The Experts below are selected from a list of 291 Experts worldwide ranked by ideXlab platform
T. Redon - One of the best experts on this subject based on the ideXlab platform.
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A new approach to sensitivity computation of Microwave Circuits
1988. IEEE International Symposium on Circuits and Systems, 1Co-Authors: G. Vasilescu, T. RedonAbstract:The authors introduce an approach to first and second-order sensitivity computation of Microwave Circuits, based on the adjoint network concept applied to an all-lumped equivalent circuit. A general sensitivity analysis program has been written for Microwave Circuits. It computes the absolute and relative first and second-order sensitivity of any selected response (gain, reflection coefficient, VSWR, etc.), with respect to all parameters. The adopted procedure totally avoids matrix inversions or multiplications; it is therefore accurate and fast. It is concluded that the results are useful in the tolerance characterization of Microwave Circuits or in optimization by efficient gradient methods. >
Tatsuo Itoh - One of the best experts on this subject based on the ideXlab platform.
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an unconditionally stable extended use finite element time domain solution of active nonlinear Microwave Circuits using perfectly matched layers
International Microwave Symposium, 2001Co-Authors: Hsiaoping Tsai, Yuanxun Wang, Tatsuo ItohAbstract:This paper proposes an extension of the unconditionally stable finite-element time-domain (FETD) method for the global electromagnetic analysis of active Microwave Circuits. This formulation has two advantages. First, the time-step size is no longer governed by the spatial discretization of the mesh, but rather by the Nyquist sampling criterion. Second, the implementation of the truncation by the perfectly matched layers (PML) is straightforward. An anisotropic PML absorbing material is presented for the truncation of FETD lattices. Reflection less than -50 dB is obtained numerically over the entire propagation bandwidth in waveguide and microstrip line. A benchmark test on a Microwave amplifier indicates that this extended FETD algorithm is not only superior to finite-difference time-domain-based algorithm in mesh flexibility and simulation accuracy, but also reduces computation time dramatically.
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full wave analysis of packaged Microwave Circuits with active and nonlinear devices an fdtd approach
IEEE Transactions on Microwave Theory and Techniques, 1997Co-Authors: Chiennan Kuo, B Houshmand, Tatsuo ItohAbstract:This paper presents a comprehensive full-wave analysis of packaged nonlinear active Microwave Circuits by applying the extended finite-difference time-domain (FDTD) method. Based on the approach of using equivalent sources, the device-wave interaction is characterized and incorporated into the FDTD time-marching scheme. As a consequence, analysis of linear and nonlinear properties, including harmonic generation and intermodulation, can be accomplished by employing a large-signal device circuit model. The implementation is first validated by comparing results of FDTD and HP MDS simulation of the circuit without the packaging structure. The analysis then goes beyond the capability of the circuit simulator to include the packaging effect. This analysis is useful in circuit design involving electromagnetic compatibility/electromagnetic interference (EMC/EMI) problems.
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Piecewise stability analysis in Microwave Circuits
IEEE Microwave and Guided Wave Letters, 1995Co-Authors: S. Basu, Stephen A Maas, Tatsuo ItohAbstract:A novel method for analyzing the global stability of Microwave Circuits under multi-parameter variation is presented. In this method, an arbitrary linear circuit is divided up into subCircuits containing parametric elements and a fixed linear circuit. This approach improves the computational efficiency by eliminating the need for recalculation of the Y-parameters of the fixed part of the linear circuit. >
Diego Masotti - One of the best experts on this subject based on the ideXlab platform.
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general noise analysis of nonlinear Microwave Circuits by the piecewise harmonic balance technique
IEEE Transactions on Microwave Theory and Techniques, 1994Co-Authors: Vittorio Rizzoli, Franco Mastri, Diego MasottiAbstract:This paper presents a self-consistent set of algorithms for the numerical computation of noise effects in forced and autonomous nonlinear Microwave Circuits. The analysis relies upon the piecewise harmonic-balance method, and thus retains all the peculiar advantages of this technique, including general-purposeness in the widest sense. The noise simulation capabilities include any kind of forced or autonomous nonlinear circuit operated in a time-periodic large-signal steady state, as well as Microwave mixers of arbitrary topology. The limitations of the traditional frequency-conversion approach to noise analysis are overcome. The analysis takes into account the thermal noise generated in the passive subnetwork, the noise contributions of linear and nonlinear active devices, and the noise injected by sinusoidal driving sources of known statistical properties. The nonlinear noise models of two representative families of Microwave devices (FET's/HEMT's and Schottky-barrier diodes) are discussed in detail, and several applications are illustrated. >
Jose E Rayassanchez - One of the best experts on this subject based on the ideXlab platform.
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em based monte carlo analysis and yield prediction of Microwave Circuits using linear input neural output space mapping
International Microwave Symposium, 2006Co-Authors: Jose E Rayassanchez, Vladimir GutierrezayalaAbstract:A computationally efficient method for highly accurate electromagnetics-based statistical analysis and yield estimation of RF and Microwave Circuits is described in this paper. The statistical analysis is realized around a space-mapped nominal solution. Our method consists of applying a constrained Broyden-based linear input space-mapping approach to design, followed by an output neural space-mapping modeling process in which not only the responses, but the design parameters and independent variable are used as inputs to the output neural network. The output neural network is trained using reduced sets of training and testing data generated around the space-mapped nominal solution. We illustrate the accuracy and efficiency of our technique through the design and statistical analysis of a classical synthetic problem and a microstrip notch filter with mitered bends
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em based optimization of Microwave Circuits using artificial neural networks the state of the art
IEEE Transactions on Microwave Theory and Techniques, 2004Co-Authors: Jose E RayassanchezAbstract:This paper reviews the current state-of-the-art in electromagnetic (EM)-based design and optimization of Microwave Circuits using artificial neural networks (ANNs). Measurement-based design of Microwave Circuits using ANNs is also reviewed. The conventional Microwave neural optimization approach is surveyed, along with typical enhancing techniques, such as segmentation, decomposition, hierarchy, design of experiments, and clusterization. Innovative strategies for ANN-based design exploiting Microwave knowledge are reviewed, including neural space-mapping methods. The problem of developing synthesis neural networks is treated. EM-based statistical analysis and yield optimization using neural networks is reviewed. The key issues in transient EM-based design using neural networks are summarized. The use of ANNs to speed up "global modeling" for EM-based design of monolithic Microwave integrated Circuits is briefly described. Future directions in ANN techniques to Microwave design are suggested.
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neuromodeling of Microwave Circuits exploiting space mapping technology
International Microwave Symposium, 1999Co-Authors: John W. Bandler, Jose E Rayassanchez, M A Ismail, Qijun ZhangAbstract:For the first time, we present modeling of Microwave Circuits using artificial neural networks (ANN's) based on space-mapping (SM) technology, SM-based neuromodels decrease the cost of training, improve generalization ability, and reduce the complexity of the ANN topology with respect to the classical neuromodeling approach. Five creative techniques are proposed to generate SM-based neuromodels. A frequency-sensitive neuromapping is applied to overcome the limitations of empirical models developed under quasi-static conditions, Huber optimization is used to train the ANN's. We contrast SM-based neuromodeling with the classical neuromodeling approach as well as with other state-of-the-art neuromodeling techniques. The SM-based neuromodeling techniques are illustrated by a microstrip bend and a high-temperature superconducting filter.
Wang Jun - One of the best experts on this subject based on the ideXlab platform.
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TheHarmonic-Balance Analysis oftheNoiseofNonlinear Microwave Circuits
2005Co-Authors: Wang JunAbstract:Thispaperpresented a unified frequency-domain formulation andalgorithm for computing noise inthenonlinear Microwave Circuits. The methodusesstationary components and harmonic powerspectral density inits formulation to capture time-varying noise statistics. A description of noisespectrum fortheinteresting portsinthe nonlinear Microwave Circuits isthecentral results enabling fast andaccurate computation. Themethod isefficient forlarge Circuits withCAD andcan generate information useful fornoise macromodels. Finally, the experimental results verifyits practicability intheapplication. IIntroduction Manymodemmobile radio communication system, suchasspacetelemetry systems, communication satellites andmilitary radars, havebeenbasedon phased arrayantennas withlarge aperture, where eachtransmit/receive (T/R) moduleisinterfaced to thecentral processor bya fiber-optic link, which distributes reference, data,andcontrol signal. Thereinto, maintaining thephaseandfrequency purity ofthereference signal isofgreat importance forestablishing acoherent carrier ateachactive T/R module. Andwiththedevelopment ofMMIC technique, moreandmorecomplex Microwave Circuits are integrated intoonechip. Then,howtoanalyze its noiseperformance toguidetheoptimumdesign becomes ofgreat importance also. Thisisbecause the noise perturbation factors maybetheobstacles for MMIC toobtain thehighperformance. Forinstance, withtheintegration degree ofMMIC increased, the coupling andcrosstalk noise wouldbeincreased; and withthelowpowerconsumption ofthechipinthe handyphone demanded,itsreduction of power-supply voltage makesthenoise margin ofchip lowered. Nowadays, thefirst-line taskof low-noise electronic system design isusually todetermine the low-noise active devices withexcellent quality. For example, GaAsMESFETischosen extensively in nonlinear Microwave Circuits since itcanprovide relatively highoutput powerswithhighefficiency andhasconvenient power-supply requirement. However, although GaAsMESFETgenerates little highfrequencies noise, oscillators using itgenerally
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PIMRC - Unified noise analysis method of nonlinear Microwave Circuits
14th IEEE Proceedings on Personal Indoor and Mobile Radio Communications 2003. PIMRC 2003., 1Co-Authors: Wang JunAbstract:A unified frequency-domain formulation and algorithm has been presented for computing noise in the nonlinear Microwave Circuits. The method uses stationary components and harmonic power spectral density in its formulation to capture time-varying noise statistics. A description of noise spectrum for the interesting ports in the nonlinear Microwave Circuits is the central results enabling fast and accurate computation. The method is efficient for large Circuits with CAD and can generate information useful for noise macromodels. Finally, the experimental results verify its practicability in the application.
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The harmonic-balance analysis of the noise of nonlinear Microwave Circuits
2005 Asia-Pacific Microwave Conference Proceedings, 1Co-Authors: Wang JunAbstract:This paper presented a unified frequency-domain formulation and algorithm for computing noise in the nonlinear Microwave Circuits. The method uses stationary components and harmonic power spectral density in its formulation to capture time-varying noise statistics. A description of noise spectrum for the interesting ports in the nonlinear Microwave Circuits is the central results enabling fast and accurate computation. The method is efficient for large Circuits with CAD and can generate information useful for noise macromodels. Finally, the experimental results verify its practicability in the application.
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The harmonic-balance algorithm to the unified noise analysis of nonlinear Microwave Circuits
ICMMT 4th International Conference on Proceedings Microwave and Millimeter Wave Technology 2004., 1Co-Authors: Wang JunAbstract:This paper presented a unified frequency-domain formulation and algorithm for computing noise in the nonlinear Microwave Circuits. The method uses stationary components and harmonic power spectral density in its formulation to capture time-varying noise statistics. A description of noise spectrum for the interesting ports in the nonlinear Microwave Circuits is the central results enabling fast and accurate computation. The method is efficient for large Circuits with CAD and can generate information useful for noise macromodels. Finally, the experimental results verify its practicability in the application.
