Effects of Sintering Behavior, Structure, Packing Fraction, and Bond Valence on the Microwave Dielectric Properties of Low-Permittivity Na2Ba6Si4O15 Ceramics

Low-permittivity microwave dielectric ceramics could improve the transmission rate of devices. It is important to explore low-permittivity materials with excellent performances. In this paper, a low-permittivity microwave dielectric ceramic Na2Ba6Si4O15 (NBSO) was prepared by a solid-state reaction method. NBSO ceramics belong to a monoclinic system (space group: P2(1)/c). With the increase of sintering temperature, the bulk density and relative density of ceramics also increases. The Q x f is explained by analysis of the packing fraction of NBSO ceramics. When the sintering temperature was 975 degrees C, the packing fraction of the NBSO ceramic reached the maximum values of 57.38%. At the same time, the Q x f value of NBSO reaches its maximum. In addition, the tau(integral) value is affected by bond valence. The NBSO ceramic has good microwave dielectric performances of epsilon(r) = 8.81, Q x f = 26,346 GHz, tau(integral) = - 9.21 ppm/degrees C) and a low sintering temperature, indicating that it is a strong candidate in the field of low-temperature co-firing technology and has good application prospects in the field of mobile communication base stations.