The impedance matrix interpolation approach combined with the domain decomposition has been examined in this paper as a tool for generating wide-band data from the frequency-domain method-of-moments electromagnetic simulation. The capability of the approach has been illustrated by its application to a circular helix antenna with a truncated-cone ground plane. The approach significantly reduces the time it takes to perform computations of the antenna input impedance over a wide frequency band. The relevant numerical procedures can be easily incorporated into the existing MoM-based electromagnetic simulators. In spite of encouraging results of this preliminary study showing a great potential of the approach, much work remains to be done to exhaustively investigate features of the approach and improve its capabilities.