This paper is aimed to investigate the plasma antenna parameters to help the optimization of plasma antenna dimensions (length and radius of plasma antenna). Five different configurations of plasma antenna have been simulated with the help of high frequency structure simulator (HFSS 13.0). The observations have been made on variation in antenna parameters like resonance frequency, directivity, gain and radiation pattern with the radius and length of the plasma column. The results of the study indicate that plasma column of radius r< 1.5 cm shows better performance in the sense of directivity and gain than the plasma column of radius r> 0.5 cm. In addition, tunability of the plasma antenna has been studied with respect to the resonance frequencies. Moreover, simulation results have been matched with experimental results, e.g., directivity and radiation patterns, providing more interesting results which cannot be measured due to experimental restrictions
