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Hao et al. Soft Sci. 2025, 5, 39 https://dx.doi.org/10.20517/ss.2025.48 Page 9 of 25

energy dissipation, while another portion is reflected toward the surfaces of adjacent functional units,
leading to subsequent reflection and dissipation events. Even if the conductivity of the functional units
increases, leading to a slight deterioration in the impedance matching of the metacomposites,
electromagnetic waves can still reflect among the functional units instead of being reflected into free space.
Therefore, MSMCs have a strong ability to dissipate electromagnetic waves, benefiting from the
contributions of reflection and scattering.

More importantly, the design of the dimensions and spatial configuration of sub-wavelength functional
units can manipulate the reflection behavior of electromagnetic waves among functional units. The
extended propagation paths of electromagnetic waves significantly promote energy dissipation by
intensifying their interaction with lossy media. Although optimized multiple-reflection dynamics facilitate
the effective attenuation of electromagnetic energy through longer paths inside functional units, excessive
reflections can also prevent electromagnetic waves from entering the material. Therefore, it is of vital
importance to design structures and functional units that can effectively balance multiple reflections and
scattering. MSMCs demonstrate superiority in matching the size of functional units with the wavelength of
electromagnetic waves; the electromagnetic waves can be controlled to reflect and scatter between
functional units by adjusting the electrical conductivity of functional units, thereby promoting the
absorption of electromagnetic waves.

The exceptional electromagnetic absorption performance of MSMCs stems from the synergistic effects of
multiple loss mechanisms, primarily including conductive loss, polarization loss, and enhanced attenuation
resulting from multiple reflection-scattering effects [Figure 2]. Taken together, MSMCs achieve significant
improvements in microwave absorption performance by integrating multiple absorption mechanisms
through ingenious structural design and multi-component synergy. However, further research is needed to
elucidate the synergistic interplay among the absorption mechanisms, as well as the quantitative
relationships between structure and performance. With the continuous advancement of research, it is
anticipated that the intrinsic mechanisms of wave absorption in MSMCs will be further unraveled, thereby
providing a robust theoretical foundation for the development of higher-performance microwave
absorption materials.

MICROWAVE ABSORPTION PERFORMANCE ENHANCEMENT STRATEGIES
Controllable dispersion of fillers
Conventional MAMs are typically prepared by simple mixing of fillers and matrix. However, this approach
suffers from significant drawbacks due to the ineffective control of filler dispersion, leading to serious
agglomeration in the matrix. The agglomeration of fillers not only leads to inhomogeneous internal
structures but also generates larger particle clusters, hindering the sufficient interaction between
electromagnetic waves and fillers during propagation, thereby greatly reducing absorption efficiency.
Additionally, the agglomeration phenomenon may also alter the electrical and magnetic properties of the
material, disrupt its inherent impedance matching, and consequently lead to a marked decline in overall
absorption performance.

To address this issue, engineering fillers into mesoscopic functional units has emerged as a transformative
strategy. Mesoscopic functional units, characterized by well-defined geometric morphologies and
dimensions spanning the nanometer to micrometer range, enable precise control over structural
architecture and chemical composition through advanced fabrication techniques. For instance, integrating
electrospinning, size tailoring, microfluidics, and spray drying technologies enables the fabrication of
functional units with well-defined morphologies (e.g., spheroidal or lamellar) and hierarchical internal