Microwave dielectric properties of BaY2(MoO4)4 ceramic with low sintering temperature

Abstract

A low firing microwave dielectric ceramic BaY 2 (MoO 4 ) 4 with monoclinic phase was prepared by using solid state reaction method. Microstructure and microwave dielectric properties of the ceramic were investigated. Optimized microwave dielectric properties were obtained in the ceramic sintered at 925°C for 2 h with a relative permittivity *11.5, a Q 9 f value about 47,200 GHz (at 10.3 GHz) and a temperature coefficient of resonant frequency of -35 ppm/°C. Furthermore, 0.5BaY 2 (MoO 4 ) 4 -0.5TiO 2 ceramic sintered at 970°C for 2 h with a relative permittivity *13.6, a Q 9 f value about 30,800 GHz (at 9.6 GHz) and a near zero s f value of ?0.8 ppm/°C.

Structure and microwave dielectric properties of ALn4(MoO4)7 (A = Ba, Sr, Ca, Ln = La, Pr, Nd, and Sm) ceramics

“…The optimized sintering temperature, sintered density, dielectric constant, quality factor and temperature coefficient of resonant frequency of the ALn 4 (MoO 4 ) 7 (A = Ba, Sr, and Ca, Ln = La, Pr, Nd, and Sm) ceramics under study are given in Table . The BLM ceramic shows maximum density of 4.5 g/cm 3 at the sintering temperature of 710°C for 1 hour, with a dielectric constant ε r of 11.8, Q u x f of 39 300 GHz and τ f −68 ppm/ o C. SLM exhibits maximum density of 4.4 g/cm 3 at the sintering temperature of 740°C for 1 hour, with a dielectric constant of 11.7, Q u x f of 44 200 GHz and τ f −83 ppm/ o C. CLM shows maximum density of 4.2 g/cm 3 at the sintering temperature of 750°C for 1 hour, with a dielectric constant of 11.4, Q u x f of 30 200 GHz and τ f −90 ppm/ o C. Among the compositions under study CaPr 4 (MoO 4 ) 7 shows very high quality factor Q u x f of 91 000 GHz, with a dielectric constant of 10.6 and τ f −39 ppm/ o C. The ALn 4 (MoO 4 ) 7 (A = Ba, Sr, Ca, Ln = La, Pr, Nd, Sm) ceramics have dielectric constant ε r ranging from 9 to 11.8 and very high quality factor Q u x f values ranging from 30 200 to 91 000 GHz compared to the reported molybdate based LTCC compositions …”

“…Several molybdate‐based compositions have been reported as excellent ceramics for LTCC applications. Scheelite type molybdates AMoO 4 and single phase compositions with structure type BaLn 2 (MoO 4 ) 4 in the alkaline earth molybdate‐ rare‐earth molybdate phase diagram are reported as ceramics for low temperature co‐firing applications . This paper focuses on the preparation and microwave dielectric characterization of single phase compositions in the alkaline earth molybdate ‐ rare‐earth molybdate phase diagram with structural formula ALn 4 (MoO 4 ) 7 (A = Ba, Sr, and Ca, Ln = La, Pr, Nd, and Sm).…”