Differential-difference equations for the transient simulation of lossy MTLs

In this paper, we address the differential representation of the time-domain characteristics of lossy MTLs. This approach is of great interest for the efficient simulation of circuits with long interconnects and nonlinearities. The properties of this characterization method are discussed with particular emphasis on the bandwidth and on the order of the differential operators used. Our discussion is supported by a complete characterization example for a realistic wideband 3-conductor interconnec

A Parameterization Scheme for Lossy Transmission Line Macromodels with Application to High Speed Interconnects in Mobile Devices

We introduce a novel parameterization scheme based on the generalized method of characteristics (MoC) formacromodels of transmission-line structures having a cross section depending on several free geometrical and material parameters. This situation is common in early design stages, when the physical structures still have to be finalized and optimized under signal integrity and electromagnetic compatibility constraints. The topology of the adopted line macromodels has been demonstrated to guarantee excellent accuracy and efficiency. The key factors are propagation delay extraction and rational approximations, which intrinsically lead to a SPICE-compatible macromodel stamp. We introduce a scheme that parameterizes this stamp as a function of geometrical and material parameters such as conductor-width and separation, dielectric thickness, and permettivity. The parameterization is performed via multidimensional interpolation of the residue matrices in the rational approximation of characteristic admittance and propagation operators. A significant advantage of this approach consists of the possibility of efficiently utilizing the MoC methodology in an optimization scheme and eventually helping the design of interconnects.We apply the proposed scheme to flexible printed interconnects that are typically found in portable devices having moving parts. Several validations demonstrate the effectiveness of the approac

Modeling of the Maximum Induced Currents in Automotive Radiated Immunity Tests via Thevenin-based Metamodels

This paper presents three different metamodels for the prediction of the maximum current induced on key vehicle electronic units during an automotive radiated immunity test. The proposed modeling approach is based on a Thevenin circuital interpretation of the test setup which is estimated from a small set of measurements or simulations. The FFT-based trigonometric regression, the support vector machine and the Gaussian process regression are then applied to provide three different metamodels able of predicting the spectrum of the induced currents for any value of the incidence angle of the external EM field. The accuracy and the convergence of the proposed alternatives are investigated by comparing model predictions with the results obtained by means of a parametric full-wave electromagnetic simulation

Efficient computation of transient responses of frequency-dependent nonlinearly loaded transmission lines

The authors address the combined time and frequency domain analysis of nonlinearly loaded low-loss transmission lines. They show that a variety of interconnects are characterized by transfer functions, whose impulse responses have a fast initial-time structure and a slow long-time component. A piecewise linear approximation of the transient functions with nonuniform sampling is proposed as an effective method to obtain high accuracy with low computational cost

Topological modelling of gas networks for co-simulation applications in multi-energy systems

This paper focuses on the modelling and simulation of gas networks to be used in an integrated multi-carrier energy scenario. A topological approach is followed, where a simplified graph-based description of the gas network is adopted and a systematic analysis of the metrics of three real test cases is carried out with the aim of discovering relevant network features. The governing equations of the basic building blocks such as pipelines, compressors and pressure reduction stations are readily derived under the assumptions of steady-state operation and isothermal behaviour, allowing a good matching between model compactness and accuracy. In addition, a circuit-based interpretation of model equations and well-established tools for circuit analysis are used. The obtained results proved that the proposed approach offers a feasible tool for gas networks, which can be readily integrated in a co-simulation framework

Machine learning for the performance assessment of high-speed links

This paper investigates the application of support vector machine to the modeling of high-speed interconnects with largely varying and/or highly uncertain design parameters. The proposed method relies on a robust and well-established mathematical framework, yielding accurate surrogates of complex dynamical systems. An identification procedure based on the observation of a small set of system responses allows generating compact parametric relations, which can be used for design optimization and/or stochastic analysis. The feasibility and strength of the method are demonstrated based on a benchmark function and on the statistical assessment of a realistic printed circuit board interconnect, highlighting the main features and benefits of this technique over state-of-the-art solutions. Emphasis is given to the effects of the initial sample size and of input noise on the model estimation