High Quality and Low Loss Millimeter Wave Passives Demonstrated to 77-GHz for SiP Technologies Using Embedded Wafer-Level Packaging Platform (EMWLP)
With the increasing demand for system integration to cater to continuously increasing number of I/Os as well as higher operating frequencies, reconfigured wafer-level packaging, or embedded WLP (EMWLP) is emerging as a promising technology for integration. This platform allows integrated passives to be designed in the redistribution layers using the mold compound as a substrate, which significantly improves the passives performance compared to those of on-chip. In this paper, we present low loss passives on EMWLP platform demonstrated in a 5.5-GHz band pass filter targeted for wireless local area network (WLAN) applications. To ascertain the feasibility of designing for low loss millimeter wave passives on EMWLP, transmission lines were designed and their loss characteristics investigated up to 110 GHz, which are reported here. Subsequently we demonstrate for the first time a narrowband low loss 77-GHz band pass filter on EMWLP platform, with a good correlation obtained between simulation and measurement results. In addition, a temperature dependence characterization was performed on the 77-GHz filter, with little variation in the measured filter characteristics observed.