Structure refinement, Raman vibration, impedance spectra and microwave dielectric properties of MgZrNb_2-x(Ge_1/2W_1/2)_xO₈ (0.02≤x≤0.08) ceramics with the high quality factor

The prosperous development of 5G technology requires the development of new high-performance microwave dielectric ceramics. MgZrNb_2-x(Ge_1/2W_1/2)_xO₈ (MZNGW) (0.02≤ x ≤ 0.08) ceramics were synthesized by the solid-state reaction with the high quality factor. The connection between the microstructure and microwave dielectric properties of MZNGW ceramics was systematically analyzed. Crystal structure refinement showed that MZNGW ceramics with monoclinic wolframite structure were synthesized in all samples. The sintering behavior and surface morphology indicate that doping of (Ge_1/2W_1/2)⁵⁺ can improve the densification and promote the grain growth. The effect of (Ge_1/2W_1/2)⁵⁺ doping on the phonon vibration can be obtained from Raman spectra, and the shift of Raman vibrational mode at 840 cm⁻¹ and the change of half-height width have a great influence on the dielectric constant and quality factor. XPS spectra and AC impedance spectra are analyzed to show the influence of the crystalline defects on the macroscopic properties of the interlayer. The MgZrNb_1-x(Ge_1/2W_1/2)_xO₈ (x = 0.04) ceramic exhibits excellent microwave dielectric performance sintered at 1420 °C for 4 h: ε_r = 27.1, Qf = 94,450 GHz, τ_f = −41.65 ppm/°C, with great potential for applications in modern communications.