Electronics packaging evolution involves both systems, technology & materials considerations. In this paper, we present a novel 3D integration approach for system-on-package (SOP) based solutions for wireless communication applications. This concept is proposed for the 3D integration of a C band Wireless LAN (WLAN) RF front-end module by means of stacking LCP (Liquid Crystal Polymer) substrates using µBGA technology. LCP substrates fabrication, high Q inductor design and the associated physical based modeling are detailed. Then stacking techniques using µBGA technology is presented. Characterization and modeling of RF vertical board-to-board transition, using µBGA process are detailed and show that this vertical transition is suitable for C-band wireless communication applications.