Application of LE-FDTD method to HF circuit analysis

A circuit simulation technique is discussed, which accounts for the "full-wave" analysis of signal propagation along the interconnections of an arbitrary circuit, including active, non-linear devices. A number of electromagnetic propagation effects have significant influence over high-frequency (either analog or digital) circuit performances and can be accurately modeled by means of the approach described: among them, interconnection behavior, cross-talk phenomena, package interactions. Conventional circuit CAD tools allow the analysis of such effects by resorting to equivalent-circuit, lumped-element descriptions of interconnecting lines. Although this technique is highly computationally efficient, the definition of the equivalent circuit topology and the estimation of its parameters often relies on rather drastic approximations, because of the inherently "distributed" nature of most propagation effects. To tackle this problem, the Lumped-Element, Finite-Difference Time-Domain (LE-FDTD) technique has been conceived. Within this approach, SPICE-like compact device models are coupled to the numerical solutions of Maxwell\´s equation over distributed domains. The extension of LE-FDTD technique to circuits including GaAs MESFET devices is reported, and a few simulation examples are illustrated.