Patent ID: 6870440

Claim:
A surface acoustic wave duplexer having an antenna terminal, a transmitting terminal and a receiving terminal, comprising: a transmitting SAW filter coupled between the antenna terminal and the transmitting terminal; a receiving SAW filter coupled between the antenna terminal and the receiving terminal: a common piezoelectric substrate on which both of the transmitting SAW filter and the receiving SAW filter are formed; and a package covering the common piezoelectric substrate, wherein the antenna terminal, the transmitting terminal and the receiving terminal are formed on the package; a frequency adjusting circuit being coupled between the antenna terminal and the transmitting SAW filter or the receiving SAW filter, wherein the frequency adjusting circuit has a capacitance element; and a branching filter circuit coupled between the frequency adjusting circuit and the transmitting SAW filter or the receiving SAW filter, wherein the branching filter circuit is formed on the package.