Dielectric, thermal and mechanical properties of zirconium silicate reinforced high density polyethylene composites for antenna applications

Abstract

A low cost and low dielectric loss zirconium silicate (ZrSiO₄) reinforced HDPE (high-density polyethylene) composite has been developed for antenna applications. The 0–3 type composite is prepared by dispersing ZrSiO₄ fillers for various volume fractions (0.1 to 0.5) in the HDPE matrix by the melt mixing process. The composite shows good microwave dielectric properties with a relative permittivity of 5.6 and a dielectric loss of 0.003 at 5 GHz at the maximum filler loading of 0.5 volume fraction. The composite exhibits low water absorption, excellent thermal and mechanical properties. It shows a water absorption of 0.03 wt%, a coefficient of thermal expansion of 70 ppm per °C and a room temperature thermal conductivity of 2.4 W mK⁻¹. The composite shows a tensile strength of 22 MPa and a microhardness of 13.9 kg mm⁻² for the filler loading of 0.5 volume fraction. The HDPE–ZrSiO₄ composites show good dielectric, thermal and mechanical properties suitable for microwave soft substrate applications. A microstrip patch antenna is designed and fabricated using the HDPE–0.5 volume fraction ZrSiO₄ substrate and the antenna parameters are investigated.