Home > Seminars > Feedback Techniques for Broadband RF Front-End Receivers

Feedback Techniques for Broadband RF Front-End Receivers


4/22/2014 at 2:00PM


4/22/2014 at 3:00PM


258 Fitzpatrick Hall


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Thomas Fuja

Thomas Fuja

VIEW FULL PROFILE Email: tfuja@nd.edu
Phone: 574-631-7244
Office: 275 Fitzpatrick Hall


Wireless Institute Professor
Prof. Fuja research addresses reliable communication over inherently unreliable and/or constrained communication links. He has recently focused his research on the changing role that channel codes play in the context of wireless networks, i.e., to not only provide physical-layer robustness but ...
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Future wireless communication devices must support multiple standards and features on a single-chip. The trend towards software-defined radio (SDR) requires flexible and efficient RF building blocks, which justifies the adoption of broadband receiver front-end in modern and future communication systems. Broadband receiver front-end significantly reduces cost, area, pins, and power, and can process several signal channels simultaneously. Since the invention of negative feedback amplifiers by Harold S. Black, feedback techniques have been widely used in various analog circuits. Low distortion and high precision baseband circuits unanimously employ closed-loop feedback amplifiers. However, the use of feedback techniques has been limited to low-frequency regime due to the scare power gain at RF frequency and the fear of in-stability. With the recent advances in the transistor’s cut-off frequency (ft), it becomes more promising to employ feedback in the design of RF ICs. Analog and RF circuit design is often faced with multiple design trade-offs and those cannot be satisfied simultaneously. This talk is centered on the feedback techniques for broadband RF front-end receivers and shows how feedback can de-couple several design trade-offs. First part of the talk concentrates on the wideband common-gate LNA that overcomes the fundamental trade-off between power and noise match without compromising its stability. The proposed architecture achieves broadband impedance matching, low noise, large gain, enhanced linearity, and wide bandwidth concurrently by employing an efficient and reliable dual negative-feedback. For single low noise trans-conductance receiver architecture, positive feedback is applied to achieve low noise and large gain without breaking the fixed relationship between input impedance, trans-conductance gain, and load impedance. The innovations in both circuit and architecture improve the receiver dynamic range for multi-standard applications.

Seminar Speaker:

Jusung Kim

Jusung Kim

Qualcomm, Inc.

Jusung Kim received the B.S. degree with highest honors in electrical engineering from Yonsei University, Seoul, Korea, in 2006, and the Ph.D. degree in electrical engineering from Texas A&M University, College Station, TX, in 2011. In the summer of 2008, he was an Analog Integrated (IC) Design Engineer Intern with Texas Instrument Incorporated, Dallas, TX, where he designed the RF front-end for multi-standard analog and digital TV silicon tuners. Since January 2012, he has been with Qualcomm Inc., San Diego, CA, where he designs RF integrated circuit (RFIC) products for third-generation (3G) and fourth-generation (4G) cellular systems. His research interests include transceiver system and circuit design at RF and millimeter-wave frequencies. Dr. Kim currently serves as Associate Editor for IEEE Transactions on Circuits and Systems Part II from January, 2014.