Effect of glass fillers in Cu2ZnNb2O8 ceramics for advanced microwave applications

The effect of glass addition on sintering temperature and microwave dielectric properties of Cu2ZnNb2O8 (CZN) is investigated for possible low temperature co-fired ceramic (LTCC) application. The CZN ceramic was prepared by the solid-state ceramic route. The phase formation, microstructure and elemental composition of the ceramics were studied using X-Ray Diffraction, Scanning Electron Microscopy, Transmission Electron Microscopy and Energy Dispersive Analysis. The CZN sintered at 975 degrees C/4 h has epsilon(r) = 15.2, tan delta = 0.0007 (at 5.1 GHz) and tau(f) of -98 ppm degrees C-1 and CTE = 1.9 ppm degrees C-1. The addition of LBS and LMZBS glasses lowered the sintering temperature of CZN to below the melting point of silver. The 1 wt% LBS added CZN sintered at 935 degrees C/4 h had. epsilon(r) = 14.7, tan delta = 0.001 (at 5.1 GHz), tau(f) = -19 ppm degrees C-1 and CTE = -0.6 ppm degrees C-1. The addition of 0.7 wt% LMZBS to CZN and sintered at 935 degrees C/4 h had epsilon(r) = 14.8, tan delta = 0.002 (at 5.1 GHz), tau(f) = -39 ppm degrees C-1 and CTE = -0.9 ppm degrees C-1. (C) 2012 Elsevier B.V. All rights reserved.