Linearization of Highly-Efficient Monolithic Class E SiGe Power Amplifiers with Envelope-Tracking (ET) and Envelope-Elimination-and-Restoration (EER) at 900MHz

The linearization of highly efficient monolithic SiGe Class E power amplifiers (PAs) using both Envelope-Tracking (ET) and Envelope-Elimination-and-Restoration (EER) techniques has been studied at 900MHz. Without applying any linearization, the fully-integrated SiGe PAs achieve power-added efficiency (PAE) of 66% with no off-chip matching. The overall PAE of an ET-linearized PA system is 45% at an output power of 20dBm for an 881MHz EDGE (Enhanced Data Rate for GSM Evolution) modulated signal. The ET-linearized PAs pass the stringent EDGE transmit spectrum mask, but the EER-linearized PAs do not. The PAE of the ET system is expected to reach ~50% with further efficiency improvement on the envelope amplifier.