Grating Lobe Suppression in Lens Loaded Circularly Polarized Phased Array with One Wavelength Element Spacing

This paper presents a low grating lobe lens loaded circularly polarized phased array with one wavelength element spacing at 28GHz band. The 2×2-element slot-coupled corner-truncated patch antenna is fed through a sequential feeding network, which, as a subarray, further forms a 4×4 phased array. A lens is placed above each patch sub array to suppress the grating lobe during the angle scanning. The results show that within ±15° scanning angle, the difference between the main lobe and the grating lobe remains below -11 dB within 25-31GHz. Besides, at broadside, the 3-dB axial ratio bandwidth is 21.4% and the aperture efficiency is above 60% in 19.9% bandwidth.