Study of a polar sigma-delta transmitter associated to a high efficiency switched mode power amplifier for mobile WiMax

This paper presents the analysis and simulation of a high efficiency transmitter combining a polar sigma-delta modulator and a high efficiency amplifier. This study is carried out considering high PAPR (peak to average power ratio) mobile WiMax signals. Due to its high efficiency, the class E amplifier was chosen. Performances and behavior of the designed amplifier were validated through simulations. In a second step the amplifier was associated to the polar transmitter to analyze the overall performances. Results confirm the challenges of transmitting high PAPR signals. Perspectives encourage the possibilities of providing efficient power amplification using a polar SigmaDelta architecture.