Three-dimensional (3-D) volumetric board architectural design provides technical solutions to technical problems facing miniaturization of circuit boards. The 3-D volumetric architecture includes using more of the unused volume in the vertical dimension (e.g., Z-dimension) to increase the utilization of the total circuit board volume. The 3-D volumetric architecture is realized by mounting components on a first PCB and on a second PCB, and inverting and suspending the second PCB above the first PCB. The use of 3-D volumetric board architectural design further enables formation of a shielded FEMIE, providing shielding and improved volumetric use with little or no reduction in system performance or increase in system Z-height.