Forward behavioral modeling of concurrent dual-band power amplifiers using extended real valued time delay neural networks

The distortions induced by inter-modulations and cross-modulations in concurrent dual-band power amplifiers (PAs) are evidenced and characterized using multi-tone signals. Given the presence of cross-modulations, a comprehensive extended real-valued time-delay neural network (extended-RVTDNN) is proposed to model the nonlinear behavior of concurrent dual-band Pas. Two three-carrier WCDMA signals are applied to a dual-band Doherty PA prototype for modeling verification. The experimental results show that the proposed model approximates the PA with normalized mean square errors (NMSEs) of -38.48dB and -35.42dB in the lower and upper bands, respectively. Compared with the conventional single-band RVTDNN, this new method achieves an improvement in accuracy of more than 10dB.