**9. References**

198 Modern Metrology Concerns

*EG*

Fig. 12. Rectangular waveguide power sensor calibration system setup

ડ

further developed for different case analyses in future studies.

calculate its value from equation (27). The measurement uncertainty in the S-parameters is then evaluated (EURAMET, 2011). Reference (Ridler and Salter, 2001) presented the law of propagation of uncertainty using matrix notation, treating the complex quantities with real

Since the calculation method from S-parameters is sensitive to small measurement errors, several different measurement methods were proposed, such as the "passive open circuit" and "active open circuit" method (Moyer, 1987), and the direct calibration method (Juroshek,1997). In the direct calibration method, the splitter is connected through ports 1 and 3 to a VNA. This effectively gives a new one port VNA at splitter port 2. This new VNA is calibrated using a one port calibration algorithm, e.g. short-open-load. The

then obtained as one of the three one-port VNA error terms. References (Rodriguez, 2000; Yhland & Stenarson, 2007) assessed the measurement uncertainty and traceability in power splitter effective source reflection coefficient. Reference (Furrer, 2007) compared direct calibration method with the calculation method. It seems that the similar results

From simple direct comparison transfer method, to coaxial splitter based direct comparison transfer, and then to the general models with signal flow graph analyses, the chapter has meticulously discussed RF and microwave power sensor calibration methods. The models and equations provided target for practical usage. The examples and case studies have shown the practical applications. The traceability and measurement uncertainty with GUM and MCM have provided in details. The calibration models and methods described are useful for the coaxial and waveguide power sensor calibrations. The general models can be

One possible way of determining

and imaginary evaluation.

were obtained.

**7. Conclusion** 

22 21

*<sup>S</sup> S S*

32

31

*EG* is to measure the splitter's complex S-parameters and

ડ*EG* is

*S*


<http://www.iso.org/sites/JCGM/GUM-introduction.htm>

