Conducting metallic metameshes with perfect electromagnetic transparency for arbitrary polarization and angle of incidence

Metallic meshes have long demonstrated outstanding electromagnetic shielding capabilities against low-frequency electromagnetic waves, facilitating vital applications like Faraday cages. Here, we demonstrate a metallic metamesh with tailored metallic patterns that is conducting like normal metallic meshes, but also exhibits remarkable perfect transparency for arbitrary electromagnetic waves at the working frequency. Based on special resonances introduced by the designed composite structures, such metameshes have achieved omnidirectional impedance matching with free space, regardless of the polarization and incident angle. This property enables near-100% transmission through the metamesh, with unchanged wave front. This transition from electromagnetic shielding to perfect transparency has been validated through both numerical simulations and microwave experiments. Our work paves the way towards realizing metastructures that are both conducting and transparent to electromagnetic waves, opening possibilities in radomes and wireless communications.