A high percentage bandwith microwave filter network, according to an embodiment of the present invention, comprises a T-network of capacitors implemented with thin-film techniques by applying a groundplane to one side of an alumina substrate and a first plate to the other side. A silicon nitride dielectric layer having a high density of capacitance is deposited over the first plate, and then a second and third capacitor plate are deposited on the dielectric over the first plate.
A thin-film, lumped element filter utilizing spiral inductors and capacitive pi networks is disclosed. The filter is fabricated from a planar dielectric substrate having a ground plane on one side thereof and two thin-film metal layers and an insulation layer disposed therebetween on the opposite side of the dielectric substrate. The metal and insulation layers are configured to form one or more capacitive pi networks and spiral inductors, which are electrically interconnected to form the filter.