Multilayer co-fired microwave dielectric ceramics in MgTiO3-Li2TiO3 system with linear temperature coefficient of resonant frequency

To address the nonlinear variation of resonant frequency in a MgTiO3-CaTiO3 system over a wide temperature range (-40-105 degrees C), MgTiO3-Li2TiO3 system ceramics with multilayer architectures are designed. Trilayer MgTiO3-Li2TiO3-MgTiO3 ceramics (mass ratio = 0.2:0.56:0.2) sintered at 1275 degrees C possess a linear and near-zero temperature coefficient of resonant frequency (rf + =-3.0 ppm/ degrees C (25-105 degrees C), rf-= 2.7 ppm/ degrees C (-40-25 degrees C)). Compared with that of random distribution-type MgTiO3-Li2TiO3 ceramics, the Q x f value of trilayer ceramics is significantly improved (Q x f = 80,0 0 0 GHz (@7.6 GHz)). The electric field distribution is examined by the eigenmode solver of High Frequency Structure Simulator software to analyze the effect of the Li2TiO3 content and the stacking scheme on the dielectric properties. The cross-sectional morphologies show a dense intermediate layer formed by ion diffusion, which acts as a glue to bond each layer. This work can be conceived as a new strategy for developing 5G wireless communication components with linear temperature-related resonant frequency (-40-105 degrees C) and low dielectric loss. (C) 2021 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.