The HMC203 chip is a miniature doublebalanced mixer which can be used as an upconverter or downconverter. Excellent isolations are provided by on-chip baluns, which require no external components and no DC bias. The mixer chip can be integrated directly into MIC hybrid applications including 18 GHz TVRO, 23 GHz telecom radios and military systems. Unless otherwise stated, all data was measured with the mixer mounted in a MMIC test fixture. The MMIC was connected to thinfilm 50 ohm transmission lines with 1 mil diameter wirebonds of <10 mils in length.