A New SOLT Calibration Method for Leaky On-Wafer Measurements Using a 10-Term Error Model

We present a new short-open-load-thru (SOLT) calibration method for on-wafer S-parameter measurements. The new calibration method is based on a 10-term error model which is a simplified version of the 16-term error model. Compared with the latter, the former ignores all signal leakages except the ones between the probes. Experimental results show that this is valid for modern vector network analyzers. The advantage of using this 10-term error model is that the exact values of all error terms can be obtained by using the same calibration standards as the conventional SOLT method. This avoids not only the singularity problem with approximate methods, such as least squares, but also the usage of additional calibration standards. In this paper, we first demonstrate how the 10-term error model is developed, and then, the experimental verification of the theory is given. Finally, a practical application of the error model using a 10-dB attenuator from 140 to 220 GHz is presented. Compared with the conventional SOLT calibration method without crosstalk corrections, the new method shows approximately 1-dB improvement in the transmission coefficients of the attenuator at 220 GHz.