Patent ID: 8063717
Filing Date: 2011-11-22
Classification: H03H

Abstract:
1. A duplexer interfacing a receiver and a transmitter with a common antenna, the duplexer comprising: a first filter comprising at least four first series resonators connected in series between the antenna and one of the receiver and the transmitter, four first shunt resonators respectively connected between at least one of the four first series resonators and ground voltage, and a mutual inductance commonly connected between two adjacent first shunt resonators; and a second filter comprising at least four second series resonators connected in series between the antenna and one of the transmitter and the receiver, four second shunt resonators respectively connected between at least one of the four second series resonators and the ground voltage, and a cross-coupling capacitor connected between a first capacitor node connected to at least one of the second series resonators and a second capacitor node connected to one of the second shunt resonators, and an inductor connected in series between second capacitor node and ground, wherein three of the at least four second series resonators and the one of the second shunt resonators to which the cross-coupling capacitor is connected are positioned between the first capacitor node and the second capacitor node.