Modeling of Deterministic Output Emissions of Power Amplifiers Into Adjacent Receive Bands

This paper discusses the measurement and modeling of the deterministic components of power amplifier (PA) emissions into neighboring receive (Rx) bands caused by PA nonlinearity, and proposes ways to distinguish these components from stochastic components. A method is presented to determine the orders of nonlinearity that are the principal contributors to the Rx band emissions. A Volterra-based model for their estimation is proposed, along with considerations for estimation accuracy. A criterion based on the matrix condition number for efficient pruning of the Volterra-based models is also presented. The proposed techniques are verified with measurements. The proposed model can be used to gain a deeper understanding of the nonlinearity mechanisms responsible for PA spurious emissions, and offers the possibility of canceling the deterministic components to improve receiver sensitivity.