Electromagnetic (EM) metasurface with wireless signal control function fabricated by 3D printing.

This paper proposes a novel 3D printing technology for fabricating high-performance volumetric electronic circuits. It introduces a particle-free conductive system based on a nontoxic reductant-functionalized polymer coating, offering a microscopic localized enhancement technique. By in-situ reducing silver onto custom-designed substrates, highly conductive and controllable coatings are formed, allowing frequency selective surfaces (FSS) to be extended from planar to spatial volumes (3DFSS). As a result, more desirable FSS characteristics can be achieved, such as significantly stable filtering performance for different incident angles and polarization modes of electromagnetic waves regardless of obliquity, compared to corresponding 2DFSS. The proposed FSS achieves a bandwidth of 4.4-7.8 GHz (fractional bandwidth of 54.8%) with a reflection coefficient below -10 dB. Design guidelines based on the equivalent circuit model (ECM) illustrate the transition from this 3DSS to a filter response. The designed array FSS boasts excellent structural compactness and mechanical robustness, enabling seamless integration with building materials. It provides electromagnetic signal modulation across scales, offering a technological solution for electromagnetic compatibility and signal transmission quality issues in miniaturized communication systems.