A novel microwave omnidirectional antenna for wireless communications

A novel microwave omnidirectional antenna is proposed in this paper for wireless communications. This antenna is constructed with cavity-restrained multi-stacked dielectric disks. Vertical polarized omnidirectional radiation patterns are obtained from radiative ring slots in the side wall of dielectric-metal cavities operating on TM/sub 01/spl delta// mode. High omnidirectional gain is realized with stacked cavities with multi-radiative slots. Ring slots between the adjacent cavities are used to enhance the excitation of the desired radiating mode in phase, which actually eliminates the feed network. A special technique is adopted for excitation of the antenna from coaxial line, with which very good matching is achieved. This type of antennas could be ideal for the base or center stations for wireless and indoor communications. Experimental results of a prototype of the antennas working at 12.6 GHz is given to demonstrate the great potentials for wireless applications.