Low-loss microwave dielectrics using (Mg 1− xZn x) 4Nb 2O 9 ( x = 0.02–0.08) solid solutions

Abstract

The microwave dielectric properties and microstructures of (Mg 1− x Zn x ) 4Nb 2O 9 ( x = 0.02–0.08) solid solutions prepared by the conventional solid-state route have been investigated. Lattice parameters of the ceramics were also measured and linearly increased with the increase of x. The formation of solid solutions (Mg 1− x Zn x ) 4Nb 2O 9 ( x = 0.02–0.08) was confirmed by the X-ray diffraction patterns, the EDS analysis and the measured lattice parameters. A substantial increase in the Q × f was achieved in the solid solution system whereas the dielectric constant and the temperature coefficient of resonant frequency retained similar compared to that of the pure Mg 4Nb 2O 9. A fine combination of microwave dielectric properties ( ɛ r ∼ 13, Q × f ∼ 247,000 GHz, τ f ∼ −67 ppm/°C) can be achieved for specimen using (Mg 0.95Zn 0.05) 4Nb 2O 9 ceramics sintered at 1340 °C for 4 h.