The upcoming fifth generation (5G) of mobile communication that can enhance the capacity andrndata rates attracts many attentions in recent years. One drawback of 5G technology is that it isrnmore prone to interference comparing to the other technologies. To overcome this problem 5Grninfrastructure uses much smaller base stations instead of using the large cellular antenna that wernuse today. To cover large area multiple number of small cells can be used. This makes the antennarncosty. So, nowadays omnidirectional circularly polarized antennas are commonly designed in 5Grntechnology to reduce sector antenna and the interference. Hence. Due to the various advantages ofrnomnidirectional circularly polarized antennas different methodology was used to design. However,rngetting a good performed antennas based on their gain, radiation efficiency, low reflectionrncoefficient and small electrical size of antenna are the major challenges.rnTherefore, in this paper a circularly polarization omnidirectional antenna which is applied to 5Grncommunication is designed to improve the gain. The essence of this research is combining tworndifferent kinds of antenna in High Frequency Structure Simulator (HFSS) to achieve therncharacteristic of omnidirectional radiation pattern and circular polarization. The two kinds ofrnantenna are dipole and negative magnetic permeability zeroth-order resonator respectively.rnBecause both of them are linear polarization and omnidirectional radiation pattern, therncharacteristic of omnidirectional radiation pattern and circular polarization can be achieved as longrnas they are combined in physical space with 90 degrees. The radiation pattern of antennas isrnsimulated to generate the gain. For the antenna designed at 6 GHz the gain is 1.9 dBi and for thernantenna at 28 GHz the gain is 2.0 dBi. Both antennas achieve circular polarization performancernand Omni-directional radiation within the operational band. This research output can be especiallyrnapplied to 5G small base stations in the future.