Research Group

Current Group Members · Visiting Researchers · Alumni · Alumni Entrepreneurs · Awards

The microwave & RF research group at the University of Colorado is advised by Dr. Zoya Popović. Since its inception in 1990 more than 40 Ph.D. theses have been completed, as well as several M.S. degrees. The group is typically comprised of between 10-15 graduate students, 1-2 post-doctoral researchers and a few visting researchers.

Zoya Popovic Professor Zoya Popović received the Dipl.Ing. degree from the University of Belgrade, Serbia, Yugoslavia, in 1985, and the Ph.D. degree from the California Institute of Technology, Pasadena, in 1990. Since 1990, she has been with the University of Colorado at Boulder, where she is currently a Distinguished Professor and holds the Hudson Moore Jr. Chair in the department of Electrical, Computer and Energy Engineering. In 2001, she was a Visiting Professor with the Technical University of Munich, Munich, Germany. Since 1991, she has graduated 40 Ph.D. students. Her research interests include high-efficiency, low-noise, and broadband microwave and millimeter-wave circuits, quasi-optical millimeter-wave techniques for imaging, smart and multibeam antenna arrays, intelligent RF front ends, and wireless powering for batteryless sensors. Prof. Popovic was the recipient of the 1993 and 2006 Microwave Prizes presented by the IEEE Microwave Theory and Techniques Society (IEEE MTT-S) for the best journal papers, and received the 1996 URSI IssacKoga Gold Medal. In 1997, Eta Kappa Nu students chose her as a Professor of the Year. She was the recipient of a 2000 Humboldt Research Award for Senior U.S. Scientists from the German Alexander von Humboldt Stiftung. She was elected a Foreign Member of the Serbian Academy of Sciences and Arts in 2006. She was also the recipient of the 2001 Hewlett-Packard(HP)/American Society for Engineering Education(ASEE) Terman Medal for combined teaching and research excellence. [full CV]

Current Group Members

Ignacio Ramos Ignacio Ramos was born in Chicago Illinois in 1985. He received the Bachelors of Science at the University of Illinois Chicago in 2009. From 2009 to 2011 he was with the Power and Electronic Systems Department at Raytheon IDS in Sudbury Massachusetts. While at Raytheon, he was involved with radars, power systems, renewable energy systems and high power energy conversion. He moved to Boulder Colorado in 2011 to pursue his PhD in Electrical Engineering with the active antenna group. His research interest s include high-efficiency microwave PAs, microwave DC/DC converters, power oscillators, radar systems and wireless power transmission. When not working, he enjoys biking, climbing, reading, backpacking, and drinking good beer.

Mike Litchfield Mike Litchfield grew up in New Hampshire where he graduated from the University of New Hampshire with a B.S. in Electrical Engineering in 2011. After graduation, he worked for Mercury Computers completing the design of quadrature up and down converters for a DRFM system. In September of 2011 he married his wonderful wife, Kaitlin. He joined Dr. Popovic's Microwave laboratory at the University of Colorado in January of 2012 and is currently pursuing a PhD. His current research is on the outphasing architecture for highly efficient, linear amplification, which is implemented in the TriQuint GaN process. Outside of work, Mike enjoys basketball, hiking, and reading.

Mike Coffey Mike Coffey grew up in Southern California and attended the California Polytechnic State University, Pomona from 2005 to 2010 and earned a BSEE. He then was employed by the Wavestream Corporation from 2010 to 2012 and worked in the advanced technology group there on analog predistorters, various microwave front end circuits and X - Ka band high power amplifiers for military and airborne applications. Mike then joined the Microwave and RF research group at the University of Colorado, Boulder in August, 2012 and has been working on high efficiency power amplifier topologies and taking classes in RF/microwave circuits and techniques and switched mode power supply electronics in the pursuit of a MSEE/PHD. Mike and other members of the Microwave and RF research group will be working on the DARPA NEXT program with HRL Laboratories, LLC.

Sushia Rahimizadeh Sushia Rahimizadeh received a B.S. in Electrical and Computer Engineering from the University of Colorado at Boulder, where he has continued his research in power amplifier technologies. As an undergraduate, Sushia developed embedded systems and RF communication experience with his extensive involvement in the design of electrical systems of satellite-based projects funded by NASA, Lockheed-Martin, and the Department of Defense. Prior to his joining the group in 2013, Sushia also worked with First RF as an RF engineer intern on radar and tracking systems. The subject of his research upon involvement with the group began with wireless powering technologies and has continued towards efficiency enhancement techniques in high-power LDMOS-based power amplifiers.

Parisa_MR Parisa MomenRoodaki received her MSc. Degree in Electrical Engineering from Amirkabir University of Technology in 2012 where she has worked on high efficient linear power amplifier design. In 2013, she joined University of Colorado Boulder and started working on non-invasive wearable radiometer for core body temperature measurement. She has several teaching assistantship and industrial experiences in the area of RF/Microwave circuit design. Her research interests include biomedical antennas/circuits, stretchable bio-sensors, wireless energy harvesting, RFIC/MMIC, high efficiency power amplifier and envelope tracker. Outside of work, Parisa enjoys biking, playing volleyball, reading, and hiking.

MauricioPinto Mauricio Pinto received his B.S. degree in Electrical Engineering from the California State Polytechnic University, Pomona, CA, in 2010. From 2010 to 2014, he was with the Naval Air Warfare Center, Weapons Division, CA, where he worked on RF front ends for various airborne and land-based defense systems. While working, he received an M.S. degree in Engineering Management from the University of Southern California, Los Angeles, CA. Mauricio joined the group in Fall of 2014 and is currently working towards his Ph.D at the University of Colorado under the advisement of Prof. Zoya Popovic. His current research interests include design of millimeter-wave power amplifier MMICs. During his free time you can find him squatting a few hundred kilos in the rec center.

Maxwell Duffy Maxwell Duffy was born in Mahwah New Jersey in 1992. He attended The College of New Jersey graduating with his Bachelor of Science in Electric Engineering in 2015. While attending college he was employed by Linearizer Technology from 2013-2015. In the fall of 2015 he joined the Microwave and RF group at the University of Colorado Boulder. Currently he is working on a project with Boeing for a highly efficient amplifier using envelope tracking. His hobbies include reading and hiking.

Allison Duh Allison Duh joined the group in the fall of 2015. After graduating from Columbia University in New York in 2014 with a B.S. in Electrical Engineering, she completed a year-long fellowship in Germany with the Congress-Bundestag Youth Exchange for Young Professionals and worked on a synthetic aperture radar code and test set-up with Perisens GmbH and the Technical University of Munich.

WillHaines Will Haines was born in New Orleans in 1992. He received a B.S. in Electrical and Computer Engineering from the University of Colorado at Boulder in 2015 and immediately joined the group. Currently he is working on a radiometer at 1.4 GHz for a non-invasive method of measuring internal body temperature. This has impacts for athletics, medicine, and health monitoring. His hobbies include camping, skiing, and playing tennis.

Visiting Researchers

TibaultReveyrand Tibault Reveyrand received the Ph.D. degree from the University of Limoges, France, in 2002. From 2002 to 2004, he was a Post-Doctoral Scientist with CNES (French Space Agency). From 2005 to 2013, he was a CNRS engineer at XLIM. In 2013, he joined the University of Colorado at Boulder as a Research Associate. His research interests include the characterization and modeling of RF and microwave nonlinear components and devices. Dr. Reveyrand was the recipient of the 2002 European GaAs Best Paper Award and is a member of the IEEE MTT-11 "Microwave Measurements" Technical Committee.


Gregor Lasser Gregor Lasser received his Dipl.-Ing. degree from Vienna University of Technology in 2008, and his Dr. techn. degree in 2014 from the same university, both with distinction. The RFID testbed developed during his diploma thesis received the second position of the EEEfCOM innovation award in 2008. For the presentation of his doctoral dissertation entitled Passive RFID for Automotive Sensor Applications he earned the faculty award of the electrical engineering and information technology department of the Vienna University of Technology. Since June 2015 Dr. Lasser is a research associate with the University of Colorado, Boulder, where he is working on broadband envelope tracking power amplifiers and compact intelligent antenna systems. He is a licensed ham radio operator and enjoys to bring vintage and unconventional radio gear on air as OE1GLC. [Publications]


Ph.D. graduates and post-docs:

M.S. graduates:

Alumni Entrepreneurs

Past Visiting Researchers

  • Tommaso Cappello, University of Bologna
  • Jérôme Tissier, Associate Professor at ESEO Angers, France
  • Gregor Lasser, Vienna University of Technology
  • Gonzalo Expósito
  • César Sánchez Pérez
  • Christoph Ullrich, Technische Universiät München
  • Marcelo Perotoni, Sao Paulo University (USP) 2003-2004.
  • Florian Helmbrecht, Technische Universitat Munchen, (Diplomarbeit, 2002)
  • Johannes Russer, Univ. of Karlsruhe
  • Pal Matyas, Technische Universitat Munchen
  • Holger Mater, Technische Universitat Munchen
  • Ileana Carrasquillo, University of Puerto Rico, Mayaguez
  • Martin Kaleja, Technische Universitat Munchen


Professor Popović

  • IEEE MTT Distinguished Educator, 2013
  • Holland Teaching Award, University of Colorado, 2011
  • Distinguished Professor, University of Colorado, 2010
  • Coleman Research Fellow, Coleman Institute, 2008
  • Faculty Research Award, College of Engineering and Applied Science, 2007
  • Elected Foreign Member of Serbian Academy of Sciences and Arts, 2006
  • Microwave Prize, IEEE MTT Society, 2005, best journal paper award
  • Microwave Prize, IEEE MTT Society, 1993, best journal paper award
  • Fellow, IEEE, 2002
  • ASEE HP/Terman Award 2001, for combined teaching and research excellence
  • Humboldt Research Award for Senior Scientists, German Alexander von Humboldt Foundation, 2000/2001
  • Margaret Willard Award, University of Colorado, 1997, as female role model
  • Eta Kappa Nu professor of the year award, 1997, by student vote
  • URSI Issac Koga Gold Medal, Lille, France, 1996, awarded once every three years
  • White House NSF Presidential Faculty Fellow Award, 1993
  • URSI Young Scientist, Kyoto, Japan, 1993
  • Best Student Award for the division of Electronics, University of Belgrade, 1985
  • City of Belgrade October Award for the Diploma Thesis in 1985

Student Papers

  • Mike Litchfield won the student paper competition at the Compound Semiconductor IC Symposium (CSICS) October 2015 with his paper titled "Multi-Level Chireix Oupthasing GaN MMIC PA".
  • Sean Regalia-Korhummel won best paper at Wireless Power Transfer Conference (WPTC) 2013. Paper
  • "A Transmit/Receive Active Antenna with Fast Low-Power Optical Switching," J. Vian and Z. Popović, 2000 IEEE IMS Symposium Digest, pp 847-850, Boston, June 2000 [Received 2nd place, Student Paper Competition]
  • "A Frequency Tunable Half-Wave Resonator using a MEMS Variable Capacitor," Bell, P., Hoivik, N., Bright, V., Popovic, Z., 35th International Symposium on Microelectronics (IMAPS) 2002, Denver, CO, Sept 2002 [Received 2nd place, Best Student Paper]
  • "Recycling Ambient Microwave Energy with Broadband Antenna Arrays," J.A. Hagerty, F. Helmbrecht, W. McCalpin, R. Zane, Z. Popovic, IEEE Trans. Microwave Theory and Techn., pp. 1014-1024, March 2004 [Winner of IEEE Microwave Prize]


  • Graduate students Mike Litchfield and Scott Schafer placed 2nd in the IMS Power Amplifier contest IMS 2014 (Tampa Bay, Florida).
  • Graduate students Ignacio Ramos placed 2nd in the IMS Wireless Powering contest IMS 2014 (Tampa Bay, Florida).
  • Graduate students Rob Scheeler and Sean Regalia-Korhummel won the IMS Wireless Powering contest achieving highest efficiency in IMS 2013 (Seattle). (IEEExplore, PDF)
  • Graduate student Bradley Lindseth won the NXP PA competition with a 449MHz 2.6kW 63% efficient circuit in IMS 2011, Baltimore. (Denver Post, NXP)
  • Graduate student Michael Roberg participated in IMS Power Amplifier contest and achieved highest efficiency (83% PAE at 2.11GHz) prize and overall second prize in IMS 2010 (Anaheim). (TriQuint)
  • Jacques Hung Loui received the Sandia Truman Fellowship in 2006 (Sandia National Laboratories established the President Harry S. Truman Fellowship in National Security Science and Engineering to attract the best nationally recognized new Ph.D. scientists and engineers).
  • A number of students received Lincoln Laboratory, Sandia, Navy, NSF and Dept of Education GAANN fellowships.