Optimization of a bistatic microwave scattering measurement setup: From high to low scattering targets

Measurement accuracy is a key point when dealing with microwave scattering measurements of 3-D targets. This is even more drastic when the targets are small compared to the wavelength. In order to be able to fully exploit a 3-D spherical multistatic setup and to measure the scattering pattern from 3-D targets in copolarization and in cross polarization, a detailed analysis of the experimental errors that disturb the scattered field was carried out, and a measurement methodology was derived. Such analysis was performed in the anechoic chamber of Institut Fresnel in Marseille, France. So far, our institute has provided experimental scattered fields in the microwave domain for 2-D targets. We can now provide 3-D ones thanks to the analysis presented below. The influence of each error is discussed in this paper, and solutions are proposed to correct for systematic errors, positioning errors, as well as for drift problems. In addition, random errors are characterized, providing confidence intervals for each measurement.