a technique for measuring the current , voltage and phase of a radio frequency power wave to an rf load , accounts for the finite length of the voltage and current pickups , and corrects for effects of standing wave components of voltage and current . voltage and current are computed as complex functions of the voltage pickup signal and the current pickup signal , based on coefficients precalibrated for the predetermined radio frequency . alternatively , a corrected current value can based on the corrected voltage value and complex load impedance . the correction coefficients can be obtained , for each of a plurality of calibrating radio frequencies within an rf range , from voltage and current pickup signals under conditions of open circuit load , short circuit load , fixed known impedance load ; and one of voltage and current being applied at a precise input level to a known load from an rf calibration source .