Multi-frequency approach to the coaxial multiline through-reflect-line calibration

We present an improved coaxial multiline through-reflect-line calibration method which allows to correct for errors in the description of calibration standards. Our approach is based on the multi-frequency formulation of the vector-network-analyzer calibration problem which accounts for the physical relationships between calibration standard S-parameters at different frequencies. We illustrate our approach with experimental results for the coaxial multiline through-reflect-line calibration with type-N airlines. We show that our calibration method significantly improves the measurement accuracy as compared with the classical multiline through-reflect-line calibration method.