Shield structure for use in microwave circuit device

Abstract

The present invention provides a shield structure for shielding a microwave circuit device, which can establish a reliable electric contact between the ground wiring patterns of a circuit substrate, and can completely prevent external noise from entering into the circuit, with the use of a light and compact shield case. A circuit substrate has microwave components mounted thereon, ground patterns formed on peripheral portions of the upper surface of the substrate, and a ground pattern formed in the lower surface of the substrate along the entire periphery thereof. A shield case main body receiving the circuit substrate comprises a case main body, a top plate, and a bottom plate. The thickness of the case main body increases from a predetermined position such that it contacts the ground patterns. The bottom plate is coupled integral with the case main body with the circuit substrate interposed therebetween, in a state where the circuit substrate is received in the body. The shield case bottom plate has a surface, which is opposed to the lower surface of the circuit substrate and has a continuous groove formed therein along the periphery thereof. A shield line, which consists of an elastic conductor with a diameter greater than the depth of the groove, fills the continuous groove. The top plate is coupled integral with the upper surface of the shield case main body.