Water-Controlled 1-Bit Reconfigurable Surface

In this paper, a reconfigurable surface (RS) is demonstrated using water in microfluidic channels as the control elements. The pattern reconfigurability is achieved through selectively filling the channels in an array with water. Different from conventional electronic-based RSs where the tuning elements are placed on the reflective elements, the phase change in the proposed design is induced by switching the states of the defected ground plane by using water to load or unload a ring slot structure. This approach minimizes the adverse impact of the tuning elements and the associated actuation mechanism on the RF performance of the reconfigurable metasurfaces. The capability of the 1-bit RS to generate multi-beam deflection patterns at 14.45 GHz is demonstrated. Both a broadside pattern and a two-beam reflection at 10° are shown. The measured results verify the multi-beam reflections at 14.45 GHz. Additionally, the proposed RS achieves a measured broadside gain of 6.82 dBi.