Magnetodielectric composite with ferrite inclusions as substrates for microstrip patch antennas at microwave frequencies

Abstract

A study has been conducted to estimate the complex permittivity and permeability along with magnetic characterization of different volume fractions of magnetodielectric composites with cobalt ferrite nano inclusions. Using an in touch superstrate technique dielectric properties are estimated. Cavity perturbation technique is used to study the complex permeability of the samples. 4πMs value and coercivity is measured using vibrating sample magnetometry. Structural and surface morphologies on the composite samples are conducted to determine the size and homogeneous distribution of nano inclusions. The average grain size of cobalt ferrite nanoparticles is found to be ∼10nm. The real part of permittivity and permeability of the samples varies from ∼1–2.905 to ∼1.01–1.05 with increase in inclusion content from 1%VF to 5%VF, respectively. The tanδ of permittivity and imaginary part of permeability is found to be of the order of ∼10−3 and ∼10−1 respectively. Verification of these composites as potential substrates for microstrip patch antenna is carried out by fabricating simple rectangular patch at 9.5GHz using transmission line model. Rectangular patch is designed on 5%VF composite system. The return loss for the composite system was found to be ∼−19.451dB which is comparable with that designed on standard glass epoxy substrate (ɛr=4.5).