Simplified RF receive frontend architecture for active array applications

A new concept for receive front end circuits is presented, which proposes the use of the low noise amplifier (LNA) in a second role as an amplifier of the local oscillator (LO) signal. Based on this concept, much of the complexity of the active array signal distribution networks (calibration and LO) can be reduced. It is shown that the danger of saturation, intermodulation and noise degradation can be overcome by using an unbalanced active mixer circuit which requires an LO-power level compatible with the limitations of modern LNAs.