Prediction of smart antenna transmitter characteristics using a new behavioral modeling approach

A new technique for analysis of nonlinear effects in smart antenna array transmitter systems is presented. The analysis is founded on a new type of dual-input circuit behavioral model which allows nonlinear effects caused by antenna mutual-coupling and mismatch to be predicted under realistic wideband signal excitations. The model formulation enables direct interface with multi-port antenna S-parameters and detailed prediction of radiated field characteristics. The method is validated by over-the-air WCDMA measurements on a dual-antenna 2.14 GHz MIMO transmitter. The results demonstrate that antenna mutual coupling may lead to significant nonlinear distortion that cannot be compensated for by conventional linearization techniques.