Characterization of metal (Fe, Co, Ni, Cu) and fluorine codoped barium strontium titanate thick-films for microwave applications

Abstract

The influence of codoping of Fe, Co, Ni, Cu as acceptors and F as donor on the dielectric properties of screen-printed Ba 0.6 Sr 0.4 TiO 3 ceramic thickfilms has been investigated. The undoped and codoped Ba 0.6 Sr 0.4 TiO 3 powders were synthesized through a solgel route. The thermal gravimetric analysis revealed the difference of the thermal decomposition behaviour between the undoped and codoped precursors. The ceramic powders were characterized with x-ray diffraction, scanning electron microscopy and BET measurements. Larger crystallite sizes of the codoped powders were observed. The densification behaviour of the powders was recorded by dilatometry and indicated that codoping influences the sintering mechanism. The permittivity, dielectric loss and tunability of the undoped and codoped thick-films were characterized with coplanar waveguide structures up to 30 GHz.

Structural and multiferroic properties of Fe-doped Ba0.5Sr0.5TiO3 solids

“…BST thin films have also been widely investigated for microwave applications such as phase shifters, tunable filters, tunable resonators, and switches [26][27][28][29][30]. Metal ion-doped BST samples, including thin films and ceramics, have also been investigated [31][32][33][34][35][36][37][38]. Especially, concerning Fe-doped Ba x Sr 1 À x TiO 3 samples, the overwhelming majority focus on BSTF thin films [34][35][36][37][38].…”

“…Metal ion-doped BST samples, including thin films and ceramics, have also been investigated [31][32][33][34][35][36][37][38]. Especially, concerning Fe-doped Ba x Sr 1 À x TiO 3 samples, the overwhelming majority focus on BSTF thin films [34][35][36][37][38]. One typical example is the fact that Fe doping of BST films is remarkably effective in suppressing decreasing dielectric constant, and BST films show a minimum dielectric loss with varied Fe doping concentration [34].…”

Implementation of Ba0.6Sr0.4TiO3‐ZnO‐B2O3 based tunable microwave phase shifters in LTCC technology

“…As composite system, Cu‐F‐codoped BST with 5 vol.% ZnO‐H 3 BO 3 as additive system was selected. First, Cu‐F‐codoped BST powder with a nominal composition of Ba 0.6 Sr 0.4 Ti 0.99 Cu 0.01 O 3−x F 0.09 was prepared based on a modified sol‐gel process . This powder was mixed with 5 vol.% of ZnO‐H 3 BO 3 as additive system and ball‐milled with zirconia grinding media.…”

VSWR protection of power amplifiers using BST components

“…The ratio of Barium to Strontium, as well as addition of doping materials are used to control several properties of BST such as ε r , tunability, sintering temperature and dielectric losses. Possible additives are ZnO-B 2 O 3, Fe-F or Cu-F [12].…”