A Double Quadrature Topology for High Accuracy Upconversion in CMOS Transmitters

In this paper a high performance double quadrature topology for SSB upconversion is presented. The use of the double quadrature architecture allows to achieve a sideband suppression of more than 30 dB over a 225 MHz band from 700 to 925 MHz. This corresponds to a phase and amplitude accuracy of better than 1° and 10mdB. A first order input quadrature generator in combination with a 2nd order polyphase output filter result in an effective 3rd order suppression of the unwanted quadrature errors without sensitivity to component mismatch so that no tuning or trimming is required.