Oregon State University

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Event Details

PhD Oral Preliminary Examination – Sanket Jain

Monday, April 23, 2018 10:00 AM - 12:00 PM

Integrated receiver architectures tolerant to co-channel and in-band self-interfering blocker signals

Simultaneous transmit-and-receive (STAR) radios enable higher spectrum efficiency and dynamic spectrum access. Furthermore, integrating the shared antenna-interface is attractive for small-form factor and MIMO channel estimation. This research focuses on receiver architectures which enable better spectral efficiency by handling blockers in the same spectral range as the signal. The presence of such blockers, without the use of blocker cancelling/filtering techniques leads to gain compression and hence, consequent performance degradation of receivers leading to reduced spectrum efficiency. Two approaches have been devised, implemented in silicon and measured to demonstrate that they alleviate the problems associated with blockers. A system capable of handling co-channel spatially separated blockers is implemented in the first work and another system capable of handling self-interference caused due to the transmitter during full-duplex operation constitutes the second work. In the first work, a 4-channel phased array based on a novel architecture incorporating a coupler and a noise-cancelling LNA in combination with a polyphase filter was implemented to eliminate spatial co-channel blockers. This approach allows signal reception from all directions except from the direction of the blocker providing better than 20dB blocker cancellation in the X-band. The second work is aimed at achieving true STAR performance through a hybrid coupler based full-duplex integrated N-path based circulator-Rx architecture. Implemented for frequencies ranging from 550MHz to 900MHz this work addresses the challenge of low-noise wideband self-interference-cancellation by demonstrating a wideband hybrid-coupler circulator antenna interface using N-path mixers that achieves low noise figure while preserving the linearity of passive-mixer first receiver. Better than +5.5dBm power handling of self-interference while providing over 40dB average cancellation over a bandwidth of 56MHz with a 2.7dB noise figure has been measured.

Major Advisor: Arun Natarajan
Committee: Un-Ku Moon
Committee: Andreas Weisshaar
Committee: Thinh Nguyen
GCR: William Warnes

Kelley Engineering Center (campus map)
Calvin Hughes
1 541 737 3168
Calvin.Hughes at oregonstate.edu
Sch Elect Engr/Comp Sci
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