Effect of the Method of Excitation of the Plasma Antenna on the Spectral Characteristics of the Radiated Signal

The radiation of signal by the plasma asymmetrical dipole antenna is studied for two methods of its excitation. Earlier, it was shown that the 2nd and 3rd harmonics of the input signal frequency in the radiation spectrum of the plasma antenna are 10–20 dB stronger than those of a metal antenna with the same geometry. In this work, we study experimentally and by computer simulations the effect of the method of excitation of the plasma asymmetrical dipole antenna on the spectral characteristics of the signal that it radiates. For the two excitation methods of the antenna, through an electrode and through a coaxial coupler, it was shown that the strength of the signal components at the frequency of the radiated signal and its multiple harmonics is different. The introduction of the coaxial coupler in the antenna excitation scheme allowed us to improve the coupling at the input signal frequency and decrease its components at the 2nd and 3rd harmonics. For the plasma antenna with the coaxial coupler, the difference between the 1st and 2nd harmonics was increased by almost 6 dB, and between the 1st and the 3rd ones by almost 20 dB compared to the antenna excitation scheme through the electrode.