Design of a Configurable Complex IF Receiver Supporting LTE Carrier Aggregation

A design methodology based on close interaction between algorithm development and analog implementation is used to develop a configurable complex IF receiver front-end with 60 dB image rejection ratio (IRR). To achieve this high IRR, calibration of the IQ-mismatch is needed. By using statistical link simulations, feasible analog components for calibration are determined and the corresponding required calibration ranges and resolutions are found. In a wideband system, as considered here, both frequency dependent and frequency independent IQ-mismatch are treated. The results from the statistical simulations are based on optimum calibration parameters, and agree very well with those achieved with the implemented algorithm, confirming that 60 dB image rejection ratio is achieved.