Inductance Extraction Research Articles

Political Institutions and Their Historical Dynamics

Traditionally, political scientists define political institutions deductively. This approach may prevent from discovery of existing institutions beyond the definitions. Here, a principal component analysis was used for an inductive extraction of dimensions in Polity IV data on the political institutions of all nations in the world the last two centuries. Three dimensions of institutions were revealed: core institutions of democracy, oligarchy, and despotism. We show that, historically and on a world scale, the dominance of the core institutions of despotism has first been replaced by a dominance of the core institutions of oligarchy, which in turn is now being followed by an increasing dominance by the core institutions of democracy. Nations do not take steps from despotic, to oligarchic and then to democratic institutions, however. Rather, nations hosting the core democracy institutions have succeeded in historically avoiding both the core institutions of despotism and those of oligarchy. On the other hand, some nations have not been influenced by any of these dimensions, while new institutional combinations are increasingly influencing others. We show that the extracted institutional dimensions do not correspond to the Polity scores for autocracy, “anocracy” and democracy, suggesting that changes in regime types occur at one level, while institutional dynamics work on another. Political regime types in that sense seem “canalized”, i.e., underlying institutional architectures can and do vary, but to a considerable extent independently of regime types and their transitions. The inductive approach adds to the deductive regime type studies in that it produces results in line with modern studies of cultural evolution and memetic institutionalism in which institutions are the units of observation, not the nations that acts as host for them.

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With the lower supply voltage and the higher operating frequency in integrated circuits, the analysis of the power distribution network (PDN) including on-chip inductances becomes more important. In this paper, an effective inductance extraction method for a regular on-chip power grid structure is proposed. The loop inductance model applicable to chip layout is proposed and the inductance extraction tool using the proposed inductance model based on post layout RC circuits is developed. The accuracy of the proposed loop model and the developed tool is verified by comparing the test circuit simulation results with those from the partial element equivalent circuit (PEEC) model. The voltage fluctuation from the RLC circuits extracted by the developed tool was examined for the analysis of on-chip inductance effects. The significance of on-chip power grid inductance was investigated by the co-simulation of chip-package-PCB.

Three-dimensional multi-terminal superconductive integrated circuit inductanceextraction

Accurate inductance calculations are critical for the design of both digital and analoguesuperconductive integrated circuits, and three-dimensional calculations are gainingimportance with the advent of inductive biasing, inductive coupling and sky plane shieldingfor RSFQ cells. InductEx, an extraction programme based on the three-dimensionalcalculation software FastHenry, was proposed earlier. InductEx uses segmentationtechniques designed to accurately model the geometries of superconductive integratedcircuit structures. Inductance extraction for complex multi-terminal three-dimensionalstructures from current distributions calculated by FastHenry is discussed. Results forboth a reflection plane modelling an infinite ground plane and a finite segmentedground plane that allows inductive elements to extend over holes in the groundplane are shown. Several SQUIDs were designed for and fabricated with IPHT’s1 kA cm − 2 RSFQ1D niobium process. These SQUIDs implement a number of loop structures thatspan different layers, include vias, inductively coupled control lines and ground planeholes. We measured the loop inductance of these SQUIDs and show how theresults are used to calibrate the layer parameters in InductEx and verify theextraction accuracy. We also show that, with proper modelling, FastHenry canbe fast enough to be used for the extraction of typical RSFQ cell inductances.

Introduction to the special issue on SM2ACD 2010

Welcome to the Special Issue of SM2ACD 2010 workshop (initially SMACD). This workshop is the XIth International Workshop on Symbolic and Numerical Methods, Modeling and Applications to Circuit Design held on 4–6 October 2010 in Gammarth—Tunisia. The history of SM(2)ACD workshops goes back to the early nineties. The first SMACD was held in 1991 in France. Throughout the past 20 years, SMACD has been organized at various European locations: Italy (1992), Spain (1994), Belgium (1996), Germany (1998), Portugal (2000), Romania (2002), Poland (2004), Italy (2006), and Germany (2008). This Special Issue of the Analog Integrated Circuits and Signal Processing consists of the expanded and carefully revised version of papers presented at SM2ACD 2010. Based on workshop review scores and feedback from the sessions chairs on the presentations, nine best papers were selected for publication in this issue from all the contributions at the workshop, and were subject to the normal journal review and refereeing process. These papers cover a large variety of the SM2ACD topics. (Eleven invitations for contribution to this special issue were sent. Ten were received. After the assessment of the reviewers, nine of them have been accepted for publication). The first paper, by Zhigang Hao, Sheldon X.-D. Tan, Esteban Tlelo-Cuautle, Jacob Relles, Chao Hu, Wenjian Yu, Yici Cai and Guoyong Shi, presents a novel method for statistical inductance extraction and modeling for interconnects considering process variations. The proposed method uses the collocation-based spectral stochastic method where orthogonal polynomials are used to represent the statistical processes. The second paper, by Francesco Grasso, Antonio Luchetta, Stefano Manetti and Maria Cristina Piccirilli, presents a novel identification technique for lumped models of general distributed circuits (microwave transmission lines, monolithic integrated circuits and filters) that is based on a hybrid multi-valued neuron neural network with a modified layer and learning process. The third paper, by David Guilherme, Jorge Guilherme and Nuno Horta, presents an optimization methodology for continuous time loop-filters design applied to class-D amplifiers. The proposed methodology is based on an evolutionary optimization approach which integrates both the topology selection and circuit sizing by automatically generating optimal sized topologies and performance tradeoffs. The fourth paper, by Antonietta De Nardo, Nicola Femia and Walter Zamboni, presents a new symbolic method for the design of filter capacitors in DC–DC switching converters, using a combination of a ceramic and an electrolytic capacitor; an effective method for the design of mixed electrolytic/ceramic capacitor-based passive filters. The fifth paper, by Pedro Pereira, Maria Helena Fino, Fernando Coito and Mario Ventim-Neves, addresses a technology-aware modified genetic optimization-based approach for the design of RF integrated inductors where the double p-model is used for the characterization of the inductor’s behavior. The sixth paper, by Florin Constantinescu, Miruna Nitescu, Alexandru Gabriel Gheorghe, Aurelian Florea and Olivier Llopis, presents a nonlinear circuit model of power BAW resonators and filters, which takes into account the parasitic of the resonator connection to the measurement bench. New models for the anti-series and the anti-parallel connections of two resonators are also proposed. The seventh paper, by Elisenda Roca, Manuel VelascoJimenez, Rafael Castro-Lopez and Francisco V. Fernandez, M. Fakhfakh (&) University of Sfax, B.P. 1069, 3018 Sfax, Tunisia e-mail: mourad.fakhfakh@ieee.org

Direct Extraction Method of HBT Equivalent-Circuit Elements Relying Exclusively on $S$-Parameters Measured at Normal Bias Conditions

A new direct parameter-extraction scheme applied to a heterojunction bipolar transistor (HBT) small-signal equivalent circuit with distributed base-collector junction capacitance is presented. The proposed method relies exclusively on <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">S</i> -parameters measured at low and high frequencies in normal bias conditions, and without using approximations based on anticipated values. The extraction results obtained from low-frequency modeling allow the extraction of the parasitic inductances at high frequency. This is performed by formulating expressions based on ac-current-source consideration different from the previously published one, without affecting the physical signification of the HBT model. This method presents a simple way for the extraction of the model parameters directly. An experimental validation on an InP double HBT device was carried out, using the <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">S</i> -parameters measured in a frequency range of 40 MHz-50 GHz over a wide range of bias points. The modeling results are presented, showing that the proposed method can yield a good fit between measured and calculated <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">S</i> -parameters.

Statistical extraction and modeling of inductance considering spatial correlation

In this paper, we present a novel method for statistical inductance extraction and modeling for interconnects considering process variations. The new method, called statHenry, is based on the collocation-based spectral stochastic method where orthogonal polynomials are used to represent the statistical processes. The coefficients of the partial inductance orthogonal polynomial are computed via the collocation method where a fast multi-dimensional Gaussian quadrature method is applied with sparse grids. To further improve the efficiency of the proposed method, a random variable reduction scheme is used. Given the interconnect wire variation parameters, the resulting method can derive the parameterized closed form of the inductance value. We show that both partial and loop inductance variations can be significant given the width and height variations. This new approach can work with any existing inductance extraction tool to extract the variational partial and loop inductance or impedance. Experimental results show that our method is orders of magnitude faster than the Monte Carlo method for several practical interconnect structures.

Using ontologies to facilitate post-processing of association rules by domain experts

Data mining is used to discover hidden patterns or structures in large databases. Association rule induction extracts frequently occurring patterns in the form of association rules. However, this technique has a drawback as it typically generates a large number of association rules. Several methods have been proposed to prune the set of extracted rules in order to present only those which are of interest to the domain experts. Some of these methods involve subjective analysis based on prior domain knowledge, while others can be considered to involve objective, data-driven analysis based on numerical measures that provide a partial description of the interestingness of the extracted association rules. Recently it has been proposed that ontologies could be used to guide the data mining process. In this paper, we propose a hybrid pruning method that involve the use of objective analysis and subjective analysis, with the latter involving the use of an ontology. We demonstrate the applicability of this hybrid method using a medical database.

Physics-Based Inductance Extraction for Via Arrays in Parallel Planes for Power Distribution Network Design

A systematic approach for inductance extraction for via arrays between two parallel planes is presented. Both self and mutual inductance values are obtained based on a cavity model. The physics associated with the via inductances is analyzed, and a rigorous method is developed to derive an equivalent total inductance for multiple via arrays. Analytical equations for the equivalent total inductance are derived in closed forms for simple cases. The proposed method is corroborated with measurements, and application of the method for power distribution network designs is demonstrated.

Mutual coupling between two superconducting strip lines horizontally-placed in niobium integrated chips

We evaluate mutual inductance between two horizontally-placed strip lines in niobium integrated chips, by means of both experiments and numerical calculations. In the experiments, one strip line is used as a part of a superconducting quantum interference device (SQUID) loop, and the other is used as a control line for applying external magnetic flux to the SQUID loop. The mutual inductance is obtained from the modulation period of the SQUID. In the numerical calculations, we employ a three-dimensional inductance extraction software (FastHenry). Three types of strip line structures on a lower ground plane (GP) are examined: two horizontally-placed microstrip lines without an upper GP (MSLs), two horizontally-placed strip lines with a floating upper GP (FLSLs), and two strip lines with an upper GP connected to the lower GP (COSLs). We have found that each strip line structure has different dependence of mutual inductance on the line center distance. The mutual inductance between the MSLs exhibits strong dependence on the line center distance, whereas that between FLSLs is almost independent on the distance. Negligible mutual inductance is obtained for the COSLs.

Surface Integral Equation Formulation for Inductance Extraction in 3-D Interconnects

A novel surface integral equation based algorithm is proposed for accurate inductance and resistance extraction in 3-D interconnects. The surface integral equation is obtained by using the skin-effect cross-sectional approximation of the volumetric current density in the traditional volumetric integral equation. The method allows for substantial reduction of computational complexity in the pertinent boundary-element formulation compared with widely adopted volumetric models. For a fixed number of samples per skin-depth establishing a desired accuracy of extraction, the number of degrees of freedom in the proposed discretized problem scales with frequency ¿ as <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">O</i> (¿¿), as opposed to <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">O</i> (¿) exhibited by the volumetric models. The accuracy of extraction is shown to be maintained from dc to the limit of magneto-quasistatic approximation.

Magnetic Isolation Enhanced by a Superconducting Loop in Josephson Integrated Circuits

Mutual inductance between two superconducting strip lines coupled through a grounded shield layer is evaluated by both experiments and numerical calculation. A conventional superconducting quantum interference device (SQUID) method on a Nb Josephson IC chip is employed for experiments, whereas a three-dimensional inductance extraction program “FastHenry” is used in numerical calculation. Five test circuits are designed to investigate the effects of two ground contacts placed parallel to the strip lines with different spacing. Both the experimental and numerical results confirm that the mutual inductance is at its minimum when the contacts are placed close to the Josephson junctions, that is, the edges of the SQUID line under evaluation. In the experiments, the minimum value of the mutual inductance is 26% of the value for the reference circuit with a floating shield layer. A model including the Meissner effect in a superconducting loop is found to provide a quasi-quantitative explanation for the dependence on the spacing between two contacts.

Inductance Extraction for Interconnects in the Presence of Nonlinear Magnetic Materials

The existence of nonlinear magnetic materials poses a challenge to the interconnect inductance extraction for circuits in micromotors, radio-frequency identification, and magnetoresistive random access memory. In this paper, we present a fast algorithm to extract inductance in the presence of nonlinear magnetic materials. The new algorithm models the nonlinear magnetic characteristics by solving the Landau-Lifshitz-Gilbert equation, and the nonhomogeneous magnetic characteristics by introducing a fictitious magnetic charge. To speed up the algorithm, we apply a number of innovative techniques, including the approximation of magnetic charge effect and the modeling of currents with solenoidal basis. Experimental results demonstrate the accuracy and efficiency of the new algorithm. Its relative error with respect to the commercial tool is below 3%, while its speed is up to one magnitude faster.

Surface Interaction Matrices for Boundary Integral Analysis of Lossy Transmission Lines

A method intended to characterize enclosed computational electromagnetic domains in terms of interaction and response of a defined set of surface excitations is described. The finite-element method is used to compute a matrix relating surface current and tangential field in terms of an appropriate basis set such that a coupled solution with a boundary integral formulation is rendered seamless. The proposed method allows for a decoupled finite-element boundary-integral system through use of a discrete-frequency surface interaction matrix, computed in an alternative way, that is still independent of the properties of the background in which the enclosed region resides. The method is applied to per-unit-length resistance and inductance extraction of a variety of multiconductor lossy transmission lines. The primary advantage the proposed method presents for this particular application is reuse of matrices given recurrence of specific conductor cross sections.

Accelerated Modeling of Massively Coupled RLC Interconnects Using the Relative Inductance Extraction Method

A new inductance extraction method is defined to accelerate modeling of massively coupled resistance-inductance-capacitance ( <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">RLC</i> ) interconnects. The new relative inductance generates a sparse inductance matrix. Therefore, it enables modeling of large circuits with reasonable speed and accuracy. It maintains accuracy for a wide frequency range, even for the cases that there are far inductance couplings. It is demonstrated that the relative inductance matrix is equivalent to the conventional partial inductance matrix. Simulations done for a 16-bit bus with each bus line divided into 32 segments show that the simulations using the relative inductance method is 20 times faster and requires 9.5 times less memory compared to the established partial inductance method.

ACCURATE ANALYTICAL MODELING OF FREQUENCY DEPENDENT LOOP SELF-INDUCTANCE

Parasitic inductance of global interconnects has gained much attention in the recent past since the inductance can no longer be neglected due to different design and fabrication issues. This has led to a paradigm shift from RC to RLC modeling of global interconnects in modern integrated circuits. However, the extraction of inductance is often expensive and presents a bottleneck in performing RLC analysis of interconnects. Unlike capacitance, the frequency dependence of current distribution through return paths present a major challenge in inductance extraction. In this paper, an efficient analytical model of frequency dependent self-inductance that can be applied to model a wide range of real design scenarios was presented. The model is based on the determination of the inductances at low and very high frequencies, an intermediate frequency point and the corresponding slope of the inductance frequency response. It is demonstrate that the approach is computationally efficient and it produces accurate values of frequency dependent inductance. It is also investigate how the frequency dependence of loop self-inductance affects the RLC delay and show that the pessimism in RLC propagation delay estimation could be as high as 49% if the frequency dependence of inductance is not considered properly. Thus, realistic (less pessimistic) delay values can be obtained using our model, leading to improved system performance.

Grounding positions of superconducting layer for effective magnetic isolation in Josephson integrated circuits

Mutual inductances between two superconducting strip lines coupled through a grounded shield layer are evaluated by both experiments and numerical calculation. A conventional superconducting quantum interference device method on a Nb Josephson integrated circuit chip is employed for experiments. Four test circuits are designed to investigate the effects of ground contacts. Grounding the shield layer at one point or at two points located perpendicular to the line direction does not improve the shielding effect, whereas grounding at two points located parallel to the line direction reduced the mutual inductance by 67%. Mutual inductances calculated using an inductance extraction program, FASTHENRY, agree with the experimental results. Numerical results of current distributions in the shield layers demonstrate that the enhanced shielding current improves the magnetic isolation.

Preconditioned Iterative Solvers for Inductance Extraction of VLSI Circuits

Parasitic extraction techniques are used to estimate signal delay in VLSI circuits. Inductance extraction is a critical component of the parasitic extraction process that involves estimation of on‐chip inductive effects with high accuracy. The problem requires the solution of a large, dense, complex linear system of equations, where the unknown current must satisfy the constraint imposed by Kirchoff’s current law. In this paper, we describe a solenoidal basis method to transform the constrained linear system into an unconstrained one. The method uses discrete local solenoidal flows to represent the unknown current, and to obtain a reduced linear system. The paper proposes preconditioning techniques that do not require explicit construction of the reduced system. Numerical experiments are presented to illustrate the effectiveness of the preconditioning approach. Comparisons with a well‐known inductance extraction package are provided to highlight the advantages of the proposed scheme.

Si-Substrate Modeling toward Substrate-Aware Interconnect Resistance and Inductance Extraction in SoC Design

This paper proposes a simple yet sufficient Si-substrate modeling for interconnect resistance and inductance extraction. The proposed modeling expresses Si-substrate as four filaments in a filament-based extractor. Although the number of filaments is small, extracted loop inductances and resistances show accurate frequency dependence resulting from the proximity effect. We experimentally prove the accuracy using FEM (Finite Element Method) based simulations of electromagnetic fields. We also show a method to determine optimal size of the four filaments. The proposed model realizes substrate-aware extraction in SoC design flow.

Flexible approaches in the design of subcutaneous immunotherapy protocols for Hymenoptera venom allergy

Venom immunotherapy is an effective method for the treatment of Hymenoptera venom allergy. Different extracts and treatment schedules are available. To compare the safety and efficacy of immunotherapy in 3 cohorts of patients sensitized to Vespula species. In this open study, 43 patients were treated with a subcutaneous aqueous extract for induction and maintenance (AA), 34 with a subcutaneous depot extract for induction and maintenance (DD), and 29 with subcutaneous aqueous and subcutaneous depot extracts for induction and maintenance, respectively (AD). Cluster schedules were followed to reach maintenance, and adverse effects during treatment and after naturally occurring stings were recorded. Depot immunotherapy was better tolerated mainly owing to the lower frequency of local adverse effects in the induction phase (5.9% vs 42.5% and 1.3% vs 5.1% on a per patient and per dose basis, respectively; P < .001 for both) and for effects occurring within 60 minutes after vaccination (2.9% vs 19.2% and 0.2% vs 2.8% on a per patient and per dose basis; P = .03 and P < .001, respectively). Furthermore, 19 of 20 AA, 9 of 9 AD, and 10 of 10 DD patients who were restung experienced only minor local effects. Venom immunotherapy is efficacious. Although there was no decrease in systemic reactions, depot immunotherapy to Vespula venom induced fewer early local adverse effects. Patients undergoing an induction phase with an aqueous extract can benefit from switching to a depot extract during maintenance. Increasing the flexibility of the immunization schedules may improve compliance with this potentially lifesaving treatment.

Loop-based inductance extraction and modeling for multiconductor on-chip interconnects

An efficient extraction and modeling methodology for self and mutual inductances within multiconductors for on-chip interconnects is investigated. The method is based on physical layout considerations and current distribution on multiple return paths, leading to loop inductance and resistance. It provides a lumped circuit model suitable for timing analysis in any circuit simulator, which can represent frequency-dependent characteristics. This novel modeling methodology accurately provides the mutual inductance and resistance as well as self terms within a wide frequency range without using any fitting algorithm. Measurement results for single and coupled wires within a multiconductor system, fabricated using 0.13 and 0.18 /spl mu/m CMOS technologies, confirm the validity of the proposed method. Our methodology can be applicable to high-speed global interconnects for post-layout as well as prelayout extraction and modeling.