Controllable τ _f value of barium silicate microwave dielectric ceramics with different Ba/Si ratios

Abstract

Abstract Ba 1+1/ M [Si 2 O 5+1/ M ] low‐permittivity microwave dielectric ceramics are prepared using the conventional solid‐state method. Pure phases are obtained in barium silicates with M = 1, 3, 4, 5, and ∞, except for M = 7, in which two phases, Ba 5 Si 8 O 21 and BaSi 2 O 5 , are observed. As the complexity of the crystal structure described by the Shannon information per reduced unit cell increases, the τ f value tends to change from a negative to a positive value, except for M = 5, which has the highest complexity. A single Ba 5 Si 8 O 21 phase with ε r anomaly peak at −180°C exhibits a rare positive τ f value (+25 ppm/°C), which is a novel temperature compensator.