Abstract: An impedance synthesis method for fundamental and harmonic frequencies using multi section tuners, because of the huge amount of possible tuning permutations, employs a search strategy based on the minimization of an ERROR FUNCTION (EF), in two steps: in a first step a coarse calibration grid is generated and the raw area is found which allows an approximate solution to the tuning task at the fundamental frequency; then a fine impedance grid is generated around the first solution using calibrated and interpolated points at all harmonic frequencies; a second search step, using the same EF, then allows fine tuning. Among the several, numerically found solutions, the most reliable one is selected based on a sensitivity criterion, which calculates the impedance change for a possible small error in repeatability of each tuning element and selects the one with the lowest sensitivity to element setting errors.