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High‐Q Microwave Dielectrics in the (Mg 1− x Co x ) 2 TiO 4 Ceramics
Author(s) -
Huang ChengLiang,
Chen JhihYong
Publication year - 2009
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2008.02742.x
Subject(s) - dielectric , materials science , microwave , ceramic , microstructure , analytical chemistry (journal) , ilmenite , x ray crystallography , dielectric loss , phase (matter) , diffraction , solid solution , mineralogy , lattice constant , composite material , optics , metallurgy , chemistry , optoelectronics , physics , organic chemistry , chromatography , quantum mechanics
The microwave dielectric properties and the microstructures of (Mg 1− x Co x ) 2 TiO 4 ceramics prepared by the conventional solid‐state route were investigated. Lattice parameters were also measured for specimens with different x . The formation of solid solution (Mg 1− x Co x ) 2 TiO 4 ( x =0.02–0.1) was confirmed by the X‐ray diffraction patterns, energy dispersive X‐ray analysis, and the lattice parameters measured. By increasing x from 0 to 0.05, the Q × f of the specimen can be tremendously boosted from 150 000 GHz to a maximum of 286 000 GHz. A fine combination of microwave dielectric properties (ɛ r ∼15.7, Q × f ∼286 000 GHz at 10.4 GHz, τ f ∼−52.5 ppm/°C) was achieved for (Mg 0.95 Co 0.05 ) 2 TiO 4 ceramics sintered at 1390°C for 4 h. Ilmenite‐structured (Mg 0.95 Co 0.05 )TiO 3 was detected as a second phase. The presence of the second phase would cause no significant variation in the dielectric properties of the specimen because it possesses compatible properties compared with that of the main phase. In addition, only a small deviation in the dielectric properties was monitored for specimens with x =0.04–0.05 at 1360°–1420°C. It not only provides a wide process window but also ensures an extremely reliable material proposed as a very promising dielectric for low‐loss microwave and millimeter wave applications.