Free Space Vertical Interconnects Using Near Field Coupling Antennas in a Fabry-Perot Cavity Environment
Vertical interconnects (or vias) are used extensively with the aggressive scaling of device geometries and to obtain more performance from a limited area in 3D integrated systems. As circuit layers increase, so do fabrication challenges and high frequency performance degradation with vias. A novel low loss free space vertical interconnect is proposed using Fabry-Perot-Cavity antenna system in the near field. A 12GHz design is demonstrated that couples signal between two patch antennas through a frequency selective surface (FSS). The design has an insertion loss of 1.34dB and is close to the insertion loss (0.8dB) of a though line. When compared to a 2 layer microstrip line with metal vias, the proposed solution’s insertion loss is 2.64dB lower. In summary, this novel system offers low loss and isolation in an approach that is scalable for use in higher frequency applications (i.e. 60GHz or 5G) where excessive loss is prohibitive.