The HMC256 chip is a compact, 2.08 mm2, I/Q Mixer MMIC which can be used as a Image Reject Mixer (IRM), SSB upconverter or downconverter. The chip utilizes two standard Hittite double-balanced mixer cells and a Lange Coupler realized in GaAs MESFET technology. This IRM MMIC is designed to be used in microwave point-to- point radios, VSAT, and other SATCOM applications. All data is with the chip in a 50 ohm test fixture connected via 0.025 mm (1 mil) diameter wire bonds of minimal length <0.51 mm (<20 mils). A low frequency quadrature hybrid was used to interface the MMIC IF ports to a 120 MHz IF USB output. This provides an example of the I/Q Mixer in an IRM application. The IF may be used from 1 to 1500 MHz. This I/Q Mixer is a more reliable, much smaller replacement to hybrid drop-in style I/Q Mixer assemblies.