The Experts below are selected from a list of 3306 Experts worldwide ranked by ideXlab platform
Ram Achar - One of the best experts on this subject based on the ideXlab platform.
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Delay extraction-based passive Macromodeling techniques for transmission line type interconnects characterized by tabulated multiport data
Analog Integrated Circuits and Signal Processing, 2009Co-Authors: Andrew Charest, Michel Nakhla, Ram Achar, I. ErdinAbstract:This paper introduces a novel algorithm for delay extraction-based passive Macromodeling of multiconductor transmission line type interconnects characterized by multiport (Y, Z, S, or H) tabulated parameters. The algorithm determines a unique logarithm of the H parameters, which is then approximated using a low-order rational function. Subsequently, the DEPACT (delay extraction-based passive compact transmission line Macromodel) algorithm is applied to obtain a passive and causal Macromodel for SPICE simulation. The new method leads to compact, low-order Macromodels resulting in faster transient simulations.
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Fast transient analysis of incident field coupling to multiconductor transmission lines
IEEE Transactions on Electromagnetic Compatibility, 2006Co-Authors: G. Shinh, Anestis Dounavis, Ram Achar, Michel Nakhla, N. Nakhla, I. ErdinAbstract:Due to the rapid surge in operating frequencies and complexity of modern electronic designs, accurate/fast electromagnetic compatibility/interference analysis is becoming mandatory. This paper presents a closed-form SPICE Macromodel for fast transient analysis of lossy multiconductor transmission lines in the presence of incident electromagnetic fields. In the proposed algorithm, the equivalent sources due to incident field coupling have been formulated so as to take an advantage of the recently developed delay extraction based passive transmission line Macromodels. Also, a method to incorporate frequency-dependent per-unit-length parameters is presented. The time-domain Macromodel is in the form of ordinary differential equations and can be easily included in SPICE like simulators for transient analysis. The proposed algorithm while guaranteeing the stability of the simulation by employing passive transmission line Macromodel, provides significant speed-up for the incident field coupling analysis of multiconductor transmission line networks, especially with large delay and low losses
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DEPACT: delay extraction-based passive compact transmission-line Macromodeling algorithm
IEEE Transactions on Advanced Packaging, 2005Co-Authors: N. Nakhla, Anestis Dounavis, Ram AcharAbstract:With the continually increasing operating frequencies, signal integrity and interconnect analysis in high-speed designs is becoming increasingly important. Recently, several algorithms were proposed for Macromodeling and transient analysis of distributed transmission line interconnect networks. The techniques such as method-of-characteristics (MoC) yield fast transient results for long delay lines. However, they do not guarantee the passivity of the Macromodel. It has been demonstrated that preserving passivity of the Macromodel is essential to guarantee a stable global transient simulation. On the other hand, methods such as matrix rational approximation (MRA) provide efficient Macromodels for lossy coupled lines, while preserving the passivity. However, for long lossy delay lines this may require higher order approximations, making the Macromodel inefficient. To address the above difficulties, this paper presents a new algorithm for passive and compact Macromodeling of distributed transmission lines. The proposed method employs delay extraction prior to approximating the exponential stamp to generate compact Macromodels, while ensuring the passivity. Validity and efficiency of the proposed algorithm is demonstrated using several benchmark examples
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Passivity verification in delay-based Macromodels of electrical interconnects
IEEE Transactions on Circuits and Systems I: Regular Papers, 2005Co-Authors: Changzhong Chen, Michel Nakhla, Ram AcharAbstract:This paper presents a new theory that addresses the issue of passivity in Macromodels of electrical interconnects constructed based on the method of characteristics (MoC). The proposed approach develops a new algebraic test to check for passivity in Macromodels generated using MoC. The theory behind the developed test is based on deriving the necessary and sufficient conditions for the loss of positive-realness in the admittance matrix of the developed Macromodel. An algorithmic procedure is proposed to verify passivity of general Macromodels derived from the MoC. The results presented in this paper can be employed to test for positive-realness in dynamical systems described by algebraic delay-differential equations with discrete commensurate delays.
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Fast transient analysis of incident field coupling to multiconductor transmission lines
2004 10th International Symposium on Antenna Technology and Applied Electromagnetics and URSI Conference, 2004Co-Authors: G. Shinh, I. Erdin, Ram Achar, Michel Nakhla, N. Nakhla, Anestis DounavisAbstract:This paper presents an algorithm for fast transient analysis of multiconductor transmission line interconnects in the presence of incident fields. In the proposed approach: (a) The formulation of equivalent external sources due to incident fields is independent of the type of the Macromodel used to represent the MTL system and can be represented analytically in the time-domain solely based on the information of per-unit-length parameters of the line and incident field parameters, (b) An efficient passive Macromodel based on delay extraction and closed-form representation is used to describe the distributed nature of the MTL stamp. The time-domain Macromodel is in the form of ordinary differential equations and can be easily included in SPICE like simulators for transient analysis. The proposed algorithm, while guaranteeing the stability of the simulation by employing passive Macromodels, provides significant speed-up for transmission line networks, especially with large delay and low-losses.
Tom Dhaene - One of the best experts on this subject based on the ideXlab platform.
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variability analysis of multiport systems via polynomial chaos expansion
IEEE Transactions on Microwave Theory and Techniques, 2012Co-Authors: Domenico Spina, Luc Knockaert, Tom Dhaene, Francesco Ferranti, G Antonini, Dries Vande GinsteAbstract:We present a novel technique to perform variability analysis of multiport systems. The versatility of the proposed technique makes it suitable for the analysis of different types of modern electrical systems (e.g., interconnections, filters, connectors). The proposed method, based on the calculation of a set of univariate Macromodels and on the use of the polynomial chaos expansion, produces a Macromodel of the transfer function of the multiport system including its statistical properties. The accuracy and the significant speed up with respect to the classical Monte Carlo analysis are verified by means of two numerical examples.
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Parameterized Macromodels of multiconductor transmission lines
2009 IEEE Workshop on Signal Propagation on Interconnects, 2009Co-Authors: Giulio Antonini, Tom Dhaene, Francesco Ferranti, Luc KnockaertAbstract:We introduce a novel parametrization scheme for lossy and dispersive multiconductor transmission lines (MTLs) having a cross-section depending on geometrical and physical parameters, that is suitable to interconnect modeling. The proposed approach is based on the dyadic Green's function method for the analysis of lossy and dispersive MTLs which is parameterized by using the Multivariate Orthonormal Vector Fitting (MOVF) technique to build parametric Macromodels in a rational form. Design parameters, such as substrate or geometrical layout features, in addition to frequency, can be easily handled. The rational form of the multi-port Macromodel describing the MTL is a direct consequence of the MOVF technique and is especially suited to generate state-space Macromodels or to be synthesized into equivalent circuits, which can be easily embedded into conventional SPICE-like solvers. A numerical example is presented providing evidence of the accuracy of the proposed approach in both frequency and time-domain.
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fast passivity enforcement of s parameter Macromodels by pole perturbation
IEEE Transactions on Microwave Theory and Techniques, 2009Co-Authors: Dirk Deschrijver, Tom DhaeneAbstract:This paper presents a fast iterative algorithm for passivity enforcement of large nonpassive Macromodels that share a common set of poles. It is ensured that the maximum passivity violation is monotonically decreasing in each iteration step, and convergence to a passive Macromodel is guaranteed.
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Fast passivity enforcement technique for common-pole S-parameter multiport systems
2009 IEEE Workshop on Signal Propagation on Interconnects, 2009Co-Authors: Dirk Deschrijver, Tom DhaeneAbstract:This paper applies a reliable and efficient algorithm for passivity enforcement of common-pole multiport S-parameter Macromodels. It ensures that the maximum passivity violation decreases monotonically in each iteration step, and convergence to a uniformly passive Macromodel is guaranteed.
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Accurate passivity enforcement algorithm for broadband S-parameter Macromodels
AFRICON 2009, 2009Co-Authors: Dirk Deschrijver, Tom DhaeneAbstract:This paper applies a reliable and efficient algorithm for passivity enforcement of multiport S-parameter Macromodels. It minimizes the passivity violations in each iteration step, and converges to a uniformly passive Macromodel. The method iteratively updates the residues of the Macromodel by means of a simple least-squares fitting procedure. Numerical examples indicate that passive Macromodels are obtained at a limited computational cost while preserving a good accuracy.
Ronald S. Fearing - One of the best experts on this subject based on the ideXlab platform.
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Macromodel for the mechanics of gecko hair adhesion
2008 IEEE International Conference on Robotics and Automation, 2008Co-Authors: Michael P. Reyes, Ronald S. FearingAbstract:In this work, we explore the mechanical behavior of gecko hairs by means of Macromodels. The Macromodel has four spatular hairs operating by magnetic forces instead of van der Waals forces. The purpose of the models is to simulate the mechanics of the actual gecko seta. For additional hair compliance, a two degree of freedom double bent spatular hair geometry is chosen. A mathematical model for the displacement and forces (slide, peel, and pull-off) for the macro scale gecko hairs is presented. Experiments showed good agreement with the model and a directional adhesion effect which could be useful for locomotion.
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ICRA - Macromodel for the mechanics of gecko hair adhesion
2008 IEEE International Conference on Robotics and Automation, 2008Co-Authors: Michael Reyes, Ronald S. FearingAbstract:In this work, we explore the mechanical behavior of gecko hairs by means of Macromodels. The Macromodel has four spatular hairs operating by magnetic forces instead of van der Waals forces. The purpose of the models is to simulate the mechanics of the actual gecko seta. For additional hair compliance, a two degree of freedom double bent spatular hair geometry is chosen. A mathematical model for the displacement and forces (slide, peel, and pull-off) for the macro scale gecko hairs is presented. Experiments showed good agreement with the model and a directional adhesion effect which could be useful for locomotion.
Michel Nakhla - One of the best experts on this subject based on the ideXlab platform.
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Delay extraction-based passive Macromodeling techniques for transmission line type interconnects characterized by tabulated multiport data
Analog Integrated Circuits and Signal Processing, 2009Co-Authors: Andrew Charest, Michel Nakhla, Ram Achar, I. ErdinAbstract:This paper introduces a novel algorithm for delay extraction-based passive Macromodeling of multiconductor transmission line type interconnects characterized by multiport (Y, Z, S, or H) tabulated parameters. The algorithm determines a unique logarithm of the H parameters, which is then approximated using a low-order rational function. Subsequently, the DEPACT (delay extraction-based passive compact transmission line Macromodel) algorithm is applied to obtain a passive and causal Macromodel for SPICE simulation. The new method leads to compact, low-order Macromodels resulting in faster transient simulations.
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Fast transient analysis of incident field coupling to multiconductor transmission lines
IEEE Transactions on Electromagnetic Compatibility, 2006Co-Authors: G. Shinh, Anestis Dounavis, Ram Achar, Michel Nakhla, N. Nakhla, I. ErdinAbstract:Due to the rapid surge in operating frequencies and complexity of modern electronic designs, accurate/fast electromagnetic compatibility/interference analysis is becoming mandatory. This paper presents a closed-form SPICE Macromodel for fast transient analysis of lossy multiconductor transmission lines in the presence of incident electromagnetic fields. In the proposed algorithm, the equivalent sources due to incident field coupling have been formulated so as to take an advantage of the recently developed delay extraction based passive transmission line Macromodels. Also, a method to incorporate frequency-dependent per-unit-length parameters is presented. The time-domain Macromodel is in the form of ordinary differential equations and can be easily included in SPICE like simulators for transient analysis. The proposed algorithm while guaranteeing the stability of the simulation by employing passive transmission line Macromodel, provides significant speed-up for the incident field coupling analysis of multiconductor transmission line networks, especially with large delay and low losses
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Passivity verification in delay-based Macromodels of electrical interconnects
IEEE Transactions on Circuits and Systems I: Regular Papers, 2005Co-Authors: Changzhong Chen, Michel Nakhla, Ram AcharAbstract:This paper presents a new theory that addresses the issue of passivity in Macromodels of electrical interconnects constructed based on the method of characteristics (MoC). The proposed approach develops a new algebraic test to check for passivity in Macromodels generated using MoC. The theory behind the developed test is based on deriving the necessary and sufficient conditions for the loss of positive-realness in the admittance matrix of the developed Macromodel. An algorithmic procedure is proposed to verify passivity of general Macromodels derived from the MoC. The results presented in this paper can be employed to test for positive-realness in dynamical systems described by algebraic delay-differential equations with discrete commensurate delays.
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Fast transient analysis of incident field coupling to multiconductor transmission lines
2004 10th International Symposium on Antenna Technology and Applied Electromagnetics and URSI Conference, 2004Co-Authors: G. Shinh, I. Erdin, Ram Achar, Michel Nakhla, N. Nakhla, Anestis DounavisAbstract:This paper presents an algorithm for fast transient analysis of multiconductor transmission line interconnects in the presence of incident fields. In the proposed approach: (a) The formulation of equivalent external sources due to incident fields is independent of the type of the Macromodel used to represent the MTL system and can be represented analytically in the time-domain solely based on the information of per-unit-length parameters of the line and incident field parameters, (b) An efficient passive Macromodel based on delay extraction and closed-form representation is used to describe the distributed nature of the MTL stamp. The time-domain Macromodel is in the form of ordinary differential equations and can be easily included in SPICE like simulators for transient analysis. The proposed algorithm, while guaranteeing the stability of the simulation by employing passive Macromodels, provides significant speed-up for transmission line networks, especially with large delay and low-losses.
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enforcing passivity for rational function based Macromodels of tabulated data
Electrical Performance of Electronic Packaging, 2003Co-Authors: D Saraswat, Ram Achar, Michel NakhlaAbstract:With the continually increasing operating frequencies, complex high-speed package and interconnect modules require characterization based on measured/simulated data. Several efficient algorithms were recently suggested for Macromodeling of such data to enable transient analysis in the presence of external circuit elements. One of the difficult issues involved here is the passivity violations associated with the computed Macromodel. To address this issue, an efficient algorithm is presented in this paper to enforce passivity for Macromodels with passivity violations.
Stefano Grivet-talocia - One of the best experts on this subject based on the ideXlab platform.
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An Adaptive Algorithm for Fully Automated Extraction of Passive Parameterized Macromodels
2019 IEEE MTT-S International Conference on Numerical Electromagnetic and Multiphysics Modeling and Optimization (NEMO), 2019Co-Authors: Elisa Fevola, Stefano Grivet-talocia, Alessandro Zanco, Tommaso Bradde, Marco De StefanoAbstract:We present a general framework for the fully automated extraction of stable and passive parameterized Macromodels from sampled frequency responses. The proposed iterative algorithm provides an automated selection of the optimal parameter configurations to be simulated by a field solver, based on a combination of data-driven and model-driven metrics. The resulting frequency responses are fitted by a parameterized rational Macromodel, whose uniform stability and passivity are enforced. We demonstrate the effectiveness of this framework on a transmission-line network test case.
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IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES 1 On Passivity Characterization of Symmetric Rational Macromodels
2016Co-Authors: Stefano Grivet-talocia, Senior MemberAbstract:Abstract—This paper provides a theoretical framework for passivity characterization of symmetric rational Macromodels. These may be obtained for linear and time-invariant recipro-cal structures if structural symmetry is preserved during the rational fitting stage of the Macromodel generation. Standard Hamiltonian-based methods can be used to characterize any passivity violation of such Macromodels. Recent developments suggested however that the same results may be obtained at a reduced computational cost, using so-called “half-size ” passivity test matrices. In this paper, we generalize such results by provid-ing a complete theoretical framework. In addition to imaginary Hamiltonian eigenvalues, we present a complete characterization of associated eigenvectors, allowing for precise localization of passivity violations. Since half-size matrices are also used for computing the eigenvectors, the overall computational cost is reduced up to a factor of eight. Several numerical examples validate and confirm the theoretical developments
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On Passivity Characterization of Symmetric Rational Macromodels
IEEE Transactions on Microwave Theory and Techniques, 2010Co-Authors: Stefano Grivet-talociaAbstract:This paper provides a theoretical framework for passivity characterization of symmetric rational Macromodels. These may be obtained for linear and time-invariant reciprocal structures if structural symmetry is preserved during the rational fitting stage of the Macromodel generation. Standard Hamiltonian-based methods can be used to characterize any passivity violation of such Macromodels. Recent developments have suggested, however, that the same results may be obtained at a reduced computational cost, using so-called ?half-size? passivity test matrices. In this paper, we generalize such results by providing a complete theoretical framework. In addition to imaginary Hamiltonian eigenvalues, we present a complete characterization of associated eigenvectors, allowing for precise localization of passivity violations. Since half-size matrices are also used for computing the eigenvectors, the overall computational cost is reduced up to a factor of eight. Several numerical examples validate and confirm the theoretical developments.
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Time-domain and frequency-domain Macromodeling: application to package structures
2003 IEEE Symposium on Electromagnetic Compatibility. Symposium Record (Cat. No.03CH37446), 1Co-Authors: Stefano Grivet-talocia, Igor Simone Stievano, Ivano Adolfo Maio, Flavio CanaveroAbstract:This paper applies different Macromodeling strategies for the generation of SPICE-ready equivalent circuits of complex multiport package structures. In particular, accuracy comparisons are performed between two techniques capable of processing either time-domain or frequency-domain responses for the derivation of the Macromodel. The time-domain tool is an implementation of a Subspace-based State-Space System Identification (4SID) technique specifically designed for the analysis of structures with a large number of ports. The frequency-domain tool is the powerful pole relocation algorithm known as Vector Fitting. The two methods are compared through application to a realistic package example. The passivity of the Macromodels is enforced using a powerful technique based on perturbation of associated Hamiltonian matrices.
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ISCAS (6) - Linear and nonlinear Macromodels for power/signal integrity
2005 IEEE International Symposium on Circuits and Systems, 1Co-Authors: Igor Simone Stievano, Stefano Grivet-talocia, I.a. Maio, Flavio CanaveroAbstract:In this paper, a systematic methodology for the assessment of power/signal integrity effects in high-speed communication and information systems is presented. The proposed methodology leads to accurate and efficient Macromodels for logic devices, transmission-line interconnects and discontinuities that can be easily implemented in any commercial tool and can be combined for the simulation of the whole system. The SPICE implementation of Macromodels is used for the prediction of power/ground noise and signals propagating on interconnects. An assessment of the impact that possible simplifications in the Macromodel generation phase have on the simulation of a realistic application example is discussed.
