Patent ID: 6965285
Filing Date: 2005-11-15
Classification: H01P

Abstract:
1. A filter circuit including a pair of dielectric insulating layers, upper and lower, each having a ground pattern formed on an outer side thereof, and an inner wiring layer formed between the dielectric insulating layers and having capacitively coupled resonator conductive patterns each connected at one end thereof to the ground patterns via inter-layer connecting vias and open-circuited at the other end, the filter circuit having formed: on the inner wiring layer thereof a plurality of capacitive load patterns adjacent the open-circuit ends of the resonator conductive patterns and electrically isolated from each other; and on one of the dielectric insulating layers, a plurality of capacitive load adjusting patterns each being electrically connected by at least one corresponding inter-layer connecting via to a corresponding capacitive load pattern; each of the capacitive load adjusting patterns are formed fringed by a frame-shaped insulating pattern between an adjacent portion of the ground pattern; and a predetermined one of the capacitive load adjusting patterns is connected to the ground pattern via a conductive material.