The presentation discusses properties of ionized gases (plasmas), such as those used in fluorescent lights, from the standpoint of their potential application to tunable and reconfigurable radio-frequency (RF) electronics: antennas, resonators, filters, etc. Plasmas have important advantages in comparison with other (e.g. semiconductor) solutions, especially in high-power regimes. Although the RF applications motivate the plasma research, the focus of this presentation is on the relevant fundamental aspects.

First, we show that plasmas can combine resistive, capacitive, and inductive properties and that all three can be tuned over very wide ranges. We then discuss recent proof-of-principle experiments on using simple gas discharges as tunable elements in resonant LC filters, resonators, and limiters. The next topic is plasma antennas that can be switched on/off and tuned within a wide frequency band. We show that plasma antennas generally have lower gain than metallic antennas do, but the cross-coupling between different elements of an array is also lower, which is an important plasma advantage. Finally, we discuss the critical problem of Johnson-Nyquist noise in plasma antennas and show that, although conventional plasma antennas are very “noisy”, a novel approach of sustaining the plasma by nanosecond repetitive pulses could enable low-noise plasma antennas and thus make such antennas practical.

Sergey Macheret has received his M.S. and Ph.D. degrees from Moscow Institute of Physics and Technology and Kurchatov Institute of Atomic Energy, respectively. Since moving to the US in 1991, he worked at the Ohio State University (1991-1994) and Princeton University (1994-2006). Since 2006, he has been with Lockheed Martin Aeronautics Company’s Advanced Development Programs (the Skunk Works), where he is the leader of a team engaged in a number of both government-sponsored and company-funded research and development projects on aerospace applications of weakly ionized plasmas. Prof. Macheret has made contributions to the theory of nonequlibrium physical and chemical processes in high-enthalpy flows, to highly efficient generation of nonequilibrium plasmas, and to aerospace applications of plasmas and magnetohydrodynamics. Dr. Macheret is an author or co-author of over 160 journal and conference papers, 10 patents, and 2 books. In the last decade, he gave dozens of invited presentations and lectures and chaired AIAA conferences and sessions.

Department of Physics General Colloquia

Researchers should cite this work as follows:

• Sergey Macheret (2017), "Weakly Ionized Plasmas for Reconfigurable RF Systems," https://nanohub.org/resources/26515.

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