Theoretical and experimental investigations of surface-waves plasma column and microwave plasma source for applications in reconfigurable plasma antenna

Abstract

In this paper, we have investigated plasma column excited by surface-waves using monopole plasma antenna. Since the plasma frequency has an important role in conductivity of the plasma column and antenna radiation characteristics, determining the distribution electron density and plasma frequency in the inhomogeneous plasma column axis is particularly important. For this purpose, the plasma column is modelled by fluid equations for high-frequency discharges. Because of significant advantages such as high power handling capability at 2.45 GHz, the surfaguide launcher is chosen from the other conventional launchers to propagate the surface wave along plasma column. The surfaguide is experimentally excited an argon gas-filled tube at a pressure of 0.2 torr as a surface-wave plasma source. In this work, because of safety considerations about high power radiation, plasma frequency measurements was impractical using conventional methods. Therefore, a new system is designed consists of a solid-state VCO, amplifier, circulator, attenuator and two double-ridged horn antennas. The plasma frequency is obtained close to 5.7 GHz, which is consistent with theoretical concepts.

Experimental characteristics of 2.45 GHz microwave reconfigurable plasma antennas

“…The surface wave sustains the discharge, its power tending to gradually decrease along the z axis according to figure 3. Following the power flux, the electron density decreases to a minimum value of n D at z = h. In our research, the minimum zone is located at the end of the plasma column, and the power falls below the required threshold for sustaining the discharge of plasma [36]. Therefore, the requirement for a surface wave to propagate along the plasma column is:…”

“…When a surface wave propagates along a plasma column, the maximum value of the EM field in an ideal space environment decreases exponentially in the radial direction of the column. The electric field intensity by surface waves is maximal along an interface with a dielectric and tends to decay exponentially on both sides of the boundary [36]. This is caused by the negative permittivity of the plasma at frequencies smaller than the cut-off plasma angular frequency ω pe , which can be expressed as…”

“…In this paper, we use another excitation device, a surfaguide, to generate and maintain the plasma in the flexible antenna system [12,20,36]. The surfaguide was first proposed in [12].…”

A Reconfigurable Solid-state Plasma Dipole Antenna Based on SPiN Diodes

“…With the rapid development of the information technology and the continuous progress of the electronic reconnaissance means, there is a tremendous effort to dramatically change the antenna characteristics, such as dynamic reconfiguration and stealth [1,2]. The antenna with reconfigurable can be dynamically modified to enable different functions at different times, which increase their capabilities, expand their functionality, and widen their operating bandwidths [3,4,5].…”