Analytical Estimation of the Efficiency of Surface-Wave-Excited Plasma Monopole Antennas

Experimental characterization of TIAGO torch discharges: surface wave discharge behavior and (post-)discharge kinetics

“…Interestingly, according to figure 7(a), the intensity of the FNS in Zone II increases, reaching a maximum slightly before the end of the dart, while T gas reaches its maximum at the end of the dart and then tends to be constant. This behavior can be explained by the destruction of nitrogen ions detailed previously through reaction (9), providing this region with a higher density of nitrogen -atoms. Indeed, the emission of the FPS, N 2 (B 3 Π g → A 3 Σ + u ) started being detectable in positions where the FNS reaches its maximum, tending to be more noticeable as FNS intensity decreases, supporting the idea of the destruction of N + 2 in the latter positions of Zone II by (9) since nitrogen atoms are required for the emission of the FPS [59,60].…”

“…Therefore, another process must be involved in the kinetics in this region. It is worth also remarking that in Zone I, T gas tends to increase (figure 4); this is more noticeable in discharges sustained at 600 W. According to Moon and Choe [56] who studied the effects of ambient air in argon-based discharges working at atmospheric pressure, the N + 2 ion can be destroyed through reaction (9) giving place to nitrogen atoms that provide energy to increase T gas (assumed to be equal to T rot ) since they have a relatively high kinetic energy via exothermic dissociative recombination reactions. Hence, this process could explain the constancy in Zone I of n e and the emission of the FNS and increase in T gas in this region as well.…”

“…When plotting in the z− system, this maximum is observed to appear in the same z = 1.9 ± 0.2 position (z = 1.9 ± 0.2 mm) regardless of the input power. This derives from the fact that reaction (9), which governs the decrease of FNS intensity, is mediated by electrons, and electron density has been found to have no dependence on the input power in the z− system (figure 9).…”

Reconfigurable Antennas Based on Plasma Reflectors and Cylindrical Slotted Waveguide

“…Based on this relation, the plasma is a dispersive medium with permittivity εp, which is a function of the operating angular frequency ω (rad/s). The permittivity of the plasma is also a function of the electron-neutral collision frequency υ in Hz, and the plasma angular frequency ω p (rad/s), which is defined as follows [13,14]:…”

“…Various realizations of antennas with reconfigurable radiation characteristics and/or tunable resonance frequencies based on plasma radiating element (s) have been reported in [1,. However, due to the finite conductivity of the plasma elements, these antennas generally suffer from low efficiency [12,33]. This problem may be worse for small plasma antennas on which there are high current densities.…”