ECE Seminar with Taylor Barton

4:00 pm on Monday, March 4, 2013
Photonics Center, 8 Saint Mary’s St., Room 339
Energy Efficient Design: Amplifiers for High Data Rate Wireless Communications With Taylor Barton Postdoctoral Research Associate Microsystems Technology Laboratories MIT Faculty Host: Enrico Bellotti Refreshments will be served outside Room 339 at 3:45 p.m. Abstract: The past few years have shown an explosive increase in demand for smartphones and mobile devices with high data rate capabilities. Data streaming and mobile connectivity anywhere, anytime has become ubiquitous. In order to meet this ever-increasing demand for data traffic, modern communications standards require wide-bandwidth circuits that transmit signals with high peak-to-average ratios. At the same time, a combination of the rising cost of energy and interest in limiting energy consumption has increased demand for energy-efficient systems. The combination of these two effects has generated an urgent need for efficient RF power amplifiers in order to avoid a future energy crunch in wireless networking. Power efficiency in RF amplifiers has been a longstanding challenge. The difficulty stems from the linearity/efficiency tradeoff in conventional designs, which is at odds with the modern requirement of power amplifiers with linear output control that is efficient over a wide operating range. As we move toward multi-gigabit data rates, it will be necessary to employ aggressive modulation schemes to higher frequency bands, exacerbating the design difficulty. In order to surmount this challenge, I have developed a new power combining system for wireless communications based on the principle of outphasing, i.e. phase-based output power control using multiple switched-mode power amplifiers. In contrast to conventional outphasing techniques such as Chireix outphasing, this new power combining system provides nearly resistive load modulation, and thus considerably improved loading conditions for the power amplifiers. The architecture takes advantage of GaN devices, which enable the development of switched-mode power amplifiers that operate efficiently at high frequencies and high power. In this seminar, I will present the architecture along with its implementation in both discrete and microstrip-based forms. About the Speaker: Taylor Barton received an ScD degree from the Massachusetts Institute of Technology in 2012 for her research in energy-efficient power amplifiers for wireless communications. Dr. Barton also holds ScB, MEng, and EE degrees from MIT's department of electrical engineering and computer science. Her research interests and background are in the areas of analog and RF circuits, particularly applied to microwave communications. She is currently a postdoctoral research associate at MIT in the Microsystems Technology Laboratories. Dr. Barton received the Goodwin Medal for effective teaching at MIT and the Analog Devices Outstanding Student Designer Award in 2011. Her extracurricular pursuits include building autonomous sailing robots.