By Taha KhanReviewed by Louis CastelFeb 12 2026

Stealth technology aims to reduce the detectability of military platforms through angular aircraft designs, radar-absorbing coatings, advanced electronic countermeasures, and related strategies. While these methods have proven effective, they also face inherent limitations. Most conventional materials derive their electromagnetic behavior from their chemical composition, which constrains how precisely their properties can be tailored for specific stealth requirements. Metamaterials, by contrast, are engineered so that their internal structure, rather than composition alone, governs how waves interact with them, enabling tighter control over electromagnetic, infrared, and acoustic wave interactions.

Image Credit: Guguart/Shutterstock.com

Understanding Metamaterials

Traditional materials interact with electromagnetic waves according to their intrinsic properties, such as electrical permittivity and magnetic permeability. These properties determine how materials reflect, absorb, or transmit electromagnetic radiation. By contrast, metamaterials rely on engineered micro- or nano-scale architectures that can manipulate waves in an unnatural manner.^{1, 2}

Metamaterials incorporate subwavelength structural elements, often referred to as meta-atoms, that are smaller than the wavelength of the waves they are designed to influence. Engineers arrange these structures in carefully designed patterns to create materials with effective electromagnetic properties that can be precisely controlled. As a result, metamaterials can exhibit unusual behaviors, such as wave bending, and electromagnetic cloaking. This structure-driven performance gives materials scientists the ability to develop stealth solutions tailored to specific detection systems.^{1, 2, 3}

No time now? Download the PDF for later

Electromagnetism and Refractive Index Control

Metamaterial-based stealth is governed by precise control over electromagnetism and refractive index. In conventional materials, refractive index values are positive and constrained by natural molecular arrangements. Metamaterials, however, can be engineered to achieve near-zero, or even negative, refractive indices, enabling wave interactions that are not possible with naturally occurring materials.³

Materials with a negative refractive index cause electromagnetic waves to bend in the opposite direction compared to their behavior in natural materials. This counterintuitive response allows designers to guide waves around an object, minimizing or even preventing them from scattering back to detection systems such as radar. The result is a cloaking effect that creates the impression the object is not present in the wave’s path.

What’s more, gradient-index metamaterials can gradually vary the refractive index across a surface, allowing incoming waves to be smoothly redirected rather than abruptly reflected. This controlled transition reduces scattering and helps minimize detectable signatures.^{1, 3}

Subwavelength Structuring and Wave Manipulation

Metamaterials interact with waves in a highly controlled manner due to their subwavelength structuring. By carefully designing the size, shape, and arrangement of meta-atoms, engineers can tune these materials to operate across a broad spectrum, including radio frequency, microwave, infrared, and even acoustic ranges.

For instance, in the context of radio stealth, metamaterials are designed to either absorb incident electromagnetic energy or scatter it away from radar receivers. Engineered resonant structures, such as split-ring resonators and patterned conductive elements, can trap electromagnetic energy and dissipate it as heat. Metasurfaces can also manipulate wavefronts to redirect signals, effectively masking the presence of an object.^{1, 4}

In infrared stealth, metamaterials are used to control thermal emissions. These materials can suppress or redistribute heat signatures by engineering surface emissivity, making aircraft, drones, or ground vehicles difficult to detect using thermal imaging systems.^{1, 5}

Similarly, acoustic metamaterials can be engineered to manipulate sound waves, helping reduce sonar signatures in naval platforms or suppress noise emissions from aircraft engines. By controlling sound propagation through structured cavities or resonant channels, these materials can lower detectability in both underwater and airborne environments.⁶

Image Credit: Mike Mareen/Shutterstock.com

Materials Design and Fabrication Techniques

The development of metamaterials relies on advanced manufacturing techniques capable of producing precise micro- and nano-scale architectures. Additive manufacturing, lithography, and advanced machining processes are used to fabricate metamaterial structures with high accuracy and repeatability.^{7, 8}

For instance, high-resolution 3D printing allows engineers to create complex internal geometries that are difficult to achieve using traditional manufacturing methods. Multi-material additive manufacturing helps integrate conductive, dielectric, and structural materials within a single component.

Photolithography and nanoimprinting techniques are also used to fabricate metamaterials operating at optical and infrared frequencies. These methods can create detailed surface patterns with nanometer-scale precision.^{7, 8}

Finally, computational design is also important in metamaterial development. Advanced simulation tools allow engineers to model wave interactions with proposed structures, optimizing performance before physical production. Artificial intelligence and topology optimization are also used to identify novel metamaterial architectures that maximize stealth performance with minimum weight and manufacturing complexity. ^{9, 10}

Grab the PDF of the article now!

Challenges and Future Directions

Metamaterials face several technical and practical challenges, notably bandwidth performance. Many metamaterial designs are optimized for specific frequency ranges, which can restrict their effectiveness against broadband detection systems. Researchers are developing tunable and multi-band metamaterials to address this limitation.

Durability and environmental resistance are critical for more specific applications. For instance, in aerospace and naval applications, materials must withstand extreme temperatures, mechanical stress, and corrosive environments while maintaining their designed electromagnetic or acoustic performance.^{11, 12}

Although advanced manufacturing techniques have made metamaterials increasingly attainable, producing them at scale is complex. Advancements in additive manufacturing and automated fabrication processes are expected to improve scalability and reduce production costs over time.^{11, 12}

Integrating smart and adaptive metamaterials could further progress stealth technology. Materials capable of dynamically altering their electromagnetic or acoustic properties in response to evolving detection threats may enable stealth platforms with near-absolute concealment and greater operational flexibility.

Need to brush up on metamaterials? We have it all here

References

1. Zheng, B., & Zhu, P. (2025). Advances in Metamaterials: Structure, Properties and Applications. Materials. https://doi.org/10.3390/ma19010085
2. Chen, H. T., Taylor, A. J., & Yu, N. (2016). A review of metasurfaces: physics and applications. Reports on progress in physics. http://doi.org/10.1088/0034-4885/79/7/076401
3. Khan, M. S., Shakoor, R. A., Fayyaz, O., & Ahmed, E. M. (2024). A focused review on techniques for achieving cloaking effects with metamaterials. Optik. https://doi.org/10.1016/j.ijleo.2023.171575
4. Islam, M. R., Islam, M. T., Soliman, M. S., Baharuddin, M. H., Mat, K., Moubark, A. M., & Almalki, S. H. (2021). Metamaterial based on an inverse double V loaded complementary square split ring resonator for radar and Wi-Fi applications. Scientific reports. https://doi.org/10.1038/s41598-021-01275-6
5. Chen, X., Qin, L., Huang, J., Liu, Y., Zheng, S., & Qian, M. (2025). Controlling thermal radiation by metasurface for infrared and laser compatible stealth with radiative cooling. Optics & Laser Technology. https://doi.org/10.1016/j.optlastec.2025.113017
6. Croënne, C., Vasseur, J. O., Roux, L., Audoly, C., & Hladky, A. C. (2025). A review of acoustic metamaterials for naval and underwater defense applications: from historical concepts to new trends. Acta Acustica. https://doi.org/10.1051/aacus/2024086
7. Subeshan, B., Hamzat, A. K., & Asmatulu, E. (2025). Fabricating Three-Dimensional Metamaterials Using Additive Manufacturing: An Overview. Journal of Manufacturing and Materials Processing. https://doi.org/10.3390/jmmp9100343
8. Suhas, P., Quadros, J. D., Mogul, Y. I., Mohin, M., Aabid, A., Baig, M., & Ahmed, O. S. (2025). A review of mechanical metamaterials and additively manufacturing techniques for biomedical applications. Materials Advances. https://doi.org/10.1039/D4MA00874J
9. Bonfanti, S., Hiemer, S., Zulkarnain, R., Guerra, R., Zaiser, M., & Zapperi, S. (2024). Computational design of mechanical metamaterials. Nature Computational Science. https://doi.org/10.1038/s43588-024-00672-x
10. Zhang, C., Zou, C., Guo, S., Zhao, Y., & Shen, T. (2025). Deep Learning-Based Inverse Design of Stochastic-Topology Metamaterials for Radar Cross Section Reduction. Materials. https://doi.org/10.3390/ma18214841
11. Zheng, H., Pham, T. S., Chen, L., & Lee, Y. (2023). Metamaterial perfect absorbers for controlling bandwidth: single-peak/multiple-peaks/tailored-band/broadband. Crystals. https://doi.org/10.3390/cryst14010019
12. Shuchi, T. Z., Rafat, M. T., & Begum, S. (2025). Recent Advances in Additive Manufacturing of Composite-Based Acoustic Metamaterials for Marine Cloaking: Challenges and Opportunities. Nano Trends. https://doi.org/10.1016/j.nwnano.2025.100156

Disclaimer: The views expressed here are those of the author expressed in their private capacity and do not necessarily represent the views of AZoM.com Limited T/A AZoNetwork the owner and operator of this website. This disclaimer forms part of the Terms and conditions of use of this website.