A Dual-Band Metasurface Reflector Using Ring Resonator with Interdigital Capacitor

Abstract

This research presents a metasurface reflector to support dual-band applications at 1.8 GHz and 5.5 GHz for LTE and WLAN, respectively. The proposed unit cell creating the metasurface has the property of an epsilon negative medium (ENG) that is one of the reflector requirements. The novel design of unit cells uses the ring resonator pattern associated with an interdigital capacitor to control resonant frequencies and relative permittivity. The epsilon negative medium can be controlled by using an interdigital capacitor that can create the electric field at the unit cell. Therefore, the size of the metasurface can be reduced from λ /2 to λ /4 which is much smaller than the conventional structure, resulting in a compact reflector when it works together with an antenna. The proposed unit cell was designed to obtain the dual-frequency operation with simulated bandwidth of 1.71 GHz - 2.48 GHz at 1.8 GHz and 5.15 GHz - 6.00 GHz at 5.5 GHz, respectively. The proposed metasurface was designed by using an array of 7 × 7 unit cells. The simulation and experimental results agree very well with the gains of 8.52 dB and 9.55 dB at 1.8 GHz and 5.5 GHz, respectively.