New broadband balun structures for monolithic microwave integrated circuits

Two novel passive balun structures for use in MMICs (microwave monolithic integrated circuits) are described. They are especially relevant to wideband push-pull power amplifiers, being capable of handling several watts of power. They operate over bandwidths of up to 3:1 and can provide large impedance level transformations. Exact network synthesis procedures are used to generate prototypes and a three-dimensional field simulator is used to verify the corresponding physical circuits. A family of designs for 6-18 GHz and 6.15-13.5 GHz bands has been established.<>