Decoupling and Wide-Angle Scanning Design of a Millimeter-Wave Phased Array Using Square-Ring Metasurface

A wide-angle scanning millimeter-wave (mm-wave) phased array using square-ring metasurface (SRMS) is presented in this letter. SRMS not only improves the element gain owing to enhancing the radiation efficiency and directivity of the antenna element, but also decreases the mutual coupling between elements as a partially reflective surface. Due to the reduced mutual coupling, both the active impedance matching and the total efficiency of the proposed array are significantly improved. Furthermore, thanks to the improved active impedance matching and the small element spacing of 0.43λ
₀
(λ
₀
is the wavelength at the center frequency of 27 GHz in free space), the 3 dB scanning angle of the proposed array is significantly extended. Measured results show that the phased array achieves a wide 3 dB scanning angle greater than ±68° over a wide operating band of 24.11–29.68 GHz (20.7%), which is very suitable for 5G mm-wave terminal applications.