Magnetodielectric composite with NiFe2O4 inclusions as substrates for microstrip antennas

Magnetodielectric composite relevance as substrate for microstrip antenna is studied. Synthesized nano nickel ferrite (NiFe₂O₄) of crystallite size ~12 nm dispersed in low density polyethylene (LDPE) is developed for the said purpose with varying filler concentration (volume %) from 1% to 5% (0.01 to 0.05). Morphological characterization of the composite is carried out using scanning electron microscopy. Permittivity and permeability of the composites in X-band frequency range is determined using in-touch non-destructive technique and cavity perturbation technique, respectively. The complex permittivity of the substrates varies from ~6.091 - 8.427 and complex permeability, ~1.0345 - 1.1998 for different filler concentrations s. 4πMs value and coercivity is measured using vibrating sample magnetometry. Verification of these composites as potential substrates for microstrip patch antenna is carried out by fabricating simple rectangular patch at 10 GHz using transmission line model. Rectangular patch is designed on 0.01, 0.03 and 0.05 filler concentration composite system. The return loss for the 0.01 vol.% composite system is found to be ~-17 dB. E and H plane radiation pattern shows high directivity and negligible side lobe level.