Compact omnidirectional circularly polarized dielectric resonator antenna

In this paper, a compact omnidirectional circularly polarized (CP) cylindrical dielectric resonator antenna (DRA) is presented. The DRA is excited in its TM01δ mode by a probe located at the center, giving linearly polarized (LP) omnidirectional radiation patterns. Four interleaved strips serving as a wave polarizer are placed on the top of the DRA. By tuning the strips, the LP fields can be changed into CP fields. The idea was verified at ~ 2.4 GHz for WLAN applications. The impedance bandwidth (|S11|<;-10 dB) and the 3-dB axial-ratio (AR) bandwidth are 14.5% (2.36-2.73 GHz) and 8.6% (2.33-2.54 GHz), respectively. Their overlapping bandwidth is 7.3% (2.36- 2.54 GHz), which can entirely cover the designed frequency band.