Evanescent Mode Resonance in Metasurface Antenna On Metal Surface

We present a metasurface antenna comprising periodic arrangement of interconnected rectangular unit cells. The proposed antenna is designed to utilize evanescent mode resonance. The resonance is achieved by utilizing strong cavity mode oscillation, when the antenna is placed over a metallic surface. However, when the antenna is freely suspended in the air, in its natural state, the resonance is absent. At an optimized feed point, the antenna can be excited directly with a 50 ohm impedance line.