Wide-band semi-reflection/transmission film based on diluted Drude metal

We investigate the electromagnetic response of a composite structure consisting of two diluted Drude metal layers with sub-wavelength spacing at microwave frequencies. Simulations show that our structure can be considered as two equivalent thin films with different permittivity layered together so as to effectively tune the transmission T ( ω ) and reflection R ( ω ) in a frequency band. We demonstrate a wide band between 5.98 GHz to 8.15 GHz where T ( ω ) and R ( ω ) are tuned within 50% ± 2%. Parametric explorations show that the working band can be further shifted by geometric scaling. Our structure has potential to construct a metamaterial-based beam splitter which can be applied in a microwave or even terahertz system.