Effects of (Co_1/3Nb_2/3)⁴⁺Substitution on Microstructure and Microwave Dielectric Properties of Li₂Ti_1-x(Co_1/3Nb_2/3)_xO₃Ceramics for Applications in Ceramic Antenna

Dielectric properties of Li2Ti1-x(Co1/3Nb2/3)xO3 (x = 0.1–1.0) ceramics using a solid-state reaction method were investigated. Substitution ratio effects on different phase changes and dielectric characteristics of Li2Ti1-x(Co1/3Nb2/3)xO3 (x = 0.1–1.0) ceramics were improved because of the solid solution of (Co1/3Nb2/3)4+ substitution in a Ti site. Therefore, optimal microwave dielectric properties (εr ~ 21.3, Q × f ~ 110,000 GHz, τf ~ 0 ppm/oC were achieved for Li2Ti0.7(Co1/3Nb2/3)0.3O3 ceramics sintered at 1150°C for 3 h, which is thus a favorable material for dielectric substrate applications involving a monopole antenna. The monopole antenna fed by a microstrip-line was printed on Li2Ti0.7(Co1/3Nb2/3)0.3O3 ceramic substrate.