Radar Cross Section Reduction Metamaterials: A Review of Principles, Design Methods, and Applications Beyond

Electromagnetic (EM) metamaterials have seen significant advances in their design and application, especially for radar cross section (RCS) reduction and stealth applications. The growing complexity of design methods, the wide variety of techniques explored, and the broad range of applications make it necessary to consolidate this knowledge into a comprehensive survey. Despite the wealth of research in this domain, no unified review covers theoretical foundations and practical guidelines. This review offers a detailed synthesis of the most important advances, providing a clear and structured understanding of how different techniques, such as beam diffusion, field cancelation, polarization conversion, and wave absorption, are exploited within the broader context of EM metamaterials for RCS reduction. In addition, expressions are provided for the evaluation of the reduction in RCS, guidelines are offered for the design of innovative metamaterials, and novel application areas beyond traditional defense applications are explored, highlighting the potential of these technologies in commercial and civilian domains. Moreover, this work compiles and evaluates the key milestones and contributions that have shaped the field, presenting them in a manner that allows for the rapid identification of critical developments and trends. By identifying the challenges still faced in the area of RCS reduction and providing insights into future research directions, this review serves as both a resource and a roadmap for future innovations in the field.