Patent ID: 8547188

Claim:
A filter disposed within a multilayer substrate, the filter comprising: a first and second resonator, the first and second resonators respectively having a short circuit end and an open circuit end, the respective short circuit ends of the first and second resonators coupled to a first ground plane; an input coupled to the first resonator; an output coupled to the second resonator; a first loading capacitor coupled to the open circuit end of the first resonator, the first loading capacitor comprising a first capacitor plate and a second capacitor plate; a second loading capacitor coupled to the open circuit end of the second resonator, the second loading capacitor comprises a first capacitor plate and a second capacitor plate; and wherein the first and second resonators are disposed in a resonator plane substantially parallel to and vertically displaced from at least one of the respective first capacitor plate and the second capacitor plate of the respective first and second loading capacitors, wherein at least one of the first and second resonators is at least partially overlapped by at least one of: the first capacitor plate or the second capacitor plate of the first loading capacitor, or the first capacitor plate or the second capacitor plate of the second loading capacitor; and wherein the first ground plane includes at least one void area wherein the void area forms a substantially isolated region of the first ground plane; the filter further comprising an inductor coupled between at least one of the second capacitor plates of the first and second loading capacitors and the first ground plane; and wherein the value of the inductor is controlled by a predetermined dimension of a conductive coupling region disposed between at least two edges of the at least one void area of the first ground plane.