Ba 5 Li 2 W 3 O 15 : A New Li ‐Containing Perovskite‐Type Microwave Ceramic with High Q and Low τ f

A new Li ‐containing microwave ceramic Ba 5 Li 2 W 3 O 15 with hexagonal perovskite structure was prepared through a solid‐state ceramic route. Small amount of scheelite BaWO 4 appeared as a second phase during sintering. The Ba 5 Li 2 W 3 O 15 could be well densified at 1120°C and exhibits good microwave dielectric properties with permittivity (ε r ) of 25.4, high Q  ×  f value about 39 000 GHz, and low temperature coefficient of resonate frequency (τ f ) of 10 ppm/°C. The addition of BaCu ( B 2 O 5 ) can effectively lower the sintering temperature from 1120°C to 900°C and does not induce degradation of the microwave dielectric properties. These results indicate that the Ba 5 Li 2 W 3 O 15 ceramic might be a promising candidate in microwave dielectric resonators.