A compact dielectric resonator antenna with wideband circular polarization characteristics for C and X-band applications

A wideband circularly polarized (CP) stacked rectangular dielectric resonator antenna (RDRA) is proposed in this article. The 3 dB axial ratio (AR) and10 dB impedance bandwidth overlap of more than 66% is obtained. For increased bandwidth, the antenna comprises two dielectric resonatorsseparated by an air gap. The upper dielectric layer is rotated at<45(degrees) relative to the lower layer to obtain orthogonal modes for CP Both layers havedielectric constant epsilon(r)=9.8. The rotation aids excitation of orthogonal modes (TE delta 11TE1 delta 1y )-T-x TE(delta 31 )(x)TE(3 delta 2 )(y )and TE delta 21x /TE(1 delta 2)(y )The higher-ordermodes generate left-hand circular polarization at frequencies 6.75, 7.8, and10.7 GHz, respectively. The upper layer consists of three holes giving a 10 dBimpedance bandwidth of 66.7% from 6.52 to 11.02 GHz. The CP gain of 8.7, 6.8,and 6.4 dBi for 6.75, 7.8, and 10.7 GHz, respectively, is measured. Theconformal orthogonal feeds enable a 72%3 dB AR bandwidth across the entirefrequency band. The radiation efficiency is observed above 89%in the entireband (6.5-11 GHz). This work demonstrates a 66.7%overlap of 10 dBimpedance and 3 dB AR bandwidth along with high gain in a single designwhich is suitable for 5G applications in C-band as well as other X-bandapplications.