The advancement of computer technology has led numerical methods to obtain a widespread usage. One of the most frequently used numerical methods in recent years is finite difference time domain method (FDTD). The behaviour of electromagnetic waves at the boundaries of the problem space has been studied by using perfectly matched layer (PML) type boundary conditions in FDTD. On the other hand, the majority of the substances in the universe are plasma. Plasma is a well known reconfigurable medium with different dielectric and conductive properties. Operating frequency of a plasma antenna is investigated in this paper. The field distributions around the plasma antenna have been evaluated using three dimensional FDTD. It has been shown that the plasma antenna can operate with characteristics similar to a wire antenna. C/C++ and MATLAB programming environments are used for simulations.