Multiphysics Enabled Numerical Modeling of a Plasma Based Electrically Small VHF-UHF Antenna

TL;DR

This paper presents a 3D plasma-based small antenna model operating at VHF-UHF frequencies, demonstrating wide-band impedance matching, radiation efficiency, and surpassing the Chu-limit, validated through simulations and experimental data.

Contribution

Introduces a novel plasma-based small antenna model using COMSOL Multiphysics, showing practical design insights and performance metrics at low pressure and plasma conditions.

Findings

A wide-band impedance matching from 213-700 MHz achieved.

Radiation efficiency of 16% at 700 MHz demonstrated.

Performance exceeds the Chu-limit with a bandwidth-efficiency product of 0.168.

Abstract

A three-dimensional model of a novel plasma based electrically small antenna is developed for investigating the gas properties and antenna parameters under a low pressure, low plasma temperature environment. The antenna exhibits dipole antenna-like behavior with wide-band impedance matching from $213-700$ MHz. Plasma is sustained by $0.9$ W of RF input power at $100$ MHz and the gas pressure is strategically controlled at $500$ mili-Torr. The simulated $S_{11}$ is verified against the available experimental data and further antenna parameters are extracted. The proposed ESA shows dipole-like radiation pattern with a radiation efficiency of $16\%$ at $700$ MHz. The performance metric for ESAs, the Chu-limit, is exceeded by this antenna with the $Bandwidth\times Efficiency$ reaching $0.168$ with a $ka$ of $0.5571$.The findings from this letter demonstrate the practicability of using COMSOL Multiphysics as a tool for predicting plasma behavior and antenna performance while the boundary conditions for all the coupled physics are respected.