Wideband frequency reconfigurable plasma antenna launched by surface wave coupler

Abstract

A wideband reconfigurable plasma antenna excited by a surface wave coupler (SWC) operating at 13.56 MHz is presented in this study. The plasma antenna and SWC are designed and modeled in CST Studio. A detailed analysis of the SWC is carried out using CST Studio, and experimental measurements supplement the performance. This work explores the signal transmission capabilities of a plasma antenna excited at 13.56 MHz for the first time. A SWC is a two-port device that is modified for radiating electromagnetic waves through a plasma column produced at a frequency of 13.56 MHz with a coupling efficiency of 99%. The power port and signal port of the SWC are isolated for better coupling efficiency and to reduce interference. The return loss and isolation between the ports of the SWC at 13.56 MHz are −22 dB and −46.81 dB, respectively. The plasma antenna excited by a surface wave has a wider bandwidth than its metallic counterpart. It varies from 280 to 540 MHz for input plasma power ranging from 2 W to 10 W. In addition, a reconfigurability frequency span of 240 MHz for power ranging from 2 to 10 W is achieved experimentally. Moreover, we attained an enhanced peak gain of -5 dBi. The radiation efficiency of the plasma antenna is around 20%. The experimental results of the SWC and plasma antenna are in coherence with its simulations.