Independently controllable 3/sup rd/- and 5/sup th/-order analog predistortion linearizer for RF power amplifier in GSM

An individually controllable 3/sup rd/-order intermodulation (IM3) and 5/sup th/-order intermodulation (IM5) predistortion linearizer for RF power amplifiers of band-type global system of mobile (GSM) repeaters is proposed. In order to effectively improve the linearity of RF power amplifiers, the IM3 and the IM5 powers are canceled by the predistortion circuit, which independently controls amplitude and phase of the IM3 and the IM5. The fabricated predistorter linearizes the power amplifier at 940 MHz. The IMD3 and the IMD5 suppressions of 30 dB and 26 dB, respectively, are achieved with an average power of 33 dBm for the GSM repeaters.