Feedthrough cancellation in a class E amplified polar transmitter. - Simo Hietakangas; Timo Rautio; Timo Rahkonen (ECCTD, 2007)

Envelope tracking power amplifier with static predistortion linearization. - Timo Rautio; Henri Harju; Simo Hietakangas; Timo Rahkonen (Int. J. Circuit Theory Appl., 2009)

AM-PM distortion caused by transistor's signal-dependent input impedance. - Timo Rahkonen; Simo Hietakangas; Janne Aikio (ECCTD, 2011)

1.8 W, 19 MHz envelope amplifier for envelope tracking and envelope elimination and restoration. - Simo Hietakangas; Mikko Hietanen; Timo Rahkonen (NORCHIP, 2013)