High-Aspect-Ratio Micro Metal Mesh for 5G Millimeter-Wave Optically Transparent Metasurface Antenna

A micro metal mesh is a representative technology that can implement transparent applications and has the advantage of having stable current flow and excellent transparency to other transparent electrodes. A high-aspect-ratio metal mesh offers enhanced conductivity at the same transmittance and reduces radio frequency (RF) energy loss, enabling lower heat generation and improved efficiency in transparent electronics. Conventional metal mesh manufacturing methods are implemented by sputtering and etching. Due to the grain growth, long processing time under vacuum conditions, and compatibility issues with polymer films, achieving a thickness greater than 1 μm is limited. This paper proposes a metal mesh fabrication technique using ultraviolet (UV)-curable resin and silver nanoparticles. One notable outcome is the achievement of an 8 μm thickness at a 5 μm line width, which highlights the feasibility of our approach. The fabricated metal mesh achieves a sheet resistance of 0.23 Ω/sq at 83% transmittance, corresponding to a high figure of merit of 8504. For the RF validation of the proposed metal mesh, a millimeter-wave (mmWave) band metasurface antenna was designed, fabricated, and measured. The proposed metasurface antenna has a 10-dB bandwidth of 28.0–29.6 GHz. The antenna has a measured peak gain of 13.13 dBi and a measured efficiency of 61% at 27.5 GHz.