Electrical And Magnetic Properties Of The Large Target Analysis Method

With the development of the electromagnetic technology, the higher frequency is used in the area of wireless communication and radar, so analyzing the electromagnetic characteristic of the electrically large size targets becomes important. The high frequency method is widely applied to analyze the electrically large size targets for its advantages, such as the efficiency of computation and the low require for memory. Compared with the numerical method, the computational accuracy and applicability of different high frequency methods are discussed in this dissertation. Many engineering problems are researched with the high frequency method, such as the radar cross scattering (RCS) and the time domain scattering analysis of moving objects.Firstly, physical optical (PO) method, equivalent edge currents (EEC) method, and iterative physical optical (IPO) method are described in detail, and used for computing the RCS of the electrically large size targets. For the content computational accuracy, different high frequency methods are selected to solve the according matters, on the basis of the principle of the high frequency scattering. Compared with the numerical method, computational accuracy of the high frequency method is discussed from the amplitude and phase information of scattering field.Following, Physical optical (PO) method is used for computing the RCS of the planar dielectric objects in this dissertation, and a good result is got in the directions of reflection and transmission. The method is applied to analyze the electromagnetic characteristic of large multilayer dielectric radome. The computational accuracy and universality is improved by discrete exciting, changed integral mode and amended coefficients of reflection and transmission.Next, the transient electromagnetic scattering problem is studied. The time domain physical optical (TDPO) method and time domain equivalent edge currents (TDEEC) method are described in brief. Then, the two methods are used for computing the transient scattering echo of perfect electric conductor (PEC). The time domain iterative physical optics (TDIPO) approach is presented to compute the scattering field of strongly coupling objects in this dissertation, which extends the applied range of the high frequency method in time domain. These high frequency methods are applied to analyze the transient electromagnetic characteristic of moving PEC objects.Finally, the characteristic of bodies of revolution (BOR) and the principle of bodies of revolution method of moment (BORMOM) are introduced, and the method is applied to compute RCS of the electrically large size BOR targets, which can reduce the computational complexity, and has a good accuracy. BORMOM can be applied to analyze different material objects, such as metal, dielectric and coated targets.The research work presented in this dissertation provides a fundation for the wide application of high frequency method, as well as an efficient method for analyzing the scattering characteristic of electrically large size targets.