A novel Ba3(ZnB5O10)PO4 microwave dielectric ceramic with near-zero τf value for LTCC applications

A novel Ba 3 (ZnB 5 O 10 )PO 4 (BZBPO) phosphate ceramic was synthesised using a conventional solid-state technology. The BZBPO ceramic sintered at 850 °C demonstrated exceptional microwave dielectric properties : ε r = 5.88 ± 0.08, Q×f = 52,896 ± 1200 GHz ( f 0 = 16.5 GHz) and τ f = 0.34 ± 0.25 ppm/°C. Raman spectroscopy revealed that ε r and Q×f were negatively correlated with the Raman shift and full width at half maximum of the BZBPO ceramic, respectively. Meanwhile, Phillips–Vechten–Levine theory revealed that Q×f was highly correlated with the lattice energy ( U b ), and τ f was closely related to the bond energy ( E b ) and the thermal expansion coefficient. Among contribution ratios of individual chemical bonds, the B–O bond mainly contributed to U b , E b and ionicity, proving that the bond dominantly affected the dielectric properties of the BZBPO ceramic. Finally, the BZBPO ceramic was co-fired with silver, demonstrating its potential applicability towards low temperature co-fired ceramic technology.