Miniaturization of omnidirectional circularly polarized antennas

The paper reports miniaturization of recently introduced planar omnidirectional circularly polarized antennas. The technique relies on folding the antennas patch underneath itself, decreasing overall footprint. The connectivity between layers is provided by vias, enabling cost efficient PCB manufacturing techniques. The average axial ratio in the xz-plane is less than 3 dB in the band of 2.392 to 2.407 GHz. This is better than previously reported antennas of this type.