Title: Energy Efficient GaN PAs for Pico-Cell Base Stations
Speaker: Jeffery Walling, Assistant Professor, University of Utah
Abstract: GaN devices are fast emerging as the go to technology for medium to high power applications in the RF and MW regimes. GaN devices offer high breakdown and mobility, which offers the opportunity to yield high power and efficiency simultaneously in bands commonly used for commercial and military communications and radar. In this talk, we will present a 20 W wideband GaN PA linearized with outphasing. This PA simultaneously achieves greater than 50% peak efficiency over one-octave of bandwidth while achieving, while amplifying OFDM signals with large PAPR. The design is accomplished in less than 4 square inches, using novel power combining designs and discrete GaN devices. A second design that incorporates an FBAR filter and operates the device in a switching regime shows promise for future linearized PAs/Transmitters. The FBAR filter is integrated into a class-E matching network to suppress high order harmonic content owing to switching operation and helps to ensure ZVS operation. A demonstrated design shows significant promise for operation in envelope elimination and restoration (EER) and outphasing operation.
Speaker Bio: Dr. Walling received the B.S. degree from the University of South Florida, Tampa, in 2000, and the M.S. and Ph. D. degrees from the University of Washington, Seattle, in 2005 and 2008, respectively. Prior to starting his graduate education he was employed at Motorola, Plantation, FL working in cellular handset development. He interned for Intel, Hillsboro from 2006-2007, where he worked on highly-digital transmitter architectures and CMOS power amplifiers and continued this research while a Postdoctoral Research Associate with the University of Washington. He is currently an assistant professor in the ECE department at University of Utah. His current research interests include low-power wireless circuits, energy scavenging, high-efficiency transmitter architectures and power amplifier design for software defined radio. Dr. Walling has authored over 30 articles in peer reviewed journals and refereed conferences and holds two patents. Recently he received the Best Paper Award at Mobicom 2012. He has also received the Yang Award for outstanding graduate research from the University of Washington, Department of Electrical Engineering in 2008, an Intel Predoctoral Fellowship in 2007-2008, and the Analog Devices Outstanding Student Designer Award in 2006.