New $W$ -Band Scattering Measurement System: Proof of Concept and Results for 2-D Objects

This paper deals with a detailed study of an original system dedicated to scattering measurements of millimeter waves in the W-band. The system's main innovations lie in its high-precision swivel arm, semianechoic environment, flexibility for positioning the object on the measurement tower, as well as the postprocessing developed to correct measurement errors. We use canonical objects, i.e., cylinders, for tests and evaluate measurement errors and system performance by comparisons with the theoretical scattered field, which has an analytical expression. For the sake of generality, we work with both vertical-vertical and horizontal-horizontal polarizations. We propose a complete workflow that performs noise suppression and positioning error correction, relying on two quantities: 1) the cutoff frequency of a low-pass filter and 2) the predetermination of the position of the device under test (DUT). The originality of our approach is that both quantities are fully defined by the measurement data without apriori knowledge of the DUT. Since different steps of the workflow are generic, it can easily be transposed to any scattering measurement system. Finally, once corrected, measurements at 75, 95, and 110 GHz exhibit signal-to-noise ratios of close to 15 dB for dielectric cylinders and up to 25 dB for metallic ones. To the best of our knowledge, this is the first time that such values have been exhibited in the W-band.