Wideband low-scattering metasurface with an in-band reconfigurable transparent window

Active metasurfaces with dynamically reconfigurable functionalities are highly demanded in various practical applications. Here, we propose a wideband low-scattering metasurface that can realize an in-band reconfigurable transparent window by altering the operation states of the PIN diodes loaded on the structures. The metasurface is composed of a band-pass frequency selective surface (FSS) sandwiched between two polarization conversion metasurfaces (PCMs). PIN diodes are integrated into the FSS to switch the transparent window, while a checkerboard configuration is applied in PCMs for the diffusive-reflective function. A sample with 20x20 elements is designed, fabricated, and experimentally verified. Both simulated and measured results show that the in-band functions can be dynamically switched between beam-splitting scattering and high transmission by controlling the biasing states of the diodes, while low backscattering can be attained outside the passband. Furthermore, the resonant structures of FSS also play the role of feeding lines, thus significantly eliminating extra interference compared with conventional feeding networks. We envision that the proposed metasurface may provide new possibilities for the development of an intelligent stealth platform and its antenna applications.