The Experts below are selected from a list of 30276 Experts worldwide ranked by ideXlab platform

G Leuzzi - One of the best experts on this subject based on the ideXlab platform.

  • stability analysis and design criteria of paralleled device power amplifiers under large signal regime
    IEEE Transactions on Microwave Theory and Techniques, 2016
    Co-Authors: Leonardo Pantoli, G Leuzzi, Alberto Santarelli, F Filicori
    Abstract:

    This paper describes a method for the stability analysis and stabilization criteria in multi-device paralleled power amplifiers (PA) under large-signal operating conditions. The symmetry of the amplifier is exploited for a simple and effective study of odd- and even-order modes. The overall stability analysis is transformed into a sequence of analyses on single-mode single-transistor large-signal equivalent amplifiers, which are carried out by using a Conversion Matrix approach. Examples of application of the method are provided on a 9-GHz GaAs pHEMT monolithic-microwave integrated-circuit (MMIC) PA and a 590-MHz power silicon bipolar hybrid microwave integrated-circuit (HMIC) PA.

  • nonlinear microwave circuit design
    2004
    Co-Authors: F Giannini, G Leuzzi
    Abstract:

    Preface.Chapter 1. Nonlinear Analysis Methods.1.1 Introduction.1.2 Time-Domain Solution.1.3 Solution Through Series Expansion1.4 The Conversion Matrix.1.5 Bibliography.Chapter 2. Nonlinear Measurements.2.1 Introduction.2.2 Load/Source-Pull.2.3 The Vector Nonlinear Network Analyser.2.4 Pulsed Measurements.2.5 Bibliography.Chapter 3. Nonlinear Models.3.1 Introduction.3.2 Physical Models.3.3 Equivalent-Circuit Models.3.4 Black-Box Models.3.5 Simplified Models.3.6 Bibliography.Chapter 4. Power Amplifiers.4.1 Introduction.4.2 Classes of Operation.4.3 Simplified Class-A Fundamental-Frequency Design For High Efficiency.4.4 Multi-Harmonic Design For High Power And Efficiency.4.5 Bibliography.Chapter 5. Oscillators.5.1 Introduction.5.2 Linear Stability and Oscillation Conditions.5.3 From Linear To Nonlinear: Quasi-Large-Signal Oscillation And Stability Conditions.5.4 Design Methods.5.5 Nonlinear Analysis Methods For Oscillators.5.6 Noise.5.7 Bibliography.Chapter 6. Frequency Multipliers and Dividers.6.1 Introduction.6.2 Passive Multipliers.6.3 Active Multipliers.6.4 Frequency Dividers-The Rigenerative (Passive) Approach.6.5 Bibliography.Chapter 7. Mixers. 7.1 Introduction.7.2 Mixer Configurations.7.3 Mixer Design.7.4 Nonlinear Analysis.7.5 Noise.7.6 Bibliography.Chapter 8. Stability and Injection-locked Circuits.8.1 Introduction.8.2 Local Stability Of Nonlinear Circuits In Large-Signal Regime.8.3 Nonlinear Analysis, Stability And Bifurcations.8.4 Injection Locking.8.5 Bibliography.Appendix.A.1. Transformation in the Fourier Domain of the Linear Differential Equation.A.2. Time-Frequency Transformations.A.3 Generalized Fourier Transformation for the Volterra Series Expansion.A.4 Discrete Fourier Transform and Inverse Discrete Fourier Transform for Periodic Signals.A.5 The Harmonic Balance System of Equations for the Example Circuit with N=3.A.6 The Jacobian MatrixA.7 Multi-dimensional Discrete Fourier Transform and Inverse Discrete Fourier Transform for quasi-periodic signals.A.8 Oversampled Discrete Fourier Transform and Inverse Discrete Fourier Transform for Quasi-Periodic Signals.A.9 Derivation of Simplified Transport Equations.A.10 Determination of the Stability of a Linear Network.A.11 Determination of the Locking Range of an Injection-Locked Oscillator.Index.

Diego Masotti - One of the best experts on this subject based on the ideXlab platform.

  • state of the art harmonic balance simulation of forced nonlinear microwave circuits by the piecewise technique
    IEEE Transactions on Microwave Theory and Techniques, 1992
    Co-Authors: Vittorio Rizzoli, Alessandro Lipparini, Alessandra Costanzo, Franco Mastri, C Cecchetti, Andrea Neri, Diego Masotti
    Abstract:

    The theoretical foundations and the numerical performance of an advanced nonlinear circuit simulator based on the piecewise harmonic-balance (HB) technique are discussed. The exact computation of the Jacobian Matrix for Newton-iteration based HB simulation and the related Conversion-Matrix technique for fast mixer analysis are formulated in a general form. Convergence problems at high drive levels are solved by a parametric formulation of the device models coupled with an advanced norm-reducing iteration. A physics-based approximation is shown to allow the HB equations to be effectively decoupled in many practical cases, bringing large-sized jobs, such as pulsed-RF analysis, within the reach of ordinary workstations. The exact Jacobian is used in conjunction with an exact formula for the gradient of the objective function, to implement an efficient broadband nonlinear circuit optimization capability. Examples are presented. >

Vittorio Rizzoli - One of the best experts on this subject based on the ideXlab platform.

  • state of the art harmonic balance simulation of forced nonlinear microwave circuits by the piecewise technique
    IEEE Transactions on Microwave Theory and Techniques, 1992
    Co-Authors: Vittorio Rizzoli, Alessandro Lipparini, Alessandra Costanzo, Franco Mastri, C Cecchetti, Andrea Neri, Diego Masotti
    Abstract:

    The theoretical foundations and the numerical performance of an advanced nonlinear circuit simulator based on the piecewise harmonic-balance (HB) technique are discussed. The exact computation of the Jacobian Matrix for Newton-iteration based HB simulation and the related Conversion-Matrix technique for fast mixer analysis are formulated in a general form. Convergence problems at high drive levels are solved by a parametric formulation of the device models coupled with an advanced norm-reducing iteration. A physics-based approximation is shown to allow the HB equations to be effectively decoupled in many practical cases, bringing large-sized jobs, such as pulsed-RF analysis, within the reach of ordinary workstations. The exact Jacobian is used in conjunction with an exact formula for the gradient of the objective function, to implement an efficient broadband nonlinear circuit optimization capability. Examples are presented. >

Giovanni Ghione - One of the best experts on this subject based on the ideXlab platform.

  • a unified approach to the sensitivity and variability physics based modeling of semiconductor devices operated in dynamic conditions part ii small signal and Conversion Matrix sensitivity
    IEEE Transactions on Electron Devices, 2016
    Co-Authors: Simona Donati Guerrieri, Fabrizio Bonani, Francesco Bertazzi, Giovanni Ghione
    Abstract:

    We present here and in Part I a general framework for the modeling of semiconductor device variability through the physics-based analysis of the small-change sensitivity. While Part I focuses on the sensitivity of the device terminal currents in periodic large-signal (LS) operation, we extend here the analysis to the linearized device representations, i.e., to the sensitivity of the small-signal (SS) admittance Matrix (SS sensitivity) and the Conversion admittance Matrix (SS-LS sensitivity). The proposed technique is based on the linearization of a physical device model around a nominal process parameter, and on the evaluation of relevant Green’s functions linking the parameter variations to the terminal performance. This provides, for the first time, a unified and computationally efficient simulation framework for the device physics-based sensitivity in dc, SS, LS, and SS-LS conditions. To highlight the accuracy of the approach when compared with the incremental evaluation, we discuss two case studies, concerning the SS-LS sensitivity of a class A GaAs MESFET-based amplifier and the SS sensitivity of an AlGaN/GaN microwave HEMT.

Changseok Kim - One of the best experts on this subject based on the ideXlab platform.

  • determination of an optimized Conversion Matrix for device independent skin color image analysis
    Lasers in Surgery and Medicine, 2005
    Co-Authors: Changseok Kim, Moon Ki Kim, Byungjo Jung, Bernard Choi, Wim Verkruysse, Myung Yung Jeong, Stuart J Nelson
    Abstract:

    Author(s): Kim, Chang-Seok; Kim, Moon Ki; Jung, Byungjo; Choi, Bernard; Verkruysse, Wim; Jeong, Myung-Yung; Nelson, J Stuart | Abstract: Background and objectiveA cross-polarized diffuse reflectance (CDR) color imaging system was developed for quantitative evaluation of port wine stain (PWS) response to laser therapy. To obtain calibrated Commission International de l'Eclairage (CIE) color space images from RGB (red, green, and blue) images, it was necessary to derive an optimized Conversion Matrix specific to our imaging system.Study design/materials and methodsA chromameter (CR-200, Minolta) and CDR imaging system were used to acquire CIELAB (CIE L*, a*, and b*) tristimulus values and RGB image values, respectively. A cost function was defined using these sample data sets and then a minimization algorithm was applied to obtain an optimized Conversion Matrix for our imaging system and illumination conditions. CIELAB color space values (L*, a*, and b*) obtained with the chromameter and CDR color images were compared to assess the accuracy of the derived Matrix.ResultsIn measurements using in vitro standard color patch or in vivo human skin samples, use of the optimized Conversion Matrix resulted in a good correlation with standard chromameter values for PWS human skin sites.ConclusionsThe cost function minimization algorithm resulted in an optimized Conversion Matrix for our CDR imaging system. Use of the optimized Matrix improved the utility of CDR color image analysis as a simple non-contact measurement technique to monitor quantitatively PWS response to laser therapy.