Dielectric performance of composites of BaTiO₃ and polymers for capacitor applications under microwave frequency

Abstract

Composites of nano‐sized barium titanate (BaTiO3) with volume fractions up to 0.5 and poly(butylene terephthalate) (PBT) or linear low‐density polyethylene (LLDPE) were made via extrusion. Scanning electron microscopy demonstrated that BaTiO3 is well dispersed in the polymer matrices. The crystalline content (DSC) and thermal stability (TGA) of both polymers decreased with increasing BaTiO3 loading. Dielectric properties of the composites were measured using a vector network analyzer. Both dielectric permittivity and tangent loss increased with increasing BaTiO3 content. At 2.45 GHz, the dielectric permittivity for 48 vol% BaTiO3‐filled LLDPE and 43 vol% BaTiO3‐filled PBT was 25 and 21.2, respectively. There was a good fit between the Lichtenecker model and experimental data obtained up to a certain value, with the permittivity variations being dependent on volume fraction. The improved dielectric performance achieved on inclusion of BaTiO3 confirms both composite systems as potential candidates for microwave frequency capacitor applications.

Dielectric Characterization of Heterogeneous Composites Using Time Domain Spectroscopy and Microwave Test Benches in Microwave Frequency

“…It has been noted that the dielectric permittivity increases with an increase in the volume fraction of barium titanate. The same behavior was observed in 14,18,52 which are binary and ternary composites based on barium titanate and other materials. The graph shows that the experimental results follow a similar pattern and match those of the empirical models.…”

“…12,13 The composites dielectric characteristics depend on several parameters such as permittivity and electrical conductivity of the composite phases as well as the volume fraction size and distribution in the polymer matrix. 14 Recent ceramics and polymers are the first good quality insulators. Currently, dielectrics are the focus of many studies for microwave applications, such as tunable dielectric resonators or phase shifters.…”

Dielectric Properties of BaTiO3–Epoxy Nanocomposites in the Microwave Regime

“…Polymers doped with conductive fillers, such as graphene [ 11 ], silver [ 12 ] or other metals [ 13 ], are able to increase the dielectric constant drastically, but at the expense of low compatibility with printed circuit boards (owing to large leakage current) and high signal attenuation (due to severe Ohmic loss). On the other hand, ferromagnetic dopants, e.g., Fe 3 O 4 [ 14 ], and ferroelectric dopants such as PZT [ 15 ], TiO 2 [ 16 , 17 , 18 ], SrTiO 3 [ 19 ], BaTiO 3 [ 3 , 4 , 5 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 ] or other oxides [ 17 , 18 ], are also good candidates. BaTiO 3 –polymer composites have attracted great attention among various combinations due to their high- k properties with high mechanical tunability and thermal stability.…”

Enhanced dielectric properties and energy storage performances by selectively distributed BaTiO3 in polyvinylidene fluoride/low‐density polyethylene blends

“…Polyethylene (PE) is widely used in the fields of electrical and electronic systems due to its excellent insulation properties, low dielectric loss, good processability, and relatively low cost. [1][2][3] In view of its low dielectric constant, PE faces great challenges in the applications as dielectric materials. 4 By incorporating dielectric fillers, the dielectric constant of the PE-based composites can be increased significantly.…”