Ba2Ti9O20-Ba1.85Sm4.1Ti9O24 layered dielectric resonators with adjustable effective dielectric constant

The layered dielectric resonator structures composed of Ba₂Ti₉O₂₀ (BTO) and Ba_1.85Sm_4.1Ti₉O₂₄ (BSTO) ceramic pellets were introduced to design new microwave dielectric materials with adjustable dielectric constant between 50 and 70. Good combination of microwave dielectric properties (?_r,eff = 50 ~ 70, Qf = 11,700-19,100 GHz and τ_f = − 4.3 to − 1.5 ppm/°C) was obtained by the present approach, and such combination could be optimized by adjusting the volume fraction of BSTO and stacking scheme. For practical applications, the BTO and BSTO layers could be bonded by low-loss adhesive, and the effects of the adhesive on the microwave dielectric properties were limited.