Matching requirements in LINC transmitters for OFDM signals

This paper presents a complete analysis of the effect of mismatches in linear amplification with nonlinear components transmitters for orthogonal frequency-division multiplexing modulated signals. Gain and phase imbalances between the two amplification paths can severely degrade the linearity performance introducing both out-of-band spectral regrowth and in-band distortion. Analytical expressions are derived to readily evaluate the contribution of mismatches to the adjacent-channel power ratio and error vector magnitude of the transmitter. A direct evaluation of the matching requirements can thus be obtained from the linearity specifications, without the need of time-consuming simulations.