Design and fabrication of a C-band patch antenna using novel low permittivity SrGa2Si2O8 microwave dielectric ceramic

A novel microwave dielectric ceramic of SrGa 2 Si 2 O 8 was synthesized using the traditional solid-state method. Its phase composition, microstructure, and microwave dielectric properties were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy , and network analyzer . XRD results indicated that the space group of the ceramic transformed from I 2 /c to P 21 /a at 700 °C. A combination of good microwave dielectric properties was obtained at 1260 °C with ε r = 6.3, Q × f=  96,600 GHz and τ f = −45.2 ppm/°C at 16.5 GHz. The negative τ f can be tuned to near zero by adding 15 mol% CaTiO 3 . The densification temperature can be reduced to 940 °C by adding 4 wt% LiF. Moreover, the SrGa 2 Si 2 O 8 ceramic had good chemical compatibility with the Ag electrode. A patch antenna was designed using the 0.85SrGa 2 Si 2 O 8 + 0.15CaTiO 3 + 4 wt% LiF ceramic. The antenna had a high radiation efficiency of 99.2 % and a gain of 2.988 dBi at the center frequency of 4.261 GHz. All results indicated that the SrGa 2 Si 2 O 8 ceramic has promising potential for applications in 5 G wireless communication technology.