Optically Transparent Microstripline With Micro- And Wired-Metal Mesh

Optically transparent microstriplines designed using a conductive micro-metal mesh film (mu-MMF) and a conductive wired-metal mesh (WMM) are presented. The transparent microstriplines are fabricated on a transparent acryl substrate with thickness (h(s)) of 1.25 mm, relative permittivity (epsilon(r)) of 2.6, and loss tangent (tan delta) of 0.009. The average optical transmittance of m-MMF and WMM is 62% and 71%, respectively, in the visible band (400-750 nm). The sheet resistance of mu-MMF and WMM is 0.08 and 0.01 Omega/sq, respectively. In addition, two types of copper microstriplines are fabricated for performance comparison. Insertion losses (S-21) and return losses (S-11) of transparent microstriplines of lengths 1, 3, and 5 cm are measured to be under 2 dB and higher than 15 dB up to 6 GHz, respectively.