Compact Wideband Balun Design Using Dual RDL Glass-Based Integrated Passive Device Technology

A compact wideband balun based on dual redistribution layer (D-RDL) glass-based integrated passive device (IPD) technology is presented in this work. A novel up-down placement structure is proposed and analyzed. The adoption of the structure reduces the coupling effect between inductors while enabling chip miniaturization. Moreover, a modified balun circuit topology incorporating phase compensation structures is proposed to achieve wideband and good phase imbalance performance. The proposed balun utilizing the novel up-down placement structure has a chip size of 1.35 mm × 1.35 mm, representing about 32.5% size reduction compared to the traditional planar placement structure. Performance-wise, the balun achieves a relative bandwidth of 91.89% with amplitude and phase imbalance below 1.20 dB and 7.86°, respectively. The simulation and measured results show good consistency.