The Li2O-Nb2O5-TiO2 Composite Microwave Dielectric Ceramics with Adjustable Permittivities

A group of new y M‐phase/(1−y) Li2+xTi1−4xNb3xO3 composite ceramics with adjustable permittivities for low‐temperature co‐fired ceramic applications was initially investigated in the study. The 0.5 M‐phase/0.5 Li2+xTi1−4xNb3xO3 (x=0.01, 0.02, 0.04, 0.06, 0.081) composite ceramics were first investigated to find the appropriate “Li2TiO3ss” composition (x value). The best dielectric properties of ɛr=40.1, Q×f values up to 9318 GHz, τf=25 ppm/°C, were obtained for the ceramics composites at x=0.02. Based on the good dielectric properties, the suitable “Li2TiO3ss” composition with x=0.02 was mixed with the Li1.0Nb0.6Ti0.5O3 powder as the ratio of y“M‐phase”/(1−y) “Li2TiO3ss” (y=0.2, 0.4, 0.5, 0.6, 0.8). By adjusting the y values, the group of composite ceramics could exhibit largely are adjustable permittivities varying from ∼20 to ∼60, while Q×f and τf values relatively good. Nevertheless, in this study, because there are interactions between the M‐phase and Li2TiO3ss during sintering process, their microwave dielectric properties could not be predicted precisely by the empirical model.