Design and analysis of terahertz filters based on multilayer metamaterials

We numerically and experimentally demonstrate a series of multilayer metamaterial filters in the terahertz region. The designed structure consists of multiple metal–polyimide composite layers and cyclic olefin copolymer layers. The transmission spectra of the filters are characterized by terahertz time-domain spectroscopy, and the measured results agree well with simulations. In addition, the mechanism of the multilayer structure is theoretically studied by a thin film multibeam interference model. The proposed filters exhibit high efficiency at passband and can be broadly utilized as compact devices in practical applications at terahertz frequencies.