Miniaturized Dual-Band FSS Suitable for Curved Surface Application

Based on a single metallic layer printed circuit board (PCB), a miniaturized dual-band frequency selective surface (FSS) is proposed that could fulfill thin substrate design for curved application and provide stable resonant frequency. Due to the property that the element size can be altered by using different thicknesses of substrate, the FSS could either be designed for the compact size or in a very thin substrate. Two practical designs for dual-band wireless local area network (WLAN) are demonstrated featuring a flexible and straightforward design method. The compact one has an element size of only 5.2% of the free space wavelength at the lower resonant frequency, which is the smallest dual-band WLAN FSS by using only one metallic layer in published literature. Another thin substrate design (0.4 mm PCB) is fabricated and measured to confirm that the FSS exhibits stable resonant frequency on curved surfaces with different curvatures. The measured frequency shift is only 2.2%, which is among the smallest percentage in the literature.