A package structure includes a semiconductor die, an insulating encapsulant, a first redistribution layer, a second redistribution layer, antenna elements and a first insulating film. The insulating encapsulant is encapsulating the at least one semiconductor die, the insulating encapsulant has a first surface and a second surface opposite to the first surface. The first redistribution layer is disposed on the first surface of the insulating encapsulant. The second redistribution layer is disposed on the second surface of the insulating encapsulant. The antenna elements are located over the second redistribution layer. The first insulating film is disposed in between the second redistribution layer and the antenna elements, wherein the first insulating film comprises a resin rich region and a filler rich region, the resin rich region is located in between the filler rich region and the second redistribution layer and separating the filler rich region from the second redistribution layer.