Flexible Ink-Minimized Screen-Printed Frequency Selective Surfaces With Increased Optical Transparency for 5G Electromagnetic Interference Mitigation

A thin, flexible, and transparent polyethylene terephthalate (PET) based screen-printed band-stop frequency selective surface (FSS) with ink minimization is experimentally demonstrated at 28 GHz using both planar and conformal configurations. A miniaturized conventional FSS unit cell is ink-minimized using surface meshing without compromising the angular stability of the transmission response of the surface within ±60°. This not only leads to reduced amount of expensive ink required in prototyping, thereby lowering the overall manufacturing cost, but also increases the optical transparency of the structure by a factor of 65% using an 80 $\mu \text{m}$ linewidth tolerance. Finally, the operation of the ink-minimized FSS is experimentally shown using a conformal geometry with two radii of curvature (60 and 114 mm) and a good filtering performance is confirmed. Useful for 5G electromagnetic interference (EMI) applications, these FSSs feature increased feasibility through improved transparency and reduced cost due to ink minimization.