Feedforward Power Amplifier Control Method Using Weight Divided Adaptive Algorithm

Kenichi HORIGUCHI  Atsushi OKAMURA  Masatoshi NAKAYAMA  Yukio IKEDA  Tadashi TAKAGI  Osami ISHIDA  

IEICE TRANSACTIONS on Electronics   Vol.E86-C    No.8    pp.1494-1500
Publication Date: 2003/08/01
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Microwave and Millimeter Wave Technology)
normalized least mean square,  adaptive algorithm,  feedforward,  power amplifier,  microwave,  

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Weight divided adaptive control method for a microwave FeedForward Power Amplifier (FFPA) is presented. In this adaptive controller, an output signal of a power amplifier is used as reference signal. Additionally, reference signal is divided by the weight of adaptive filter, so that characteristics of the power amplifier, such as temperature dependence, do not have influence on the convergence performances. The proposed adaptive algorithm and the convergence condition are derived analytically and we clarify that the proposed weight divided adaptive algorithm is more stable than the conventional Normalized Least Mean Square (NLMS) algorithm. Then, the convergence condition considering phase calibration error is discussed. The effectiveness of the proposed algorithm are also verified by the nonlinear simulations of the FFPA having AM-AM and AM-PM nonlinearity of GaAsFET.