Bistatic scattering measurements using near-field scanning

Accurate characterization of bistatic scattering responses of targets is of practical importance for a number of military and remote sensing applications. In this paper a novel approach for efficient and accurate bistatic scattering pattern measurement of point and distributed targets using a near-field system is demonstrated. This system is equipped with a relatively large XY-table (3 m×3 m) and makes use of an HP 8720D vector network analyzer as its transmitter, receiver, and signal processing units. The near-field probe of this system is dual polarized to facilitate polarimetric bistatic scattering measurements. Issues such as calibration procedure for removing systematic errors such as channel imbalances, probe cross-talk, and characterization of radiometric calibration constants are discussed. Finally the feasibility and the accuracy of the proposed method are demonstrated by measuring the bistatic scattering of point and distributed targets with known bistatic RCS and scattering coefficient and comparing the measured results with the theoretical one