Consideration on Radiation from an Unbalanced-Mode Spiral Antenna

摘要

This paper describes the radiation from an unbalanced-mode two-arm spiral antenna,where the antenna arms are defined by the Archimedean spiral function.The input impedance,current distribution,radiation pattern,axial ratio,and gain are investigated.The investigation reveals that the unbalanced-mode spiral radiates a circularly polarized wave over a wide frequency range as the balanced-mode spiral.