Improved quality factor of NdNbO4 microwave dielectric ceramic by Mn2+ substitution

(Nd1−xMn1.5x)1.02Nb0.988O4 (x = 0.0, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06) microwave dielectric ceramics with improved quality factors were prepared by conventional mixed oxide route. The effects of Mn2+ substitution on the microstructures and microwave dielectric properties of NdNbO4 ceramics were investigated systematically. Microscopic analysis showed that the specimens presented single NdNbO4 phase in the range of x = 0.0 to x = 0.03, with the substitution content increasing, MnNb2O6 peak appeared in the system. The microwave dielectric properties of NdNbO4 ceramics were strongly dependent on the Mn2+ substitution. An optimal quality factor Q × ƒ = 80,000 GHz was achieved for (Nd1−xMn1.5x)1.02Nb0.988O4 (x = 0.03)ceramics sintered at 1250 °C for 4 h.