Dissipation in composites with high-loss and lossless components

Summary form only given. Use of low-loss magnetic materials in high-power microwave devices can improve significantly their performance. We have demonstrated1 that the electromagnetic losses in the composite structure can be reduced by up to two orders of magnitude, compared to those of the uniform magnetic sample made of the same lossy magnetic material. Importantly, the dramatic absorption reduction is not a resonance effect and occurs over a broad frequency range covering a significant portion of the respective photonic frequency band. The optimal configuration of the composite may depend on the dominant physical mechanism of absorption, such as electric conductivity or domain wall friction.