Ka/Q-band doubly balanced MMIC mixers with low LO power

An InP-based broadband double-balanced mixer was developed having interchan geable RF/LO-ports and covering frequencies from 30 to 45 GHz, with a conve rsion loss of 12 +/- 2 dB at the low LO power of 4 dBm, This broadband char acteristic was achieved through the use of side-coupled baluns far both the RF and LO ports. The ring quad-diodes used state-of-the-art superlattice l ayers, which provided goad control of turn-on voltage and were monolithical ly integrable with in-house HEMT's and TWT's. The diodes exhibited a very l ow turn-on voltage of 0.15 V at 1 mA, low series resistance, and high cutof f frequencies.