Characteristics of an Atmospheric Discharge Plasma as an RF Antenna

摘要

The plasma produced by a laser-guided, electric discharge in the atmosphere has been formed in the shape of a folded monopole antenna with a characteristic frequency of 112 MHz. This plasma antenna has been used to transmit and receive signals at 112 MHz. While the plasma conductivity remained above a certain value, the signal transmitted from, and received on, the plasma antenna was within -l + or - 1 dB of that transmitted from and received on a 'standard' copper folded monopole antenna of the same size. During this time the signal transmitted from, and received on, the plasma antenna also remained approximately constant in amplitude (fluctuations about + or - 1 dB). This useful lifetime of the plasma antenna was varied from about 200 microsecs to about > 2000 microsecs by changing the duration of the electric discharge sustaining the plasma columns. In these experiments, the noise from the plasma antenna was not distinguishable from that developed using a copper antenna, but in both cases the noise was much larger than the true thermal noise background.