Wideband Low-Sidelobe Circularly Polarized Array Using Sequential Subarray Rotation

This work presents a wideband low-sidelobe 2x10 circularly polarized helix antenna array using sequential subarray rotation. To avoid grating lobes in uniformly distributed sequential rotation arrays, adjacent subarrays are rotated by 180 degrees. A wideband low-sidelobe array is designed. Each subarray consists of four sequentially rotated helix elements for high-purity circular polarization. A 3-dB hybrid coupler provides wideband 90 degrees phase difference. Taylor-distributed excited coefficient is implemented in feed network to suppress sidelobe. Simulated results show that the sidelobe level on horizontal plane is below -22 dB in 6-7.5 GHz, while the axial ratio is lower than 1.7 dB.