A Novel Rotated Antenna Array Topology for Near-Field 3-D Fully Polarimetric Imaging

In this communication, a novel approach to rotated antenna array topology design is proposed for fully polarimetric short-range imaging. The rotated antenna array proposed acquires two co-pol and one cross-pol signals in terms of the "local" polarization basis by means of three antenna pairs. Then, the fully polarimetric signals in a global polarization basis are retrieved via simple polarization basis transformation, which overcomes the spatially varied polarizations of the signals acquired at different positions and makes valid the assumption of traditional imaging algorithms that the polarization is constant within the aperture. The proposed rotated antenna array takes advantage of the synthetic aperture technique to synthesize a 2-D array for 3-D full-pol imaging. It utilizes a significantly smaller number of antennas in comparison to traditional fully polarimetric imaging arrays and also provides sufficiently accurate estimation to the full-pol electromagnetic signals scattered from targets. Both numerical simulations and experimental measurements have been performed and the results show the tolerance of the antenna array topology proposed to the quasi-monostatic measurements, its effectiveness, and accuracy for full-pol short-range microwave imaging.