Insights into polarization relaxation of electromagnetic wave absorption

Electromagnetic wave absorbers (EWAs) exert considerable influence in the information age, and polarization relaxation has been vital to regulating the electromagnetic response toward high-performance EWAs. However, polarization relaxation still confronts several hurdles in understanding the intrinsic mechanisms and modulating the performance. In view of this, we first introduce the main dielectric polarizations including dipole polarization, interface polarization, and defect-induced polarization. The concepts of corresponding polarization relaxations and their correlations are then clarified, and the influencing factors of polarization relaxations in EWAs are elucidated. Subsequently, we detail the tailoring strategies of dielectric polarization from the perspectives of components modulation and structure regulation, together with state-of-the-art achievements. Finally, the challenges and future exploration directions for dielectric EWAs are proposed.