Design and Rectangular Waveguide Validation of 2-Bit Wideband Reconfigurable Reflective Metasurface Element in X-Band

This letter presents a new design and rectangular waveguide validation of a wideband 2-bit reconfigurable reflective metasurface (RRM) element in the
X
-band. The element consists of a U-slot microstrip patch, a ground plane, and a 2-bit reflection-type phase shifter (RTPS) controlled by four p-i-n diodes. The direct circuit (DC) biases are elaborated for the 2-bit RTPS so that only two DC bias lines are required to regulate the four p-i-n diodes. The proposed RRM element has a wideband 2-bit phase resolution from 9.1 to 10.85 GHz and can be recognized with great angle stability. The rectangular waveguide experiment was conducted to prove the effectiveness of the proposed element further. The experimental results show that the 17.5% relative bandwidth is achieved under a total phase difference of 270° ± 20° with reflection losses less than 3 dB.