Constructing Repairable Meta-Structures of Ultra-Broad-Band Electromagnetic Absorption from Three-Dimensional Printed Patterned Shells

Abstract

Ultra-broad-band electromagnetic absorption materials and structures are increasingly attractive for their critical role in competing with the advanced broad-band electromagnetic detection systems. Mechanically soft and weak wax-based materials composites are known to be insufficient to serve in practical electromagnetic absorption applications. To break through such barriers, here we developed an innovative strategy to enable the wax-based composites to be robust and repairable meta-structures by employing a three-dimensional (3D) printed polymeric patterned shell. Because of the integrated merits from both the dielectric loss wax-based composites and mechanically robust 3D printed shells, the as-fabricated meta-structures enable bear mechanical collision and compression, coupled with ultra-broad-band absorption (7-40 and 75-110 GHz, reflection loss smaller than -10 dB) approaching state-of-the-art electromagnetic absorption materials. With the assistance of experiment and simulation methods, the design advantages and mechanism of employing such 3D printed shells for substantially promoting the electromagnetic absorption performance have been demonstrated. Therefore, such universal strategy that could be widely extended to other categories of wax-based composites highlights a smart stage on which high-performance practical multifunction meta-structures with ultra-broad-band electromagnetic absorption could be envisaged.

Ionic Conductive Gels for Optically Manipulatable Microwave Stealth Structures

“…In the determination of the complex permittivity, a polymeric chamber with dimension of 15.8 mm × 7.9 mm × 4 mm was 3D printed with VeroWhite resin, according to our previous studies . Subsequently, the aqueous PVA‐based gels were transferred into the chamber to achieve complex permittivity in the Ku band (12.4–18 GHz).…”

“…Second, optically transparent polymeric gels here open a novel platform for microwave absorption materials and structures. As is well known, microwave absorption materials are usually optically opaque dielectric materials with ability to attenuate electromagnetic energy in terms of converting into electrical and thermal energy . In the previous studies for achieving optically transparent microwave absorption, electrical conductive materials, such as ITO and metals, were processed into electrically conductive patterns, serving as the effective materials for electromagnetic attenuation.…”

“…According to the state‐of‐the‐art of transparent microwave absorption structures, the active materials for manipulating the microwaves are also electrically conductive and they have certain capabilities in absorbing optical lights due to their intrinsic conductive features. It is an urgent to develop novel prototypes of materials that enable to absorb microwave, but allow optical light for transmitting.…”

Current advances and future perspectives of additive manufacturing for functional polymeric materials and devices

“…3D printed separators or gaskets with hole structures are capable of constructing EMI shielding devices with good mechanical properties. [84][85][86] The spacers or gaskets are generally 3D printed nonconductive polymers, which F I G U R E 4 (A) PLA/Graphene/CNT composite material and thereof FDM printing process. Reproduced with permission: Copyright 2020, American Chemical Society.…”

“…3D printed separators or gaskets with hole structures are capable of constructing EMI shielding devices with good mechanical properties 84–86 . The spacers or gaskets are generally 3D printed nonconductive polymers, which are wave‐transmitting materials that mainly affect the mechanical properties.…”