The origin of reflection loss peaks in the double-layer electromagnetic wave absorber

► The origin of reflection loss peaks in the double-layer electromagnetic wave absorber was investigated. ► The Co2Z particle composite and carbonyl iron particle composite were used as the outer and inner layer of the absorber. ► The electromagnetic wave is partially reflected at the interface between the outer and the inner layer. ► Two RL loss peaks could be produced by quarter-wavelength cancellation at different interfaces of the double-layer absorber.