Electrostatic discharge protection for guided wave microwave structures is provided by a protection device that imposes minimal disruption on the microwave structures and negligible interference with the normal operation of the structures. The protection device provides a discharge path between a signal conductor and a ground conductor when electrostatic charges on the signal conductor reach a predetermined voltage level. The protection device includes an insulating base that bridges a space between the signal conductor and the ground conductor and that supports a dispersion of metal particles adhered to the base.