Impact of waveguide aperture dimensions and misalignment on the calibrated performance of a network analyzer from 140 to 325GHz

We present experimental results from studying the impact of waveguide aperture dimensions and misalignment on the calibrated electrical performance of a vector network analyzer from 140 to 325GHz. It is shown that the calibrated transmission response is not adversely affected by waveguide irregularities or aperture misalignment. In contrast, we observed that the calibrated reflection response is much more sensitive to these mechanical imperfections. Our initial results suggest that waveguide misalignment may have a greater impact on the calibration accuracy of network analyzers operating beyond 140GHz.