A passive magnetic device (PMD) has a base electrode, a multi-port signal structure (MPSS), and a substrate therebetween. The MPSS has a central plate residing in a second plane and at least two port tabs spaced apart from one another and extending from the central plate. The substrate has a central portion that defines a mesh structure between the base electrode and the central plate of the multi-port signal structure. A plurality of magnetic pillars are provided within the mesh structure, wherein each of the plurality of the magnetic pillars are spaced apart from one another and surrounded by a corresponding portion of the mesh structure. The PMD may provide a magnetically self-biased device that may be used as a radio frequency (RF) circulator, an RF isolator, and the like.