Low loss finite width ground plane, thin film microstrip lines on Si wafers

Abstract

Si RFICs on standard, 2 /spl Omega/-cm Si wafers require novel transmission lines to reduce the loss caused by the resistive substrate. One such transmission line is commonly called thin film microstrip (TFMS), which is created by depositing a metallic ground plane, thin insulating layers, and the microstrip lines on the Si wafer. Thus, the electric fields are isolated from the Si wafer. In this paper, it is shown through experimental results that the ground plane of TFMS may be finite width and comparable to the strip width in size while still achieving low loss on 2 /spl Omega/-cm Si. Measured effective permittivity shows that the field interaction with the Si wafer is small.