Frequency-scalable SiGe bipolar RFIC front-end design

Abstract

A highly-optimized SiGe RF bipolar front-end design is proposed. The optimum noise figure (NF/sub opt/) of a bipolar device is introduced in contrast with the minimum noise figure (NF/sub min/). An analytical method to design the low noise amplifier (LNA) at the optimum noise figure point is derived. The optimized LNA design scales linearly with frequency for multi-band RF front-end design. The optimization method is extended to the design of an improved Gilbert cell active mixer. The technique was demonstrated on a 1800 MHz SiGe bipolar RF front-end whose LNA achieves a 1.3 dB NF at a bias current of 4.5 mA while the mixer achieves a single-sideband noise figure (SSB NF) of 6.5 dB at only 4.8 mA.