A novel CPW-to-stripline vertical via transition using a stagger via structure and embedded air cavities for V-band LTCC SiP applications

We present a novel LTCC CPW-to-stripline (SL) vertical via transition utilizing a novel stagger via (STV) structure and embedded air cavities for 60 GHz system-in-package (SiP) applications. In order to minimize radiation due to abrupt via discontinuity, the STV structure and the air cavities are proposed and implemented in the vertical via transition. The fabricated three-segment transmission line (CPW-SL-CPW) composed of the new vertical via transitions achieves an insertion loss of 1.6 dB and return losses below -10 dB over 60 GHz. The transition loss per STV transition is 0.7 dB at 60 GHz.