Patent ID: 8766744

Claim:
A duplexer comprising: a multilayer substrate having multiple layers and having a back surface having a rectangular shape; an antenna terminal provided on the back surface so as to be close to a center of a first side of the back surface; a transmission terminal provided on the back surface so as to be close to a second side of the back surface crossing the first side and to be farther away from the antenna terminal than a center of the second side; a first reception terminal provided on the back surface so as to be close to a third side of the back surface opposite to the second side and to be farther away from the antenna terminal than a center of the third side; a first conductor provided on a first surface of a first layer out of the multiple layers so as to surround at least one of a first area defined by projecting the transmission terminal onto the first layer and a second area defined by projecting the first reception terminal thereon; and a ground terminal provided on a second surface of the first layer opposite to the first surface and located between the transmission terminal and a fourth side opposite to the first side and/or between the first reception terminal and the fourth side.