Patent ID: 8896401

Claim:
A calibration method for multi frequency-range impedance tuners, said tuners comprising a cascade of at least two tuning modules, each said module capable of creating controllable reflection factor in a distinct frequency range, said distinct frequency ranges being in the MHz region and the GHz region, said tuners in the GHz region being slide screw tuners and said tuners in the MHz region being Line-Capacitor (LC) tuners, said slide screw tuners comprising an input (test) port and an output (idle) port and a slotted airline (slabline) between said ports, and one or more mobile carriages travelling across said slabline, said carriages carrying metallic tuning probes capacitively coupled with the center conductor and adjustable, inside the slot of said slabline, at various distances from said center conductor whereby creating adjustable reflection factor in the GHz frequency range, and whereby said LC tuners comprising at least three mechanically adjustable shunt variable capacitors being inter-connected using sections of coaxial cable, and having a common ground terminal, whereby adjusting the capacitance of said shunt capacitors creates adjustable reflection factor in the MHz frequency range, whereby said slide screw tuner module of the cascade is connected on the side closest to the DUT, and whereby said LC tuners are bypassed in the GHz frequency range by a bypass network creating low reflection at GHz frequencies, said MHz and GHz range tuner modules being remotely controllable using associated gear, stepper motors, motor control circuitry and interface to a control processor, and whereby each said tuner module is calibrated individually at all frequencies of interest, including frequencies outside the range of said module, said calibration procedure comprising measuring scattering (S-) parameters of each said tuner module separately for a plurality of tuner states using a vector network analyzer and saved in tuner calibration files.