Temperature compensated Sr2Al2SiO7 ceramic for microwave applications

The Sr–Gehlenite (Sr2Al2SiO7) ceramic has been prepared by the conventional solid-state ceramic route. Phase pure Sr2Al2SiO7 (SAS) ceramic sintered at 1525 °C for 4 h has ɛr = 7.2 and Qu × f = 33,000 GHz. The SAS showed large negative τf of −37.0 ppm/ °C. A low value of τf was achieved by preparing SAS–CaTiO3 composite. The composite with 0.04 volume fractions (Vf) CaTiO3 sintered at 1500 °C for 4 h showed good microwave dielectric properties: ɛr = 8.6, Qu × f = 20,400 GHz and τf = +8.5 ppm/°C.