Repeatability of 220 - 330 GHz Variable Waveguide Attenuator and Frequency Extenders for 6G Measurements

Mechanical waveguide attenuators are used above 100 GHz frequencies to control signal levels in power sweep measurements to avoid compression of the device or the extender. However, manual settings of the attenuators are prone to human errors, and thus the repeatability of each measurement need be studied case-basis. This paper studies calibration accuracy of extenders, and the repeatability and reproducibility of a waveguide attenuator operating at 220 to 330 GHz. The average calibration variation of S21 with three operators and three repeated calibrations over frequencies was -0.009 dB and 0.072° for directly connected frequency extenders. The measured setting accuracy of any waveguide setting was 1.4 dB (±2σ) over 15 dB range. The primary source of measured variation in S11 and S21 in variable attenuator setting measurements was due to repetition of measurements since there was no significant statistical difference between three operators.