Flexible terahertz metamaterial filter with high transmission intensity and large tuning range for optical communication application

The resonant frequency of indoor wireless communication based on wireless fidelity (Wi-Fi) and Bluetooth is limited to several gigahertz (GHz). Following the international mobile telecommunications specification proposed by international telecommunication union in 2020 (ITUIMT-2020), communication links with subterahertz (sub-THz) waves are desired for indoor networks in the coming years. In this study, we present a flexible terahertz (THz) metamaterial (FTM) filter consisting of cross-shaped metamaterial configurations on a polydimethylsiloxanes (PDMS) substrate. As a band-stop filter, such designed FTM filters possess the selectivity of resonant frequency and thus provide a controllable transmission carrier for a broad frequency range in the subTHz window. The FTM filters can generate a tuning range of over 85-GHz resonant shift from 360.6 GHz to 446.1 GHz by changing the distance between the top and bottom metamaterial layers. For specific frequency carriers in passband, the proposed FTM filters show the transmission intensity higher than 94%. This design will play a key role in the future indoor wireless communication with miniaturization, large tuning range, and high transmission intensity characteristics.