Patent ID: 7941103
Filing Date: 2011-05-10
Classification: H03H

Abstract:
1. A duplexer comprising: a transmit filter of a ladder type filter, connected between a common terminal and a transmitting terminal, wherein the transmit filter includes one or more parallel resonators and a transmitting inductance, the one or more parallel resonators being grounded through the transmitting inductance; a receiver filter of the ladder type filter, connected between the common terminal and a receiving terminal, wherein the receiver filter includes multiple parallel resonators, a first receiving inductance and a second receiving inductance, the multiple parallel resonators being grounded through the first receiving inductance and the second receiving inductance in a manner wherein at least one of the multiple parallel resonators is grounded through the first receiving inductance and the remainder multiple parallel resonators are grounded through the second receiving inductance, and wherein at least one of the first receiving inductance and the second receiving inductance is connected to more than one of the multiple parallel resonators; a stacked package with multiple layers, in which the transmit filter and the receive filter are mounted; a transmitting ground line pattern provided on one of the multiple layers and partially composing the transmitting inductance, wherein the transmitting ground line pattern is provided on a different layer from the first receiving ground line pattern and the second receiving ground line pattern; and a first receiving ground line pattern provided on one of the multiple layers and partially composing the first receiving inductance; and a second receiving ground pattern provided on one of the multiple layers and partially composing the second receiving inductance; wherein the first receiving ground line pattern and the second receiving ground line pattern are not provided on the one of the multiple layers on which the transmitting ground line pattern is provided.