Omni-directional Circularly Polarized Microstrip Antenna using Dual-Patch Radiators

A circularly polarized microstrip antenna with omnidirectional radiation pattern is proposed using coplanar waveguide feed. The antenna consists of dual-slotted-patch radiators and in between a single feed. The design includes back to back configuration of radiating patches with respect to the ground plane. The metallic patches include circular slots and rectangular slots and are identical. The antenna is optimized for circularly polarized omnidirectional radiation. The antenna is fabricated and measured. The measured axial ratio (AR) < 3-dB is obtained in all direction over a 3-dB AR bandwidth with gain of 2.31 dBic. The measured results showed that the proposed design exhibit good CP characteristics in the omnidirectional radiation.