Patent ID: 9722575
Date: 2017-08-01
CPC Classifications: H03H

Claim:
1. A duplexer comprising: a transmit filter connected between a transmit terminal and an antenna terminal and including series resonators and parallel resonators connected in a ladder form; and a receive filter connected between a receive terminal and the antenna terminal, wherein at least one of resonators, which are resonators other than a first series resonator and a first parallel resonator located at a first stage as viewed from a side of the transmit terminal and a second series resonator and a second parallel resonator located at a first stage as viewed from a side of the antenna terminal and have electrostatic capacitances less than an electrostatic capacitance of at least one of the first series resonator, the first parallel resonator, the second series resonator, and the second parallel resonator in the series resonators and the parallel resonators, is divided in series, and the at least one of resonators includes at least one of the series resonators other than the first series resonator and the second series resonator and at least one of the parallel resonators other than the first parallel resonator and the second parallel resonator.