A Reconfigurable Metasurface With Precise Phase Distribution for Both Transmission and Reflection Functions

An electrically reconfigurable metasurface (RM) element (RME) is proposed, which can realize both transmission and reflection functions with 360° phase coverage by a single switch (PIN diode). Through modifying the operating state of the PIN diode, the RME can switch between transmission and reflection functions. To achieve continuous phase compensation, the RME employs a classical multilayer structure. To ensure that the RME’s phase response follows the approximate trend in both states, the reconfigurable structure’s location is optimized. Based on the phase response curves of the RME in two states, the phase distribution function constructing the metasurface aperture is fit. Then, the RM can be designed and obtain precise phase distribution in both states simultaneously. A <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$9\times 9$ </tex-math></inline-formula>-element RM is simulated and fabricated. It can obtain 360° continuous phase compensation and high-gain pencil beam with the same polarization in both states. The measured peak aperture efficiency is as high as 32.2%–33.7% in the two states. In addition, the proposed RM has an integrated biasing circuit network, which is controlled by a single voltage source and realizes the fusion design of transmission/reflection functions at a low cost.