Synthesis and microwave characterisation of (Zr_0.8Sn_0.2)TiO₄-epoxy composite and its application in wideband stacked rectangular dielectric resonator antenna

摘要

In this study, (Zr_0.8Sn_0.2)TiO₄-epoxy composites are synthesised, characterised and used in dielectric resonator antenna applications. (Zr_0.8Sn_0.2)TiO₄ and epoxy are mixed in five different ratios, that is, 50:50, 60:40, 70:30, 80:20 and 90:10 with small amount of hardner (HY 951). The crystal structure and cell parameters of (Zr_0.8Sn_0.2)TiO₄ are confined by Rietveld analysis. The complex permittivity of the composite is measured at different microwave frequencies in X-band (8.2-12.4 GHz). It has been found that the permittivity is reduced by increasing the percentage of epoxy in composite system. The optimised weight percentage ratio of (Zr_0.8Sn_0.2)TiO₄ and epoxy composite material are used in a two-layer rectangular dielectric resonator antenna using coaxial excitation for obtaining wideband performance. The effects of the antenna parameters like length, width and probe length are investigated using Ansoft's high-frequency structure simulator (HFSS) software. The agreement between simulated and experimental data is very good. The proposed design provides the measured impedance bandwidth of 58.7% (at resonance frequency 8.40 GHz) from 6.45 to 11.38 GHz for reflection coefficient (S₁₁) of less than -10 dB with a measured average gain of 6.99 dB in the frequency range of 6.0-11.5 GHz. The radiation patterns are consistent throughout the operational bandwidth.