Theoretical and experimental investigation of plasma antenna characteristics on the basis of gaseous collisionality and electron density

Abstract

This paper reports plasma antenna characteristics investigated theoretically and experimentally, on the basis of the plasma parameters: gaseous collisionality and electron density. The antenna structure is a basic quarter-wavelength monopole antenna in the UHF band. The dependence of the antenna gain on the plasma parameters is obtained by analytical equations from plasma and antenna theory, and by numerical simulations. In the plasma antenna, the ratio of the electron elastic collision frequency to the total number of electrons at the plasma cross section determines the antenna’s internal loss and the electrical equivalent antenna length, whereas the ratio of the radio wave frequency to the total number of electrons at the plasma cross section determines the antenna’s resonant frequency. These results are confirmed by experimental results of the antenna’s impedance and radiation patterns.

Characterisation of a thermionic plasma source apparatus for high-density gaseous plasma antenna applications

“…In particular, whether plasma discharges are used as active antenna elements (e.g., plasma dipole [17] or monopole [18]), the first resonance frequency [4] of such devices can be increased by up to 50% when varying the plasma density from 1 × 10 18 to 1 × 10 19 m −3 [17]. With such an increase in plasma density, the antenna gain can also increase by an order of magnitude [19]. Higher values of the neutral background pressure result in a reduction of the antenna performances due to collisionality reducing the achievable antenna gain [17].…”

Experimental characteristics of 2.45 GHz microwave reconfigurable plasma antennas

“…Moreover, the results show that the simulated and experimental antenna gains increase with increasing discharge power, the reason being that both n e and σ increase. The relation between the gain and electron density is found in [37,40]. It is necessary to mention that the scope of the experimental electron density is from 10 15 to 10 19 m −3 , so it is impossible to cover all simulation ranges (from 10 15 to 10 22 m −3 ).…”