Preparation of ZnAl2O4-based microwave dielectric ceramics and GPS antenna by aqueous gelcasting

A novel forming method-aqueous gelcasting was used to prepare 90 wt.% (0.75ZnAl2O4–0.25TiO2)–10 wt.% MgTiO3 (ZTM) microwave dielectric ceramics and GPS antenna. The effects of aqueous gelcasting and dry pressing on the phase compositions, microstructures and microwave dielectric properties of ZTM ceramics were investigated. The samples’ cracking problem happening in the process of drying and binder removal was successfully overcome. The phase compositions are completely the same no matter what forming method is adopted, but the ZTM ceramics prepared by aqueous gelcasting are denser than that prepared by dry pressing. Fewer pores and more uniform microstructures are observed in the ZTM ceramics prepared by aqueous gelcasting. Therefore, much better microwave dielectric properties are obtained in the ZTM ceramics prepared by aqueous gelcasting. Finally, a GPS antenna was successfully fabricated by aqueous gelcasting using the ZTM material, which meets the requirements of GPS application.

The effects of aqueous gelcasting and dry pressing on the phase compositions, microstructures and microwave dielectric properties of 90 wt.% (0.75ZnAl2O4–0.25TiO2)–10 wt.% MgTiO3 (ZTM) ceramics were investigated, and a large dimension GPS antenna was also successfully fabricated by aqueous gelcasting.Figure optionsDownload as PowerPoint slideHighlights
► The cracking problem happening in the fabrication of devices prepared by aqueous gelcasting was overcome.
► The phase compositions are completely the same no matter what forming method is adopted.
► Fewer pores and more uniform microstructures were observed in the ZTM ceramics prepared by aqueous gelcasting.
► ZTM ceramics prepared by aqueous gelcasting exhibit more excellent microwave dielectric properties.
► A large dimension GPS antenna was fabricated by aqueous gelcasting using the ZTM material.