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(omega) and reflection R(omega) in a frequency band. We demonstrate a wide band between 5.98 GHz to 8.15 GHz where T(omega) and R(omega) are tuned within 50% +/- A 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.