Enhanced Microwave Absorption Properties of Double-Layer Absorbers Based on Spherical NiO and Co_0.2Ni_0.4Zn_0.4Fe₂O₄ Ferrite Composites

Pei-Jiang Liu^1,2,3，Zheng-Jun Yao^1,2，Vincent Ming Hong Ng³，Jin-Tang Zhou^1,2，Zhi-Hong Yang¹，Ling-Bing Kong³

1. College of Materials and Technology, Nanjing University of Aeronautics and Astronautics2. Jiangsu Key Laboratory of Advanced Structural Materials and Application Technology3. School of Materials Science and Engineering, Nanyang Technological University

摘 要：Microwave absorption properties of spherical NiO particles and Co_0.2Ni_0.4Zn_0.4Fe₂O₄（CNZF） ferrites with single-layer and double-layer absorbers were studied in the frequency range of 2–18 GHz. The spherical NiO particles were synthesized by using a hydrothermal process, while the CNZF powders were prepared by using a sol–gel autoignition method. The double-layer absorbers, composed of 30 wt% NiO as matching layer and 30 wt% CNZF as absorption layer,with a total thickness of 3.2 mm, exhibited a maximum reflection loss（RL） of –67.0 d B at 9.2 GHz and an effective absorbing bandwidth below –10 d B to be 3.9 GHz from 7.0 to 10.9 GHz. The excellent microwave absorption performance of the double-layer absorbers should be ascribed to the high impedance matching ratio, the great microwave attenuation capability, and well-coupled layer.

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