Definition

Virtual ground is the effective ground reference that exists equidistant between two differentially-driven traces, even without a physical ground plane. When traces carry equal but opposite signals, every point equidistant from both conductors sits at 0V potential, creating an effective ground reference without physical copper. This allows differential pairs to function under Ethernet connectors where no adjacent plane exists, on two-layer boards, or in cost-sensitive designs without continuous ground planes. Impedance can be calculated as a surface microstrip with H equal to half the trace separation, then doubling the result.