Synergies of Plasma-Electromagnetic Interaction in RF Electronic Applications*

Reconfigurable RF electronics have become a subject of extensive research due to the escalating congestion and competition within the electromagnetic spectrum. Previously, switching between different RF subsystems for various applications was the norm. However, a recent trend has emerged, advocating fully reconfigurable miniaturized systems capable of supporting multiple frequency bands for different applications. At the core of these reconfigurable systems are tunable devices, serving as the fundamental building blocks. Traditionally, semiconductor-based devices have been mainly employed as high-frequency tuning elements. In addition, other technologies, such as microelectromechanical systems (MEMS), liquid crystals, and ferrite-based materials, have also been utilized for high-frequency tuning. However, they all share two fundamental shortcomings: (1) limited tuning capability across a restricted frequency range and (2) suboptimal performance in high-power scenarios—an essential requirement for many emerging systems.

Cold plasma presents a promising solution to address the abovementioned limitations, mainly through gaseous microelectronics. By controlling internal parameters such as electron density and pressure, plasmas' dielectric permittivity and conductivity can be unprecedentedly tuned. Additionally, the varying thickness of the plasma sheath introduces another variable capacitance, further enhancing its tunability. Hence, plasma offers a highly versatile and reconfigurable medium suitable for emerging high-frequency applications. In this talk, our recent progress in plasma RF electronics, including frequency-selective plasma protection against high-power microwaves [1], plasma-matched wideband electrically small antennas [2], and plasma-based electromagnetically induced transparency (EIT) for protection against high-power waves are discussed.