A CMOS adaptive RF front-end receiver for wireless applications

Design and implementation of an image-rejection double-quadrature radio frequency front-end receiver based on tunable polyphase filters (PPF) are presented in this article. The front-end consists of two sets of PPFs and a double-quadrature down-converter. The design contains devices that allow process spread and frequency drift control, making it suitable for multi-standard applications. Formal analysis and statistical method leading to the polyphase filter optimal sizing have been dealt with in this article. The effects of parasitic capacitances and component mismatch are also considered and discussed. Steps within CMOS polyphase filter design flow are then provided to guarantee high image rejection ratio (IRR) performance. The front-end receiver exhibits more than 60 dB IRR and good linearity in high-frequency applications.