Microwave dielectric ceramic and preparation method thereof

The invention provides microwave dielectric ceramic. The microwave dielectric ceramic comprises compound oxide; the compound oxide has a general formula shown as follows: Ba2-xSm4+2/3xTi9-yMnyO26, wherein x is greater than or equal to 0 and less than or equal to 0.32 and y is greater than or equal to 0 and less than or equal to 0.02. Compared with the prior art, the microwave dielectric ceramic provided by the invention takes the compound oxide shown as the specific general formula as a main body material, the dielectric constant can be adjusted in a range of 73 to 80 through adjusting the content of Sm and the frequency-temperature coefficient is continuously adjustable; on one hand, Ti is replaced with less Mn and is used as an acceptor for doping; on one hand, the radius of an Mn atom is slightly greater than the Ti; when the Mn is added, a space structure can be stabilized and the Q*f value is improved; on the other hand, the reduction of the Ti is inhibited by utilizing valence alternation of the Mn in a