Study Of Scattering And Reconstruction Imaging Problem In MIMO System

Multiple input multiple output (MIMO) technology is one of the most important abilities. It has been widely used in these years. This paper based on the electromagnetic computation algorithm, studied on the MIMO channel model and3D reconstruction and imaging of large complex target in background surface. Numerically computation is used to study the influence of the model geometry on the MIMO system capacity and complex target’s3D reconstruction. The main contents in this dissertation are summarized as follows:1. Multiple input-multiple output (MIMO) system has becomes one of key techniques for developing B3G/4G systems. In this paper, a model of the MIMO system above a3-D randomly rough surface is presented. Using Monte Carlo method, underlying randomly rough surface is realized. The Kirchhoff approximation (KA) is applied to numerical calculation of rough surface scattering for implementing multi-path propagation and the channel transfer matrix of MIMO system. It numerically shows the dependence of the MIMO system capacity upon physical parameters of the MIMO antenna arrays and underlying surface. It is found that when the inter-element separation of the antenna array is small, the underlying rough surface can significantly increase the MIMO capacity; However, when the separation is large, the capacity of the rough surface model is lower.2. A SIMO (single input and multiple output) system of a step-frequency (SF) radar is developed. It is working in downward-looking spotlight mode and moving within a2D synthetic plane array to produce a3D matrix of backscattering fields in both the amplitude and phase from a3D (three-dimensional) complex-shaped electric-large target above background. Its3D imaging is applied to reconstruct the target profile.In numerical simulations, the bidirectional analytic ray tracing (BART) method is applied to calculations of bistatic scattering in SIMO observations from a volumetric target above background rough surface. An improved3D RMA (range migration algorithm) is then utilized to making the radar imaging. It shows a3D scene of the target above background surface. As validation and comparison, the scattering fields of some simple targets are computed with comparisons of the BART and FEKO software. The SIMO techniques of imaging and reconstruction for a3D target, such as a tank-like object over rough surface and a ship-like are presented.