Home » International Journal

International Journal

Find a document written by the best international scientists in our secure database.

940 documents found for International Journal
Space-FFT-accelerated marching-on-in-degree methods for finite periodic structures
Amir Geranmayeh, Wolfgang Ackermann, Thomas Weiland
Published online : 01-08-2009
Article Access
View abstract
A fast, yet unconditionally stable, solution of time-domain electric field integral equations (TD EFIE) pertinent to the scattering analysis of uniformly meshed and/or periodic conducting structures is introduced. A one-dimensional discrete fast Fourier transform (FFT)-based algorithm is proffered to expedite the calculation of the recursive spatial convolution products of the Toeplitz?block?Toepl
Tunable microwave devices based on left/right-handed transmission line sections in multilayer implementation
Polina Kapitanova, Dmitry Kholodnyak, Stefan Humbla, Ruben Perrone, Jens Mueller, Matthias A. Hein, Irina Vendik
Published online : 01-08-2009
Article Access
View abstract
Metamaterial transmission lines can be realized as a combination of right- and left-handed transmission line (TL) sections exhibiting positive and negative dispersion. This approach gives additional degrees of freedom for improving the performance of microwave devices. Artificial right- and left-handed sections, which are based on lumped-element unit cells consisting of inductance and capacitances
Digitally assisted equalization of third-order intermodulation products in wideband direct conversion receivers
Edward A. Keehr, Ali Hajimiri
Published online : 01-08-2009
Article Access
View abstract
An effective linearization technique capable of equalizing IM3 products resulting from an arbitrary out-of-band blocking scenario in a wideband direct conversion receiver is presented. IM3 products are regenerated in the RF analog domain of a low-power mixed-signal feedforward path and are used to cancel analogous signal terms in the original receiver at digital baseband via adaptive equalization.
Design and performance of multi-channel switched sequential amplifiers
Thomas Lehmann, Reinhard Knoechel
Published online : 01-08-2009
Article Access
View abstract
This paper presents switched sequential amplifiers (SSAs) using reconfigurable directional couplers as power splitters and combiners. The SSA concept allows matching the efficiency characteristics to the amplitude probability density distribution of the applied modulated signal. Therefore the back-off efficiency can be increased significantly. A three-channel SSA can e.g. theoretically achieve a ?
A subharmonic front-end in SiGe:C technology for 94-GHz imaging arrays
Erik Öjefors, Johannes Borngräber, Falk Korndörfer, Ullrich Pfeiffer
Published online : 01-08-2009
Article Access
View abstract
The design of a subharmonic downconverter for 94-GHz imaging arrays in SiGe:C technology is presented. A three-stage differential low-noise amplifier (LNA) with lumped matching networks is used together with a subharmonic mixer driven by a single-pole local-oscillator poly-phase network to form the front-end. The LNA yields 15 dB gain at 94 GHz, while the mixer provides 5 dB conversion gain over a
X-band T/R-module front-end based on GaN MMICs
Patrick Schuh, Hardy Sledzik, Rolf Reber, Andreas Fleckenstein, Ralf Leberer, Martin Oppermann, Rüdiger Quay, Friedbert van Raay, Matthias Seelmann-Eggebert, Rudolf Kiefer, Michael Mikulla
Published online : 01-08-2009
Article Access
View abstract
Amplifiers for the next generation of T/R modules in future active array antennas are realized as monolithically integrated circuits (MMIC) on the basis of novel AlGaN/GaN (is a chemical material description) high electron mobility transistor (HEMT) structures. Both low-noise and power amplifiers are designed for X-band frequencies. The MMICs are designed, simulated, and fabricated using a novel v
50 GHz S-shaped rat-race balun with 1.4 dB insertion loss in a wafer-level chip-size package process
Ahmet Oncu, Chiaki Inui, Yasuo Manzawa, Minoru Fujishima
Published online : 01-08-2009
Article Access
View abstract
In millimeter-wave CMOS circuits, a balun is useful for connecting off-chip single-end devices and on-chip differential circuits to improve noise immunity. However, an on-chip balun occupies a large chip area. To reduce the chip area required for the on-chip balun, a new rat-race balun using a rewiring technology with a wafer-level chip-size package (W-CSP) is proposed. The W-CSP balun occupies no
Integrated on-chip antennas for communication on and between monolithic integrated circuits
Hristomir Yordanov, Peter Russer
Published online : 01-08-2009
Article Access
View abstract
The rate of signal transmission on or between monolithic integrated circuits is limited by the cross-talk and the dispersion due to the wired interconnects. The bandwidth limitations can be overcome by wireless chip-to-chip and on-chip interconnects via integrated antennas. In this work the utilization of the electronic circuit ground planes as radiating elements for the integrated antennas has be
An L-band SiGe HBT differential amplifier with frequency and rejection-level tunable, multiple stopband
Masaki Shirata, Toshio Shinohara, Minoru Sato, Yasushi Itoh
Published online : 01-08-2009
Article Access
View abstract
An L-band frequency and rejection-level tunable SiGe HBT differential amplifier with dual stopband is presented. To achieve frequency and rejection-level tunable performance, dual LCR-tank circuit with an active load is incorporated into the design of the series feedback loops of the differential amplifier. The active load consists of a varactor diode represented as a variable and a common-emitte
A double H-shaped resonator and its use as an isotropic ENG metamaterial
Michal Blaha, Jan Machac, Martin Rytir
Published online : 01-08-2009
Article Access
View abstract
This paper presents a new planar particle that shows negative effective permittivity under irradiation by an electromagnetic wave. The mutual coupling between the couples of these particles is studied in particular. The response of this particle sensitive to an electric field is strongly anisotropic. The particle is aimed to be used to compose an isotropic epsilon-negative metamaterial in two form
Self-heating phenomena in high-power III-N transistors and new thermal characterization methods developed within EU project TARGET
Jan Kuzmik, Sergey Bychikhin, Emmanuelle Pichonat, Christophe Gaquière, Erwan Morvan, Erhard Kohn, Jean-Pierre Teyssier, Dionyz Pogany
Published online : 01-04-2009
Article Access
View abstract
In the framework of the Top Amplifier Research Groups in a European Team (TARGET) project, we developed a new electrical method for the temperature measurement of HEMTs and performed several unique studies on the self-heating effects in AlGaN/GaN HEMTs. This method, in combination with transient interferometric mapping (TIM), provides a fundamental understanding of the heat propagation in a transi
IJMWT special issue on the European Microwave Week 2008
Peter Hoogeboom, Dominique Schreurs
Published online : 01-08-2009
Article Access
View abstract
MRF volume 1 issue 3 Cover and Back matter
Published online : 01-06-2009
Article Access
View abstract
MRF volume 1 issue 3 Cover and Front matter
Published online : 01-06-2009
Article Access
View abstract
On the losses in substrate-integrated waveguides and cavities
Maurizio Bozzi, Marco Pasian, Luca Perregrini, Ke Wu
Published online : 01-10-2009
Article Access
View abstract
This paper presents a study of losses in substrate-integrated waveguides (SIWs) and cavities. Three mechanisms of losses are considered and separately investigated, namely radiation leakage, ohmic loss, and dielectric loss. A systematic comparison of waveguides with different geometry, operating at different frequencies, is reported. This study permits to give a physical interpretation of the loss
MRF volume 1 issue 4 Cover and Back matter
Published online : 01-08-2009
Article Access
View abstract
MRF volume 1 issue 4 Cover and Front matter
Published online : 01-08-2009
Article Access
View abstract
A compact semi-lumped tunable complex-impedance transformer
Anne-Laure Perrier, Jean-Marc Duchamp, Olivier Exshaw, Robert Harrison, Philippe Ferrari
Published online : 01-10-2009
Article Access
View abstract
This article describes the design and performance of a compact tunable impedance transformer. The structure is based on a transmission line loaded by varactor diodes. Using only two pairs of diodes, the circuit is very small with a total length of only /10. Both the frequency range and the load impedance can be tuned by varying the varactor bias voltages. Our design provides a tunable operating fr
Analysis and design of an efficient, fully integrated 1?8 GHz traveling wave power amplifier in 180 nm CMOS
Joerg Carls, Frank Ellinger, Yulin Zhang, Udo Joerges, Silvan Wehrli
Published online : 01-10-2009
Article Access
View abstract
Traveling wave amplifiers (TWAs) offer the advantage of broadband amplification and a closed set of equations that allow deriving the RF gain by means of treating TWAs as discrete transmission line approximations. Up to now, however, the significant losses associated with CMOS integrated inductors have been neglected. This work presents a new approach for determining the transmission line losses a
High permeability and high permittivity heterostructures for the miniaturization of Radiofrequency components
Evangéline Bènevent, Kevin Garello, Dominique Cros, Bernard Viala
Published online : 01-12-2009
Article Access
View abstract
This paper discusses on the miniaturization of radiofrequency (RF) front-end components such as half-wavelength resonators based on new magneto-dielectric heterostructures combining high permeability (µ = 150?250) and high permittivity (? = 18?150). Size reduction is evaluated by means of 2-cm-long coplanar waveguides realized with silicon technology and having a resonance frequency of about 3 GHz
Multi-access antenna for an opportunistic radio mobile communication of fourth generation
Walid El Hajj, François Gallée, Christian Person
Published online : 01-12-2009
Article Access
View abstract
A new model of two-access reconfigurable antennas for future mobile communication systems is presented in this article. This structure is based on a slot antenna with two separated access ports, isolated and matched at 1 and 2 GHz, respectively. The novelty of this element lies in the fact that first a filtering structure is integrated in the antenna, and then any additional switching or frequency
Study of electromagnetic field stress impact on SiGe heterojunction bipolar transistor performance
Ali Alaeddine, Moncef Kadi, Kaouther Daoud, Hichame Maanane, Philippe Eudeline
Published online : 01-12-2009
Article Access
View abstract
This paper deals with the various aspects of electromagnetic field impact modeling on the SiGe heterojunction bipolar transistor (HBT) device for microwave applications. This study differs from conventional HBT device reliability research associated with other stresses. The originality of this study comes from the generation of a localized electromagnetic field using the near-field bench. A coupli
Characterization of a loaded high impedance surface
Fabrice Linot, Xavier Begaud, Michel Soiron, Christian Renard, Michèle Labeyrie
Published online : 01-12-2009
Article Access
View abstract
A high impedance surface (HIS) consisting of metallic square patches electrically connected one to each other with resistors is shown. Tunability of the absorption factor is achieved by the resistor value. The absorbing band of the loaded HIS is determined by the phase of the signal reflected by this structure. The main contribution of the paper is to demonstrate the absorption behavior over a wid
Opto-microwave experimental mapping of SiGe/Si phototransistors at 850 nm
Marc D. Rosales, François Duport, Julien Schiellein, Jean-Luc Polleux, Catherine Algani, Christian Rumelhard
Published online : 01-12-2009
Article Access
View abstract
This paper presents measurement results providing the mapping of the opto-microwave transfer function performed on an SiGe microwave heterojunction phototransistor (HPT). This measurements will be used to extract a guideline for designing phototransistors. A mapping of the HPT's gain in low frequency helps to estimate the shape of the optical beam used for the measurement. The study also focuses o
Implementation of electrothermal system-level model for RF power amplifiers in Scilab/Scicos environment
Florent Besombes, Raphaël Sommet, Julie Mazeau, Edouard Ngoya, Jean-Paul Martinaud
Published online : 01-12-2009
Article Access
View abstract
This paper presents a behavioral electrothermal model implementation for high RF power amplifiers dedicated to the simulation of radar application in the Scilab/Scicos environment. This model, based on the direct coupling between a behavioral electrical model and a physics-based reduced thermal model, allows to predict nonlinear effects, high-frequency memory effects, and thermal effects due to th
0 document found for International Journal

ArtWhere Création de site Internet