TABLE OF CONTENTS Real interconnect circuits have numerous features that circuit simulators simply don't know how to deal with. The presence of such features does not render the simulator useless; rather, it usually means some other tool is needed to translate the feature into language the circuit simulator understands. Such an approach applies to things such as corners, end effects, bends in edge-coupled pairs, and vias.
Other features are random in nature and deviate from the ideal characteristics that SPICE presumes. These features, such as roughness and etching variations, are modeled in SPICE only when the simulation deck is intentionally designed to include such characteristics. In some instances, the major loss mechanism is radiation. SPICE simulators do not know about radiation. Finally, there are solutions to Maxwell's equations that do not conform to circuit theory, and, in instances where these higher order modes become significant, the accuracy of circuit simulators decreases. The following few paragraphs describe several examples of such features and how they can be accommodated.
