Microwave Dielectric Properties and Structure of the Ba_6-3xSm_8+2xTi₁₈O₅₄ Solid Solutions

Abstract

The microwave dielectric properties of the Ba6-3 x Sm8+2 x Ti18O54 (0.3≤x≤0.7) solid solutions are studied in relation to the crystal structure. Q·f of suitable materials obtained by optimizing the sintering condition is in inverse proportion to the dielectric constant (ε r ). With increase of x, ε r decreased and Q·f increased. Good-quality microwave resonators with ε r =80 and Q·f=9720 GHz can be obtained in the composition range of x=0.5 to 0.7 in the solid-solution region. Substitution of 2Sm3+ for 3Ba2+ in the large cation sites results in the creation of vacancies and crystal distortion, showing that the shrinkage of the TiO6 octahedral site plays an important role for improvement of the microwave dielectric properties.

Frequency and temperature dependence of dielectric and electric properties of Ba2-xSm4+2x/3Ti8O24 with structural analysis

“…Since in our research, an increase in the dielectric loss with an increase in temperature has been observed, therefore, it seems that the losses due to electrical conductivity are more dominant than those due to the relaxation effects [8,10]. The observed properties and their trends are similar to the trends observed in [4,8,9] and [12]. Decrease with frequency and increase with temperature is a general behavior observed in this category of ceramics.…”

“…With time, rare earth metals have been intentionally doped in the structure with the formula of Ba 2−x Sm 4+2x/3 Ti 8 O 24 [3] to improve their properties. These developments include the ceramics: Ba-R 2 O 3 -TiO 2 , (Zr,Sn)TiO 4 system, BaO-TiO 4 * E-mail: sukhleen2@yahoo.com titanium rich system, Ba (B 1/3 Ta 2/3 )O 3 (B = Mg, Zn) [4][5][6][7].…”

Research and Development of Microwave Dielectric Ceramics for Wireless Communications

“…Figure 2 shows the dielectric properties of Ba 6ࢬ3x R 8ࢪ2x Ti 18 O 54 solid solutions as a function of the composition x. 4,19 Similar results for Sm and Nd systems are reported by Negas et al 20 . The characteristic phenomenon is that Qɿf values varied non linearly as a function of composition, though e r and t f vary proportional to the composition.…”

Structural, dielectric and electrical analysis of Ba2−xLa4 + 2x/3Ti8O24ceramics system with frequency and temperature

“…However, those technologies have been struggled to fulfill the increasing demand for cost reduction, linearity and compactness. Recently, liquid crystals (LC) has become an interesting alternative to design tunable filters, because of its advantage in low power consumption, small cost and size reduction compared to other technologies [4]. Recent research on tunable resonators and filters based on LC are presented in [5][6][7][8][9][10], where various degrees of tunability have been quoted for various structures.…”

“…With time, rare earth metals were intentionally doped in this structure with structural formula Ba 2 2 x La 4 1 2x/3 Ti 8 O 24 [3] to have better properties. These developments included the ceramics: Ba-R 2 O 3 -TiO 2 , (Zr,Sn)TiO 4 system, BaO-TiO 4 titanium rich system, Ba (B 1/3 Ta 2/3 )O 3 (B 5 Mg, Zn) [4][5][6][7].…”