High speed calibration method for impedance tuner

A calibration method for computer-controlled slide screw impedance tuner, wherein

• the slide screw impedance tuner comprises:
• a test port,
• an idle port,
• a slabline with a center conductor between the ports and,
• at least one stepper motor remotely controlled metallic RF tuning probe, insertable vertically (Y) into the slabline between full withdrawal (Y=0) and closest proximity to the center conductor (Y=YMAX), and movable horizontally (X) along the slabline from a position closest to the test port (X=0) to a position at least half a wave length X=XMAX=λ(F)/2 further away, at a test frequency F;
• and
• an electronic control board, configured to:
• detect limit switches of horizontal and vertical tuning probe movement limits,
• control the stepper motors, and
• emit electronic trigger pulses to a vector network analyzer;
• and wherein the calibration method for the computer-controlled slide screw impedance tuner comprises:
• (a) a data-sampling technique, wherein the vector network analyzer is triggered by electronic pulses, emitted by the electronic control board, during the mechanical movement of the at least one tuning probe to instantaneously retrieve and temporarily store internally s-parameter data of the slide screw impedance tuner corresponding to the instantaneous horizontal and vertical positions of the at least one tuning probe,
• (b) a tuner control and s-parameter collection procedure, wherein the control computer controls the stepper motor and downloads, in batch format at pre-determined intervals, in the vector network analyzer internally temporarily saved S-parameter data;
• (c) a reflection factor scaling method, wherein the control computer inserts gradually the at least one tuning probe vertically into the slabline, while measuring, registering and numerically describing a reflection factor at the test port as a function of the vertical position (Y) of the at least one tuning probe.