Design and Analysis of Cavity Backed Spiral Antenna for Effective Antenna-Plasma Coupling in Tokamak Environments

Abstract

The study presents a novel approach to the designing and analyzing spiral antennas with cylindrical and conical-disc backings that are circularly polarized and optimized for antenna-plasma coupling in Tokamak settings. The intended frequency range for operation of the suggested antenna arrangement is 0.1 to 1.0 GHz. Unlike the traditional spiral antenna, which is supplied by a horizontally or vertically oriented balun, the proposed design is powered directly by a coaxial cable with a planar feeding section that has been specially calibrated to produce wide-band input impedance matching. The spiral antenna was designed with the steady state superconducting tokamak (SST-1) port area constraints in mind. With reflection coefficients of –24.05 dB to feed conical backed cavities and –30.37 dB to feed cylindrical backed cavities, respectively, the proposed antenna amply showed intrinsic resonance at 0.5GHz through modeling. The findings show encouraging progress in attaining efficient antenna-plasma interaction.