Patent ID: 7511591

Claim:
A balun of distributed type, formed of planar conductive windings defining inductive elements comprising: in a first conductive level, a first winding between a first common-mode access and a first central end and a second winding between a first differential-mode access and a second central end; in a second conductive level, a third winding having a central end electrically connected to the first central end of the first level and having an external end defining a second common-mode access, and a fourth winding having an external end defining a second differential-mode access and having a central end electrically connected to the second central end of the first level; and a third conductive level forming a ground plane to which are electrically connected the central interconnected ends of the second and fourth differential-mode windings, the external end of the third winding being electrically connected to a surface defining a first electrode of a capacitor having a second electrode connected to the ground plane, and the value of the capacitor being selected according to the impedance ratio desired for the transformer.