Zoya Popovic

Zoya Popovic is a Distinguished Professor of Electrical Engineering at the University of Colorado, Boulder. She obtained her Dipl.Ing. degree at the University of Belgrade, Serbia, and her Ph.D. at Caltech. She holds an honorary doctorate from the Carlos III University in Madrid. She was a Visiting Professor with the Technical University of Munich in 2001/03, ISAE in Toulouse, France in 2014, and was a Chair of Excellence at Carlos III University in Madrid in 2018/19. She has graduated over 70 PhDs and currently advises 18 doctoral students. Her research interests are in microwave and millimeter-wave high-performance circuits for communications and radar, medical and industrial applications of microwaves, and RF quantum sensing. She is a Fellow of the IEEE and the recipient of two IEEE MTT Microwave Prizes for best journal papers, the White House NSF Presidential Faculty Fellow award, the URSI Issac Koga Gold Medal, the ASEE/HP Terman Medal and the German Alexander von Humboldt Research Award. She was named IEEE MTT Distinguished Educator in 2013. Prof. Popovic is a Fellow of the National Academy of Inventors and a Member of the National Academy of Engineering. She is currently Editor in Chief of the Proceedings of the IEEE.

This talk presents transmitter and receiver circuit designs for a range of microwave applications. The content can be tailored to the audience, with emphasis on either high-power GaN front ends or sensitive radiometric receivers.

Topic 1, GaN-based microwave and mm-Wave circuits (X through W band)

GaN-based circuits will be presented spanning X through W band, including power amplifiers (PAs) that target high efficiency and good linearity for signals with wide instantaneous bandwidths (>100 MHz) and high peak-to-average power ratios (PAPR > 10 dB).

• Supply-modulated GaN PAs: examples include a 2 to 4 GHz single-ended hybrid PA, an X-band MMIC PA, and a K-band MMIC PA.
• W-band GaN MMIC front ends: an overview of W-band PAs, switches, phase shifters, isolation circuits, and an integrated T/R front end.

Topic 2, near-field radiometric receiver for internal temperature sensing

The second topic presents a receiver project for near-field internal temperature measurements of the human body. In this approach, the total blackbody power from a tissue stack is received by a 1.4 GHz probe placed on the skin.

• Temperature retrieval: sub-surface tissue temperatures are estimated using near-field weighting functions, obtained from full-wave simulations with known tissue complex electrical parameters.
• Experimental validation: measurements are demonstrated using a calibrated Dicke radiometer at 1.4 GHz with various phantom tissues.
• Result: temperature can be tracked within a fraction of a degree for a phantom muscle layer beneath phantom fat and skin layers.