Multifunctional and intelligent electromagnetic wave absorbing materials: from passive dissipation to multifunctional...

Electromagnetic wave absorbing materials (EMWAMs) are evolving from conventional passive electromagnetic (EM) absorber toward multifunctional and intelligent regulation systems to meet the demands of increasingly complex EM environments and application scenarios. Although conventional performance metrics (strong attenuation, broad effective absorption bandwidth, low density, and thin matching thickness) remain essential, they are insufficient to evaluate EMWAMs in complex operating environments. This review systematically summarizes recent advances in multifunctional and intelligent EMWAMs. First, the fundamental principles of impedance matching and EM attenuation are briefly outlined to clarify how additional functions or external stimuli alter EM responses. Subsequently, multifunctional EMWAMs are analyzed as materials designed to maintain reliable EM wave absorbing performance (EMWAP) under practical service conditions, including thermal management, mechanical adaptability, and environmental robustness. And the trade-offs between EMWAP and additional functionalities are analyzed. Finally, intelligent EMWAMs are discussed according to thermal, mechanical, electrical, moisture, and magnetic regulation mechanisms, highlighting how external stimuli dynamically modulate EMWAP through variations in conductivity, polarization relaxation, phase states, or macroscopic structures. By consolidating recent progress, this review aims to provide a guide for the rational development of next-generation EMWAMs toward multifunctional integration and intelligent regulation.