Design and analysis of a compact circularly polarized DRA for off-body communications

A compact single fed circularly polarized dielectric resonator antenna (CPDRA) for off-body communication in wireless body area network (WBAN) applications is proposed. The proposed antenna consists of a modified rectangular DRA made of Al2O3 with a permittivity of εr = 9.8 and fed by a 50-Ω coaxial probe. Two unequal vertical slits are etched off from both the corner edges of the rectangular dielectric resonator to generate TEδ11x and TE1δ1y modes, and to reduce the overall size of the proposed antenna. Moreover, an efficient single layer equivalent phantom model is designed to reduce the simulation time for the analysis of off-WBAN communications. The proposed antenna is fabricated and characterized in free space as well as in on-body environment. It provides measured impedance and axial ratio (AR) bandwidths of 66.19% (4.72–9.39 GHz) and 15.01% (6.22–7.23 GHz) respectively in free space, 65.91% (4.73–9.38 GHz) and 16.02% (6.20–7.28 GHz) respectively in on-body environment. A full ground plane is used to provide unidirectional radiation pattern and greater isolation from the human body with low SAR i.e. 0.397 W/kg and 0.193 W/kg for 1 g and 10 g tissue respectively. These features make the proposed CPDRA is suitable for off-body communication and can easily be integrated in wireless devices.