Ka-Band Multi-port Power Amplifier Calibration Experiment and Results

A multi-port power amplifier (MPA) is a multi-input multi-output system that is capable of amplifying multiple input signals simultaneously by a set of shared power amplifiers without mutual interference. In a practical MPA, the component imperfections reduce the port isolation, which introduces leakage or cross-port interference. A patent-pending type-based calibration technique is studied in this paper. It exploits the uniqueness of the statistics for a given communication signal to estimate a calibration matrix that minimizes the effects of the MPA impairments and suppresses the cross-port interference. Experimentation with a 4-port 20 GHz prototype MPA subsystem is conducted to evaluate the type-based calibration technique. Results show that it can accurately estimate the calibration matrix to improve the MPA performance significantly.