A Saddle Pattern Dual-CP DRA for Wide-Angle Scanning Array with Low Gain Fluctuation

A saddle-pattern dual circularly polarized (CP) dielectric resonator antenna (DRA) with a broad half-power beamwidth (HPBW) and axial ratio beamwidth (ARBW) is proposed in this letter. A circular patch fed by two orthogonally placed dual L-probes is utilized for dual-polarized operation, and a cylindrical dielectric resonator (CDR) excited by the patch is located on the top of the proposed DRA, which is used as the main radiator. An optimized air slot is loaded in the CDR to strengthen the side radiation, and an electromagnetic bandgap (EBG) structure surrounding the slot loaded CDR is used for reducing normal radiation and further enhancing low-elevation radiation, thereby achieving a saddle-shaped wide beam for the proposed antenna. The proposed DRA exhibits a saddle-shaped pattern in both E- and H-planes, with HPBW of more than 160° and 3dB ARBW exceeding 175° in 19.7GHz-22.7GHz. Based on the proposed DRA element,the left hand circular polarization (LHCP) 1×8 array antennas with two feeding networks corresponding to scanning angles of 0° and 70° are designed, fabricated and measured, demonstrating a ±70° scanning ability with only 1.23 dBic low gain fluctuation (GF) and a 3 dB axial ratio bandwidth of 14.1%.