Low-Loss Microwave Dielectric Ceramics Using (Mg1-xMnx)2TiO4 (x=0.02-0.1) Solid Solution

Composite ceramics in a solid solution of (Mg1-x Mn-x)(2)TiO4 (x=0.02-0.1) have been prepared by the mixed oxide route. Formation of the solid solution was confirmed by the X-ray diffraction, the EDX analysis, and the measured lattice parameters, which varied linearly from Mg2TiO4 (a=b=c=8.4410 angstrom) to (Mg-0.9 Mn-0.1)(2)TiO4 (a=b=c=8.4445 angstrom). The XRD analysis also confirmed the co-existence of a cubic-structured (Mg1-xMnx)(2)TiO4 and an ilmenite-structured second phase (Mg1-xMnx)TiO3. The composition expected to have a maximum Q x f (276 200 GHz at 10.5 GHz) is (Mg0.95Mn0.05)(2)TiO4 with epsilon(r)similar to 15.69 and tau(f)similar to-52.6 ppm/degrees C. The existence of the second phase, however, would lead to no significant variation in the dielectric properties of the specimen because it possesses compatible properties compared with that of the main phase.