Synthesis, characterization and evaluation of reflectivity of nanosized CaTiO₃/epoxy resin composites in microwave bands

Abstract

Microwave absorbing materials play a major role in electromagnetic interference and compatibility measurements in anechoic chambers. Nanocrystalline calcium titanate (CT) was synthesized by hydrothermal method and further composites of CT/epoxy resin were fabricated as thin solid slabs of four different weight ratios. The composite material was analyzed by X-ray diffraction (XRD) and transmission electron microscopy (TEM), which reveals that CT was observed to be in the monoclinic phase with an average crystallite size of 24 nm. The reflectivity measurement of the composite materials was carried out by the transmission/reflection method using a vector network analyzer R&S: ZVA40, in the X- and Ku-bands. The effective permittivity and permeability of the samples was also computed with the help of measured transmission and reflection coefficients. The results show that CT with equal weight of epoxy resin provides −30 dB at 8.5 GHz in the X-band and −19.5 dB at 18.0 GHz in the Ku-band. Reflectivity was found to be better than −10 dB for 2.2 GHz and 1.9 GHz for X-band and Ku-band, respectively and encourages use of it as potential microwave absorber material.