Time-Varying Transmission Line (TVTL) for Broadband, Low Noise, Nonreciprocal and Cross-Frequency RF Applications
Prof. Y. Ethan Wang
University of California at Los Angeles, USA
Abstract: Passive electromagnetic devices such as transmission lines, filters and antennas are essential parts of a wireless system. They often dominate the system’s efficiency, bandwidth and noise performance. Traditional passives often operate in a time-invariant manner as they are built with materials and structures that have time independent properties. They are subject to many well-known fundamental limits such as the reciprocity of the transmission line, limit of quality factors of passive filters and limit of efficiency bandwidth product. Utilization of transistor based active electronics may help to overcome some of these challenges but they oftentimes incur noise and power handling issues. Transmission lines, with time-varying impedances, can help to overcome many of those traditional limits in passives while offering a better noise and power handling performance comparing to the active transistor based circuits. In this talk, multiple initiatives supported by NSF and DARPA will be reported on the development of a new class of electromagnetic devices based on time-varying transmission lines. These devices include circulators, mixers, filters and correlators that may be constructed on integrated semiconductor platforms with time-dependent property enforced through parametric modulation or dynamic switching. Potential new applications such a full-duplex radios, tunable RF front-ends may be developed with this novel device concept.
Speaker’s Bio: Dr. Yuanxun Ethan Wang received his M.S. and Ph.D. degrees in electrical engineering from University of Texas at Austin, in 1996 and 1999. He became an Assistant Professor with the Electrical and Computer Engineering department of UCLA since Nov. 2002 and is now a Professor with the same department. Dr. Wang is an IEEE fellow and has served as an associate Editor of IEEE Transactions on Antennas and Propagation. He has published more than 300 journal and conference papers. He has been the leading PI for multiple DARPA programs including SPAR, M3IC and AMEBA. His research is in the general area of microwave system, and he often blends digital technologies and concepts into RF design, creating novel devices with performances beyond the conventional bound.