A study of nonlinearity calibration for six-port direct conversion receivers

Abstract

A six-port receiver can restore the original modulated signal by calculating the detected envelopes and system parameters of the six-port circuit. The system parameters have been determined at each frequency in advance. The six-port receiver has an advantage in the point that the user can select the frequency arbitrarily, but there is a problem of nonlinear distortion in the detector because we use diode detectors for the envelope detection. We propose a novel compensation method for distortion of multiport nonlinear circuits. Computer simulation and experiments were done at frequency 2.45 and 5.85 GHz, and also we evaluate the accuracy by constellation pattern and error vector magnitude (EVM) value.