INALAS INGAAS HBT X-BAND DOUBLE-BALANCED UP-CONVERTER/

We report on an InAlAs/InGaAs HBT Gilbert cell double-balanced mixer w hich upconverts a 3 GHz IF signal to an RF frequency of 5-12 GHz. The mixer cell achieves a conversion loss of between 0.8 dB and 2.6 dB fro m 5 to 12 GHz. The LO-RF and IF-RF isolations are better than 30 dB at an LO drive of +5 dBm across the RF band. A pre-distortion circuit is used to increase the linear input power range of the LO port to above +5 dBm. Discrete amplifiers designed for the IF and RF frequency port s make up the complete upconverter architecture which achieves a conve rsion gain of 40 dB for an RF output bandwidth of 10 GHz. The upconver ter chip set fabricated with InAlAs/InGaAs HBT's demonstrates the wide st gain-bandwidth performance of a Gilbert cell based upconverter comp ared to previous GaAs and InP HBT or Si-bipolar IC's.