US Patent 7683733 Balun transformer with improved harmonic suppression

An electronic assembly includes a substrate (66), a balun transformer (42) formed on the substrate (66) and including a first winding (50) and a second winding (52), each having respective first and second ends, and a reaction circuit component (48) formed on the substrate (66) and electrically coupled to the second winding (52) between the first and second ends thereof. The balun transformer (42) and the reaction circuit component (48) jointly form a harmonically suppressed balun transformer having a fundamental frequency, and the reaction circuit component (48) is tuned such that the harmonically suppressed balun transformer resonates at a selected harmonic of the fundamental frequency.