In this article, a wideband circularly polarized rectangular dielectric resonator antenna (RDRA) coupled through orthogonal slots and excited with a new microstrip circular ring has been investigated. Circular polarization has been achieved by using plus shaped (+) slot on the ground plane and excited through a new microstrip circular ring feed. TE11 δ mode has been excited in the RDRA which has been confirmed through the distribution of E-field and dielectric waveguide model (DWM) method of RDRA. Circularly polarized (CP) RDRA offering measured −10 dB input impedance bandwidth of 20.79% (centered at 3.27 GHz) and 3 dB axial ratio bandwidth in broadside direction of 12.09% (centered at 3.39 GHz), respectively. From the CP radiation pattern, proposed design confirms that right-handed CP (RHCP) in broadside direction. The difference between RHCP field and left-handed CP (LHCP) field are above −26 dB in operational band. In addition, the proposed CP antenna offers stable gain and radiation efficiency in working bands and it is suitable for IEEE 802.16e/d Wi-MAX (3.3-3.7 GHz) band. © 2017 Wiley Periodicals, Inc.