An Accurate Millimeter-Wave Imaging Algorithm for Close-Range Monostatic System

Abstract

An efficient and more accurate millimeter-wave imaging algorithm, applied to a close-range monostatic personnel screening system, with consideration of dual path propagation loss, is presented in this paper. The algorithm is developed in accordance with a more rigorous physical model for the monostatic system. The physical model treats incident waves and scattered waves as spherical waves with a more rigorous amplitude term as per electromagnetic theory. As a result, the proposed method can achieve a better focusing effect for multiple targets in different range planes. Since the mathematical methods in classical algorithms, such as spherical wave decomposition and Weyl identity, cannot handle the corresponding mathematical model, the proposed algorithm is derived through the method of stationary phase (MSP). The algorithm has been validated by numerical simulations and laboratory experiments. Good performance in terms of computational efficiency and accuracy has been observed. The synthetic reconstruction results show that the proposed algorithm has significant advantages compared with the classical algorithms, and the reconstruction by using full-wave data generated by FEKO further verifies the validity of the proposed algorithm. Finally, the proposed algorithm performs as expected over real data acquired by our laboratory prototype.

Geometric approach for determining stationary phase points in radar imaging

“…For the monostatic case, both the non-spectral form and the spectral form of the Green's function can be used to derive the wavenumber spectrum of the scattered field. The algebraic approach is not provided in this section since it has been implemented in [42], in which the first derivatives are used to find the stationary phase points. In this section, only the spectral form of the Green's function is used to derive the wavenumber spectrum of the scattered field, in which an approximation is made to obtain the FT relationship between the wavenumber spectrum of the scattered field and the reflectivity map.…”