Patent ID: 7369018

Claim:
A dielectric filter comprising a dielectric multilayered substrate having an upper surface and a lower surface when the filter is in a horizontal position, comprising: first and second resonant elements in an inner layer of the substrate, each comprising: an open end and a grounded end; a wide portion at the open end for electromagnetically coupling the first and second resonant elements with each other, and a narrow portion at the grounded end; first and second input/output electrodes located entirely above the wide portions; a first upper ground electrode in a layer above the input/output electrodes; said first upper ground electrode located above said wide portions of the resonant elements, and not located above said narrow portions of the resonant elements, and being above substantially all of the surface area of said wide portions; a second upper ground electrode in a layer above said first upper ground electrode, said second upper ground electrode located above substantially only said narrow portions of the resonant elements, a first lower ground electrode in a layer below said first and second resonant elements, said first lower ground electrode located below said wide portions of the resonant elements and not located below said narrow portions of the resonant elements, and being below substantially all of the surface area of said wide portions; and a second lower ground electrode in a layer below said first lower ground electrode and located below substantially only said narrow portions of the resonant elements.