  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.
