Helical antenna characterization using the singularity expansion method

This paper presents the application of the Singularity Expansion Method (SEM) to model the measured field backscattered by a high gain helical antenna. The SEM allows modeling its late time response using poles which are theoretically independent of the incident wave angle. These poles can thus be used for antenna identification. One of the major limitations of the SEM is its complexity to extract the physical poles of the antenna, i.e. those which are independent of the direction. In this paper, we show that it is possible to estimate one physical set of poles by considering only the boresight direction. This poles´ set allows modeling the late time measured field backscattered the antenna with a very high accuracy in both time and frequency domains. Then, these poles are compared to those extracted from other directions and we observe a very good stability of the poles regarding the incident wave angle.