Properties of DC-biased plasma antenna

Plasma antenna is a general terms representing using plasma as a conductive medium to transmit or reflect signals. It has unique properties like low RCS, tunable impedance, and instant on-off capability. Previous plasma antenna uses 500 MHz 100 W RF power to generate a plasma column, which is limited in energy efficiency and bandwidth. We developed DC-biased plasma antenna, which has no operation frequency upper limit and low sustaining power. Signal is coupled to the plasma antenna via capacitive coupling. Plasma antennas of different length were studied, together with variant gas filled. Positive gain can be achieved at frequencies above the plasma characteristics frequency. Some frequencies shows resonance behavior when plasma is present. Impedance shifts slightly with the DC current. Radiation pattern is less uniform than metal antenna. Gain is related to signal power.