Novel RF Analysis and Design Techniques
Oct 31, 2013
from 10:00 AM to 12:00 PM
|Where||Engr. IV Bldg, Maxwell Room 57-124|
|Contact Name||Ali Homayoun|
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Advisor: Prof. Behzad Razavi
The design of RF integrated circuits continues to challenge engineers and researchers, demanding new circuit topologies and transceiver architectures. New ideas often require new analysis techniques as well so that the designer can insightfully quantify the underlying principles.
This research addresses three problems in RF circuits: (1) analysis of phase noise in phase/frequency detectors (PFDs), an essential component in RF synthesizers; (2) analysis of the relation between the phase noise of delay lines and ring oscillators; and (3) design of a new low-power RF CMOS receiver for IEEE802.11a. The first analysis derives equations for the phase noise and shows that an octave increase in the input frequency raises the phase noise by 6 dB if flicker noise is dominant and by 3 dB if white noise is dominant. The second analysis reveals a simple “shaping” function and also dispels the commonly-accepted premise that symmetric rise and fall times in a ring oscillator suppress the upconversion of flicker noise.
This presentation primarily deals with the design of a low-power 5-GHz receiver. While advances in the art have considerably reduced the power consumption of RF oscillators, frequency dividers, and analog-to-digital converters, the main receiver chain in 5-GHz systems draws a disproportionately high power, about 46 mW. It is therefore desirable to develop low-power RX front ends and baseband filters for WiFi applications. This work introduces a complete 5-GHz CMOS receiver that meets the 11a sensitivity, blocking, and filtering requirements while consuming 11.6 mW. This fourfold reduction in power is achieved through the use of a transformer as a low-noise amplifier, passive mixers, and non-invasive baseband filtering. A new analysis of passive current-driven mixers also reveals a fundamental mistake in previous derivations.
Ali Homayoun received the B.S. and M.S. degrees in electronics engineering from Sharif University of Technology, Tehran, Iran, in 2006 and 2009, respectively. In fall 2009, he joined the University of California, Los Angeles, to pursue the Ph.D. degree. His research interests include RF, analog, and mixed-mode integrated circuit design.