An Integrable Analog Domain Linearization Architecture for the Power Amplifiers in MIMO Systems

This paper presents an integrable analog domain linearization architecture for power amplifiers (PAs) in MIMO systems using spectrum shaping circuits with nonlinear feedback. The architecture consists of a nonlinear distortion extracting loop and an N-order spectrum shaping circuit. The extracting loop aligns the PA input and output signals in amplitude with a 180-degree phase difference and then adds them to extract the nonlinear distortion. The spectrum shaping circuit reshapes the distortion using N identical analog chains with different group delays and attenuation parameters, injecting it back into the PA input after adjusting the attenuations, realizing nonlinear distortion suppression at different target frequencies. Moreover, the delays in the spectrum shaping channels have multiple relationships, enabling easy integration into the PA design stage with low complexity. While high integration was not achieved due to practical constraints, an experimental testbed with off-the-shelf components demonstrated robust nonlinear distortion suppression performance at different target frequencies.