Microwave dielectric properties of (1-x)Na0.5Y0.5MoO4-xNa0.5Bi0.5MoO4 ceramics for LTCC applications

A series of microwave dielectric ceramics, (1-x)Na0.5Y0.5MoO4-xNa0.5Bi0.5MoO4, with low sintering temperatures and excellent microwave dielectric properties, were prepared by solid-state reaction. The ceramics were sintered well at 820 oC, and the structure, microwave dielectric properties, and chemical compatibility were investigated. When x=0.1, the microwave dielectric constant (εr), the quality factor (Q × f value), and the temperature coefficient of resonant frequency (TCF value) of the 0.9NYM-0.1NBM ceramic were 10.9(±0.2), 54,060(±1,000) GHz, and -48.6(±1) ppm/°C, respectively. When x=0.7, the εr of the 0.3NYM-0.7NBM ceramic was 23.6(±0.5), the Q × f value was 19,020(±400) GHz, the TCF value was -3.1(±0.1) ppm/°C and the room temperature thermal conductivity was 1.21(±0.01) W/(m.K). After co-firing with 20 w.t.% silver powder at 820°C, it was found that (1-x)NYM-xNBM ceramics were chemically compatible with Ag electrodes, indicating their potential as alternative materials for low-temperature co-fired ceramics (LTCC).