Patent ID: 8797120

Claim:
A radio frequency (RF) filter, comprising: a substrate; a signal transmission path having an input and an output; a plurality of resonant elements disposed on the substrate along the signal transmission path between the input and the output; a plurality of non-resonant elements disposed on the substrate for coupling the resonant elements together to form a stop band having a plurality of transmission zeroes corresponding to respective frequencies of the resonant elements, and at least one sub-band between the transmission zeroes, wherein the non-resonant elements comprise at least one variable non-resonant element for selectively introducing at least one reflection zero within the stop band to create a pass band in one of the at least one sub-bands; and at least one tuning element disposed on the substrate and respectively electrically coupled to at least one of the resonant elements, wherein a portion of each of the at least one tuning element is configured for being removed from the substrate to modify the frequency of the respective resonant element.