Radar-Absorbing Materials, Metamaterials, and Metasurfaces: Design Methods, Considerations, and Best Practices

Radar-absorbing materials (RAMs) are crucial for reducing radar cross-section (RCS), suppressing electromagnetic interference (EMI), and enhancing the efficiency of antennas and wireless systems. Several design approaches have been established, ranging from conventional dielectric and magnetic composites to multilayer structures, frequency-selective surfaces (FSS), and metamaterial-based absorbers. Each method provides specific advantages, such as wide bandwidth, compactness, or tunability, but also poses challenges, including structural thickness, fabrication complexity, or polarization dependence. More recent advances involve graphene- and metasurface-based absorbers, which offer ultra-thin, lightweight, and reconfigurable solutions suitable for emerging 5G/6G communication platforms, stealth applications, and multifunctional devices. This chapter presents a comprehensive overview of RAM design methods, key considerations, and best practices. The discussion emphasizes fundamental trade-offs between absorption depth, bandwidth, and thickness, as well as challenges related to angular stability, scalability, and integration with antenna systems. Practical case studies are included to illustrate the performance of multilayer absorbers, FSS and metamaterial-based designs, and hybrid configurations, highlighting their effectiveness in balancing design constraints with application demands. The chapter concludes by addressing future trends, such as machine learning–driven optimization, adaptive material platforms, and scalable fabrication techniques, which are expected to advance the development of broadband, lightweight, and highly efficient absorbers. By consolidating theoretical foundations, design strategies, and practical implementations, this work provides a structured reference for researchers and engineers aiming to develop next-generation RAMs for defense, aerospace, and modern communication systems.