INVESTIGATION OF CYLINDRICALLY-CONFORMED FOUR-ARM SPIRAL ANTENNAS

by Glass, Douglas J.

A four-arm spiral antenna offers broadband frequency response, wide beamwidths, reduced size compared to other antenna designs, and the ability to determine the relative direction of an incident signal with appropriate mode-forming. The reduced overall area projection of the four-arm spiral antenna compared to other antenna designs and the ability to be manufactured in a planar format allows the antenna to reside within an Unmanned Air Vehicle (UAV) fuselage. This thesis investigates the effects of cylindrically-conforming two different designs of a four-arm spiral antenna to reside within the fuselage of a medium-sized UAV. Theoretical predictions of antenna performance were created using the Numerical Electromagnetics Code (NEC) package and compared to measured results of flat and cylindrically-conformed four-arm spiral antennas with and without ground plane apertures.