Influence of phase and gainimbalances on recombined signals in LINC transmitters

This paper discusses the influence of phase and gain imbalances between two branches of LINC transmitter on the recombined signals. Experiments are carried out on a model of LINC transmitter using a 3 dB Wilkinson RF combiner which is designed with micro-strip line. Then the phase and gain errors that can be tolerated in the LINC transmitter with high efficiency and good linearity are discussed. The signal used in the Validation experiment is a two-carrier WCDMA signal with the sample rate of 61.44 M Sample/s. The Validation results demonstrate that the correction for phase and gain imbalances is necessary in LINC transmitter.