The physics of radar absorption is deceptively simple to state and notoriously difficult to engineer. When an electromagnetic wave strikes a surface, it can be reflected, transmitted, or absorbed. For a target to disappear from a radar screen, the material must first let the wave enter rather than bounce off—an impedance-matching problem, where the material’s effective permittivity and permeability must be tuned to resemble free space. Once inside, the wave must then be dissipated, typically through dielectric losses such as interfacial polarization, electron hopping, and aggregation-induced charge transfer, or through magnetic losses in ferrite and carbonyl-iron fillers. If either step fails, the wave either reflects away or passes through unattenuated. The review emphasizes that performance metrics such as reflection loss in decibels, absorption bandwidth, matching thickness, and radar cross section reduction must be evaluated together, because optimizing one often degrades the others.

The historical arc traced by the authors begins with the Salisbury screen, a simple resistive sheet placed a quarter-wavelength in front of a conducting backing, patented in 1952. That elegant but narrowband concept dominated for decades, alongside iron-ball paints and ferrite coatings. But modern threats operate across an ever-wider spectrum—from high-frequency over-the-horizon radar in the megahertz range, through the S-, C-, X-, and Ku-bands used by tracking and fire-control systems, up to millimeter-wave, terahertz, infrared, and even laser detection. Single-layer absorbers simply cannot cover this span, which has driven the evolution toward multilayer stacks, graded structures, and resonant architectures that combine broadband and narrowband absorption in one design.

Among the most significant architectural innovations highlighted in the review are frequency-selective surfaces and their absorbing cousins, the so-called rasorbers. These are engineered periodic patterns—printed circuits, resistive meshes, or coated fabrics—that allow certain frequencies to pass through while absorbing others. When integrated into composite laminates, they enable radomes that protect an antenna yet suppress radar returns at other frequencies. The authors describe designs ranging from resistive frequency-selective surfaces embedded in glass/epoxy composites to switchable, dual-polarized absorbers that can flip between absorbing and reflecting states using active elements such as PIN diodes and varactors. Active frequency-selective surfaces take this a step further, allowing both the frequency and the amplitude of absorption to be tuned in real time, a capability demonstrated with graphene-based capacitor structures.

Metamaterials represent another leap in design freedom. By arranging subwavelength resonant elements into carefully patterned arrays, researchers can create perfect absorbers with responses that nature does not offer in bulk materials. The review covers metamaterial absorbers spanning from the optical regime to extremely high frequencies, including polarization-insensitive terahertz absorbers, infrared and laser-compatible stealth structures, and reconfigurable metasurfaces based on phase-change materials such as vanadium dioxide. Shape-memory polymers and kirigami metastructures add mechanical tunability, stretching or deforming to shift absorption bands on demand. The authors note that information metamaterials—programmable surfaces whose electromagnetic behavior is controlled digitally—are pushing the field toward absorbers that can adapt to changing threat environments in real time.

Yet the heart of the review is polymer matrix composites, and for good reason. Aerospace structures are increasingly built from carbon-fiber-reinforced polymers, which are lightweight and strong but electrically conductive in ways that can produce strong radar reflections. The multifunctional solution is to design the structural material itself to absorb. Glass or polyimide fabrics reinforced with carbon black, carbon nanotubes, graphene, or nickel-coated fibers can be tailored layer by layer so that impedance rises gradually from the surface inward, drawing waves deep into the laminate where they are dissipated. Sandwich structures with honeycomb or foam cores add a third dimension: the cellular geometry provides mechanical stiffness while the coated cell walls create multiple internal reflections that extend the effective electrical path length. Graded honeycomb designs, in which the effective permittivity varies across the core, have demonstrated broadband absorption suitable for aircraft inlet applications, one of the most challenging scattering hotspots on a stealth platform.

The filler toolbox described in the review is remarkably diverse. Carbon nanotubes, discovered in 1991, remain a workhorse because their high aspect ratio drives electrical percolation at low loadings, enabling both absorption and mechanical reinforcement. Graphene and its derivatives add two-dimensional conductive networks and enormous interfacial area for polarization loss. MXenes—two-dimensional transition metal carbides first reported for electromagnetic interference shielding in 2016—combine metallic conductivity with low infrared emissivity, making them attractive for radar-infrared compatible stealth. Magnetic fillers such as ferrites, carbonyl iron, and MOF-derived amorphous magnetic powders contribute permeability-based losses that complement dielectric mechanisms, and hybridizing the two is a central strategy for broadband performance. Conducting polymers like polyaniline and polypyrrole, first synthesized in their conductive forms in the 1970s, offer processable, corrosion-resistant alternatives for coatings and textiles.

The review also surveys manufacturing routes, and here the comparison is critical because processing determines whether laboratory performance survives in a real structure. Solution casting and spray coating are simple but struggle with filler dispersion and scale. Electroless plating can metallize fabrics and fibers uniformly, producing nickel- or copper-coated textiles with strong shielding effectiveness. Additive manufacturing emerges as a transformative route: 3D printing enables bio-inspired concentric infill patterns, triply periodic minimal surface meta-structures in polymer-derived ceramics, and seamless meta-sandwich composites that are simultaneously lightweight, load-bearing, and broadband-absorbing—geometries that would be impossible to fabricate by conventional lamination. Nanoimprint lithography is bringing scalable production of multilayer metasurface devices within reach.

Beyond stealth, the authors point to a widening set of applications. Electromagnetic interference shielding is now essential for dense electronics, 5G and 6G hardware, and electric vehicles, and the same materials that absorb radar can suppress unwanted emissions. Flexible and wearable systems—knitted and woven fabrics with stainless steel, silver nanowires, or carbon nanostructures—combine shielding with joule heating, breathability, and durability. Thermal management is becoming a co-design requirement, since absorbed electromagnetic energy converts to heat; recent composites are engineered to absorb waves and dissipate heat simultaneously. Multispectral compatibility is another frontier, with transparent metamaterials and low-emissivity coatings working together to defeat radar, infrared, and laser detection in a single stack.

The review closes with an honest assessment of the challenges ahead. Low-frequency absorption, particularly in the S-band and below, still demands thick or heavy solutions, and achieving it with lightweight structures remains an open problem. Impedance matching across wide bandwidths, environmental durability, scalable manufacturing, and the integration of active components into structural laminates all require further work. The authors point toward high-entropy materials for extreme environments, intelligent electromagnetic materials designed with machine learning, and deeper synergy between material chemistry and structural architecture as the most promising directions. What emerges from their synthesis is a field in transition: radar absorption is no longer a coating problem but a materials-design problem, in which the airframe itself becomes the absorber. If that vision matures, the next generation of stealth platforms may owe their invisibility not to what is painted on them, but to what they are made of.

Subject of Research: Multifunctional radar-absorbing materials integrating structural and electromagnetic performance

Article Title: Review: multifunctional radar-absorbing materials—integration of structural and electromagnetic performance

Article References: Kishor, K., & Sheikh, J. (2026). Review: multifunctional radar-absorbing materials—integration of structural and electromagnetic performance. Journal of Materials Science, 61(43), 33398-33430. https://doi.org/10.1007/s10853-026-13614-x

Image Credits: AI Generated

DOI: 10.1007/s10853-026-13614-x

Keywords: radar-absorbing materials, polymer composites, stealth technology, metamaterials, frequency-selective surfaces, electromagnetic wave absorption, carbon nanotubes, graphene, MXenes, honeycomb structures, additive manufacturing, electromagnetic interference shielding