Cold sintering of microwave dielectric ceramics and devices

Microwave (MW) dielectric ceramics are used in numerous electronic components for modern wireless communication systems, including antennas, resonators, capacitors and filters. However, to date, MW ceramics are manufactured by an energy-intensive, conventional high-temperature (> 1000 degrees C) sintering technology and thus cannot be co-sintered with low melting point and base electrodes (Ag, Al, etc., < 1000 degrees C), nor directly integrated with polymers (< 200 degrees C). Cold sintering is able to densify ceramics at < 200 degrees C via a combination of external pressure and a transient liquid phase, reducing the energy consumed and facilitating greater integration with dissimilar materials. This review outlines the basics of MW ceramics alongside the mechanism of cold sintering. Recent developments in cold sintering of MW ceramics, composites and devices are described, emphasizing new materials and progress towards component/device fabrication. Future prospects and critical issues for advancing cold-sintered MW materials and devices, such as unclear mechanism, low Q x f values and poor mechanical properties, are discussed.

Automated summary

MW dielectric ceramics are essential for electronic components in wireless communication systems, but traditional high-temperature sintering methods limit their integration with other materials. Cold sintering, a process at lower temperatures, offers energy-efficient densification and better compatibility with diverse materials. Current research focuses on improving cold-sintered MW materials and devices, addressing challenges like unclear mechanisms and poor mechanical properties.