An impregnation plate and an impregnation section of a die for impregnating at least one fiber roving with a polymer resin are disclosed. The impregnation plate includes an impregnation zone configured to impregnate the roving with the resin. The impregnation zone includes an inner surface. The impregnation plate further includes a sidewall. The sidewall includes an inner surface. The inner surface of the sidewall includes a plurality of peaks and a plurality of valleys. At least one of the plurality of valleys defines a maximum height that is less than a height of the inner surface of the impregnation zone at a neighboring location along a run direction of the roving.