| Performance analysis of antennas mounted on electrically large platforms is one of the important topics in electromagnetic engineering. Among multiple computational methods, the method of moments and physical optics hybrid method(Mo M-PO) is usually used to simulate these problems. However, PO is not accurate enough for many applications, such as low sidelobe antennas.To obtain accurate results, an ideal method is using Mo M for modeling the whole model including antennas and platforms. Although the capability of Mo M has been significantly improved through the higher-order basis functions, out-of-core technique and parallel technique, it is still very difficult to simulate electrically large platforms with dimensions of hundreds of wavelengths due to the limitation of computational resources.For this kind of problem, Taylor synthesis is utilized to design low side-lobe antenna arrays, and an effective hybrid method with higher-order Mo M and multilevel fast multipole algorithm(Ho Mo M-MLFMA) is developed in this thesis. Due to the fact that antennas usually contain thinstructures and dielectric materials, the Ho Mo M is applied. Compare with traditional basis functions, for example RWG basis functions, the higher-order basis functions reduce the number of unknowns, and thus the amount of computation and storage. To avoid slow convergence in solving matrix equations, Ho Mo M uses the LU decomposition solver. MLFMA is employed to simulate the platforms, and then the coupling between antennas and platforms is taken into account through near field. Numerical results show that Ho Mo M-MLFMA is much more accurate than Mo M-PO.Based on the serial algorithms, the block partitioning parallel strategy for Ho Mo M and the adaptive plane-wave partitioning for MLFMA are studied to further improve the capability of the hybrid method. A large problem including a microstrip antenna array with 2132 elements mounted on an airplane with dimensions of 400 wavelengths issolved. |
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