Definition

Crosshatch (or mesh) ground planes use a pattern of copper lines instead of solid copper fill to improve mechanical flexibility in flex and rigid-flex circuits. The hatch pattern is defined by hatch pitch (HP), hatch width (HW), and percentage copper area. Without proper modeling, crosshatch planes significantly alter impedance versus solid-plane calculations - the reduced copper coverage increases the effective distance to the reference plane. Crosshatch is also used in interposer boards and designs requiring manufacturable trace widths on very thin substrates where solid planes would require impossibly narrow traces.