High Efficiency WCDMA Power Amplifier for MUOS Handheld Radio

The Mobile User Objective System (MUOS) is an ultra high frequency (UHF) geosynchronous satellite communication (SATCOM) system based on commercial 3G Universal Mobile Telecommunications System (UMTS) and Wideband Code Division Multiple Access (WCDMA) architecture. A well-known characteristic of MUOS signal is its “notch” in the middle of spectrum, which requires a highly-linear transmitter. Warfighters cannot charge their batteries at regular basis, hence the efficiency of transmitter is also important. To provide a low unit cost, high reliability communication capability for the warfighter, smaller and lighter weight communication devices, with high efficiency and linearity, are essentially needed. To design a highly efficient MUOS handheld transmitter, MaXentric proposes GreenAmp Mini which uses a dynamic supply modulator to provide an adaptive DC power to the power amplifier. The dynamic supply modulator tracks the envelope of the MUOS signal, and provides the appropriate DC supply power according to the envelope signal. Since the DC supply power is changing with the input envelope signal, the overall transmitter will not consume extra DC power in a low output power region. When the MUOS handset is not transmitting, the DC power is not provided to the transmitter, minimizing the power consumption in the system and improving the overall system efficiency, which increases the battery lifetime significantly.