Tdk Corporation

Shoichi Ohi

Naoto Ohyama

Hideya Matsubara

A composite balun includes a plurality of baluns, at least one capacitor, a ground terminal, and a DC voltage supply terminal. The plurality of baluns and the capacitor are built into a single chip. Each of the baluns includes first to fourth connection lines, a first balanced terminal, a second balanced terminal, and an unbalanced terminal. The first connection line is connected at one end to the unbalanced terminal. The second connection line is connected at one end to the other end of the first connection line. The third connection line is electromagnetically coupled to the first connection line and connected at one end to the first balanced terminal and at the other end to the DC voltage supply terminal. The fourth connection line is electromagnetically coupled to the second connection line and connected at one end to the second balanced terminal and at the other end to the DC voltage supply terminal. The capacitor is connected at one end to the DC voltage supply terminal and led at the other end to said ground terminal.

Composite balun

A balun comprises an unbalanced terminal, two balanced terminals, and two ground terminals. The balun further comprises: a low-pass filter provided between the unbalanced terminal and one of the balanced terminals; and a high-pass filter provided between the unbalanced terminal and the other of the balanced terminals. The low-pass filter incorporates two coils and a capacitor. The high-pass filter incorporates two capacitors and a coil. The coils and the capacitors are made up of conductor layers of a multi-layer substrate.

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Tokyo, Japan

Shoichi Ohi