A 5-10 GHZ OCTAVE-BAND ALGAAS GAAS HBT-SCHOTTKY DIODE DOWN-CONVERTER MMIC/

This work describes an AlGaAs/GaAs heterojunction bipolar transistor ( HBT)S-band down-converter monolithic microwave integrated circuit (MMI C) which integrates a double double-balanced Schottky mixer and five s tages of HBT amplification to achieve greater than 30 dB conversion ga in over an RF bandwidth from 5 to 10 GHz, In addition, an output IP3 a s high as +15 dBm has been achieved, The Schottky diodes are construct ed from the existing N- collector and N+ subcollector layers of the HB T molecular beam epitaxy (MBE) device structure, A novel HBT amplifier topology employing active feedback which provides wide bandwidth in a compact area is used for the RF, LO, and TF amplifier stages. The com plete down-converter MMIC is realized in a 3.6 x 3.4 mm(2) area, is se lf-biased through a 6 V supply, and consumes 530 mW. This MMIC represe nts the highest complexity S-band down-converter MMIC demonstrated usi ng GaAs HBT-Schottky diode technology.