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 multi-port nonlinear circuit. Computer simulation and experiment were done at frequency 2.45, and 5.85GHz, and also we evaluate the accuracy by constellation pattern and Error Vector Magnitude(EVM) value.