Exploring the Future of Circuit Simulation
Earlier this year, the IEEE Microwave Theory and Techniques Society (MTT-S) recognized Qorvo Fellow Dr. Michael Roberg with the 2021 Outstanding Young Engineer Award. The award recognizes Michael’s contributions to advancements and innovations in microwave engineering and design. Microwave Magazine spoke with him following the announcement of the award. You can watch the interview here .
Microwave Magazine spoke with Dr. Michael Roberg, recipient of the 2021 IEEE Microwave Theory and Techniques Society’s Outstanding Young Engineer Award, about his educational journey, career achievements, and lessons learned.
Those who know and have worked with Michael agree that he is a very deserving recipient of this award. For more than a decade, he has been pushing the boundaries of MMIC technology design and simulation, bringing innovative ideas to Qorvo products. This dedication stems from his love of science at a young age. In sixth grade, he invented a motor that could run continuously and won first prize in a science fair. When his sixth grade teacher bought the motor from him for $20, he became fascinated with a commercial engineering product that was both interesting and profitable.
Michael received his BS from Bucknell College in Lewisburg, Pennsylvania, where he developed an interest in microwave engineering. After joining Lockheed Martin, he also received his MS in Electrical Engineering from the University of Pennsylvania. During his PhD, he worked with Dr. Zoya Popovic at the University of Colorado Boulder on the design of high-efficiency nonlinear transmitters and high-efficiency power amplifiers (PAs). Michael then joined Qorvo, where he has been working on broadband PAs for a decade, leveraging GaN transistors to achieve higher efficiency and performance. His work on PAs has culminated in high-performance GaN solutions such as:
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The TGA2962 is capable of delivering industry-leading 10 watts of RF power, 13dB large signal gain and 20-35% power-added efficiency for radar and communication systems in the 2-20 GHz frequency range, achieving multiple performance breakthroughs.
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The TGA2239 significantly improves efficiency, gain and power performance for commercial VSAT and military satellite communications.
Additionally, he focuses on K-band communications amplifiers with very wide video bandwidth as well as 5G devices and applications.
"An amplifier is a household name, an irregular oscillator."
——Michael Roberg
Making power amplifiers perform well while pushing the limits of parameters such as power and efficiency, while increasing their design requirements, is an interesting challenge for engineers. Michael said that circuit simulation technology using device models, such as the Qorvo device models (available through Modelithics ) that engineers can use in circuit simulation, has made great progress in helping solve modern engineering problems.
“We are getting better and better at active device models and passive modeling,” Michael said. “We are able to correlate measured performance with simulated performance much better than we were even ten years ago. Frankly, I think we are experiencing a renaissance in electromagnetic problems right now.”
As high-performance computing (HPC) systems, both on-premises and in the cloud, continue to grow, increasing the computing power available to engineers, simulation and modeling techniques are also evolving. Electronic design automation (EDA) software is becoming more parallelized, making it possible to take advantage of more computing power. According to Michael, these factors are enabling engineers to solve problems that were impossible 20 or even 10 years ago. Increased computing power and software performance allow engineers to solve design problems faster.
“With the massive computing power at Qorvo’s fingertips, you can tackle simulation challenges with 1,000s of ports,” said Michael. “This allows you to further improve the performance of your design and enable more challenging designs.”
Digital Prototyping with GaN Models from Qorvo Modelithics
Accurate models and powerful simulation software allow engineers to address issues during digital prototyping and early digital circuit design, laying the right foundation when chip manufacturing first begins. Therefore, for high-frequency power amplifiers using GaN transistors, it is critical that the device models accurately predict the nonlinear behaviors of the PA transistors. These behaviors include representations of voltage-dependent current sources, capacitances, diode models, parasitic inductances, and the overall frequency-dependent resistance of the device. Modelithics performs extensive analysis on Qorvo devices to accurately represent these characteristics.
According to Michael, nonlinear models have become increasingly better over the past decade. Nevertheless, nonlinear device modeling for the MMIC industry is expected to improve further, especially when addressing certain GaN trapping issues.
Michael was recognized for his lifelong commitment to pushing the envelope, finding innovative ways to solve challenging design problems, and not accepting the impossible.
His advice to newcomers in the field: “It’s the people who work on achieving the impossible who push things forward. So don’t assume something is impossible just because it hasn’t been done before. Keep pushing the envelope, don’t stop, and don’t get complacent.”
IEEE Microwave Theory and Techniques Society (MTT-S)
https://mtt.org/ieee-mtt-s-2021-awards/
Interview Video
https://www.microwavejournal.com/articles/35491-interview-with-michael-roberg-2021-ieee-mtt-s-outstanding-young-engineer-award
Microwave Magazine
http://https//www.microwavejournal.com/articles/35491-interview-with-michael-roberg-2021-ieee-mtt-s-outstanding-young-engineer-award
TGA2962
https://cn.qorvo.com/products/p/TGA2962
TGA2239
https://cn.qorvo.com/products/p/TGA2239
Qorvo Device Models
https://www.qorvo.com/design-hub/design-tools/simulation-model-libraries/modelithics-qorvo-gan-library
Modelithics
https://www.modelithics.com/mvp/qorvo