Fabrication of Polymer@Metal Core–Shell ±45° Polarization Diversity Dipoles by Mussel-Inspired Surface Chemistry on 3-D Printed Objects

A ±45° polarization diversity dipoles' antenna is designed and fabricated by 3-D printing technology in combination with mussel-inspired surface chemistry. For the fabrication of metal-coated 3-D antenna, mussel-inspired surface functionalization and electroless deposition technique were used for metallization of printed antennas. A dopamine-based coating layer was attached onto the printed antenna by heterogenetic-induced polymerization, to capture catalyst moieties for conducting electroless metal deposition on the surface and enabling the function of antenna. To prevent particle oxidation on the surface of copper, a method of antioxidation and anticorrosion protection for the copper layer is proposed without reducing the conductivity of antenna. In addition, a method based on surface treatment and rapid electrodeposition is proposed, which solves the problem of metal layer falling off in the traditional 3-D printing antenna structure. The 3-D printing antenna is measured, and the results show a good agreement with the simulated results. Both the simulated and measured results show that a port-to-port isolation >26 dB with VSWR <; 1.5 and axial cross polarization ratio >28 dB can be achieved for the proposed antenna. The 3-D printing antenna performances indicated that resin-based 3-D printing technology is promising in fabricating the antennas with lightweight and complex structures.