Conference Paper

Time-domain descriptor models for circuits with multiconductor transmission lines and lumped elements

Karazin Kharkiv Nat. Univ., Kharkiv, Ukraine
DOI: 10.1109/UWBUSIS.2010.5609106 Conference: Ultrawideband and Ultrashort Impulse Signals (UWBUSIS), 2010 5th International Conference on
Source: IEEE Xplore

ABSTRACT We suggest a method to investigate impulse circuits with multiconductor transmission lines in time domain. The transmission lines are connected by a multi-port with linear and nonlinear lumped LCR-elements. In the general case, transient states in these circuits are described by degenerate or descriptor delay nonlinear integro-differential equations. We develop theory of such equations and numerical methods to find solutions.

  • [Show abstract] [Hide abstract]
    ABSTRACT: There is a significant need for efficient and accurate macromodels of components during the design of microwave circuits. Increased integration levels in microwave devices and higher signal speeds have produced the need to include effects previously neglected during circuit simulations. Accurate prediction of these effects involve solution of large systems of equations, the direct simulation of which is prohibitively CPU expensive. In this paper, an algorithm is proposed to form passive parametrized macromodels of large linear networks that match the characteristics of the original network in time, as well as other design parameters of the circuit. A novel feature of the algorithm is the ability to incorporate a set of design parameters within the reduced model. The size of the reduced models obtained using the proposed algorithm were less than 5% when compared to the original circuit. A speedup of an order of magnitude was observed for typical high-speed transmission-line networks. The algorithm is general and can be applied to other disciplines such as thermal analysis.
    IEEE Transactions on Microwave Theory and Techniques 01/2004; · 2.23 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: With the increasing operating frequencies and functionality in modern designs, the resulting size of circuit equations of high-frequency interconnect and microwave subnetworks are becoming large. Model-order reduction-based algorithms were recently suggested to handle the solution complexity of such circuits. The major objectives in state-of-the-art model-reduction algorithms are: 1) achieving accurate and compact models; 2) numerically stable and efficient generation of models; and 3) preservation of system properties such as passivity. Algorithms such as PRIMA generate guaranteed passive reduced-order models for large interconnect circuits described by RLC type of circuits. However, with the diverse technologies and complex geometries, it is becoming prevalent to describe some of the embedded linear modules in terms of state-space equations. In this paper, we show how to extend the scope of PRIMA-type first-level reduction algorithms for simultaneous reduction of combined circuits containing both RLC interconnects and embedded modules described by general passive state-space equations, while preserving the passivity of the resulting reduced-order model. Necessary formulation, proof of macromodel passivity, and validation examples are given.
    IEEE Transactions on Microwave Theory and Techniques 10/2004; · 2.23 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Theorems of existence, uniqueness and continuous dependence for the nonlinear functional differential equation d/dt(Au(t))+Bu(t)=f(t,ut) in a Banach space are proved. The unbounded operator A is, generally, degenerate. Abstract results are applied to nonlinear partial functional differential equations. In particular, a model of liquid filtration in fissured porous rocks is considered.
    Nonlinear Analysis 01/2003; 55(1):125-139. · 1.64 Impact Factor