No abstract

This contribution provides techniques for accurately characterizing uncertainty when measuring total radiated power at millimeter-wave frequencies. The setup is based on the reverberation chamber as a well-known measurement environment capable of performing total radiated power measurements of wireless devices. We show that by applying various stirring techniques, we can reduce the random component of measurement uncertainty to around 2%. We use a model for estimating the uncertainty for total radiated power measurements based on the K factor which is compared to uncertainties calculated from relative power measurements and we show excellent agreement. We perform a significance test to confirm that the uncertainty due to the limited number of mode-stirred samples dominates over the uncertainty due to the lack of spatial uniformity. The observed uncertainty is also compared to an ideal chamber situation and shows good agreement.Index Terms-Measurement uncertainty, millimeter wave, reverberation chamber, total radiated power, wireless systems.

We have used least-median-of-squares (LMS) regression to analyze gray-scale images of optical fiber ends. This regression is a form of robust regression that ignores outlying data points. We fitted ellipses to the images of each of two fiber ends by using LMS and least-sum-of-squares regression. The two methods yielded nearly identical results on a pristine fiber end, but the LMS method was far superior on a damaged fiber end, even though we made no effort to filter the outlying data points.