A systematic analysis of measurement uncertainties in rectangular waveguide calibrations is condcuted. Uncertainty budgets for different waveguide bands are examined, individual uncertainty contributions are discussed and the significant impact of connection repeatability is highlighted. Consequently, an investigation into misaligned waveguide interfaces is undertaken, emphasizing the importance of precise alignment, supported by simulation and experimental data.

In this study, the impact of LO signal variations on VNA measurements is investigated. The effect of LO signal changes is studied through theoretical analysis and experiments. It is found that even minor LO signal phase changes after calibration significantly affect the measured phase angles of transmission coefficients. Error correction terms are derived and applied to correct errors in the experimental data. The results shows that corrected measurements remain unaffected by the effect.

The paper shows the determination and application of the generalized efficiency of waveguide thermoelectric power sensor and the uncertainty in the direct transfer system to establish measurement traceability of the millimeter wave power to the primary standard. The waveguide thermoelectric sensor with its generalized efficiency can be used as a transfer standard to calibrate all types of power sensors to determine both the generalized efficiency and the calibration factor.

The paper gives advice to design sequentially rotated antenna arrays with rotation angles optimized for polarization quality. In antenna arrays perfect single radiators are not realizable. Differences between elements impede efficient operation. A smart approach of placing and rotating the elements improves the radiation characteristics. This effect is very efficient, if the single radiators show medium polarization quality, like e.g., mass produced inexpensive devices used in many applications.