Resonator‐Free Metamaterials Based on Ferromagnetic Dielectrics for Mandatory Microwave Loss and Compact Stealth Cloaks

The utilization of resonant-unit-based metamaterials in beam control and compact stealth applications is inherently limited by the strong correlation between unit in-plane dimensions and reflection characteristics. Therefore, this study proposes a resonator-free metamaterial based on ferromagnetic dielectric that decouples the amplitude and phase by regulating interface interference, thereby achieving phase modulation independent of the in-plane dimensions of the FD units. With the introduction of a constant phase gradient and tuning of unit dimensions, reflected waves can be deflected or even converted into surface waves that propagate along the metamaterial interface. This enables a novel electromagnetic loss mechanism wherein the reflected energy undergoes mandatory attenuation by horizontally propagating within the lossy ferromagnetic dielectric. Simulations and experiments are conducted to prove this phenomenon, yielding an improvement of 36.64% in the average power loss density, a minimum reflection loss of -52 dB. Further, the efficacy of ferromagnetic dielectric units is validated for compact stealth cloaks, and a conformal curved stealth strategy that requires only unit dimension tuning to achieve scattering-field camouflage for arbitrarily shaped targets is proposed. Given its resonator-independent operation, the proposed metamaterial exhibits miniaturization advantages of cross-scale downsizing (in-plane dimension < λ/12)-a critical advancement for compact electromagnetic defense systems.