Novel vertical interconnects with 180 degree phase shift for amplifiers, filters, and integrated antennas

In this paper, novel low loss, wide bandwidth, compact coplanar stripline/coplanar waveguide vertical interconnects with 180/spl deg/ phase shift and vertically interconnected baluns for RF/microwave integrated circuits are demonstrated. The interconnects and baluns are fabricated on high resistivity silicon wafers with a thin layer of spin-on glass as an insulator between the buried and the elevated strip conductors which are interconnected by microvias. The measured and simulated characteristics of these interconnects are presented and they show that very compact, low loss and wide bandwidth circuits are feasible with this technology. This technology has the potential to significantly enhance the performance of amplifiers, filters, and integrated antennas in Si-SiGe based RF/microwave ICs.