Optical-Transparent Frequency Selective Surface with Wide Stopband Using Indium Tin Oxide

A novel single-layer optical-transparent frequency selective surface (FSS) with a wide stopband is proposed in this paper. This structure is realized by etching patterns on the highly transparent conductive film called indium tin oxide (ITO). The working principles of the proposed FSS are explained by the analysis of the equivalent circuit models. Then, a designed example operating at 1.75 GHz is fabricated using laser etching technology. Finally, the fabricated sample is measured by free space method. The measured results illustrate that this FSS exhibit miniaturized unit-cell size of 0.193λ
₀
× 0.193λ
₀
(λ
₀
refers to the free space wavelength at the resonant frequency) and stable frequency filtering response under oblique incident angles (up to 30°).