3-D Compact Marchand Balun Design Based on Through-Silicon via Technology for Monolithic and 3-D Integration

An original concept of 3-D through-silicon via (TSV)-based Marchand baluns and its design methodology is proposed for =on-chip and 3-D integration. By utilizing a 3-D packaging process that includes a TSV and redistribution layer (RDL), a meander coupling path is established and embedded in the vertical direction of the substrate for balun design. The 3-D structure can effectively reduce the =on-chip area while maintaining good balance characteristics. Furthermore, the structure can be flexibly integrated with 3-D integrated circuits (3-D ICs) to realize signal conversion between different stacking tiers. An equivalent circuit model based on the TSV-to-TSV coupling channel and coupled transmission line has been established for initial estimation before electromagnetic (EM) optimization. To shorten the design cycle, a specific flow is proposed to meet the structural particularity and different application scenarios. To verify the design method and flow, a design case is analyzed and EM simulated with the antenna feeding network as the target application. The EM simulation results show that the design can work at 43-82 GHz with an amplitude imbalance of less than 0.3 dB and a phase imbalance of less than 1.3 degrees, which meets the requirements of balanced feeding. It only costs a $0.084 lambda_{g}{x}0.009 lambda_{g}$ footprint, which is far lower than that of the conventional planar types.