This paper aimed at investigating the performance of plasma windowing concept in terms of radiation pattern, gain, and S-parameter. The antenna structure consists of 12 tubes of commercial fluorescent lamps that contain a mixture of mercury vapor and argon gas, which upon electrification, forms plasma. After getting sufficient voltage, the gas inside the fluorescent tube will ionize to plasma and form a plasma column. When all of the tubes surrounding the antenna are electrified, the radiation is trapped inside. By leaving one or more of the tubes in a nonelectrified state, apertures are formed in the plasma shield, which allow radiation to escape. The plasma frequency in this experiment is equal to 5.634e11 Hz. This antenna design is at 4.9 GHz. The designing of plasma antenna using fluorescent tubes has created advancement in antenna industry especially in reconfigurable antenna field.

This paper design on plasma monopole antenna and to prove that a plasma column has been characterized as an antenna. The dimension of the antenna in this project is length of the plasma column l= 150mm, the radius of plasma column r = 5.2mm and the ground for this antenna using an aluminum. The radius for circular aluminum is 40mm. The frequency target range 550MHz until 600MHz. This frequency can be applied in ultra high frequency (UHF). In this project, the simulation is performed by using the simulation software Computer Simulation Technology (CST) Microwave Studio which is a commercially available electromagnetic simulator based on finite difference time domain technique. The performance of the designed antenna was analyzed in term of bandwidth, gain, return loss, voltage standing wave ratio (VSWR), and radiation pattern.

This study discusses the evaluation of oscillatory stability based on the synchronizing $K_s$ and damping $K_d$ torque coefficients for a single-machine system connected to an infinite bus (SMIB). Particle swarm optimization (PSO) technique is used to determine $K_s$ and $K_d$ values and subsequently identify the oscillatory stability conditions in the SMIB. The ability of PSO is compared with those of evolutionary programming (EP) techniques and artificial immune system (AIS). The least square (LS) method is selected as the benchmark for $K_s$ and $K_d$ values determined by PSO, EP, and AIS. Simulation results show that PSO successfully estimated $K_s$ and $K_d$ values closest to LS compared with EP and AIS. PSO also uses lower computational time compared with those of the two other techniques. The proposed technique is suitable for solving oscillatory stability problems based on the determination of eigenvalues and minimum damping ratio.