A Ku-Band Circularly Polarized Antenna Array with Low Axial Ratio

This paper presents an 8×8 scale Ku-band circularly polarized antenna array with low axial ratio. The antenna array contains four-point feeding antenna elements, rectangular shield cavities formed by metallic via-holes, and coaxial-like structures. To reduce the interface of the coaxial-like structure to the radiation performance of the antenna array, the coaxial-like structure is designed to integrate with the shield cavity. Combining multi-point feeding circularly polarized antenna element with rotating subarrays technology, the axial ratio of the synthesized beam of the antenna array is less than 2dB within the whole scanning range of -60° to 60°. The proposed antenna array can cover the bandwidth of 14.5-16.5GHz with VSWR<1.1, and has average realized radiation gain higher than 21.5dBi.