Bandwidth Enhancement by Interconnecting Double Hexagonal Loops FSS

The paper proposed a mosaic frequency selective surface (MFSS) which comprises of the integration between Koch fractal and a basic double hexagonal loop FSS. Through this integration, the bandwidth (BW) within the first bandstop and bandpass frequency responses achieved a wideband frequency response (fractional bandwidth (FBW) >50%), while the BW of the second bandstop frequency response improved (FBW $\sim 20\%$). The simulation process is conducted by using the CST software, and the FR4 substrate is used as the dielectric substrate for all of the proposed unit cells. With narrow trace width of the MFSS, the structural element can be further applied for optical transparency application with wideband filtering characteristics.