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Low-Temperature Weakly-Ionized Plasma: A Promising Technology for High-Power Microwave Tuning

Event Date: August 29, 2017
Speaker: Abbas Semnani
Speaker Affiliation: Purdue ECE Senior Research
Sponsor: Birck Nanotechnology Center
Time: 11:00am
Location: BRK 1001
Priority: No
College Calendar: Show

Bio: Abbas Semnani received his B.Sc. degree from the University of Tehran, Tehran, Iran, in 2000, and the M.Sc. and Ph.D. degrees from the K. N. Toosi University of Technology, Tehran, in 2002 and 2009, respectively, all in electrical engineering. He had a four month Ph.D. sabbatical leave in the Aristotle University of Thessaloniki, Thessaloniki, Greece, in 2008. He was also a Research and Teaching Associate with the Department of Electrical and Computer Engineering, K. N. Toosi University of Technology, from 2009 to 2012. He joined the Adaptive Radio Electronics and Sensors (ARES) Team at Purdue University as a Postdoctoral Researcher in 2012 where he is currently a Senior Research Scientist. His current research interests include reconfigurable RF electronics, low-temperature plasma, computational electromagnetics, inverse scattering, and antennas.

Abstract: Reconfigurable RF electronics are in great demand due to limited available spectral resources and the increasing need for multifunctional communication systems and sensors. Traditionally, semiconductor-based elements, such as varactors, pin diodes, and Schottky diodes, are employed as RF tunable elements. More recently, technologies such as MEMS, liquid crystals, and ferromagnetic materials, have also been used for high frequency tunability. These technologies, however, are typically limited to low-to mid-power applications. Heavy and slow coaxial and waveguide-based mechanically tunable structures are still needed for high-power applications. In this regard, recent demonstrations by Abbas Semnani et al. have shown that low-temperature plasma can be a promising solution for high-power reconfigurability. Plasma-enabled RF tuning can be achieved in the order of nanosecond while RF-ignited plasmas in the α-discharge regime are quite stable with no conventional lifetime issue. Additionally, plasmas can naturally tolerate temperatures that would be too high for normal operation of semiconductors.

In this talk, first, physics of low-temperature plasma is briefly reviewed. Then, I will discuss about plasma antennas and their potential advantages in comparison with the metallic ones. Next, destructive effects of gas breakdown in high-frequency devices working in high-power regimes are discussed. Plasma can combine resistive, capacitive, and inductive properties and that all three can be tuned over very wide ranges. At the last part, I would discuss recent proof-of-principle experiments on using simple discharge tubes as a tunable capacitor/resistor in resonators, attenuators, limiters and switches.