A broadband reflectarray using multiresonant and subwavelength elements

A reflectarray composed of double concentric square loop elements with subwavelength spacing is presented for bandwidth enhancement. It is shown that quasi-linear phase responses at a wide frequency band can be realized by such a phasing element. A 28×28-element reflectarray is designed. The preliminary simulation results show that the 1-dB gain bandwidth is 28.3%, demonstrating significant improvements to gain bandwidth for reflectarry antennas by the combination of multiresonance and subwavelength techniques.