LAUSR

Abstract LiGa5O8 ceramics with inverse spinel structure were prepared in a temperature range of 1200–1300 ℃ by solid-state reaction method. LiGa5O8 ceramics crystallized in cubic structure with space group P4332, in which Li+ and Ga3+ distributed in the octahedral B sites with 1:3 ordering. The optimal microwave dielectric properties with er =10.51, Q × f = 127,040 GHz, and τf = –60.16 ppm/℃ were achieved at 1260 ℃ for 6 h. Microwave dielectric properties were discussed in combination with the intrinsic characteristics of crystal structure by packing fraction, Raman spectra, and infrared reflectivity spectrum. Additionally, CaTiO3 was used to suppress τf of LiGa5O8 ceramics to near zero, and optimized performances of er = 12.79, Q × f = 109,752 GHz and τf = +4.07 ppm/℃ were obtained for 0.94LiGa5O8‐0.06CaTiO3 ceramics at 1260 ℃. These bright spots make LiGa5O8 ceramic a potential candidate for 5 G and millimeter wave technology.