This paper investigates frequency limitations of calibration and de-embedding techniques for S parameter measurements. First, the TRL calibration methods are analysed and the error due to the probe movement when measuring the different line lengths is quantified, next the coupling between the probe-heads and the wafer surface is investigated and finally an upper frequency validity limit for the standard Open-Short de-embedding method is given. The measured results have been confirmed thanks to the use of an electro-magnetic simulator.
 P. Chevalier, F. Pourchon, T. Lacave, G. Avenier, Y. Campidelli, L. Depoyan, G. Troillard, M. Buczko, D. Gloria, D. Céli, C. Gaquiere and A. Chantre, “A Conventional Double-Polysilicon FSA-SEG Si/SiGe:C HBT Reaching 400 GHz fMAX,” IEEE Bipolar/BiCMOS Circuits and Technology Meeting, Capri, 12-14 October 2009, pp. 1-4.
 N. Derrier, A. Rumiantsev and D. Celi, “State-of-the-Art and Future Perspectives in Calibration and De-Embedding Techniques for Characterization of Advanced SiGe HBTs Featuring Sub-THz fT/fMAX,” 2012 IEEE Bipolar/ BiCMOS Circuits and Technology Meeting (BCTM), Portland, 30 September-3 October 2012, pp. 1-8.
 J. Bazzi, C. Raya, A. Curutchet and T. Zimmer, “Investigation of High Frequency Coupling between Probe Tips and Wafer Surface,” IEEE Bipolar/BiCMOS Circuits and Technology Meeting, Capri, 12-14 October 2009, pp. 87- 90.
 J. P. Mondal and T.-H. Chen, “Propagation Constant Determination in Microwave Fixture De-Embedding Procedure,” IEEE Transactions on Microwave Theory and Techniques, Vol. 36, No. 4, 1988, pp. 706-714,. http://dx.doi.org/10.1109/22.3575