Multifunctional Metasurface for Absorption, Polarization Conversion and Transmission

A metasurface generally has a single function, as they can only absorb incident energy and, in some cases, in addition to absorbing also transmit, or convert the polarization state of an incident wave. Bringing new breakthroughs, in this manuscript, a multifunctional thin metasurface is presented. The proposed structure is composed of an array of double square loops disposed over a dielectric substrate. In this study, the full ground plane is replaced with a periodic array to reflect only the frequencies of interest. By breaking the symmetry of the resonators and inserting PIN diodes for control, we demonstrate that the structure can efficiently absorb electromagnetic waves (PIN diode ON), convert the polarization (PIN diode OFF) and allow signals to travel in other frequency band. The simulated structure showed good results for both absorption and conversion. For the frequency of 3.05GHz the absorption rate was 97%, and a conversion ratio of 98% is obtained for the resonance frequency of 4.37GHz. Furthermore, the proposed structure has a thickness of lambda/30.7 in relation to the absorption peak. Although the operating bands are narrow, the structure has potential applications such as thermal detectors, stealth field, imaging, remote sensors, and radiometers.