Patent ID: 7710216

Claim:
A balun circuit comprising: a first CPW line, a second CPW line, and a third CPW line that serve as signal input/output ports; a first CPS line that is a differential transmission line, the first CPS line relaying a center conductor of said second CPW line to a center conductor of said first CPW line and relaying a grounded conductor of said second CPW line to a grounded conductor of said first CPW line; a second CPS line that is a differential transmission line, the second CPS line relaying a center conductor of said third CPW line to another grounded conductor of said first CPW line and relaying a grounded conductor of said third CPW line to the center conductor of said first CPW line; and a connection section that connects two or more of the grounded conductors of said first CPW line, the grounded conductor of said second CPW line, and the grounded conductor of said third CPW line.