Silicate dielectric ceramics for millimetre wave applications

TL;DR

This review discusses the potential of silicate ceramics as high-performance millimetre wave dielectrics, emphasizing their microstructural properties, dielectric performance, and processing methods for future applications.

Contribution

It provides a comprehensive summary of silicate ceramics' dielectric properties and critically evaluates their suitability and processing techniques for millimetre wave applications.

Findings

High quality factors and low permittivities in silicate ceramics

Microstructure and SiO4 connectivity influence dielectric losses

New processing routes enable lower temperature fabrication

Abstract

Silicate ceramics are of considerable promise as high frequency dielectrics in emerging millimetre wave applications including high bandwidth wireless communication and sensing. In this review, we show how high quality factors and low, thermally stable permittivities arise in ordered silicate structures. On the basis of a large number of existing studies, the dielectric performance of silicate ceramics is comprehensively summarized and presented, showing how microstructure and SiO4 tetrahedral connectivity affect polarizability and dielectric losses. We critically examine the appropriateness of silicate materials in future applications as effective millimetre wave dielectrics with low losses and tuneable permittivities. The development of new soft chemistry based processing routes for silicate dielectric ceramics is identified as being instrumental towards the reduction of processing temperatures, thus enabling silicate ceramics to be co-fired in the production of components functioning in the mm wave regime.