Patent ID: 8076993
Filing Date: 2011-12-13
Classification: H01P

Abstract:
1. A balun circuit comprising: a first CPW line, a second CPW line and a third CPW line that become signal I/O ports; a first differential transmission line that links a central conductor of said second CPW line and a ground conductor of said first CPW line and links a ground conductor of said second CPW line and a central conductor of said first CPW line; a second differential transmission line that links a central conductor of said third CPW line and the central conductor of said first CPW line and links a ground conductor of said third CPW line and the ground conductor of said first CPW line; and a joint that connects two or more of the ground conductor of said first CPW line, the ground conductor of said second CPW line and the ground conductor of said third CPW line, wherein said first differential transmission line and said second differential transmission line have a first line, a second line and an underlying layer connected to a fixed potential arranged between a substrate and said second line, said first line and said second line being formed in a dielectric layer on said substrate and said second line being formed at a position nearer to said substrate than said first line and being electromagnetically coupled to said first line.