ADistributed Linearization Technique forMultistage HighPower Amplifiers

Thepaperdescribes alinearization technique applicable tocascaded multidevice poweramplifiers. Itis basedondistributed amplification andsignal injection andis particularly suitable formonolithic integrated solutions. It exploits thebiasdependence ofthetransconductance, but focuses ontheIMD products andtheir controlled generation and cancellation, ratherthan on the shapeof the transconductance and itsderivatives. The technique is capable ofpositively influencing thelinearity, including the nearback-off powerrangeprior to1dBcompression point. 30W monolithic PA isdesigned andfabricated using Philips 4 Gen LDMOS MMIC process. Simulation and measurement results areingoodagreement. 8-10dBIMD3 improvement isobserved under2-tone conditions and5-6dB ACLR andIMD3reduction with2C-WCDMAsignal.