Crystal structure and microwave dielectric properties of a new A4B3O12-type cation-deficient perovskite Ba3LaTa3O12

Effects of Sr substitution on microwave dielectric properties of Ba3LaNb3O12 ceramics

“…More recently, we have reported the synthesis and microwave properties of A 4 B 3 O 12 -type hexagonal perovskites Ba 2 La 2 TiNb 2 O 12 and BaLa 3 Ti 2 NbO 12 [12,13], and Sinclair and co-workers also reported the microwave dielectric properties of Ba 3 LaNb 3 O 12 [14]. Among these compositions, Ba 3 LaNb 3 O 12 is characterized with ε r of 44, Q u × f value of 9000 GHz, and a negative f value of −100 ppm/ • C. Consequently, modifications are strongly required in quality factor and f if microwave applications are considered [15].…”

“…To meet the requirements for use in such wide applications, the microwave materials should possess appropriate properties like (a) high dielectric constant (ε r ) for miniaturization, (b) high unloaded quality factor (Q u ) or low dielectric loss for better selectivity and (c) low temperature coefficient of resonant frequency ( f ) for frequency stability. Although several compounds such as Ba(Zn 1/3 Ta 2/3 )O 3 , BaTi 4 O 9 , Ba 2 Ti 9 O 20 , (Zr,Sn)TiO 4 , and Ba 6−3x Re 8+2x Ti 18 O 54 (Re = Nd, Sm, La) systems have been reported for practical applications [2], active research is still going on for new compounds due to the great demand for a variety of materials with varying dielectric constants [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18].…”

Microwave dielectric properties and low temperature sintering behavior of Li2CoTi3O8 ceramic

“…For application to resonators, microwave dielectric materials require a high relative permittivity (ε r ) to facilitate circuit miniaturization, a high quality factor values (Q × f) to increase their selectivity, and a near-zero temperature coefficient of the resonant frequency ( f ) to ensure the stability of the frequency against temperature changes [1]. Although some materials with excellent properties have been developed for commercial applications, such as Ba(Mg 1/3 Ta 2/3 )O 3 , (Zr,Sn)TiO 4 , and CaTiO 3 -NdAlO 3 [1], active work is still being carried out in search of sophisticated materials to perform the same or an improved function [2][3][4][5][6][7].…”

Effects of BaCu(B2O5) addition on phase transition, sintering temperature and microwave properties of Ba4LiTa3O12 ceramics

“…These materials are required to a high relative permittivity (ε r ) for miniaturization, a high quality factor (Q × f) for better selectivity and a near-zero temperature coefficient of resonant frequency ( f ) for stability, but in addition, low cost and minimization of components are two crucial requirements in commercial applications [1][2][3][4]. However, contemporary commercial resonator materials such as such as Ba(Mg 1/3 Ta 2/3 )O 3 , (Zr,Sn)TiO 4 , and CaTiO 3 -NdAlO 3 had the sintering temperatures higher than 1300 • C [4][5][6][7][8][9], which limits their applications in low-temperature cofired ceramic (LTCC) microwave devices. As a promising material for LTCC application, the sintering temperature of the ceramics should be lower than the melting point of silver (∼960 • C) [10,11].…”