contribution we will present the diffraction-limited imaging capabilities of a focal plane array (FPA) of antenna-coupled direct-detectors at submillimeter wavelengths. The FPA prototype is a tightly sampled, 12-pixel array that was developed in a 22 nm CMOS technology and it covers a band from 200 GHz to 600 GHz. A quasi-optical (QO)...conference paper 2022
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Ozzola, R. (author), Cavallo, D. (author), Freni, Angelo (author), Llombart, Nuria (author), Neto, A. (author)The number of independent links that can be hosted by an antenna platform for Line-of-Sight (LoS) communications is limited by its physical size and the interference between the beams associated with different users. For large-size platforms, the interference can be reduced by compromising the aperture efficiency, and this trade-off is the...journal article 2022
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Van Katwijk, Alexander J. (author), Neto, A. (author), Toso, Giovanni (author), Cavallo, D. (author)We present an efficient method for the analysis of finite connected slot arrays in the presence of stratified media. The formulation is based on a spectral method of moments, where only one basis function is considered for each array element and one for each slot edge. An expression for the mutual impedance is derived in terms of a double...journal article 2022
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Ozzola, R. (author), Geng, J. (author), Neto, A. (author), Freni, A. (author)The thermal emission from finite-size bodies is directly investigated without resorting to reciprocity. Specifically, an integral equation representing the electromagnetic field distribution on a conductive body under investigation is proposed. The source of the electromagnetic field is classic as it is an extension of Johnson noise sources to...conference paper 2022
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Bueno Lopez, J. (author), Huiskes, M. (author), Zhang, H. (author), Sberna, P.M. (author), Llombart, Nuria (author), Neto, A. (author)Photoconductive antennas are devices that provide power up to THz frequencies at a relatively low cost. However, the power radiated by each antenna is typically quite low and arrays have been proposed to increase it. In this paper we present the design of a leaky enhanced array architecture that surpasses the state of the art as it operates...conference paper 2022
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Nair, A. (author), Dabironezare, Shahab Oddin (author), Neto, A. (author), Llombart, Nuria (author)Future applications in sensing and communications at (sub)-millimetre wavelengths will benefit from having large integrated coherent arrays. The use of lens arrays will enable the fabrication of integrated antenna front-ends with many potential independent beams as well as dynamic scanning capabilities. For applications such as MIMO...conference paper 2022
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Ozzola, R. (author), Geng, J. (author), Llombart, Nuria (author), Freni, A. (author), Cavallo, D. (author), Neto, A. (author)A Volumetric Method of Moments accelerated by means of iterative solvers combined with FFT matrix-vector products has been presented. The method allows analyzing small lens antennas with their integrated feeds efficiently since different structures and geometries can be studied with the same discretization, just by adding the material...conference paper 2022
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Zhang, H. (author), Dabironezare, Shahab Oddin (author), Carluccio, G. (author), Neto, A. (author), Llombart, Nuria (author)We present a freely accessible graphical user interface (GUI) for analyzing antenna-fed quasi-optical (QO) systems in reception (Rx). This analysis is presented here for four widely used canonical QO components: parabolic reflectors and elliptical, extended hemispherical, and hyperbolic lenses. The employed methods are geometrical optics (GO)...journal article 2021
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Zhang, H. (author), Bosma, S. (author), Neto, A. (author), Llombart, Nuria (author)A dual-polarized 4 x 4 scanning phased array antenna with leaky-wave enhanced lenses operating at 28 GHz is presented. Such an antenna can be used for point-to-point fifth-generation (5G) communications that require high gain, wide bandwidth (BW), and limited steering ranges. The proposed array has a periodicity of two wavelengths, and the...journal article 2021
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van Schelven, R.M. (author), Fiorellini Bernardis, A. (author), Sberna, P.M. (author), Neto, A. (author)Semiconductor (SC)-based bulk absorbers operating in the (sub-) THz range are discussed. The conductivities of the bulk media are described by the Drude model for electron gas where the electron density is controlled. The Drude model predicts the existence of two frequencies of interest: one associated with the scattering time of the electrons...journal article 2021
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van Berkel, S.L. (author), Malotaux, E.S. (author), De Martino, C. (author), Spirito, M. (author), Cavallo, D. (author), Neto, A. (author), Llombart, Nuria (author)A complete system modeling and characterization of a wideband differential terahertz (THz) direct detector, integrated in a commercial CMOS technology, is presented. The detector consists of a recently developed double leaky-slot lens antenna that operates from 200 to 600 GHz in combination with a differential Schottky barrier diode (SBD) direct...journal article 2021
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Fiorellini Bernardis, A. (author), Zhang, H. (author), Sberna, P.M. (author), Bueno Lopez, J. (author), Neto, A. (author), Llombart, Nuria (author)The time evolution of voltages and currents in a pulsed photo conductive antenna (PCA) source is evaluated resorting to a rigorous procedure that stems from semiconductor physics first, to define the phenomena involved in the generation of the photocurrent, and then relies on an equivalent circuit in time domain, providing a direct estimation...abstract 2021
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Neto, A. (author), Fiorellini Bernardis, A. (author), Emer, Diego (author), Freni, Angelo (author), Llombart, Nuria (author)The observable field is defined as the portion of the incident field that can contribute to the power received by an antenna. Recently, the observable field was estimated for a plane wave incidence. Here, the procedure is extended to a general incident field expressed as a superposition of homogeneous plane waves. The observable field concept...journal article 2020
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Van Katwijk, Alexander J. (author), Neto, A. (author), Toso, Giovanni (author), Cavallo, D. (author)We present the unit cell design of a wideband wide-scanning phased array operating in both Ku- and Ka-bands, for satellite communication applications. The radiating elements are dual-polarized connected slots loaded with an artificial dielectric superstrate, acting as a wide angle impedance matching (WAIM) structure. The design of the multi...conference paper 2020
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Tokan, F. (author), Cavallo, D. (author), Neto, A. (author)Three-dimensional body scanning systems are increasingly used in sensitive public areas such as airports. By providing a high resolution image of a person from all sides, it is possible to detect potential metallic, ceramic and explosive threats. For these systems, it is essential to design broadband antennas with a fan beam, highly directional...journal article 2020
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Yepes Julia, C. (author), Gandini, E. (author), Monni, S. (author), Neto, A. (author), Vliet, F. E. van (author), Cavallo, D. (author)In this letter, we present a design of a linear array of tilted dipoles to achieve radiation patterns with asymmetric angular filtering characteristics. To realize the asymmetric radiation, the dipole elements are spaced by a distance larger than half a wavelength, thus allowing for grating lobes to occur in the visible region. Moreover, the...journal article 2020
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Arias Campo, M. (author), Blanco, Darwin (author), Neto, A. (author), Llombart, Nuria (author), Bruni, Simona (author)In order to fulfill the exponential increase in the demand of high-speed wireless links, future XG wireless networks will be developed at higher carrier signal frequencies, reaching the hundreds of gigahertz. In this contribution, a leaky-wave-fed HDPE lens antenna working at ${G}$ -band which can be useful for future XG communications is...journal article 2020