Exemplary impedance extraction methods, systems, and apparatus are
described herein. In one exemplary embodiment, for instance, a
signal-wire segment of a circuit layout is selected. A predetermined
number of return paths are identified for the selected signal-wire
segment. The selected signal-wire segment and the identified return paths
are further segmented into a plurality of bundles, which comprise
signal-wire subsegments and one or more associated return-path
subsegments that are parallel to and have the same length as the
signal-wire subsegments. Loop inductance values and loop resistance
values are determined and stored for the signal-wire subsegments in the
bundles for at least one frequency of operation. Computer-readable media
storing computer-executable instructions for causing a computer to
perform any of the disclosed methods or storing data or information
created or modified using any of the disclosed techniques are also
disclosed.