Patent ID: 8653904

Claim:
A thin film balun comprising: an unbalanced transmission line including a first line portion and a second line portion; a balanced transmission line including a third line portion and a fourth line portion that are positioned facing the first line portion and the second line portion and magnetically coupled to the first line portion and the second line portion, respectively; an unbalanced terminal connected to an end of the first line portion; a first balanced terminal connected to the third line portion; a second balanced terminal connected to the fourth line portion; and a ground terminal connected to the third line portion and the fourth line portion, wherein: the ground terminal has an extension that extends from the ground terminal to an area at the unbalanced terminal side; the third line portion and the fourth line portion are formed in a first layer; and a connection electrically connecting the third line portion and the fourth line portion and the extension connected to the connection are formed in a second layer.