Improving Temperature, Stability, and Linearity of High Dynamic Range RMS RF Power Detectors

Root-mean-square (rms) power detection is required to measure and control transmitted power in a multicarrier wireless infrastructure. Traditional power detectors using diode detection or log amps do not accurately measure power when the peak-to-average ratio of the transmitted signal is not fixed. Temperature stability of measurement circuitry is critical as is the linearity of the detector’s transfer function. This application note presents techniques to improve the temperature stability of an rms power detector and the linearity of its transfer function to less than ±0.3 dB over a dynamic range of more than 50 dB.