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Ph.D. Proposal Oral Exam - Clifford Cheon

Event Details

Thursday, September 24, 2020

1:00pm - 3:00pm


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Event Details

Title:  New Approaches to Wideband RF Switching in Silicon-Germanium Technology


Dr. Cressler, Advisor     

Dr. Li, Chair

Dr. Ayazi

Abstract: The objective of the proposed research is to develop and investigate RF switches utilizing silicon germanium (SiGe) heterojunction bipolar transistors (HBTs) to provide a novel design approach for the next-generation wideband applications. Considering a low cost, low power consumption, and high integration capability, especially with digital logic circuits, RF switches using CMOS technology have outnumbered other technologies. Substantial amount of studies has been reported to improve switch performance in terms of bandwidth, insertion loss, isolation, and power handling capability. However, because of the trade-offs between on-state resistance and parasitic capacitance of a CMOS transistor, obtaining a low loss over wide range of frequency remains a challenge. Additionally, recent developments in deep submicron CMOS processes add burdens to power handling capability. To overcome these issues, a novel RF switch based on SiGe HBTs is proposed. Because of the vertical profile, the SiGe HBT offers significantly reduced parasitic capacitance to the substrate, which is key to obtain simultaneously wide bandwidth and low insertion loss. The preliminary research demonstrates that SiGe HBTs can ably serve as competitive series switching transistors in terms of bandwidth and insertion loss and, thus, can achieve state-of-the-art performance. The proposed research includes thorough analysis on the linearity enhancement of the proposed SiGe RF switch and explores its applications by developing a wideband SPDT switch and a wideband digital step attenuator.

Last revised September 20, 2020