Conceptual design of wideband balanced circularly polarized dual-loop antenna

Preliminary design of a wideband dual-loop circularly polarized antenna is proposed in this paper. The antenna consists of two coaxially coupled, non-uniform square loops. A rectangular dipole is employed to serve as a symmetrical feeder. The designed antenna is fed by a balun mounted above a ground plane. By introducing the coaxially coupled dual-loop configuration, both the impedance and axial ratio (AR) bandwidths of the antenna can be effectively enhanced. It is numerically simulated that the -10-dB reflection coefficient bandwidth is up to 74.7%, with a correspondingly usable 3-dB AR bandwidth up to 19.1%.