Asymmetric multilevel outphasing architecture for multi-standard transmitters

We describe a new outphasing transmitter architecture in which the supply voltage for each PA can switch among multiple levels. It is based on a new asymmetric multilevel outphasing (AMO) modulation technique which increases overall efficiency over a much wider output power range than the standard LINC system while maintaining high linearity. For demonstration, the overall transmitter is simulated in a 65 nm CMOS process with HSUPA and WLAN signals. The simulation results show an efficiency improvement from 17.7% to 40.7% for HSUPA at 25.3 dBm output power and from 11.3% to 35.5% for WLAN 802.11g at 22.8 dBm while still meeting system linearity requirements.