AN 18-22-GHZ DOWN-CONVERTER BASED ON GAAS ALGAAS HBT-SCHOTTKY DIODE INTEGRATED TECHNOLOGY/

Here we report on a K-band AlGaAs/GaAs HBT-Schottky diode down-convert er which represents the highest complexity monolithic integrated GaAs HBT-Schottky MMIC so far demonstrated at ii-band frequencies. The MMIC integrates a double-balanced Schottky diode mixer with an 18-22 GHz t wo-stage li-band,radio frequency (RF) amplifier, a 6-10 GHz two-stage X-band IF amplifier, and a 12-GHz local oscillator (LO) heterojunction bipolar transistor (HBT) buffer amplifier, The Schottky diodes are co nstructed from the existing GaAs HBT base and collector vertical epita xy layers and can be easily fabricated with only one additional mask p rocessing step, The double-balanced Schottky mixer provides high IP3 a nd high 2-2 spur suppression over a broad band while consuming Little de power, The HBT-Schottky integrated down-converter MMIC achieves >16 -dB conversion gain over an RF input band from 18-22 GHz and a corresp onding IP3 >10 dBm with only +3 dBm of LO drive, The total chip is 3.8 5 x 3.75 mm(2) and can be self-biased through a single 5,5-V supply wh ile consuming 545 mW of de power, The use of GaAs HBT vertical-Schottk y-diode technology has inherent performance advantages for frequency c onversion MMIC's.