Volterra series approach to behavioral modeling: Application to an FET amplifier

In this paper nonlinearities due to FET amplifiers are described by using a novel behavioral modeling approach. While our proposed method requires the identification of delays and coefficients like in a standard diagonal memory polinomial model, the importance of out-of-diagonal terms is emphasized if the amplifier exhibits memory effects. Furthermore, the different terms, delays and coefficients are shown to be related to Volterra kernels. In order to validate this approach a HEMT amplifier has been constructed and characterized with W-CDMA signals at diverse symbol rates and input levels. The predictions obtained with the proposed model demonstrate a very good agreement with experimental results and have been compared with a diagonal memory polynomial model.