Patent ID: 7102460

Claim:
A duplexer for separating transmitted and received signals of a defined frequency band comprising: an antenna port, a reception output, and a transmission input; a reception path connected between said antenna port and said reception output; a transmission path connected between said antenna port and said transmission input; a reception bandpass filter connected in said reception path and comprised of a first partial filter and a second partial filter; said first partial filter comprising a reactance filter selected from the group consisting of a ladder-type reactance filter and a lattice-type reactance filter, said reactance filter comprising a plurality of bulk acoustic wave resonators; said second partial filter being a balun having an acoustic track proceeding in a longitudinal direction, said acoustic track comprising a plurality of surface acoustic wave transducers that are acoustically coupled to each other in said longitudinal direction; a transmission bandpass filter connected in said transmission path; and said antenna port being asymmetrical and said reception output being symmetrical.