Thin film balun

Abstract

The present invention provides a thin film balun capable of preventing a resonant frequency from being increased to a high frequency, and thus realizing a preferable passage characteristic. A thin film balun 1 includes: an unbalanced transmission line 2 having a first coil portion C1 and a second coil portion C2; and a balanced transmission line 3 having a third coil portion C3 and a fourth coil portion C4 which are magnetically coupled with the first coil portion C1 and the second coil portion C2, respectively. The first coil portion C1 is connected to an unbalanced terminal T0, and the second coil portion C2 is connected to a ground terminal G (ground potential) via a capacitor D (C component). The third coil portion C3 is connected to a balanced terminal T1 and the fourth coil portion C4 is connected to a second balanced terminal T2. The capacitor D is provided, in a plan view, in an area S1 between the outer end of the unbalanced terminal T0 and the outer end of the ground terminal G.

Dependencies are inferred from the claim text.