Design and Application of a Photo‐Thermal Dual‐Curable Resin for Architected Microwave Absorbers in the X‐Band via DLP Printing

Why It Matters

The breakthrough enables fast, cost‑effective production of precision‑engineered microwave absorbers, reducing dependence on traditional hot‑press methods and opening new opportunities in radar‑stealth, 5G infrastructure, and aerospace shielding.

Key Takeaways

• Dual-curable resin offers UV and thermal crosslinking.
• Dielectric constant stays below 3.0 across X‑band.
• Tensile strength exceeds 80 MPa, Tg above 200 °C.
• Composite achieves –59.8 dB reflection loss at 1.93 mm.
• 3D‑printed honeycomb enables precise absorber geometry.

Pulse Analysis

Microwave absorbers are critical for stealth technology, telecommunications and electromagnetic compatibility, yet conventional manufacturing relies on bulk hot‑pressing of ceramic or polymer composites. These processes struggle to produce complex geometries, limit design flexibility, and add significant weight—factors that become costly at scale. Additive manufacturing, particularly digital light processing (DLP), promises sub‑millimeter resolution and rapid iteration, but existing photopolymers lack the thermal stability and low dielectric properties required for X‑band performance.

The newly reported dual‑curable resin tackles these constraints by integrating an isocyanate‑functionalized monomer that first cures under UV light for shape fixation, then undergoes a secondary thermal crosslinking step to form a dense, thermally robust network. The resulting material maintains a dielectric constant below 3.0 and a loss tangent under 0.01 across the X‑band, while achieving a glass transition temperature above 200 °C and tensile strength exceeding 80 MPa. Such a combination of electromagnetic transparency and mechanical resilience is rare in printable polymers, enabling the fabrication of intricate honeycomb scaffolds that can be loaded with high‑loss fillers like graphene‑CoFe2O4 and finished with a conductive silver backing.

The practical impact is substantial: a 1.93 mm‑thick printed absorber reaches a reflection loss of –59.8 dB, rivaling or surpassing traditionally manufactured counterparts. This level of performance, coupled with the design freedom of DLP printing, positions the technology for rapid deployment in aerospace skins, 5G base‑station radomes, and portable stealth devices. As the industry pushes for lighter, more adaptable EM shielding solutions, dual‑curable resins could become a cornerstone material, spurring further research into multifunctional additive‑manufactured composites.