Filter device having tunable capacitance, method of manufacture and use thereof

A method of manufacturing a filter device, comprising:

• forming a foil-wound inductor from a first conductive foil strip having a first terminal and a second terminal, said first conductive foil strip wound around a core to form a plurality of winding layers such that said first terminal is proximate said core and said second terminal is located at an outermost winding layer, and a continuous dielectric insulating layer between said plurality of winding layers of said first conductive foil strip;
• forming a tunable capacitor, integral to said foil-wound inductor, from a second conductive foil strip at least partially encircling said outermost winding layer of said foil-wound inductor and a dielectric insulating layer disposed therebetween, said second conductive foil strip having a portion that can be trimmed to alter a capacitance between said second conductive foil strip and said first and second terminals of said foil-wound inductor, and
• forming a second foil-wound inductor on said core with said foil-wound inductor, said second foil-wound inductor being insulated from said foil-wound inductor, wherein said second conductive foil strip at least partially encircles said outermost winding layer of said foil-wound inductor and also at least partially encircles an outermost winding layer of said second foil-wound inductor, wherein trimming said second conductive foil strip of said tunable capacitor also alters a capacitance between said second conductive foil strip and first and second terminals of said second foil-wound inductor.