Analog Pre-Distortion Linearizer Using Self Base Bias Controlled Amplifier

Shintaro SHINJO  Kazutomi MORI  Keiki YAMADA  Noriharu SUEMATSU  Mitsuhiro SHIMOZAWA  

IEICE TRANSACTIONS on Electronics   Vol.E93-C    No.7    pp.966-974
Publication Date: 2010/07/01
Online ISSN: 1745-1353
DOI: 10.1587/transele.E93.C.966
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Recent Progress in Microwave and Millimeter-Wave Technologies)
distortion,  envelope,  linearizer,  microwave,  power amplifier,  silicon,  

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An analog pre-distortion linearizer employing a radio frequency (RF) transistor with a self base bias control circuit is proposed. The self base bias control circuit extracts the envelope from the modulated input RF signal of the RF transistor and automatically controls its base current according to the extracted envelope. As a result, the proposed linearizer realizes positive gain deviation at high input power level. By adding a resistor between the RF transistor and the self base bias control circuit, the negative gain deviation can be derived. The design of the proposed lineaizer is described with taking the envelope frequency response of the self base bias control circuit into consideration. The fabricated linearizer achieves the adjacent channel power leakage ratio (ACLR) improvement of 8.1 dB for a 2 GHz-band, 10 W-class GaAs FET high-power amplifier (HPA) with negative gain deviation for W-CDMA base stations. It also achieves the ACLR improvement of 8.3 dB for a LDMOS HPA with positive gain deviation for the same application.