A novel bistatic scattering matrix measurement technique using a monostatic radar

Abstract

Presents a new technique for measuring the bistatic scattering matrix of point targets using a monostatic radar. In this technique, the complexity of the traditional bistatic measurement setup and difficulties in retaining the phase coherence between the transmitter and the receiver are circumvented completely. The bistatic measurement is performed using a wideband, polarimetric, monostatic radar in conjunction with a rotatable ground plane positioned behind the target. Assuming that the distance between the target and the ground plane is larger than the radar resolution, the desired bistatic response (image contribution) can be isolated from the unwanted backscatter. Noting that the radar operates in the backscatter mode and using the reciprocity theorem, it is shown that the measured cross-polarized responses (/spl sigma//sub vh/and /spl sigma//sub hv/) cannot be determined uniquely. To rectify this problem, additional independent measurements are required. Additional equations for characterizing the cross-polarized components are obtained by placing an anisotropic lossless slab over the perfectly conducting flat surface. The validity and accuracy of the new bistatic measurement technique is demonstrated by measuring a number of point targets with known theoretical bistatic responses. Also, a new approach for determining the effective dielectric constant of dense random media based on the new bistatic measurement technique is developed.