Investigation of effects of various types of gases on radiation pattern in plasma antenna

Summary form only given. The term plasma antenna has been applied to a wide variety of antenna concepts that incorporate some use of an ionized medium. In vast majority of approaches, the plasma, or ionized volume, simply replaced a solid conductor. A highly ionized plasma is essentially a good conductor, and therefore plasma filaments can serve as transmission line elements for guiding waves, or antenna surfaces for radiation. The ionized volume can take a variety of forms. It can be established in air at atmospheric. Pressure by using lasers, high power microwave beams, or ultraviolet rays. A plasma might also be generated from a gas filled tube containing a noble gas like neon or argon. Methods that use a tube require less energy to excite and maintain the plasma state, because the gas is pure and the presence of the tube prevents dissipation. The radiation pattern is controlled by parameters such as plasma density, tube shape, and current distribution. In this work we designed and fabricated a helical plasma antenna that excited with 2.45 GHz microwave energy, and the effects of some types of gases like argon, helium, and O₂ on its radiation pattern were investigated and compared with wire helical antennas.