Patent ID: 7561012

Claim:
An electronic device comprising: a pair of quarter-wave resonators which are interdigital-coupled to each other; and a pair of balanced terminals, one terminal being connected to one of the pair of quarter-wave resonators, the other terminal being connected to the other of the pair of quarter-wave resonators, wherein: the pair of quarter-wave resonators have a first resonance mode where the pair of quarter-wave resonators resonate at a first resonance frequency f 1 higher than a resonance frequency f 0 , and a second resonance mode where the pair of quarter-wave resonators resonate at a second resonance frequency f 2 lower than the resonance frequency f 0 , where f 0 is a resonance frequency in each of the pair of quarter-wave resonators when establishing no interdigital-coupling, and an operating frequency is the second resonance frequency f 2 .