Microwave measurements of RF nanoelectronic devices present numerous challenges. Among these, perhaps the most difficult measurement challenge arises from the inherent, often extreme impedance mismatch between nanolectronic systems and conventional commercial test equipment. The physical origin of this mismatch may be understood by comparing two physical constants: the free space impedance and the resistance quantum.
Measurement Techniques for Radio Frequency Nanoelectronics
and Wallis, T.
Chapter 3. Extreme Impedance Measurements, Cambridge University Press, Cambridge, -1, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=920581
(Accessed September 29, 2023)