| The wireless communication systems of the military use and civilian use put forward higher requirements for the antenna with the rapid development of the information and electronics technique. It is of great theoretical and engineering significance to analyze and design high performance curved microstrip antenna. In this dissertation, we focus on the simulation technique of curved microstrip antenna based on the numerical simulation tool - method of moments (MoM). The author's major contributions are outlined as follows:1. The adaptively modified characteristic basis function method (AMCBFM)is proposed based on the electric field volume-surface integral equation (EVSIE). Based on the AMCBFM, the electromagnetic characteristics of the dielectric, metal and mixed metal/dielectric objects are analyzed and the advantages in the memory requirements as well as the CPU time are investigated. In the analysis of the electromagnetic scattering characteristics of closed PEC targets using the AMCBFM, numerical results show that the combined field integral equation can avoid the overlap between blocks in AMCBFM.2. The equivalent dipole-moment method (EDM) based on the volume integral equation (VIE) and the Schaubert-Wilton-Glisson (SWG) basis function is proposed for the analysis of the electromagnetic characteristic of dielectric objects. The two inner adjacent tetrahedron pair sharing a common face, on which the SWG basis function is set up, is viewed as a dipole model. On the surface of dielectric objects, the tetrahedron with a boundary face, on which the SWG basis function is set up, can be viewed as a dipole model too, in which the tetrahedron itself is viewed as the positive (negative) part while the boundary face is viewed as the negative (positive) part of the dipole model. The EDM is used to calculate the impedance matrix elements when the distance between the basis and the testing function locations is equal or larger than the critical distance. Numerical results show that the EDM not only can accelerate the computation of impedance matrix element significantly, but also can avoid the boundary condition treatment for the dielectric body. Furthermore, the EDM is extended in the analysis of the electromagnetic scattering characteristic of multi-layered dielectric bodies and is combined with the AMCBFM to analyze electrically large objects.3. The electromagnetic characteristics of electric anisotropic media are investigated using the proposed EDM. The VIE containing the relative permittivity tensor is set up and the corresponding discrete formulae are deduced. The EDM, AMCBFM and EDM-AMCBFM are then extended to analyze several kinds of anisotropic media objects and coated objects, respectively.4. The solid modeling and its meshing method of arbitrarily shaped microstrip antenna are investigated. The scattering characteristic of arbitrary shaped microstrip antenna and its array, such as the finite plane microstip antenna, curved microstrip antenna and microstip antenna with anisotropic substrate, are analyzed using the EVSIE-MoM and the EDM-AMCBFM. According to the continuity equation of electric current on the interface between conductor and dielectric, an efficient scheme is proposed to reduce the unknowns of the matrix equation. The CPU time and the memory requirements are reduced and the condition number of the coefficient matrix is improved. The numerical results show that the proposed method can be combined with EDM-AMCBFM together to efficiently analyze the electromagnetic scattering characteristics of microstrip antenna.5. The probe feed model and the edge feed model are built to analyze arbitrarily shaped conformal microstrip antenna. The radiation characteristics of the several kinds of antennas, such as the curved microstrip antenna, multilayed microstrip antenna, microstrip antenna with anisotropic dielectric substrate, and microstrip antenna array are analyzed and discussed using the EVSIE-MoM and EDM-AMCBFM.Finally, some conclusions are drawn and future work are proposed... |
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