A 24 GHz Sub-Harmonically Pumped Resistive Mixer in GaN HEMT Technology

This paper presents the design and the characterization of a 24 GHz sub-harmonically pumped resistive mixer (SHM) in an advanced gallium nitride (GaN) high electron mobility transistor (HEMT) technology. The mixer is desired for building up a high-performance phase-locked W-band signal source, and is designed in a single-balanced configuration, where the balanced LO input is generated by an on-chip first order lattice balun. In measurement, a conversion loss around 12 dB is achieved at the RF bandwidth of 22–28 GHz and the IF bandwidth of 3–6 GHz with a LO power of 10 dBm. The mixer exhibits an RF input P1dB of 13 dBm, and the measured LO to IF isolation achieves 40 dB at the desired LO of 10 GHz. To the best of the author's knowledge, this is the first sub-harmonically pumped mixer in GaN HEMT technology.