Strategies for reducing the reflection coefficient of polymer-based electromagnetic shielding composites: A review

Traditional polymer-based electromagnetic interference (EMI) shielding composites attenuate electromagnetic waves mainly via strong reflection, which inevitably causes severe secondary electromagnetic radiation pollution. Accordingly, low-reflection polymer-based EMI shielding composites have become a major research hotspot. While substantial advances have been made in lowering the reflection coefficient of such composites, comprehensive summaries and in-depth discussions of this topic remain surprisingly scarce. This paper systematically reviews the core strategies for mitigating the reflection coefficient of polymer-based EMI shielding composites, with a focused emphasis on the preparation methodologies and underlying mechanisms through which heterogeneous-structured fillers, multilayer structures, porous structures, and multilayer porous architectures reduce electromagnetic wave reflection. By synthesizing the current research landscape, this review presents future perspectives and furnishes systematic theoretical guidance and technical references for the design, fabrication, and industrial-scale application of high-performance, low-reflection polymer-based EMI shielding composites.