Design methodology for the optimization of transformer-loaded RF circuits

In this paper, a design methodology for the optimization of transformer-loaded RF circuits is presented. The optimization procedure is based on a novel figure of merit for the integrated transformer (namely the transformer characteristic resistance), which was introduced to quantify its performance when operated as a tuned load. Using the proposed approach, a highly linear up-converter for 5-GHz wireless LAN applications was implemented in a 45-GHz-f/sub T/ SiGe HBT technology. The circuit achieved an output 1-dB compression point of 4.5 dBm and a power gain of 18 dB, while drawing only 34 mA from a 3-V power supply.