It has recently been shown that the measurement setups usually adopted in inverse scattering problems, in which the primary sources and the receiving antennas are placed at some wavelength apart from the object under test, suffer from intrinsic limitations in the reconstruction capabilities because of the essentially finitedimensional nature of the space of data (the scattered fields). To investigate whether it is possible to overcome these limitations, two (novel to our knowledge) measurement configurations for inverse scattering experiments at a fixed frequency are analyzed and discussed. By means of an analysis of the properties of the radiation operator, it is shown that positioning the measurement probes (and possibly the primary sources) in the close proximity of the object under test allows an improvement of the reconstruction capabilities of inversion algorithms with respect to conventional setups. However, such an improvement can be achieved only in a region close to the border of the region under test. Quantitative rules for the achievable improvement are given and are exemplified through numerical examples.
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