Low-Frequency Microwave Absorption Composites

Electromagnetic wave devices and components operating in the low-frequency band of 1–8 GHz (L, S, and C bands) are widely applied in wireless data communication systems, satellite radar, and other fields. However, traditional low-frequency microwave absorption materials (MAMs) suffer from issues such as large thickness, heavy weight, difficult impedance matching, insufficient low-frequency microwave loss, and poor environmental stability, severely limiting use and development. In recent years, researchers construct composite systems combining various types of loss, coupled with component adjustments and structural design strategies, significantly improving the impedance matching and multiple loss synergy effects for low-frequency MAMs. Based on the above, this review briefly introduces the basic principle of microwave absorption and the influence factors of low-frequency microwave absorption performance, and systematically reviews the recent research progress of carbon-based composites, magnetics-based composites, polymer-based composites, ceramic-based composites, and multiphase hybrid composites. Additionally, the intrinsic relationship and mechanisms are discussed in detail between the micro-structure and macro-performance of different composites. Furthermore, the key scientific and technical bottleneck problems that need to be addressed in the design and preparation of low-frequency MAMs are identified. It is expected to provide theoretical guidance for the controlled preparation and performance regulation of low-frequency microwave absorption composites.