A semiconductor package is provided. The semiconductor package includes a semiconductor die, a stack of polymer layers, redistribution elements and a passive filter. The polymer layers cover a front surface of the semiconductor die. The redistribution elements and the passive filter are disposed in the stack of polymer layers. The passive filter includes a ground plane and conductive patches. The ground plane is overlapped with the conductive patches, and the conductive patches are laterally separated from one another. The ground plane is electrically coupled to a reference voltage. The conductive patches are electrically connected to the ground plane, electrically floated, or electrically coupled to a direct current (DC) voltage.