Estimation of RF PA Nonlinearities after Cross-correlating Current and Output Voltage

The estimation of 1 dB compression and thirdorder intercept points can be obtained after the crosscorrelation between dynamic current and output voltage of radio frequency power amplifiers. This estimation is performed using actual power measurements and not power inferred from voltage values. The underlining theory and a correlator that allows implementing this measurement onchip are presented. The trade-off between measuring voltage and the actual power is also discussed and it is shown that different information concerning the output load is obtained when observing the PA’s output voltage and power. Simulation results, obtained with the model of a prototype demonstration chip, show that good accuracy can be obtained with relatively simple measurement conditions. These results include the analysis of optimum stimuli amplitudes and the effect of noise in estimation accuracy.