Calibration of Power Meter with Tapered Waveguide at Frequency Range of 110–170 GHz

For millimeter (mm) wave power measurement at frequencies above 110 GHz, the use of a lower frequency power meter such as a W-band power meter with a tapered waveguide (PMT) is convenient and practical. However, a complex analysis of the multiple-mode in the W-band waveguide is required for precise power measurement. Therefore, we calibrated a PMT by directly comparing it with a D-band single-mode calorimeter. This comparison does not need complex analysis because the D-band calorimeter can measure the absolute value of mm-wave power at a frequency above 110 GHz. The uncertainty of the calibration was approximately 4%. This result can be a good reference for the measurement capacity of a PMT.