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1993 documents found for International Journal
3D imaging by fast deconvolution algorithm in short-range UWB radar for concealed weapon detection
Bart Nauwelaers, Frank E. van Vliet, François le Chevalier, Timofey Savelyev, Alexander Yarovoy
Published online : 01-06-2013
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A fast imaging algorithm for real-time use in short-range (ultra-wideband) radar with synthetic or real-array aperture is proposed. The reflected field is presented here as a convolution of the target reflectivity and point spread function (PSF) of the imaging system. To obtain a focused 3D image, the proposed algorithm deconvolves the PSF out from the acquired data volume with high speed due to f
MRF volume 5 issue 2 Cover and Back matter
John Wood, Eduard Beltrán
Published online : 01-04-2013
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MRF volume 5 issue 2 Cover and Front matter
John Wood, Eduard Beltrán
Published online : 01-04-2013
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A 2-bit, 3.1 GS/s, band-pass DSM receiver for active antenna systems
Bart Nauwelaers, Frank E. van Vliet, François le Chevalier, Udo Karthaus, Stephan Ahles, Ahmed Elmaghraby, Horst Wagner
Published online : 01-06-2013
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This paper presents a radio frequency (RF) continuous-time band-pass delta sigma modulator (CT BP DSM) receiver realized in a 180 nm SiGe BiCMOS technology. It also provides an introduction to active antenna systems (AAS) for cellular infrastructure base stations, which is the target application for this RF integrated circuit (IC). The internal quantizer and feedback digital to analog converter (D
Multi-channel reconfigurable front-end architecture for waveform-agile radar
Bart Nauwelaers, Frank E. van Vliet, François le Chevalier, Giacomo Calabrese, Lorenzo Pagli, Oleg A. Krasnov, Alexander G. Yarovoy
Published online : 01-06-2013
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This paper presents the design of a multi-channel reconfigurable front-end architecture for a waveform-agile radar. At first the purpose of the design is explained following the status of research on software-defined radar at MTSR. A description of the proposed system architecture is given with details on sub-systems implementation. Then some preliminary results obtained on a prototype of the plat
Enhanced tunable performance of high -factor BaSrTiO film bulk acoustic wave resonators
Bart Nauwelaers, Frank E. van Vliet, François le Chevalier, Andrei Vorobiev, Spartak Gevorgian
Published online : 01-06-2013
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Emerging intrinsically tunable film bulk acoustic wave(BAW) resonators allow the development of new generation reconfigurable and agile microwave circuits. In this paper, we demonstrate the enhancement of tunable performance of the high Q-factor BaSrTiO BAW ? solidly mounted resonators (BAW?SMR) by varying Ba concentration. The BaSrTiO BAW?SMR reveal tunability of series resonance frequency up to
Position estimation of lap joints for seam tracking applications at mm-wave frequencies
Bart Nauwelaers, Frank E. van Vliet, François le Chevalier, Jochen O. Schrattenecker, Andreas Haderer, Günther Reinthaler, Andreas Stelzer
Published online : 01-06-2013
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In this paper, we present the results of using a frequency-stepped continuous-wave radar system to estimate the position of overlapping and electrically good conductive plates. We especially focus on polarimetric scattering effects caused by the step of a lap joint, which is a common welding-geometry. To model the step's contribution to the overall scattered signal, we use a two-dimensional combin
Miniature single-sideband subharmonically-pumped 60 GHz direct upconverter in a uniplanar GaAs pHEMT technology using inductive and capacitive loading techniques
Bart Nauwelaers, Frank E. van Vliet, François le Chevalier, Khelifa Hettak, Tyler N. Ross, Nazish Irfan, Gabriel Cormier, Mustapha C. E. Yagoub, Gilbert A. Morin, Jim S. Wight
Published online : 01-06-2013
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This paper presents a novel, compact, single-sideband (SSB) subharmonically-pumped (SHP) direct upconverter developed in a uniplanar 0.18 ?m GaAs technology. A total of 100 MHz in-phase and quadrature signals directly modulate the second harmonic of a 30 GHz carrier signal, producing a 60.1 GHz output. Two pairs of antiparallel diodes reduce feed-through of the 30 GHz local oscillator (LO) signal
Toward highly scaled AlN/GaN-on-Silicon devices for millimeter wave applications
Bart Nauwelaers, Frank E. van Vliet, François le Chevalier, Farid Medjdoub, Yoann Tagro, Bertrand Grimbert, Damien Ducatteau, Nathalie Rolland
Published online : 01-06-2013
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In this work, the possibility of achieving GaN-on-Si devices for millimeter wave applications operating at high bias is demonstrated. It is shown that highly scaled AlN/GaN-on-Si double heterostructure enables us to significantly improve electron confinement under high electric field as compared to single heterostructure while delivering high carrier density (>2 × 10 cm). Subsequently, trapping ef
Study of the noise processes in microwave oscillators based on passive optical resonators
Bart Nauwelaers, Frank E. van Vliet, François le Chevalier, Khaldoun Saleh, Pierre-Henri Merrer, Amel Ali-Slimane, Olivier Llopis, Gilles Cibiel
Published online : 01-06-2013
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Two types of optoelectronic oscillators delivering high spectral purity microwave signals are presented in this paper. These oscillators use the Pound?Drever?Hall laser stabilization technique to lock the laser carrier onto two different types of passive optical resonators featuring high-quality factors: a fiber ring resonator (FRR) and a whispering gallery mode monocrystalline disk-shaped micro-r
Human motion classification using a particle filter approach: multiple model particle filtering applied to the micro-Doppler spectrum
Bart Nauwelaers, Frank E. van Vliet, François le Chevalier, Stephan Groot, Ronny Harmanny, Hans Driessen, Alexander Yarovoy
Published online : 01-06-2013
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In this article, a novel motion model-based particle filter implementation is proposed to classify human motion and to estimate key state variables, such as motion type, i.e. running or walking, and the subject's height. Micro-Doppler spectrum is used as the observable information. The system and measurement models of human movements are built using three parameters (relative torso velocity, heigh
MEMS reconfigurable millimeter-wave surface for V-band rectangular-waveguide switch
Bart Nauwelaers, Frank E. van Vliet, François le Chevalier, Zargham Baghchehsaraei, Umer Shah, Jan Åberg, Göran Stemme, Joachim Oberhammer
Published online : 01-06-2013
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This paper presents for the first time a novel concept of a microelectromechanical systems (MEMS) waveguide switch based on a reconfigurable surface, whose working principle is to block the wave propagation by short-circuiting the electrical field lines of the TE10 mode of a WR-12 rectangular waveguide. The reconfigurable surface is only 30 µm thick and consists of up to 1260 micromachined cantile
Multichannel interferometric SAR phase unwrapping using extended Kalman Smoother
Bart Nauwelaers, Frank E. van Vliet, François le Chevalier, Davide Chirico, Gilda Schirinzi
Published online : 01-06-2013
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Phase unwrapping (PU) is one of the key processing steps in reconstructing the digital elevation model (DEM) of a scene from interferometric synthetic aperture radar (InSAR) data. The PU problem entails the estimation of an absolute phase from observation of its noisy principal (wrapped) values. Recently, PU approaches based on Kalman filtering have proved their efficacy in tackling the PU problem
A 24 GHz wideband monostatic FMCW radar system based on a single-channel SiGe bipolar transceiver chip
Bart Nauwelaers, Frank E. van Vliet, François le Chevalier, Christian Bredendiek, Nils Pohl, Timo Jaeschke, Sven Thomas, Klaus Aufinger, Attila Bilgic
Published online : 01-06-2013
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In this paper a monostatic frequency-modulated continuous-wave (FMCW) radar system around a center frequency of 24 GHz with a wide tuning range of 8 GHz (?33%) is presented. It is based on a fully integrated single-channel SiGe transceiver chip. The chip architecture consists of a fundamental VCO, a receive mixer, a divider chain, and coupling/matching networks. All circuits, except for the divide
0.7?1.8 GHz multiband digital polar transmitter using watt-class current-mode class-D CMOS power amplifier and digital envelope modulation technique for reduced spurious emissions
Bart Nauwelaers, Frank E. van Vliet, François le Chevalier, Toshifumi Nakatani, Donald F. Kimball, Lawrence E. Larson, Peter M. Asbeck
Published online : 01-06-2013
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A polar transmitter driven by digital input signals for envelope and phase is demonstrated, using a band-switching output resonator to achieve multiband operation. A new digital pulse width modulation algorithm is also shown to partially suppress spurious signals associated with the digital input envelope signal. The transmitter consists of a current-mode class-D (CMCD) CMOS power amplifier (PA),
Millimeter-wave coplanar stripline power dividers
Bart Nauwelaers, Frank E. van Vliet, François le Chevalier, Chong Li, Lai Bun Lok, Ata Khalid, Vasileios Papageorgiou, James Grant, David R. S. Cumming
Published online : 01-06-2013
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We present the design, fabrication, and measurement of a 2-way modified Wilkinson divider constructed in a coplanar geometry exhibiting ultra wideband isolation, transmission, and port matching in the millimeter-wave frequency range. The proposed divider replaces the lumped resistor in the conventional Wilkinson divider with two quarter-wave length transmission lines, a phase inverter, and two 2Z
Single-layer fully-planar extended-composite right-/left-handed transmission lines based on substrate integrated waveguides for dual-band and quad-band applications
Bart Nauwelaers, Frank E. van Vliet, François le Chevalier, Miguel Durán-Sindreu, Jordi Bonache, Ferran Martín, Tatsuo Itoh
Published online : 01-06-2013
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The implementation and application of single-layer fully-planar extended-composite right-/left-handed transmission lines (E-CRLH TLs) in substrate-integrated waveguide (SIW) technology are presented. The multiband CRLH behavior of these artificial lines is explained by considering the lumped element equivalent circuit model. The potential of these lines for dual-band and quad-band applications is
Numerical and experimental characterization of a button-shaped miniaturized UHF antenna on magneto-dielectric substrate
Bart Nauwelaers, Frank E. van Vliet, François le Chevalier, Martino Aldrigo, Alessandra Costanzo, Diego Masotti, Carlo Baldisserri, Ioan Dumitru, Carmen Galassi
Published online : 01-06-2013
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The design and characterization of a new broadband small patch antenna, based on an innovative magneto-dielectric material and suitable for wearable applications at 868 MHz, is presented. To reduce antenna dimensions, while preserving its radiation and matching performance, a barium-strontium hexaferrite BaSrFeO has been synthesized as the antenna substrate to achieve magnetic permeability double
Digital PA with voltage-mode topology using envelope delta-sigma modulation
Bart Nauwelaers, Frank E. van Vliet, François le Chevalier, Andreas Wentzel, Shinichi Hori, Makoto Hayakawa, Kazuaki Kunihiro, Wolfgang Heinrich
Published online : 01-07-2013
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This paper reports on digital transmitter architecture for the 450 MHz band using an envelope delta-sigma modulator realized in CMOS and a voltage-mode class-S (VMCS) power amplifier (PA) based on GaN monolithic microwave integrated circuits (MMICs). The class-S PA is characterized for narrowband single-tone signals and a single- as well as a four-carrier downlink wideband code division multiple a
W-band active loads and switching front-end MMICs for radiometer calibration
Bart Nauwelaers, Frank E. van Vliet, François le Chevalier, Ernst Weissbrodt, Michael Schlechtweg, Oliver Ambacher, Ingmar Kallfass
Published online : 01-06-2013
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A millimeter-wave monolithic integrated circuit consisting of a W-band (75?100 GHz) single-pole-five-throw (SP5T) switch and multiple internal active and passive loads for radiometer calibration was designed and manufactured in a low noise 50 nm GaAs metamorphic high electron mobility transistor technology. This highly compact and integrated front-end device for radiometer systems is capable of ul
Dielectric contrast measurements on biological substances with resonant microwave near-field sensors
Bart Nauwelaers, Frank E. van Vliet, François le Chevalier, Nora Haase, Arne F. Jacob
Published online : 01-06-2013
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Resonant substrate integrated near-field sensors are used for characterization of aqueous solutions at three different frequencies. In addition, Chinese hamster ovary (CHO) cells in a culture medium are characterized with the same sensors. Different concentrations as well as different vital states of cell suspensions are examined. The complex permittivity of the samples is evaluated using a linear
Design, modeling and characterization of MMIC integrated cascode cell for compact Ku-band power amplifiers
Bart Nauwelaers, Frank E. van Vliet, François le Chevalier, A. Déchansiaud, R. Sommet, T. Reveyrand, D. Bouw, C. Chang, M. Camiade, F. Deborgies, R. Quéré
Published online : 01-06-2013
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This paper reports on the design of a new power cell dedicated to Ku-band power amplifier (PA) applications. This cell called ?integrated cascode? has been designed in order to propose a strong decrease in terms of circuit size for PA. The technology used relies on 0.25-?m GaAs pseudomorphic high electron mobility transistors (PHEMT) of United Monolithic Semiconductors (UMS) foundry. A distributed
Inkjet-printed paper-based substrate-integrated waveguide (SIW) components and antennas
Bart Nauwelaers, Frank E. van Vliet, François le Chevalier, Riccardo Moro, Sangkil Kim, Maurizio Bozzi, Manos Tentzeris
Published online : 01-06-2013
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This paper presents a novel technology for the implementation of substrate-integrated waveguide (SIW) structures, based on a paper substrate and realized by an inkjet-printing fabrication process. The use of paper permits to implement low-cost microwave structures and components, by adopting a completely eco-friendly implementation technology. SIW structures appear particularly suitable for implem
Antenna bandwidth broadening with a negative impedance converter
Bart Nauwelaers, Frank E. van Vliet, François le Chevalier, Oluwabunmi O. Tade, Peter Gardner, Peter S. Hall
Published online : 01-06-2013
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Cognitive radio (CR) has generated a lot of interest because of the promise of wide instantaneous bandwidths which will improve data rates. Current social trends suggest that CR nodes will ultimately be mobile and handheld. This produces a need for small wideband antennas. The Chu limit imposes a restriction on what is obtainable with passive matching. In this paper, it is shown how a negative imp
Hybrid antenna design for an optically powered SHF RFID transponder applicable in metals
Bart Nauwelaers, Frank E. van Vliet, François le Chevalier, Johannes Meyer, Stefan Franke, Bernd Geck, Ludger Overmeyer
Published online : 01-06-2013
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This paper presents a hybrid antenna design for an optically powered super high frequency (SHF) radio frequency identification transponder applicable for the integration into metal. The key feature of the antenna is its ability to receive microwave signals at SHF for data communication and optical signals for the power supply of the transponder. The antenna design is based on a circular waveguide
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