3-Arm spiral antennas for direction finding applications

This paper presents a study of 3-arm Archimedean spiral antennas for direction finding (DF) systems. First, we discuss the DF performance of the antenna using an amplitude and phase comparison method, where Mode 1 and Mode 2 radiation patterns of the spiral are used to determine the direction-of-arrival of a source signal with known polarization. Next, the antenna's DF capability is assessed using the Cramer Rao bound, which determines the lowest possible RMS error for angular estimation. Results show that a 3-arm spiral provides a low-cost, feasible alternative for multi-channel, digital reception.