A Terahertz Broadband Inverted U-shaped Band-pass Filter Based on Pseudo-periodic Two-row Grating-loaded Rectangular Waveguide

A novel broadband band-pass filter based on pseudo-periodic two-row grating-loaded rectangular waveguide is proposed and analyzed in this paper. Each unit consists of a rectangular waveguide embodying two identical ridges loaded in the same plane of the waveguide and symmetric with respect to the central plane. Unlike conventional periodic plasmonic structure, this filter is pseudo-periodic, i.e., the height of ridges in different units is taper to improve the transmission pattern and characteristics. It has a planar structure which is compatible with the state-of-the-art fabrication process. Furthermore, the topology of this structure is finite in transverse dimensions, which corresponds to practical circumstances. With a broadband inverted U-shaped bandpass specification, the filter is considered to be a feasible choice for high-integrated photonic circuits as well as vacuum electronics application like selective-transmission couplers and low transmission loss interaction circuits.