“…Low‐permittivity (ε r < 15) silicate microwave dielectric ceramics such as M 2 SiO 4 ( M = Ba, Zn, Mg, Co, and Ni), (Sr 1‐ x A x ) 2 (Zn 1‐ x B x )Si 2 O 7 ( A = Ca, Ba and B = Co, Mg, Mn, Ni), M Al 2 Si 2 O 8 ( M = Ba, Sr, and Ca), Mg 2 Al 4 Si 5 O 18 , Sr 2 Al 2 SiO 7 , and LiRe 9 (SiO 4 ) 6 O 2 (Re = rare earth elements), have attracted considerable scientific attention because they can be used for various applications, such as high‐frequency substrates, wave‐transparent windows, dielectric antennas, high‐accuracy capacitors, and millimeter‐wave components. Low‐permittivity can reduce reflection at the interface between air and dielectrics, minimize cross‐coupling with conductors, and shorten the time for electronic signal transition .…”