Compact Omnidirectional Circularly Polarized Antenna Realized by a Parallel ME-dipole Pair

A compact omnidirectional circularly polarized antenna (OCP) realized by a parallel ME-dipole pair is proposed in this paper. This antenna consists of two symmetrical meandering clues and a small ground plane, which helps to obtain a compact design. The arrangement of two clues and ground plane help to construct equivalent M-dipole and E-dipole, respectively, which are the key operation to realize OCP radiation. For the final antenna design, simulated |S-11| below -10dB is from 1.723 GHz to 1.728 GHz. At f(0) = 1.726 GHz, satisfactory OCP pattern is achieved, and the simulated 3-dB axial-ratio beamwidth in the cutting plane of phi = 45 degrees and 135 degrees are as wide as 360 degrees and 167 degrees, respectively.