Patent ID: 7688159

Claim:
A SAW duplexer comprising: a first SAW filter having a ladder-shaped circuit configuration including at least one serial arm resonator and at least one parallel arm resonator, and having a passband with a relatively low frequency; a second SAW filter having a ladder-shaped circuit configuration including at least one serial arm resonator and at least one parallel arm resonator, and having a passband with a relatively high frequency; and a bridging inductor connected in parallel to the at least one serial arm resonator in the second SAW filter; wherein the first SAW filter and the second SAW filter are defined by SAW filter chips; the SAW duplexer further includes a multilayer package substrate on which the SAW filter chips are mounted; and the bridging inductor includes: a first wire provided on a first layer of the multilayer package substrate; a first via-hole conductor connected to one end of the first wire; a second via-hole conductor connected to the other end of the first wire; and a second wire provided on a second layer of the multilayer package substrate at a height that is different from a height of the first layer and connected at one end to the second via-hole conductor; a third via-hole conductor connected to the first via-hole conductor; a fourth via-hole conductor connected to the other end of the second wire; and a third wire connected at one end to the fourth via-hole conductor and provided on a third layer of the multilayer package substrate at a height that is different from the heights of the first and second layers; wherein a coil return wire portion including at least the first and third via-hole conductors is disposed inside a coiled portion including the first wire, the second wire, and the third wire.