Journal Article

Tailoring and Fabricating Temperature-Stable ZnNbsub.2Osub.6-Casub.0.5Srsub.0.5TiOsub.3 Composite Ceramics for Next-Generation Microwave Components

Wang, Haodong, Peng, Zhijian, Fu, Xiuli, Chen, Chuying

2025

Overview

What are the main findings? * Novel ZnNb[sub.2]O[sub.6]-Ca[sub.0.5]Sr[sub.0.5]TiO[sub.3] composite ceramics were designed. * Compositional effect was systematically investigated. * Optimum sintering system was established. * Temperature-stable microwave ceramics were obtained. Novel ZnNb[sub.2]O[sub.6]-Ca[sub.0.5]Sr[sub.0.5]TiO[sub.3] composite ceramics were designed. Compositional effect was systematically investigated. Optimum sintering system was established. Temperature-stable microwave ceramics were obtained. What are the implications of the main findings? * Theoretical guide and material support for designing and fabricating high-performance thermally stable microwave dielectric ceramics for future communication technologies. Theoretical guide and material support for designing and fabricating high-performance thermally stable microwave dielectric ceramics for future communication technologies. ZnNb[sub.2]O[sub.6]-based microwave dielectric ceramics have attracted considerable attention due to their high quality factor (Q × f) and low sintering temperature, but their application was limited by poor temperature stability with a large negative temperature coefficient of resonant frequency (τ[sub.f]). Herein, novel (1 − x)ZnNb[sub.2]O[sub.6−x]Ca[sub.0.5]Sr[sub.0.5]TiO[sub.3] (x = 0.05–0.125) composite ceramics were designed and fabricated. The used ZnNb[sub.2]O[sub.6] and Ca[sub.0.5]Sr[sub.0.5]TiO[sub.3] were synthesized through solid-phase reaction by using stoichiometric metal oxides or carbonates as the raw materials at 650 and 1100 °C, respectively. The composite ceramics were prepared by solid-state sintering, and the sintering parameters were optimized at 1175 °C for 4 h by visual high-temperature deformation analysis. A focus was paid on the temperature stability and compositional effects of Ca[sub.0.5]Sr[sub.0.5]TiO[sub.3] of the obtained composited ceramics. As the Ca[sub.0.5]Sr[sub.0.5]TiO[sub.3] content increases, the dielectric constant (ε[sub.r]) and Q × f gradually decrease, while τ[sub.f] shifts toward positive values. At x = 0.075, the composite ceramics sintered at 1175 °C for 4 h exhibit near-zero τ[sub.f] (−8.99 ppm/°C), coupled with ε[sub.r] = 23.23 and Q × f = 21,686 GHz. This study provides theoretical guide and material support for designing and fabricating various high-performance thermally stable microwave dielectric ceramics for 5G communication devices and future communication technologies.

• Publisher: MDPI AG
• Subject: Electric properties / Microwave communications / Microwave devices / Raw materials / Sintering