High power GaN-FET amplifier with reduced memory effects for W-CDMA base stations

This paper describes a high power GaN-FET amplifier which is developed for wideband code division multiple access (W-CDMA) base stations. We design a bias network which is symmetrically arranged to the RF line (two way bias network) in order to reduce impedance at a baseband frequency of the multi-carrier W-CDMA signal. As a result, the amplifier with the two way bias network successfully suppressed memory effects. Therefore, the application of a DPD technique to the GaN-FET amplifier with the two way bias network demonstrates almost 20dB linearity improvement in IM3 and considerable improvement in higher order IMD, resulting in low IMD of less than -50 dBc at the highest ever reported W-CDMA average output power of 76 W.