Advantages and Disadvantages of Different Coupling Methods of Plasma Antennas

Abstract One of the important challenges in plasma antennas, is the coupling of RF signal to the plasma column. RF signal coupling has a significant effect on antenna efficiency, antenna implementation cost, structure implementation complexity, antenna pattern shape, and final structure weight and volume. In this article, firstly the various methods of coupling were introduced. Then capacitive coupling, direct coupling and sleeve coupling were presented and their advantages and disadvantages were mentioned. As a sample, a plasma folded monopole antenna with sleeve coupling was fabricated and measured. By comparison of the different coupling methods and as a result, one can conclude that the sleeve coupling method is the most suitable method. This method has the least sensitivity to change the dimensions. It is also easy and cheap to implement. In this type of coupling, the efficiency of the Nesta antenna is suitable and the coupling structure adds small weight and volume to the antenna structure.