2D multisine mapping for robust 2 band PA modeling and 2D predistorter extraction

This paper is concerned with the behavioral modeling and predistortion of power amplifiers used with discontinguous multi-band signals with wide band separation. A new 2D multisine excitation signal is proposed to assist with the system identification of such PAs. The experimental application of this new 2D multisine excitation to a GaN HEMT PA reveals that the normalized PA outputs of both band saturates for approximately a unity average combined output envelope power leaving half of the 2D output state space unmapped. The physical origin of the phenomena is briefly discussed. This saturation property suggests in turns that the Zernike polynomials may be profitably applied to the identification of the predistorter gain functions when using spline representation.