Dielectric Studies of Nano-Magnesium Silicate and Linear Low-Density Polyethylene Composite As a Substrate for High-Frequency Applications

Dielectric properties of a magnesium silicate (MgSiO₃) linear low-density polyethylene nanocomposite are studied in the X-band frequencies to realize its application as a substrate for high-frequency devices. MgSiO₃ ceramics are synthesized by conventional solid state technique. Structural and morphological characteristics of MgSiO₃ nanoparticles are confirmed by X-ray diffraction, Fourier transform infrared spectroscopy and transmission electron microscopy. Transmission electron microscopy images reveal the average particle size to be ~100 nm. Composites are prepared by uniform dispersion of the nano-inclusions MgSiO₃ in a linear low-density polyethylene matrix in three different wt.%, viz. 2%, 4% and 6%. The fractured lateral side of the composite is examined under a scanning electron microscope to ensure the uniform dispersion of the inclusions in the polymer. Water absorption measurement is carried out based on ASTM D570-98. Densities of the samples are measured by hydrostatic weighing by using Archimedes principle. Thermal conductivity of the composites is measured by modified hot plat method. Nicholson-Ross approach is used to investigate the dielectric characteristics of composites. The permittivity and dielectric loss tangent of the nano-composite in the X-band are found to be ~2.2–2.5 and 10⁻²–10⁻⁴ for all the inclusion concentration respectively. To see the applicability of the nanocomposite in the field of antenna, return losses are calculated from complex permittivity and complex permittivity data.