Effect of amorphous fillers on low loss ceramics for advanced microwave electronics

In this paper we report the development of a low-temperature sinterable Cu₂ZnNb₂O₈ (CZN) based composite for low-temperature cofired ceramic (LTCC). The CZN ceramics were prepared by the solid-state ceramic route. The calcination and sintering temperatures of CZN were optimized at 800°C and 975°C, respectively, for the best density and dielectric properties. The microwave dielectric properties of ceramic were measured by split post dielectric resonator (SPDR). The CZN sintered at 975°C had ε_r = 15.2, tanδ = 0.0009 at 5.1 GHz. The sintering temperature of CZN is lowered from 975°C to 915°C by the addition of both LBS and LMZBS glasses. CZN mixed with 0.7 wt% LBS and sintered at 915°C had ε_r = 14.8, tanδ = 0.001 at 5.1 GHz. The addition of 0.7 wt% LMZBS to CZN and sintered at 935°C/4 h had ε_r = 14.6, tanδ = 0.002 at 5.1 GHz.