Preparation, microstructure and performance of interference microwave absorbing cermet composites with frequency-selective screens

Interference microwave absorbing cermet composites with frequency-selective screens (AC/FSS) were success-fully prepared by sintering a ceramic green body embedded with stainless-steel wire mesh screens via a rapid heating method. The addition of the screens made the AC/FSS composites increase slightly in density and open porosity and remain unchanged in surface Vickers hardness and compressive strength. Both the number and structure parameters of the screens had a significant effect on the microwave absorbing performance of the AC/ FSS composites. The weak microwave absorption by the small amount of zinc oxide and poor microwave interference by the single-layer screen made the AC/FSS composites possess modest microwave absorbing performance. Moreover, the AC/FSS composites showed an improved microwave absorbing performance due to the significantly enhanced microwave interference by the double-layer screens. By optimizing the structure parameters of the upper and lower screens, the AC/FSS composites with double-layer screens possessed sur-prisingly good microwave absorbing performance with the whole reflectivity-versus-frequency curve below-10 dB, a mean reflectivity as low as-12.9 dB and the lowest reflectivity of-15.2 dB at 12.4 GHz in the 8.0-18.0 GHz frequency range.

Automated summary

By adding stainless-steel wire mesh screens, the microwave absorbing performance of interference microwave absorbing cermet composites can be improved. The double-layer screens significantly enhance microwave interference and further enhance absorption performance.