AbstractIn this paper, fully embedded circular‐stacked spiral inductors are investigated into a multilayered PCB substrate for low cost and miniaturized RF system on package (SOP) applications. The embedded circular‐stacked inductors are optimally designed to obtain high quality factor and self‐resonant frequency by using 3D EM simulator. The fabricated two‐turn circular‐stacked inductor has an inductance of 8.4 nH and a maximum quality factor of 67 at 1.2 GHz. The device size of the staked inductor is ∼65% of the planar inductor. The measured performance characteristics are well matched with the 3D EM‐simulated ones. The embedded circular stacked spiral inductors are promising for organic‐based SOP, which needs various functionality, low cost, small size and volume, and high packaging density. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1074–1077, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI.10.1002/mop.22354