應用粒子群優化算法於天線陣列之最佳化設計

Optimal Design for Antenna Arrays Using Particle Swarm Optimization Method

陳敏弦(Min-Sian Chen)

指導教授 ： 翁偉中

國立暨南國際大學/科技學院/電機工程學系通訊工程碩士班/碩士(2015年)

摘要

本論文主要之探討內容為探討運用粒子群優化算法於天線陣列的場型最佳化設計，並且計算之場型能夠包含天線元間的互耦效應。傳統的作法為透過不同的設計法則如 Hansen-Woodyard 法、Taylor 法及 Dolph-Tschebyscheff 法等計算天線陣列的陣列因子，找出符合設計規格的激勵源參數。然而，這樣的作法有二個主要的缺點，第一，若設計規格越趨嚴格或為特殊規格，則上述之設計法則將不適用，只能依靠反覆手動調整；第二，陣列因子計算式並未考慮天線元間的互耦效應，造成所設計出的天線陣列場型與實際上有落差。此外，若使用全波電磁模擬軟體模擬天線陣列結構，則將耗費大量計算資源及時程。粒子群優化算法為一種有效的全局優化算法，適合針對各種困難的電磁問題，找到問題的最佳解。若將粒子群優化算法用於場型最佳化設計，不僅能改善調整參數的效率，更能針對各種不同規格之場型進行最佳化設計。其次，若能夠以包含互耦效應的數學式計算出輻射場型，不僅能大幅改善整體設計效率，同時也提高設計上的準確度。本論文研究主題主要為提出主動天線元場型之概念，其結果為包含互耦效應之天線陣列場型，並且結合粒子群優化算法於天線陣列之場型最佳化設計，此方法對一個含有 6 個天線元之線性天線陣列之 x-z 平面進行設計目標為寬主波束場型之最佳化，同時最佳化後之結果以全波電磁模擬軟體 HFSS 進行驗證。結果顯示，最佳化之半功率波束為 65.5˚，比均勻激勵分布之結果 22.5˚ 寬 43˚。在旁波束大小方面，最佳化之旁波束大小為 -17.44 dB，比均勻激勵分布之結果 -12.87 dB 低 4.57 dB。透過本論文提出之方法，達到提升設計效率以及縮短設計之目的，並可作為未來設計天線陣列之參考。

關鍵字

陣列天線 ； 主動天線元場型 ； 互耦效應 ； 粒子群優化算法

並列摘要

The main purpose of this thesis is to study and optimize the radiation patterns of antenna arrays using particle swarm optimization method, and the method of calculating radiation patterns including the mutual coupling effect between elements. Traditionally, the design procedures are using the empirical techniques such as Hansen-Woodyard method, Taylor method, and Dolph-Tschebyscheff method to calculate the array factor, find the excitation of each antenna element to achieve design goal. However, two main drawbacks of this design method are arise. Firstly, if the design goals are more rigorous or complicated, the empirical techniques will not applicable, A trial-and-error approach can only achieve simple designs. Secondly, calculating the array factor of an antenna array does not consider the mutual coupling effect between elements, thus, it will be different between the calculating result and results using the full-wave electromagnetic simulator for the antenna array. Also, it’s very time-consuming using a full-wave electromagnetic simulator for antenna array. PSO is an effective global optimization method, it’s suitable to solve difficult electromagnetic problems. It not only can improve efficiency and quality of time of tuning, but also can optimize for various specifications of antenna pattern designs. Furthermore, if the method of calculating radiation patterns can include the mutual coupling effect, it can improve of the accuracy of result. In this thesis, the main purpose is to optimize a 6-element linear array antenna to achieve the desired radiation pattern using the proposed method. The desired radiation pattern includes the mutual coupling effect. To verify the validity of the optimized result, we compare the optimized results with that obtained by a full-wave electromagnetic simulator HFSS. Optimized results of the purposed and HFSS are good agreement. The half power beam width of optimized result is 65.5˚, which is wider 43˚ than that of the uniform excitation array, and side lobe level is -17.44 dB, which is lower 2 dB than that of the uniform excitation array. The purposed method can be used designing antenna arrays.

並列關鍵字

antenna array ； active element pattern ； mutual coupling ； particle swarm optimization

參考文獻

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[2] H. Visser, Array and phased array antenna basics, NJ: Wiley, 2005.

[3] H. L. V. Trees, Optimum Array Processing, New York: Wiley, 2002.

[4] W. W. Hansen and J. R. Woodyard, “A new principle in directional antenna design,” Proc. Inst. Radio Eng., vol. 26, no. 3, pp. 333–345, Mar. 1938.

[5] T. T. Taylor, “Design of line-source antennas for narrow beamwidth and low side lobes,” IRE Trans. Antennas Propagat., vol. AP-3, pp. 16-28. Jan. 1955.