Dual-Polarized Wideband Bandpass Metasurface-Based Filter

This letter presents a novel metasurface-based bandpass filter. The structure is realized by simply patterning a double-sided AD250 substrate, and does not require any vias or insertion of lumped elements. The top layer is an annular aperture array with multiple inner conductors, whereas the bottom layer is a first-order Hilbert-curve array. Finite element method (FEM)-based simulation results of the filter are obtained using high frequency structure simulation (HFSS). The experimental validation is carried out using a vector network analyzer (VNA), with the experimental setup placed inside an anechoic chamber. The presence of multiple length scales and fractal nature of the bottom Hilbert-curve layer results in a wide operational bandwidth, and good angular stability. The structure exhibits an operating bandwidth from 5.32 to 8.25 GHz. Good agreement between experimental and numerical results is observed. The filter also features good angular stability for both TE (s-polarized) and TM (p-polarized) polarizations. The thickness of the structure is only 0.796 mm (i.e., just 0.018λ at the center frequency of the filter), which makes it very compact.