Novel folded single split ring resonator and its application to eliminate scan blindness in infinite phased array

In this letter, a simple electric metamaterial is proposed based on grounded folded single split ring resonator (SRR). The grounded SRR results in a compacter size. The proposed metamaterial exhibits a negative effective permittivity ϵ_e and positive effective permeability μ_e under electric excitation, and its electric resonant frequency is easily changeable from 4.5GHz to 5.7GHz by adjusting the length of the folded arms. It is used to suppress the mutual coupling between elements in microstrip array by blocking the propagation of the excited surface waves in microstrip substrate, and eliminate the scan blindness in the infinite microstrip phased array. The results indicate its excellent application potential to improve the scanning performance of microstrip array. More interestingly, compared with the reported techniques, such as electromagnetic band-gap (EBG) structures and defected ground structures (DGSs), the new metamaterial almost has nearly zero thickness as an isolation wall, which means that it is very suitable for constructing the high-density array.