Phase Relation and Microwave Dielectric Properties of (Zn 1− x Co x )Ta ₂ O ₆ System

High‐dielectric constant and low‐loss ceramics in the (Zn 1− x Co x )Ta 2 O 6 ceramics have been prepared by the conventional mixed oxide route and their microwave dielectric properties have been investigated. A phase change or crossover from ZnTa 2 O 6 to CoTa 2 O 6 occurred at x =0.07 and was completed at x =0.11 and it tends to form a continuous solid solution elsewhere. An over‐sintered specimen would lead to a slight decrease in the density resulting in a decline of the dielectric constant and the Q × f value. The specimen with x =0.05 possessed an excellent combination of microwave dielectric properties: ɛ r ∼38.47, Q × f ∼112 000 GHz, and τ f ∼11.2 ppm/°C. It is proposed as a candidate material for today's 3G passive components and especially small‐sized GPS patch antennas.