A novel low permittivity microwave dielectric ceramic Sr2Ga2SiO7 for application in patch antenna

The dielectric properties of a Ga-based melilite type ceramic Sr 2 Ga 2 SiO 7 via theoretical prediction based on far-infrared spectroscopy and experimental measurement by the Hakki–Coleman method were studied in this work. Dense and single-phase ceramics were fabricated via solid-state reaction at 1330°C and exhibited comprehensive microwave dielectric properties ( ε r ∼ 7.6, Q × f ∼ 23 600 GHz, and τ f ∼ −35.2 ppm/°C) at 14.3 GHz. Chemical modifications were proposed to adjust the thermal stability and reduce the densification temperature. By adding 10 mol% CaTiO 3 , the negative τ f can be compensated to a near-zero value of −3.8 ppm/°C. The densification temperature was reduced to 940°C by adding 3 wt.% LiF. A patch antenna was designed using Sr 2 Ga 2 SiO 7 ceramic with a high radiation efficiency of 99.1% and a gain of 2.788 dBi at the center frequency of 4.371 GHz. All results indicate that the Sr 2 Ga 2 SiO 7 ceramic has promising application potential for 5G wireless communication technology.