Ube Industries, Inc.

Hirofumi Kimura

Kosuke Nishimura

Keigo Nagao

Chisen Hashimoto

Eiji Masui

A transmission band filter () having a series of elements () each composed of a film bulk acoustic resonator and grounded shunt elements () each composed of a film bulk acoustic resonator is connected between a transmission port () and an antenna port (). A reception band filter () having a series of elements () each composed of a film bulk acoustic resonator and grounded shunt elements () each composed of a film bulk acoustic resonator is connected between a reception port () and the antenna port (). A film bulk acoustic resonator () for adjustment is connected between the antenna port () and the ground. The resonance frequency of the adjusting film bulk acoustic resonator () lies between the upper limit frequency of the transmission frequency pass band of the transmission band filter () and the lower limit frequency of the reception frequency pass band of the reception band filter (). Therefore a duplexer such that it can be a monolithic element, the power handling capability is good, the size is small, and the cost is low is provided.

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Ube, Japan

Hirofumi Kimura