AN ACTIVELY BALANCED GAAS HBT-SCHOTTKY MIXER FOR 3-V WIRELESS APPLICATIONS

Here we present a novel low-voltage active mixer topology which enable s 3-V double-balanced active mixer operation from wide-bandgap GaAs-ba sed heterojunction bipolar transistors (HBT's), The compact mixer desi gn integrates directly coupled active radio frequency (RF) and local o scillator (LO) transformer baluns with a Schottky-diode ring-quad to f orm a double-balanced mixer which operates from de to 5 GHz, Biased wi th a low 3-V supply and operated as a down-converter with a fixed LO a t 800 MHz and 0 dBm, the mixer achieves 9.4-dB conversion gain (CG) at 1 GHz with positive CG out to 4 GHz and an IP3 of -5 dBm, The LO-IF i solation is >20 dB while the 2-2 spur suppression is >20 dB over a bro ad 1-5-GHz RF input band, The novel 2.1.V-BE supply design topology al lows 3-V operation from the high turn-on voltage GaAs HBT's, making th em suitable for portable wireless applications, and can enable 1.5-V o peration for Si, Si-Ge, and InP BJT/HBT technologies.