Kenneth S. Kundert’s research while affiliated with Cadence Design Systems, Inc. and other places

The principles employed in the development of modern RF simulators are introduced and the various techniques currently in use, or expected to be in use in the next few years, are surveyed. Frequency and time domain techniques are presented and contrasted, as are steady state and envelope techniques and large and small signal techniques

ing with credit is permitted. To copy otherwise, to republish, to post on servers, or to redistribute to lists, requires prior specific permission and/or a fee. Request permissions from Publications Dept, ACM Inc., fax +1 (212) 869-0481, or permissions@acm.org. 0-89791-847-9/97/0006/$3.50 hfill DAC 97 - 06/97 Anaheim, CA, USA Lumped Interconnect Models Via Gaussian Quadrature Keith Nabors, Tze-Ting Fang, Hung-Wen Chang and Kenneth S. Kundert Cadence Design Systems, San Jose, California Jacob K. White Massachusetts Institute of Technology, Cambridge, Massachusetts Abstract This paper presents a new Gaussian quadrature method for interconnect modeling which applies to one-dimensional distributions of circuit elementvalues, the line structures often used to model interconnect wires. The method takes a line circuit, whichmay be an arbitrary combination of lumped and distributed elements, and produces a small lumped model whose transfer and input characteristics approximately mat...

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In this paper we present a preconditioned recycled Krylov-subspace method to accelerate a recently developed approach for ac and noise analysis of linear periodically-varying communication circuits. Examples are given to show that the combined method can be used to analyse switching filter frequency response, mixer 1/f noise frequency translation, and amplifier intermodulation distortion. In addition, it is shown that for large circuits the preconditioned recycled Krylov-subspace method is up to forty times faster than the standard optimized direct methods

In this paper we describe an algorithm for efficient circuit-level simulation of transmission lines which can be specified by tables of frequency-dependent scattering parameters. The approach uses a forced stable section-by-section ` 2 minimization approach to construct a high order rational function approximation to the frequency domain data, and then applies guaranteed stable balanced realization techniques to reduce the order of the rational function. The rational function is then incorporated in a circuit simulator using fast recursive convolution. An example of a transmission line with skin-effect is examined to both demonstrate the effectiveness of the approach and to show its generality. 1 Introduction In the design of communication, high-speed digital, and microwave electronic systems, the behavior of transmission lines formed from packaging and interconnect can have an important impact on system performance. For this reason, including non-ideal transmission lines in circuit s...

In this paper we describe an algorithm for efficient SPICE-level simulation of transmission lines with arbitrary scattering parameter descriptions. That is, the line can be represented in the form of a frequency-domain model or a table of measured frequency-domain data. Our approach initially uses a forced stable decade-by-decade l₂ minimization approach to construct a sum of rational functions approximation, but the approximation has dozens of poles and zeros. This unnecessarily high-order model is then reduced using a guaranteed stable model order reduction scheme based on balanced realizations. Once the reduced-order model is derived, it can be combined with the transmission line's inherent delay to generate an impulse response. Finally, following what is now a standard approach, the impulse response can be efficiently incorporated in a circuit simulator using recursive convolution. An example of a transmission line with skin-effect is examined to both demonstrate the effectiveness of the approach and to show its generality

In this paper we describe an algorithm for efficient circuit-level simulation of transmission lines which can be specified by tables of frequency-dependent scattering parameters. The approach uses a forced stable section-by-section l2 minimization approach to construct a high order rational function approximation to the frequency domain data, and then applies guaranteed stable balanced realization techniques to reduce the order of the rational function. The rational function is then incorporated in a circuit simulator using fast recursive convolution. An example of a transmission line with skin-effect is examined to both demonstrate the effectiveness of the approach and to show its generality.

For each of the three classes of steady-state methods presented, finite-difference, shooting, and harmonic balance methods, there are situations where each is best. In this chapter, each method will be summarized and its advantages and disadvantages given. Each of the circuits presented in Chapter 2 are also reviewed and recommendations are given on how to find their steady-state response most efficiently.

Harmonic balance differs from traditional transient analysis in two fundamental ways. These differences allow harmonic balance to compute periodic and quasiperiodic solutions directly and in certain circumstances give the method significant advantages in terms of accuracy and efficiency. Transient analysis, which uses standard numeric integration, constructs a solution as a collection of time samples with an implied interpolating function. Typically the interpolating function is a low order polynomial. However, polynomials fit sinusoids poorly, and so many points are needed to approximate sinusoidal solutions accurately.KeywordsFourier SeriesDiscrete Fourier TransformRelaxation MethodSplitting Method Quasiperiodic SolutionThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.