A combined analysis method for determining the structural and electrical performance of very-low-frequency (VLF) T-type transmitting antennas with a complex structure is proposed. By using the finite element method for analyzing the antenna's structural performance and the moment method for determining the antenna's electrical performance, the structural entity model of the antenna is transformed into an electrical model by extracting the position and displacement information of the antenna curtain, thereby determining the electrical performance index of the transmitting antenna. An actual VLF T-type transmitting antenna is analyzed using this method. A comparison between the calculated results and the measured data shows that this method is effective and feasible. In addition, by optimizing the sag of the antenna's curtain, it is demonstrated that the radiation efficiency of the transmitting antenna can be further improved using this method, and the radiation patterns of the initial state and optimized antenna stay almost the same. This method provides guidance for the synthesis design of other VLF transmitting antennas with complex structures.
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