Low Dielectric Loss PTFE/CeO₂ Ceramic Composites for Microwave Substrate Applications

Abstract

Cerium oxide (CeO 2 ) filled polytetrafluoroethylene (PTFE) composites prepared by powder processing technique for microwave substrate application is presented in this paper. The PTFE is used as the matrix and the dispersion of CeO 2 in the composite is varied up to 0.6 by volume fraction, and the dielectric properties were studied at 1 MHz and microwave frequencies. The relative permittivity and dielectric loss increased with increase in CeO 2 content. For 0.6 volume fraction loading of the ceramic, the composite has e r of 5 and tan d of 0.0064 at 7 GHz. Different theoretical approaches have been employed to predict the effective permittivity of composite systems and the results were compared with that of experimental data. The serial mixing model shows good correlation with the experimental results.

Microwave assisted heterogeneous catalysis: effects of varying oxygen concentrations on the oxidative coupling of methane

“…When Ce 2 O 3 has a slightly lower dielectric loss factor but a higher temperature coefficient than CeO 2 [27,28], the analysis is then in line with the experimental findings which also explains why large differences in the temperature gradients are established within the catalyst when oxygen was absent.…”

Thermal properties of low loss PTFE‐CeO2 dielectric ceramic composites for microwave substrate applications

“…The dielectric loss, which is the main factor affecting the frequency selectivity of a material is influenzed by many factors, such as porosity, microstructure, and defects. 25 The coefficient of temperature variation of relative permittivity (s e ) depends on the thermal expansion coefficient of the composite according to the relation…”

“…The instrument was computer controlled and calculations were done using Pyris software. 5-10 mg of samples were sealed in aluminum pans and heated from 25 C to 600 C at rate of 5 C/min and cooled to 25 C at the same rate. Photopyroelectric technique 28,29 was used to determine the thermal conductivity of the PTFE-CeO 2 composites.…”

“…Ceria possess good dielectric and thermal properties. It has a relative permittivity of 23, dielectric loss of 0.00001 at 7 GHz, thermal conductivity of 12 W/m C and thermal expansion coefficient of 12.58 ppm/ C. [25][26][27] Anjana et al 25 reported that PTFE-CeO 2 composites possess good microwave dielectric properties useful for microwave substrate applications. The present article investigates the thermo-physical properties of PTFECeO 2 composites at room temperature for the first time to understand the thermal stability and heat transport performance.…”

Dielectric properties of modified BNT/PTFE composites for microwave RF antenna applications

“…The dielectric properties of composites depend on the size, the shape of fillers and the interaction between the two phase [23]. One important aspect regarding the design of composite materials for practical application is the prediction of dielectric constant.…”