Slots-Coupled Omnidirectional Circularly Polarized Cylindrical Glass Dielectric Resonator Antenna for 5.8-GHz WLAN Application

In this paper, a slots-coupled omnidirectional circularly polarized (CP) cylindrical dielectric resonator antenna (DRA) is proposed. The TM $_{01 \delta }$ and TE $_{\mathrm {011+\delta }}$ modes of the cylindrical DRA are simultaneously excited by four printed slots placed at 45 degrees to the radial direction. Omnidirectional CP fields are obtained when the fields of the two modes have the same amplitude and 90 degrees phase difference. Compared with the traditional probe-fed method, the structure of the proposed slots-coupled DRA is very simple, without introducing any groove, patch, choke or shorting pins. For the demonstration, a slots-coupled omnidirectional CP cylindrical glass DRA is designed for 5.8-GHz WLAN application. It is found that the proposed DRA can provide an AR bandwidth of ~8% (5.62-6.09 GHz) and a gain of ~5.6 dBic, with a height of $\sim 0.127\lambda _{0}$ . This performance is competitive with other reported omnidirectional CP DRAs.