Terahertz narrow bandpass filters based on double-layer metallic woven meshes with engineered Fabry-Perot cavities

In this work, a new narrow bandpass filter based on double-layer metallic woven meshes (MWMs) is experimental and numerically investigated. Differing from generally reported 2D planar structures, the MWM is a 3D structure consisting of metal cross-bending wires. Multiple resonant peaks with high isolation originating from the Fabry-Perot cavities are achieved by changing the distance between two MWM layers. Simulated results show that an optimized double-layer MWMs presented a sharp resonant peak whose full width at half maximum is narrower than 1.25 GHz. The achievement of such filters based on the engineered Fabry-Perot cavity would provide a new method for the design of ultra-narrowband filters and ultra-sensitive sensors in terahertz regions.