A novel omnidirectional circularly polarized (CP) slot array antenna with high gain is proposed, which is based on the coaxial cylinder structure, and the orthogonal slots radiated the circular polarization wave around the cylinder. Further, the improved dual circularly polarized (CP) omnidirectional antenna based on slot array in coaxial cylinder structure is presented too, and two ports are assigned in its two side as left hand circularly polarized (LHCP) port and right hand circularly polarized (RHCP) port, respectively. The simulation and experiment results show their novelty and good performance of omnidirectional circular polarization with about 5 dBi gain in 5.2–5.9 GHz.
Part of the book: Modern Antenna Systems