A wide-angle reconfigurable reflectarray antenna (RRA) was designed and experimentally verified utilizing a miniaturized ring patch efficiently controllable with a single bit. Based on the merits of the miniaturization of the radiating element and an elaborate study of the quantization efficiencies of the asymmetric phase differences between the on/off states of the unit cell by optimizing a reference phase on the metasurface, highly directive beam scanning is achieved in a wide ±60˚ range in both the H-and Eplanes. Furthermore, the illumination and spillover efficiencies and focal diameter ratio (F/D) are carefully optimized, resulting in a low profile configuration with F/D=0.36. The fabricated RRA prototype was measured at 9.85 GHz (X-band) with the highest aperture efficiency of 28% and a 1 dB gain bandwidth of 530 MHz, respectively.

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A miniaturized dual-band reflective metasurface unit cell is presented based on a square fractal copper-ring patch combined with a PIN diode. Its structure is optimally designed via the genetic algorithm to achieve ∘ 180 phase differences of the reflection coefficients between on and off states of the PIN diode at both C-and X-bands center frequencies. The accuracy of the proposed dual-band metasurface unit cell is verified by comparing simulations with measurements inside the C-and X-bands rectangular waveguides. The proposed miniaturized metasurface unit cell could improve the radiation efficiency of the dual-band reflective metasurface antenna by enabling fine quantization of the phase distribution and mitigating the mutual couplings among different states of the unit cells.

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