Highly-malleable microwave absorption foam

Abstract

Microwave absorption (MA) materials have made great progress in bandwidth optimization and weight reduction; however, it remains a challenge to achieve the malleability of MA materials. The performance of existing dielectric loss-type MA materials critically relies on the dielectric networks, which are fragile due to particle aggregations and junction cracks in practical processing. We here report a foam architecture strategy to attain both malleability and excellent MA properties. The foam consists of micro-balloons bound together by a deformable paste which contains H2O and ions. We observed a linear increase in permittivity with increasing H2O contents. This relationship enables a fine optimization of MA properties. The highly-malleable foam delivers an effective absorption bandwidth of 7.37 GHz at reflection loss (RL) ≤−10 dB and minimum RL of −72.6 dB.