Patent ID: 7639101

Claim:
A radio frequency (RF) filter, comprising: a signal transmission path having an input and an output; a plurality of resonant elements disposed along the signal transmission path between the input and the output; and a set of non-resonant elements 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 set of non-resonant elements comprises a first plurality of non-resonant elements respectively coupled in parallel with the resonant elements, and a second plurality of non-resonant elements respectively coupled in series with the resonant elements, wherein the first plurality of non-resonant elements comprises 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 without varying any of the second plurality of non-resonant elements.