Patent attributes
A method includes forming a first metal plate, forming a metal ring aligned to peripheral regions of the first metal plate, and placing a device die level with the metal ring, encapsulating the device die and the metal ring in an encapsulating material. The method further includes filling a dielectric material into a space encircled by the metal ring, and forming a second metal plate covering the dielectric material and the metal ring, with an opening formed in the second metal plate. A plurality of redistribution lines is formed, with one of the redistribution lines overlapping a portion of the opening. The first metal plate, the metal ring, the second metal plate, and the dielectric material in combination form an antenna or a waveguide. The redistribution line forms a signal-coupling line of the passive device.