The HMC331 is a passive miniature frequency doubler MMIC. Suppression of undesired fundamental and higher order harmonics is 40 to 60 dB with respect to input signal level and 24 to 42 dB with respect to the output level. The doubler utilizes the same GaAs Schottky diode/balun technology found in Hittite MMIC mixers. It features small size, requires no DC bias, and adds no measurable additive phase noise onto the multiplied signal. Applications include commercial point to multi-point radios, and other microwave frequency generation subsystems as well as communication systems.