A Method for Measuring Substrate Noise in the UWB Frequency Band on Lightly Doped Substrates

摘要

A measurement method for characterizing the substrate noise over the ultra-wideband(UWB) frequency band in UWB systems implemented using lightly doped CMOS processes is presented. The measurement structure in this method is based on modified ground-signal-ground (GSG) pads. In addition, the effects of the distance-based substrate resistance and the capacitive coupling between the substrate and the ground of the measurement setup are evaluated by on-wafer measurement of a test chip fabricated in a 0.18μm lightly doped CMOS process. An equivalent circuit model of the presented measurement structure is given and shows accurate fit. From the measurement results the presented method is shown to provide a measurement band from 3GHz to 10GHz. To further validate the usability of the method a practical class-E PA is used.