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Amplifier
Kinds of Amplifier Terms modified by Amplifier Selected AbstractsHigh-Gain Broadband Solid-State Optical Amplifier using a Semiconducting Copolymer,ADVANCED MATERIALS, Issue 1 2009Dimali Amarasinghe A dilute fluorene copolymer produces enhanced optical amplification. High gain with 1000 times optical amplification and a long lifetime is achieve in only 1mm of the material, and exciton,exciton annihilation is suppressed. [source] High raman gain of dispersion compensation fiber using RZ-DPSK format for long-haul DWDM transmission systemMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 11 2010Hsiu-Sheng Lin Abstract We investigated the transport of a 16 channels 40 Gb/s dense wavelength division multiplexing (DWDM) system which uses high Raman gain of dispersion compensation fiber (DCF) for long-haul DWDM transmission. Using the return to zero differential phase shift keying (RZ-DPSK) modulation format with an optimized dispersion compensation format, we demonstrate DWDM transmission with a capacity of 640 Gb/s with 0.4 nm channel spacing over 4500 km of transmission fiber. The transmission system structure uses 120 km single mode fiber and 30 km DCF for thirty spans in the C band wavelength range and a Raman Amplifier with high Raman gain to achieve long-haul transmission. We also used enhanced forward error correction for high capacity transmission over several thousand kilometers with the RZ-DPSK modulation format. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2548,2551, 2010; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25552 [source] Advanced mHEMT MMICs for 220 GHz high-resolution imaging systemsPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 6 2009Sébastien Chartier Abstract The development of advanced millimeter-wave monolithic integrated circuits for application in active and passive high-resolution imaging systems operating beyond 200 GHz is presented. A wideband 210 GHz Low Noise Amplifier has been successfully realized using one of our three metamorphic high electron mobility transistor (mHEMT) technologies in combination with grounded coplanar circuit topology (GCPW). Additionally, a 200 GHz voltage controlled oscillator (VCO) MMIC demonstrating good output power over a wide bandwidth was fabricated, using our 100 nm mHEMT technology. Finally, a high resolution 220 GHz radiometer was realized and shows very promising performance. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Spectroscopic Properties and Thermal Stability of Er3+ -Doped Germanotellurite Glasses for Broadband Fiber AmplifiersJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 1 2001Xian Feng The thermal stability and spectroscopic properties of Er2O3 -doped TeO2,GeO2,ZnO,Na2O,Y2O3 glasses for 1.5 ,m fiber amplifiers were investigated. The thermal stability of the 75TeO2·20ZnO· 5Na2O glass was improved by introducing GeO2 and Y2O3. The radiative transition and the nonradiative transition have a dominant influence on the 4I13/2 level lifetime of Er3+ in high- and low-GeO2 regions, respectively. Adding Y2O3 increases the 4I13/2 level lifetime of Er3+ significantly. The Judd,Ofelt (J-O) parameter ,6 shows a strong correlation with the 1.5 ,m emission bandwidth; and the larger the ,6, the wider the bandwidth. [source] Laser Sources for Ultrashort Pulses , Oscillators and Amplifiers for Various ApplicationsLASER TECHNIK JOURNAL, Issue 1 2007Rüdiger Paschotta Dr. [source] Combined class F monolithic PA designMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 2 2007Paolo Colantonio Abstract Experimental results on two GaAs PHEMT MMIC Class F Power Amplifiers for X-band applications are reported, aimed to validate a novel devices' combination method. In particular, 28.1 dBm output power with 44% power added efficiency and 30.6 dBm output power with 40% of power added efficiency were measured at 9.6 GHz, for single and combined devices amplifiers respectively. Both realised amplifiers exhibit 12% operating bandwidth. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 360,362, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22141 [source] Nanoparticle Supracrystals and Layered Supracrystals as Chemical Amplifiers,ANGEWANDTE CHEMIE, Issue 33 2010Bartlomiej Kowalczyk Dr. Echt stark! Kern-Schale- und Nanopartikelkristalle detektieren chemische und enzymatische Analyte mit einem verstärkten Mess-Signal. Die Kristalle werden dabei zunächst wasserunlöslich gemacht, indem ihre Oberfläche mit Dithiolen vernetzt wird, die analytspezifische Gruppen tragen. Bei Zugabe des Analyten werden diese Gruppen gespalten, woraufhin die Kristalle Millionen intensiv farbiger Nanopartikel freisetzen (siehe Bild). [source] A high-efficiency diode-clamped linear amplifierELECTRONICS & COMMUNICATIONS IN JAPAN, Issue 6 2008Hideaki Fujita Abstract This paper proposes a new power converter without any switching operation and which works as a linear amplifier. The main circuit of the proposed converter consists of series-connected MOSFETs, series-multi DC power supplies, and clamping diodes. The circuit configuration is similar to a diode-clamped multi-level inverter, except for using complementary power devices, which are n- and p-channel MOSFETs. One of the series-connected MOSFETs operates in an active state just like a linear amplifier, while the other MOSFETs operate in on or off states like an inverter circuit. As a result, the proposed converter achieves an acceptable efficiency as high as 90% without any ripples or harmonics caused by switching operation. Experimental results demonstrate that the proposed converter has the capability to drive a 2.2-kW three-phase induction motor. © 2008 Wiley Periodicals, Inc. Electron Comm Jpn, 91(6): 47,56, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecj.10120 [source] DRIFT PROMOTES SPECIATION BY SEXUAL SELECTIONEVOLUTION, Issue 3 2009Josef C. Uyeda Quantitative genetic models of sexual selection have generally failed to provide a direct connection to speciation and to explore the consequences of finite population size. The connection to speciation has been indirect because the models have treated only the evolution of male and female traits and have stopped short of modeling the evolution of sexual isolation. In this article we extend Lande's (1981) model of sexual selection to quantify predictions about the evolution of sexual isolation and speciation. Our results, based on computer simulations, support and extend Lande's claim that drift along a line of equilibria can rapidly lead to sexual isolation and speciation. Furthermore, we show that rapid speciation can occur by drift in populations of appreciable size (Ne, 1000). These results are in sharp contrast to the opinion of many researchers and textbook writers who have argued that drift does not play an important role in speciation. We argue that drift may be a powerful amplifier of speciation under a wide variety of modeling assumptions, even when selection acts directly on female mating preferences. [source] Transcriptional regulation of tumor necrosis factor-, in keratinocytes mediated by interleukin-1, and tumor necrosis factor-,EXPERIMENTAL DERMATOLOGY, Issue 6 2002S. Lisby Abstract: Irritant contact dermatitis (ICD) is an inflammatory skin reaction in which cytokines are thought to play a crucial role. In particular, tumor necrosis factor-, (TNF-,) has been implicated in the mechanism of this reaction. We report that interleukin-1, (IL-1,) that has been reported up-regulated in many inflammatory skin conditions is capable of increasing TNF-, mRNA and protein expression in murine keratinocytes. Furthermore, we show that TNF-, is capable of up-regulating itself in keratinocytes most likely in an autocrine manner. The signalling mechanisms involved in both IL-1,- and TNF-,-mediated regulation of TNF-, are critically dependent upon protein kinase C (PKC), as demonstrated by blocking studies using protein kinase inhibitors. Furthermore, the increase in TNF-, mRNA expression seen after stimulation with rTNF-, and rIL-1, involved increased transcription of TNF-, mRNA. This was demonstrated in a chloramphenicol acetyltransferase (CAT) assay using a CAT-construct containing the full-length TNF-, promoter. These observations support the notion of keratinocytes functioning as an amplifier of pro-inflammatory cytokine generation in the epidermis during ICD and other inflammatory skin conditions. [source] Cationic Polyelectrolyte Amplified Bead Array for DNA Detection with Zeptomole Sensitivity and Single Nucleotide Polymorphism SelectivityADVANCED FUNCTIONAL MATERIALS, Issue 16 2010Chun Wang Abstract A highly sensitive strand specific DNA assay, which consists of a peptide nucleic acid (PNA) probe, a cationic conjugated polymer (PFVP), and self-assembled polystyrene beads in microwell arrays on silicon chip, is reported. PFVP, as an efficient signal amplifier and signal reporter, has been specially designed and synthesized to be compatible with commercial confocal microscopes for sensing on solid substrates. The assay operates on the net increase in negative charge at the PNA surface that occurs upon single-stranded DNA hybridization, which subsequently allows complex formation with the positively charged PFVP to favor energy transfer between the polymer and Cy5-labeled target. With maximized surface contact provided by bead arrays and signal amplification provided by PFVP, this assay allows detection of ,300 copies of Cy5-labeled DNA using a commercial confocal microscope. In addition, the same strategy is also extended for label-free DNA detection with a detection sensitivity of 150 attomole. Excellent discrimination against single nucleotide polymorphism (SNP) is also demonstrated for both Cy5-labeled and label-free target detection. This study indicates that cationic conjugated polymers have great potential to be incorporated into the widely used microarray technology for simplified process with improved detection sensitivity. [source] Low-Noise Fully Differential Amplifiers Using JFET-CMOS Integration Technology for Smart SensorsIEEJ TRANSACTIONS ON ELECTRICAL AND ELECTRONIC ENGINEERING, Issue 3 2008Hidekuni Takao Member Abstract In this paper, CMOS-based low-noise amplifiers with JFET-CMOS technology for high-resolution sensor interface circuits are presented. A differential difference amplifier (DDA) configuration is employed to realize differential signal amplification with very high input impedance, which is required for the front-end circuit in many sensor applications. Low-noise JFET devices are used as input pair of the input differential stages or source-grounded output load devices, which are dominant in the total noise floor of DDA circuits. A fully differential amplifier circuit with pure CMOS DDA and three types of JFET-CMOS DDAs were fabricated and their noise performances were compared. The results show that the total noise floor of the JFET-CMOS amplifier was much lower compared to that of the pure CMOS configuration. The noise-reduction effect of JFET replacement depends on the circuit configuration. The noise reduction effect by JFET device was maximum of about , 18 dB at 2.5 Hz. JFET-CMOS technology is very effective in improving the signal-to-noise ratio (SNR) of a sensor interface circuit with CMOS-based sensing systems. © 2008 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [source] A switched-capacitor programmable gain amplifier using dynamic element matchingIEEJ TRANSACTIONS ON ELECTRICAL AND ELECTRONIC ENGINEERING, Issue 6 2007Jun Wang Non-member Abstract This paper discusses the effect of capacitor mismatch errors on gain accuracy of switched-capacitor programmable gain amplifier (SC PGA). To improve gain deviations caused by mismatch errors, the dynamic element matching (DEM) algorithm is applied to the SC PGA circuits. It uses digital gain-control signal to dynamically vary the matched capacitor combinations so that the effective capacitances of the sampling and feedback capacitor arrays are averaged, and thus the gain deviations due to capacitor mismatch errors are eliminated to a significant extent. The distortion caused by mismatch errors shift to certain frequency bands, and could be reduced or removed by subsequent processing such as lowpass filtering. A 4-bit SC PGA using DEM was designed in 0.25 µm CMOS process with 2.5 V voltage supply, including offset cancellation and clock bootstrapped circuits operating at a sampling frequency of 10 MHz. Test results have indicated that gain deviations due to mismatch errors are substantially reduced. Copyright © 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [source] Caspases and T lymphocytes: a flip of the coin?IMMUNOLOGICAL REVIEWS, Issue 1 2003Saquib Lakhani Summary:, In this review, we consider the role caspases play in cell death downstream of death receptors and cell intrinsic death mechanisms. In particular, we focus on these mechanisms in antigen-induced cell death, a mechanism which regulates the number of surviving T cells at the end of an immune response. The relative role of the apoptosome as an amplifier rather than an initiator of apoptosis is considered. Several factors that regulate the susceptibility to activation-induced cell death are considered. These factors emanate from the stimulation of the T-cell receptors and include multiple pathways. Recent work has shown that death receptor signaling can play an interesting role in cell proliferation in both humans and animals. These recent findings are discussed in the light of models of death receptor signaling. [source] Lower-bound limit analysis by using the EFG method and non-linear programmingINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 3 2008Shenshen Chen Abstract Intended to avoid the complicated computations of elasto-plastic incremental analysis, limit analysis is an appealing direct method for determining the load-carrying capacity of structures. On the basis of the static limit analysis theorem, a solution procedure for lower-bound limit analysis is presented firstly, making use of the element-free Galerkin (EFG) method rather than traditional numerical methods such as the finite element method and boundary element method. The numerical implementation is very simple and convenient because it is only necessary to construct an array of nodes in the domain under consideration. The reduced-basis technique is adopted to solve the mathematical programming iteratively in a sequence of reduced self-equilibrium stress subspaces with very low dimensions. The self-equilibrium stress field is expressed by a linear combination of several self-equilibrium stress basis vectors with parameters to be determined. These self-equilibrium stress basis vectors are generated by performing an equilibrium iteration procedure during elasto-plastic incremental analysis. The Complex method is used to solve these non-linear programming sub-problems and determine the maximal load amplifier. Numerical examples show that it is feasible and effective to solve the problems of limit analysis by using the EFG method and non-linear programming. Copyright © 2007 John Wiley & Sons, Ltd. [source] Differential amplifier with improved gain-accuracy and linearityINTERNATIONAL JOURNAL OF CIRCUIT THEORY AND APPLICATIONS, Issue 8 2010R. Wu Abstract A novel circuit design technique is presented which improves gain-accuracy and linearity in differential amplifiers. The technique employs negative impedance compensation and results demonstrate a significant performance improvement in precision, lowering sensitivity, and wide dynamic range. A theoretical underpinning is given together with the results of a demonstrator differential input/output amplifier with gain of 12,dB. The simulation results show that, with the novel method, both the gain-accuracy and linearity can be improved greatly. Especially, the linearity improvement in IMD can get to more than 23,dB with a required gain. Copyright © 2009 John Wiley & Sons, Ltd. [source] Improved analogue fault coverage estimation using probabilistic analysisINTERNATIONAL JOURNAL OF CIRCUIT THEORY AND APPLICATIONS, Issue 5 2010D. K. Papakostas Abstract A method for fault detection probability estimation using statistical multi-parameter circuit simulation is proposed, in order to check circuits for which double or multiple analogue measurements are utilized. Theoretical analysis for the estimation of the fault coverage is given, based on conditional probability calculations. The proposed method can be applied for both test measurement and input stimulus selection. Simulation results from the application of the method on typical analogue circuits,filter and amplifier,are given, showing a sufficient improvement over the fault coverage achieved by single measurements. Copyright © 2009 John Wiley & Sons, Ltd. [source] Explicit design formulas for current-mode leap-frog OTA-C filters and 300,MHz CMOS seventh-order linear phase filterINTERNATIONAL JOURNAL OF CIRCUIT THEORY AND APPLICATIONS, Issue 4 2010Yichuang Sun Abstract The leap-frog (LF) configuration is an important structure in analogue filter design. Voltage-mode LF OTA-C filters have recently been studied in the literature; however, general explicit formulas do not exist for current-mode LF OTA-C filters and there is also need for current-mode LF-based OTA-C structures for realization of arbitrary transmission zeros. Three current-mode OTA-C structures are presented, including the basic LF structure and LF filters with an input distributor or an output summer. They can realize all-pole characteristics and functions with arbitrary transmission zeros. Explicit design formulas are derived directly from these structures for the synthesis of, respectively, all-pole and arbitrary zero filter characteristics of up to the sixth order. The filter structures are regular and the design formulas are straightforward to use. As an illustrative example, a 300,MHz seventh-order linear phase low-pass filter with zeros is presented. The filter is implemented using a fully differential linear operational transconductance amplifier (OTA) based on a source degeneration topology. Simulations in a standard TSMC 0.18µm CMOS process with 2.5,V power supply have shown that the cutoff frequency of the filter ranges from 260 to 320,MHz, group delay ripple is about 4.5% over the whole tuning range, noise of the filter is 420nA/,Hz, dynamic range is 66,dB and power consumption is 200,mW. Copyright © 2008 John Wiley & Sons, Ltd. [source] Analog circuit design by nonconvex polynomial optimization: Two design examplesINTERNATIONAL JOURNAL OF CIRCUIT THEORY AND APPLICATIONS, Issue 1 2010Siu-Hong Lui Abstract We present a framework for synthesizing low-power analog circuits through global optimization over generally nonconvex multivariate polynomial objective function and constraints. Specifically, a nonconvex optimization problem is formed, which is then efficiently solved through convex programming techniques based on linear matrix inequality (LMI) relaxation. The framework allows both polynomial inequality and equality constraints, thereby facilitating more accurate device modelings and parameter tuning. Compared to traditional nonlinear programming (NLP), the proposed methodology exhibits superior computational efficiency, and guarantees convergence to a globally optimal solution. As in other physical design tasks, circuit knowledge and insight are critical for initial problem formulation, while the nonconvex optimization machinery provides a versatile tool and systematic way to locate the optimal parameters meeting design specifications. Two circuit design examples are given, namely, a nested transconductance(Gm),capacitance compensation (NGCC) amplifier and a delta,sigma (,,) analog-to-digital converter (ADC), both of them being the key components in many electronic systems. Copyright © 2008 John Wiley & Sons, Ltd. [source] Cross-correlation-based trans-impedance amplifier for current noise measurementsINTERNATIONAL JOURNAL OF CIRCUIT THEORY AND APPLICATIONS, Issue 6 2009Gino Giusi Abstract This work proposes a cross-correlation-based trans-impedance amplifier for current noise measurements in the low-frequency range. The proposed solution is compared with the classical cross-correlation trans-impedance amplifier showing a lower background noise. Furthermore, a three-step measurement method, based on the new trans-impedance amplifier, is proposed to cancel the residual background noise. SPICE simulations and noise measurements performed on prototype circuits demonstrate the validity of the proposed approach. Copyright © 2008 John Wiley & Sons, Ltd. [source] Envelope tracking power amplifier with static predistortion linearizationINTERNATIONAL JOURNAL OF CIRCUIT THEORY AND APPLICATIONS, Issue 2 2009Timo Rautio Abstract This paper presents the design method, properties and driving techniques of a linear 0.5,W 1,GHz LDMOS power amplifier used in a supply modulated envelope tracking transmitter with real-time predistortion. Causes of nonlinearities are identified, and various supply voltage drives are experimented. Measured results show that the power efficiency can be improved while maintaining high linearity. Copyright © 2008 John Wiley & Sons, Ltd. [source] CMOS digitally programmable quadrature oscillatorsINTERNATIONAL JOURNAL OF CIRCUIT THEORY AND APPLICATIONS, Issue 8 2008Hussain A. Alzaher Abstract CMOS digitally programmable quadrature oscillators based on digitally controlled current followers and voltage followers are proposed. The proposed designs provide the advantage of programmability similar to the operational transconductance amplifier-based oscillators while offering improved linearity. In mixed analog/digital systems, the digital tuning feature allows direct interfacing with the digital signal processing part. Novel realizations that provide both voltage-mode and current-mode quadrature sinusoidal signals are presented. Employing only grounded capacitors the designs achieve independent control of the frequency and condition of oscillation that can be tuned digitally. Experimental results obtained from a 0.35,µm CMOS chip fabricated using standard CMOS process are given. Copyright © 2008 John Wiley & Sons, Ltd. [source] On the realization of current transfer function using voltage amplifiers,INTERNATIONAL JOURNAL OF CIRCUIT THEORY AND APPLICATIONS, Issue 5 2006R. Raut Abstract Current transfer function is a feature of current-mode filters. Current-mode filters have so far been realized principally using current amplifiers and current conveyors. Some current-mode filter architecture using operational amplifiers have also been reported. In this article it is shown that by using the principles of transposed network and nullor model for the active device, a current transfer function can be realized in a very simple way using a voltage amplifier, i.e. operational amplifier (OA). The key concept is the knowledge that each ideal (i.e. infinite gain) controlled source is exactly equivalent to a nullor. Thus, a voltage-mode filter implemented using an ideal three terminal (output, input and ground) OA can be very easily converted to a current-mode filter using the same OA. The principle has been illustrated by considering single-OA- and multi-OA-based second-order voltage-mode filters. SPICE simulation results are provided to validate the theoretical concept. Copyright © 2006 John Wiley & Sons, Ltd. [source] gm -Extraction for rail-to-rail input stage linearizationINTERNATIONAL JOURNAL OF CIRCUIT THEORY AND APPLICATIONS, Issue 6 2005F. Palma Abstract Transconductance of rail-to-rail input stages in low-voltage operational amplifiers depends on the presence of a large common mode input signal. Corrections must be implemented in order to correct it. Nevertheless, techniques actually used, based on switching or feedforward, still give relevant deviation from the constant transconductance condition. In this paper we present a new architecture based on extraction and feedback to the gain control, directly of the value of the transconductance of the amplifier to be controlled. This quantity does not contain the signal to be amplified, and thus once fed back, it does not affect the overall stage gain. A ,reciprocal' circuit, which performs the 1/x mathematical function, is introduced in order to achieve this extraction. Copyright © 2005 John Wiley & Sons, Ltd. [source] Sensitivity improvement of the receiver module in the passive tag-based RFID readerINTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 11 2009Jonghun Chun Abstract In this paper, we have designed an RFID reader receiver system for improving the performance of the passive Tag-based 908.5,914,MHz RFID reader, and analyzed the system performance vis-à-vis frequency, reader, and tag properties. The commercial receiver system causes a loss in sensitivity because of its 24 capacitors and six inductors. To improve the overall sensitivity of the receiver, we have designed a system using a circulator, low noise amplifier (LNA) and a SAW filter. The experimental results show that the use of a circulator to separate the Tx/Rx paths eliminates interference, the LNA improves the sensitivity of the Rx module and SAW filter eliminates the noise and spurious components in the received signal. Copyright © 2009 John Wiley & Sons, Ltd. [source] Adaptive predistortion of COFDM signals for a mobile satellite channelINTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 2 2003Nibaldo Rodriguez Abstract In this paper, we consider the optimization of the performance of QPSK and 16-QAM coded orthogonal frequency division multiplexing (COFDM) signals over the non-linear and mobile satellite channel. A high power amplifier and Rician flat fading channel produces non-linear and linear distortions; an adaptive predistortion technique combined with turbo codes will reduce both types of distortion. The predistorter is based on a feedforward neural network, with the coefficients being derived using an extended Kalman filter (EKF). The conventional turbo code is used to mitigate Rician flat fading distortion and Gaussian noise. The performance over a non-linear satellite channel indicates that QPSK COFDM followed by a predistorter provides a gain of about 1.7 dB at a BER of 3×10,3 when compared to QPSK COFDM without the predistortion scheme and 16-QAM COFDM provides a gain of 0.5 dB output back-off and 1.2 dB signal to noise ratio at a BER of 3×10,5 when compared with an adaptive predistorter based on the Harmmerstein model. We also investigate the influence of the guard time interval and Doppler frequency effect on the BER performance. When the guard interval increases from 0 to 0.125T samples and the normalized Doppler frequency is 0.001, there is a gain of 0.7 and 1 dB signal to noise ratio at a BER of 6×10,4 for QPSK and 16-QAM COFDM, respectively. Copyright © 2003 John Wiley & Sons, Ltd. [source] An efficient neural network approach for nanoscale FinFET modelling and circuit simulationINTERNATIONAL JOURNAL OF NUMERICAL MODELLING: ELECTRONIC NETWORKS, DEVICES AND FIELDS, Issue 5 2009M. S. Alam Abstract The present paper demonstrates the suitability of artificial neural network (ANN) for modelling of a FinFET in nano-circuit simulation. The FinFET used in this work is designed using careful engineering of source,drain extension, which simultaneously improves maximum frequency of oscillation ,max because of lower gate to drain capacitance, and intrinsic gain AV0,=,gm/gds, due to lower output conductance gds. The framework for the ANN-based FinFET model is a common source equivalent circuit, where the dependence of intrinsic capacitances, resistances and dc drain current Id on drain,source Vds and gate,source Vgs is derived by a simple two-layered neural network architecture. All extrinsic components of the FinFET model are treated as bias independent. The model was implemented in a circuit simulator and verified by its ability to generate accurate response to excitations not used during training. The model was used to design a low-noise amplifier. At low power (Jds,10,µA/µm) improvement was observed in both third-order-intercept IIP3 (,10,dBm) and intrinsic gain AV0 (,20,dB), compared to a comparable bulk MOSFET with similar effective channel length. This is attributed to higher ratio of first-order to third-order derivative of Id with respect to gate voltage and lower gds in FinFET compared to bulk MOSFET. Copyright © 2009 John Wiley & Sons, Ltd. [source] MMICs time-domain electrical physical simulator adapted to the parallel computationINTERNATIONAL JOURNAL OF NUMERICAL MODELLING: ELECTRONIC NETWORKS, DEVICES AND FIELDS, Issue 3 2009A. El Moussati Abstract The programming method used to adapt an existing time-domain electrical circuit simulator to the parallel computation is presented. The originality of the simulator results in the semiconductor device numerical physical modeling. Thus, the organization of the existing software, initially developed to be run on a monoprocessor sequential Unix workstation, is firstly detailed. Accounting for specifications at once regarding the effort necessary to modify the software, the wished simulator application field and the constraints resulting from the available computer, two levels of parallelization have been pointed out and implemented by means of the message passing interface parallel programming tool. As an illustration, some results concerning the simulation of a microwave monolithic integrated circuit (MMIC), especially a 2,40,GHz HEMT transistor cascode stage distributed amplifier, are presented. Circuits of increasing complexity have been considered. The evaluation of the sequential/parallel computation ratio demonstrates that significant gains can be expected from the parallel computation opening the way to analysis of the operation of MMICs of mean complexity by means of a numerical physical approach. Copyright © 2008 John Wiley & Sons, Ltd. [source] Accurate substrate modelling of RF CMOSINTERNATIONAL JOURNAL OF NUMERICAL MODELLING: ELECTRONIC NETWORKS, DEVICES AND FIELDS, Issue 3 2006M. S. Alam Abstract The losses within the substrate of an RF IC can have significant effect on performance in a mixed signal application. In order to model substrate coupling accurately, it is represented by an RC network to account for both resistive and dielectric losses at high frequency (> 1 GHz). A small-signal equivalent circuit model of an RF IC inclusive of substrate parasitic effect is analysed in terms of its y -parameters and an extraction procedure for substrate parameters has been developed. By coupling the extracted substrate parameters along with extrinsic resistances associated with gate, source and drain, a standard BSIM3 model has been extended for RF applications. The new model exhibits a significant improvement in prediction of output reflection coefficient S22 in the frequency range from 1 to 10 GHz in device mode of operation and for a low noise amplifier (LNA) at 2.4 GHz. Copyright © 2006 John Wiley & Sons, Ltd. [source] Frequency reconfigurable RF circuits using photoconducting switchesINTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, Issue 1 2010D. Draskovic Abstract Designs for a frequency switchable dual-band branch-line coupler and a reconfigurable S-band power amplifier input matching network with photoconducting switches are presented. Frequency switching is achieved by increasing the power of the laser applied to the highly resistive silicon wafer and changing the properties of silicon under optical illumination. The advantages of this approach are high-speed switching, electromagnetic transparency (no interference), and thermal and electrical isolation between the device and the control circuit. A branch-line coupler frequency shift of 35% and 10% has been achieved from all switches off to all switches on in lower (900 MHz) and upper (1800 MHz) frequency bands, respectively. Frequency switchable class AB power amplifier with silicon switch in the input matching circuit has obtained the frequency tuning range of 2.5,3.5 GHz with no significant loss in efficiency and linearity. © 2009 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2010. [source] | ||||||||||||||||||||||||||||||||||||||||