Design of ultra wideband microwave absorber effectual for objects of arbitrary shape
Gong Yuan-Xun†a),b), Zhou Zhong-Xianga), Jiang Jian-Tanga), Zhao Hong-Jieb)
       
Curves of reflection coefficient versus frequency of (a) 2-layer absorber and (b) 7-layer absorber each backed by a PEC plate for different incident angles.