Electromagnetic Wave Absorption Properties of Silver-Decorated Nickel-Coated Copper with Frequency Selective Surface

In this study, Ag-decorated Ni@Cu powders were prepared by electroless plating method with Ni@Cu powders as the raw material. The various characteristics of the composite powders, such as their phase composition and structure, were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. The effects of different Ag content on the size distribution of the particles were also studied by a laser particle size analyzer. The network vector analyzer additionally measured the electromagnetic properties of Ag-decorated Ni@Cu powders/paraffin samples. The electromagnetic wave absorption properties of the samples with different thicknesses were studied. The results of XRD and SEM show that with the increase of Ag content, the Ag plating effect of Ni@Cu powders increases first and then decreases. The results of laser particle size analyzer show that with the increase of Ag content, the particle size and distribution of Ag-decorated Ni@Cu powders become larger and wider. Through the analysis of the microwave absorption performance of Ag-decorated Ni@Cu powders/paraffin sample, it can be concluded that in the frequency range of 8.2-12.4GHz, when the thickness is 2.6mm, the Ag-decorated Ni@Cu powders with a silver mass ratio of 25wt.% have good electromagnetic wave absorption performance. The reflection loss is less than -10 dB in the whole frequency range, and the peak value reaches -55.36 dB at 9.92GHz. In addition, the frequency selective surface coupled by circular element and square ring element improves the microwave absorption performance of the sample containing 15wt.% Ag content with 2mm thickness. The reflection loss is lower than -10 dB with the peak reflection loss of -36.73 dB at 10.98GHz in the whole frequency range. The simulation results show that the loading frequency selective surface can reduce the silver content and make it have better microwave absorption performance and low cost.