Patent attributes
A balun circuit is provided that includes a first coupling line in which an unbalanced line thereof is connected to a first terminal and a balanced line thereof is electrically connected to a second terminal, a second coupling line in which an unbalanced line thereof is electrically connected to the unbalanced line of the first coupling line and a balanced line thereof is electrically connected to a third terminal, a first transmission path that is serially connected between the balanced line of the first coupling line and a ground potential, a second transmission path that is serially connected between the balanced line of the second coupling line and a ground potential, and a third transmission path that is serially connected between the unbalanced line of the first coupling line and the unbalanced line of the second coupling line. These transmission lines are formed such that an amplitude characteristic of S12 is the same as an amplitude characteristic of S13 and a phase characteristic of S12 is inverted in relation to a phase characteristic of S13.
