Wideband circularly polarized hybrid dielectric resonator antenna with bi-directional radiation characteristics for various wireless applications

In this article, a wideband circularly polarized (CP) dielectric resonator (DR) over an asymmetric-slot radiator based hybrid-DR antenna is proposed with bi-directional radiation characteristics. Bi-directional CP radiation of the dual sense is obtained using a rectangular-DR over asymmetric-rectangular-slot radiator with L-shaped feed line. The asymmetric-slot radiator feed by L-shaped stub with the coplanar waveguide is used for generating two orthogonal modes, namely TE delta 11x and TE1 delta 1y in the combined (rectangular-DR and asymmetric-slot radiator) hybrid-DR antenna, which is verified by the distribution of electric field inside the rectangular DRA. The measured reflection coefficient bandwidth (S-11 < -10 dB) and axial ratio (AR) bandwidth (AR < 3 dB) of the hybrid-DR antenna are 80.5% (1.87-4.39 GHz) and 43.8% (1.75-2.73 GHz), respectively. The antenna radiation is in the broadside (theta = 0 degrees, phi = 0 degrees) direction as well as in the backside (theta = 180 degrees, phi = 0 degrees) direction with equal magnitudes in both the directions. Right-handed and left-handed CP waves are achieved respectively, in the boresight (+Z) and the backside (-Z) directions. The proposed CP hybrid-DR antenna gives an average gain of 3.55 dBic and radiation efficiency of 95.0% in both directions. The proposed antenna covers various wireless useful bands such as ISM 2400 band, Wi-Fi, Bluetooth, and Wi-MAX (2.5-2.7 GHz).