Low-loss ultralow-dielectric-constant aluminate microwave dielectric ceramics

The invention discloses low-loss ultralow-dielectric-constant aluminate microwave dielectric ceramics. The low-loss ultralow-dielectric-constant aluminate microwave dielectric ceramics are characterized by chemically comprising SmBi4Al3O12. A preparation method of the microwave dielectric ceramics includes the steps of (1) weighing and compounding above 99.9% (by weight) original powder of Sm2O3, Bi2O3 and Al2O3 according to the SmBi4Al3O12; (2), subjecting the raw materials in the step (1) to wet-type ball milling and mixing for 12 hours, drying and presintering for 6 hours at 1,000 DEG C in the air atmosphere, wherein absolute ethyl alcohol serves as a ball milling medium; (3), adding a binder into powder prepared in the step (2) prior to pelletizing prior to pressing formation, and sintering for 4 hours at 1,050-1,100 DEG C in the air atmosphere, wherein the binder refers to a 5% (by mass) polyvinyl alcohol solution, and the addition amount of polyvinyl alcohol accounts for 3% of the total mass of the powd