Effect of spiral flare rate on CP performance of a dual circular-polarized spiral antenna

In this paper, a compact center-fed reconfigurable CP Archimedean spiral antenna, capable of generating two orthogonal CP waves, is presented. Dual circular-polarization performance of the four-arm antenna is investigated in terms of its flare rate variation. It is shown as spiral flare rate varies from 2mm/rad to 3mm/rad the high-end frequency considerably increases and dual-polarization performance widens. Specifically, the antenna bandwidth, shared by both left- and right-hand circularly polarized waves, improves by more than 30%.