Microwave absorption characteristic of a double-layer X-band absorber based on MWCNTs/La0.6Sr0.4Mn0.5Fe0.5O4 coated with PEDOT polymer

Abstract

In this study, a novel double-layer microwave absorber was designed based on the MWCNTs/La0.6Sr0.4Mn0.5Fe0.5O4 (C/LSMFO) and PEDOT-coated (P@[C/LSMFO]) nanocomposites. Co-precipitation and in-situ polymerization methods were utilized to synthesize the C/LSMFO and P@[C/LSMFO] nanocomposites, respectively. XRD, FESEM, VSM, and VNA analysis were used to determine the structural, morphological, magnetic, and electromagnetic properties of the nanocomposites. Single-layer absorbers with thicknesses of 1, 1.5, and 2 mm were fabricated, and electromagnetic parameters were evaluated via VNA in the X-band frequency. Moreover, the microwave absorbing features of the double-layer absorber with various layer thicknesses were simulated with CST studio by increasing the final reflection loss of the absorber. According to the results, interfacial polarizations and synergistic effects between the two layers were the key factors for improving impedance matching and, in consequence, increasing the reflection of the samples. The optimized double-layer sample with a total thickness of 2 mm (a matching layer with a thickness of 1 mm containing the P@[C/LSMFO] nanocomposite and an absorbing layer with a thickness of 1 mm containing the C/LSMFO nanocomposite) exhibited a minimum reflection loss value of −36 dB at 8.5 GHz with a bandwidth of 2 GHz. The main advantages of the prepared absorber are reduction in total thickness and also low filler loading in the matrix which reduce the total weight of the absorber. This indicates that the present double layer absorber system is a promising candidate to be used as a lightweight and efficient microwave absorber.