Development of Broadband Noise Models and Radio Frequency Integrated Circuits using Silicon Germanium HBTs

Abstract

A novel transit time based analytical broadband noise model is developed and implemented for high frequency bipolar transistors. This model is applied to a complementary (npn + pnp) silicon germanium (SiGe) heterojunction bipolar transistors (HBT). A complete set of analytical equations are derived using this transit time noise model, to express the four fundamental noise parameters in terms of device parameters.

A comprehensive analysis on the ac, dc and broadband noise performance of a 200 GHz SiGe HBT technology, under cryogenic temperatures, is presented. The transit time based noise model is used to analyze the RF noise behavior of the SiGe HBT down to 85 K. Significant performance gain is demonstrated in cryogenic temperatures indicating the suitability of SiGe HBT for extreme environment electronics.

A sub-circuit based substrate parasitic modeling methodology, in silicon based processes, is presented. A test case low noise amplifier, operating in the 5 GHz band, is designed in a SiGe HBT process and is used to demonstrate the validity of the design methodology. A dual-band, dual-mode transceiver front end for IEEE802.11a/b/g WLAN applications, is designed in a 0.8 and #956;m SiGe HBT process. The transceiver uses a new architecture which uses an on-chip frequency doubler and a single off-chip frequency synthesizer for both the 2.4 and 5 GHz bands. The performance of the transceiver meets the specification of the IEEE802.11a/b/g standards.

The work described in the dissertation significantly advances the state-of-the-art in bipolar broadband noise modeling and RF, microwave circuit design using silicon based processes. The contributions and implications of this work for future research are discussed.