Karl F. Warnick of Brigham Young University

Active phased arrays and phased array feeds (PAFs) are increasingly being used for applications requiring high sensitivity, including astronomical observations, passive radiometry, and satellite terminals. Phased array designs that have been in use for radar and communications for many decades typically have relatively low antenna efficiencies. The signal environment for terrestrial applications has a high ambient temperature and intensive optimization of receiver sensitivity yields only modest performance gains. For radio astronomy, remote sensing, and satellite communications, the situation is different. High radiation efficiency, low noise electronics, compensation for mutual coupling effects, and careful design optimization are needed to meet stringent performance requirements. These applications have stimulated something of a renaissance in phased array antenna research. This presentation will survey results on antenna modeling, microwave network theory, antenna design, and experimental measurements for high sensitivity array receiver applications. Systems across the spectrum of applications will be considered, from cryogenic phased array feeds for astronomical observations to planar array feeds for smart satellite terminals that offer adaptive tracking at a low cost.  Antenna terms in the latest revision of the IEEE standard for antenna terms and array characterization methods will also be discussed, along with challenges such as determining the quality of active impedance matching in an array feed system, array element radiation loss modeling, and performance characterization methods.

Biography:

Karl F. Warnick received the B.S. degree and the Ph.D. degree from Brigham Young University (BYU), Provo, UT, in 1994 and 1997, respectively. From 1998 to 2000, he was a Postdoctoral Research Associate at the University of Illinois at Urbana-Champaign.  Since 2000, he has been a faculty member in the Department of Electrical and Computer Engineering at BYU, where he is currently a Professor.  Dr. Warnick has published many scientific articles and conference papers on electromagnetic theory, numerical methods, remote sensing, antenna applications, phased arrays, biomedical devices, and inverse scattering, and is the author of three books in these areas. Dr. Warnick is a Fellow of the IEEE for contributions to theoretical and numerical analysis of phased-array antennas and microwave systems and is a recipient of an Outstanding Faculty Member award for Electrical and Computer Engineering, the BYU Young Scholar Award, the Ira A. Fulton College of Engineering and Technology Excellence in Scholarship Award, and the BYU Karl G. Maeser Research and Creative Arts Award. He has served the Antennas and Propagation Society as a member and co-chair of the Education Committee and as Senior Associate Editor of the IEEE Transactions on Antennas and Propagation and Antennas.

Email:

Address:Department of Electrical and Computer Engineering, Brigham Young University, Provo, Utah, United States