**7. Conclusion**

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 further developed for different case analyses in future studies.
