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1030 documents found for International Journal
Recursive learning-based joint digital predistorter for power amplifier and I/Q modulator impairments
Lauri Anttila, Peter Händel, Olli Mylläri, Mikko Valkama
Published online : 01-04-2010
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The main implementation impairments degrading the performance of direct-conversion radio transmitters are in-phase/quadrature (I/Q) mismatch, local oscillator (LO) leakage, and power amplifier (PA) nonlinear distortion. In this article, we propose a recursive least-squares-based learning algorithm for joint digital predistortion (PD) of frequency-dependent PA and I/Q modulator impairments. The pre
Modeling and mitigation of nonlinear distortion in wideband A/D converters for cognitive radio receivers
Markus Allén, Jaakko Marttila, Mikko Valkama
Published online : 01-04-2010
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This article discusses the reduction of nonlinearities in analog-to-digital (A/D) converters using digital signal processing (DSP). Also modeling of certain essential nonlinearities is considered in detail. The main focus is on wideband radio receivers, such as the emerging cognitive radio applications, where a collection of signals at different frequency channels is converted to digital domain as
Analysis and mitigation of phase noise and sampling jitter in OFDM radio receivers
Ville Syrjälä, Mikko Valkama
Published online : 01-04-2010
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This article addresses the analysis and digital signal processing (DSP)-based mitigation of phase noise and sampling clock jitter in orthogonal frequency division multiplexing (OFDM) radios. In the phase noise studies, the basic direct-conversion receiver architecture case is assumed with noisy downconverting oscillator. In the sampling jitter case, on the other hand, the so-called direct-radio-fr
Spectrum optimization in ultra-wideband systems
Elena Pancera, Jens Timmermann, Thomas Zwick, Werner Wiesbeck
Published online : 01-04-2010
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In this paper the non-ideal and frequency-dependent behavior of the hardware components of the ultra-wideband (UWB) transmitter RF-front end is analyzed. Both digital and analytical methods to compensate for this frequency-dependent behavior are investigated, in order to optimize the radiated wave, so that its spectrum perfectly matches the given mask. An example of spectral system optimization wi
De-ghosting of tomographic images in a radar network with sparse angular sampling
Angie Fasoula, Hans Driessen, Piet van Genderen
Published online : 01-08-2010
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Taking into account sparsity of the reflectivity function of several radar targets of interest, efficient low-complexity automatic target recognition (ATR) systems can be designed. Such ATR systems would be based on two-dimensional (2D) spatial target models of low dimensionality, where critical information on the radar target signature is summarized. Discrete 2D radar target models can be estimat
MRF volume 2 issue 1 Cover and Back matter
Published online : 01-02-2010
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MRF volume 2 issue 1 Cover and Front matter
Published online : 01-02-2010
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Tunable dual-band resonators for communication systems
David Girbau, Antonio Lázaro, Albert Pérez, Esther Martínez, Lluís Pradell, Ramón Villarino
Published online : 01-08-2010
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This paper proposes the design of tunable dual-band resonators for multi-band multi-standard systems. The main objective is to provide frequency tunability in the second resonance while maintaining the first resonance fixed. To this end, two tunable resonators are proposed: the capacitive-loaded stepped-impedance resonator and the capacitive-loaded hole resonator. The work is divided into two main
Basics and first experiments demonstrating isolation improvements in the agile polarimetric FM-CW radar ? PARSAX
Oleg A. Krasnov, Galina P. Babur, Zongbo Wang, Leo P. Ligthart, Fred van der Zwan
Published online : 01-08-2010
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The article describes the IRCTR PARSAX radar system, the S-band high-resolution Doppler polarimetric frequency modulated continuous wave (FM-CW) radar with dual-orthogonal sounding signals, which has the possibility to measure all elements of the radar target polarization scattering matrix simultaneously, in one sweep. The performance of such radar depends of the level of sounding signals orthogon
Comparison of 10?18 GHz SAR and MIMO-based short-range imaging radars
Timofey Savelyev, Xiaodong Zhuge, Bill Yang, Pascal Aubry, Alexander Yarovoy, Leo Ligthart, Boris Levitas
Published online : 01-08-2010
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This paper presents an experimental investigation of two approaches to short-range radar imaging at microwaves by means of ultra-wideband (UWB) technology. The first approach represents a classical synthetic aperture radar (SAR) that employs a transmit?receive antenna pair on mechanical scanner. The second one makes use of a multiple input multiple output (MIMO) antenna array that scans electronic
A highly efficient 3.5 GHz inverse class-F GaN HEMT power amplifier
Paul Saad, Christian Fager, Hossein Mashad Nemati, Haiying Cao, Herbert Zirath, Kristoffer Andersson
Published online : 01-08-2010
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This paper presents the design and implementation of an inverse class-F power amplifier (PA) using a high power gallium nitride high electron mobility transistor (GaN HEMT). For a 3.5 GHz continuous wave signal, the measurement results show state-of-the-art power-added efficiency (PAE) of 78%, a drain efficiency of 82%, a gain of 12 dB, and an output power of 12 W. Moreover, over a 300 MHz bandwid
Forty years of European microwaves. What about the future?
André Vander Vorst, Thomas J. Brazil, Peter J.B. Clarricoats, Fred E. Gardiol, Leo P. Ligthart, Roger Marriott, Roberto Sorrentino, Andrew F. Wilson
Published online : 01-08-2010
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This paper describes some key points in the history and development of the European Microwave Conference, the European Microwave Week, and the European Microwave Association, starting from 1969. It captures the way in which the conference since the earliest days has sought to create a successful blend of scientific and industry interests and has adapted itself to and indeed shaped the many existin
RF wave visions for circuit analyses and diagnoses by live electrooptic imaging camera
Masahiro Tsuchiya, Takahiro Shiozawa
Published online : 01-08-2010
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A novel scheme involving experimental analyses and diagnoses is presented for monitoring radio-frequency (RF) and high-speed circuits. A live electrooptic imaging (LEI) camera is used in the scheme and it provides real-time images of the phase evolution of the RF electric field. Besides, it is demonstrated that essential properties of RF wave propagation are easily grasped from visual images; exam
Radar distance measurements in circular waveguides involving intermodal dispersion effects
Eckhard Denicke, Gunnar Armbrecht, Ilona Rolfes
Published online : 01-08-2010
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This contribution deals with guided radar distance measurements in the field of industrial tank level control. The aim is to achieve a submillimeter gauging accuracy even when conducting the measurement within a highly dispersive environment of large and thus overmoded circular waveguides. Normally, multimode propagation causes a decrease in measurement precision. Therefore, the effects of intermo
The TanDEM-X mission: overview and interferometric performance
Sigurd Huber, Marwan Younis, Gerhard Krieger
Published online : 01-08-2010
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TanDEM-X (TDX; TerraSAR-X add-on for digital elevation measurement) is an innovative spaceborne X-band earth observation mission that will be launched in June 2010. This paper gives an overview of the TDX mission concept, summarizes the basic products and illustrates the achievable performance. In more detail the effect of quantization on the interferometric performance is discussed. Finally, new
Development of different K-band MEMS phase shifter designs for satellite COTM terminals
P. Farinelli, S. Bastioli, E. Chiuppesi, F. Di Maggio, B. Margesin, S. Colpo, A. Ocera, M. Russo, I. Pomona
Published online : 01-08-2010
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This work presents the design, manufacturing, and testing of three 5-bit K-band Micro-Electro-Mechanical-Systems (MEMS) phase shifters based on similar architectures (combination of switched line and loaded line) but employing different MEMS switch typologies (cantilevers and air bridges) and RF junctions (SP2T and SP4T). All devices have been monolithically manufactured on 200 µm thick high resis
An adapted filament model for accurate modeling of printed coplanar lines with significant surface roughness and proximity effects
Brian Curran, Ivan Ndip, Christian Werner, Veronika Ruttkowski, Marcus Maiwald, Heinrich Wolf, Volker Zoellmer, Gerhard Domann, Stephan Guttovski, Horst Gieser, Herbert Reichl
Published online : 01-08-2010
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New technologies have resulted in transmission lines that deviate significantly from the intended rectangular cross sections. Trapezoidal cross sections and roughness that penetrate a significant depth into the surface in comparison to the skin-depth of the conductor can cause a very significant deviation in transmission line parameters from predicted values. Proximity effect further complicates t
Integrated 79 GHz UWB automotive radar front-end based on Hi-Mission MCM-D silicon platform
Duncan Platt, Lars Pettersson, Darius Jakonis, Michael Salter, Joacim Haglund
Published online : 01-08-2010
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A highly integrated silicon platform (Hi-Mission) for high frequency applications is introduced. This platform utilizes heterogeneous Multi-Chip Module-Deposited (MCM-D) technology with integrated passive devices together with silicon and GaAs Monolithic Microwave Integrated Circuit (MMIC) technology developed for the automotive Ultra Wide Band (UWB) radar (short-range radar) frequency band from 7
Full integrated process to manufacture RF-MEMS and MMICs on GaN/Si substrate
Flavia Crispoldi, Alessio Pantellini, Simone Lavanga, Antonio Nanni, Paolo Romanini, Leonardo Rizzi, Paola Farinelli, Claudio Lanzieri
Published online : 01-08-2010
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Radio Frequency Micro-Electro-Mechanical System (RF-MEMS) represents a feasible solution to obtain very low power dissipation and insertion loss, very high isolation and linearity switch with respect to ?solid state? technologies. In this paper, we demonstrate the full integration of RF-MEMS switches in the GaN-HEMT (Gallium Nitride/High Electron Mobility Transistor) fabrication line to develop RF
Compact integrated slot array antennas for the 79 GHz automotive band
Lars Pettersson, Shi Cheng, Michael Salter, Anders Rydberg, Duncan Platt
Published online : 01-08-2010
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This paper presents two compact slot array antennas for the 79 GHz automotive band integrated into a 28 µm thick benzocyclobutene (BCB) substrate attached to a 325 µm thick 5?20 ? cm bulk resistivity silicon wafer. The two antennas are a transmit (TX) 1 × 8 slot array antenna with a size of 1 × 23 mm and a receive (RX) 8 × 8 slot array antenna with a size of 15 × 23 mm. Promising performance has b
Considerations on the de-embedding of differential devices using two-port techniques
Vadim Issakov, Maciej Wojnowski, Andreas Thiede, Robert Weigel
Published online : 01-08-2010
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Differential signaling is very common for high frequency integrated circuit design. Accurate multimode de-embedding at multigigahertz frequencies, however, is a major challenge. The differential and common-mode parameters can be obtained by converting the measured four-port nodal -parameters into the mixed-mode form. Under certain conditions, it is possible to separate the modes and consider only
Analysis of differential Doppler velocity for remote sensing of clouds and precipitation with dual-polarization S-band radar
Dmitry N. Glushko, Felix J. Yanovsky
Published online : 01-08-2010
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This paper presents the results of Doppler-polarimetric radar signal analysis, computer modeling, and real data processing that show the correlation between differential Doppler velocity (DDV), which is a difference between mean Doppler velocities measured at orthogonal polarizations of electromagnetic waves, and parameters of rain including both rain microstructure (parameters of drop-size distri
Decision-directed phase noise compensation for millimeter-wave single carrier systems with iterative frequency-domain equalization
Satoshi Suyama, Junichi Onodera, Hiroshi Suzuki, Kazuhiko Fukawa
Published online : 01-08-2010
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This paper proposes a receiver that repeats iterative frequency-domain equalization (FDE) and decision-directed phase noise compensation (DD-PNC) to alleviate degradation due to the phase noise for millimeter-wave single carrier (SC) systems. High bit-rate SC-FDE transceivers based on the single-chip Si RF-CMOS IC technology in the 60-GHz millimeter-wave band have been extensively studied for wire
New class of SiGe reduced-size loaded slow wave 60 GHz CPW series/shunt stubs and its applications to the design of slow wave bandpass filters
Khelifa Hettak, Gilbert A. Morin, Malcolm G. Stubbs
Published online : 01-08-2010
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This paper proposes a practical approach for developing a new class of compact slow-wave coplanar waveguide (CPW) series/shunt stubs, which offer 40% reduction in size relative to a conventional design. It demonstrates that the technique using interdigitated capacitive loading can provide size and cost reductions, while also providing performance enhancements such as better return loss. The experi
International Journal of Microwave and Wireless Technology: Special Issue on European Microwave Week 2009
Paolo Lampariello, Roberto Sorrentino
Published online : 01-08-2010
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