Full-Wave Analysis and Computation of Radiation Characteristics for Reconfigurable Plasma Antennas

A full-wave analytical theory has been developed and numerically solved for finding the radiation characteristics of the plasma column antenna for both guided-and leaky-mode configurations using electric and magnetic field vector potentials and the polarization current method. In the guided mode, the wave propagates through the plasma column axially and is radiated in the endfire direction, while in the leaky mode, the wave leaks along the broadside of the column in the normal direction and is attenuated axially. The radiation regions for these modes are classified by the dispersion (omega-beta) diagram that determines an axial phase propagation constant as a function of frequency. The analytical radiation characteristic findings are validated computationally using CST-MW Studio software. The effective axial length of the plasma generated inside the tube can be gradually increased or decreased as a function of input power, which, in turn, helps to tune/retune the resonant plasma antenna to the desired frequency. This type of antenna is useful for RADAR and communication systems where a continuous change in frequency could be required.