Printed circuit-mounted surge suppressor matched to characteristic

Abstract

A surge suppressor for a high frequency transmission line contains a microstrip architecture comprising a dielectric sheet on a first side of which a signal conductor stripe layer is formed and on a second side of which a ground plane conductor layer is formed. The strip layer is disposed along a generally central linear region of the first surface, so as to facilitate direct connection to the center conductor of a pair of end connectors, such as type F coaxial connectors. The ground plane conductor layer is attached to the shield layer of the coaxial connectors. A gas discharge tube is coupled between a first location of the stripe layer and the ground plane layer. The discharge device may be mounted on the first side of the microstrip structure and is connected to the ground plane layer on the opposite surface by way of a plated through hole. The ground plane layer has an aperture of a prescribed area in mutual alignment with the stripe layer so as to effectively remove the distributed capacitance between the stripe layer and the ground plane along a defined length of the stripe. This decrease in the distributed microstrip capacitance coupled with the fact that the removal of ground plane metal leaves the overlying section of the center conductor as a length of inductance compensate for the alteration of the characteristic impedance by the connection of the discharge device between the stripe conductor layer and the ground plane layer.