Communication wires are provided with insulated corrugated conductors. The corrugated conductors have ridges and depressions, such that air gaps are provided between insulation and the outer surfaces of the wires in the regions of the depressions. In some embodiments, the ridges and depressions form a sine wave profile in cross-section. The insulation may be provided with corrugations, and the corrugations of the insulation may align with the corrugations of the conductors. Several wires may be combined into a communication cable.