構建了一種形式新穎的加袖雙Koch分形天線。運用矩量法，研究了天線諧振特性隨不同幾何參數如彎折角、袖間距以及袖長度等的變化規律，并將遺傳算法引入到適合于移動通信GSM和DCS系統的雙帶單極子天線的設計。研究結果表明，雙Koch分形天線比單Koch分形天線具有更低的諧振頻率，而且隨著彎折角的增加而降低。加袖后的分形天線可有效地改善天線的高頻端特性，袖長和袖間距對高頻特性有較強的調節作用。
關 鍵 詞 分形天線; Koch曲線; 彎折角; 諧振特性; 優化設計; 遺傳算法

A novel dual-koch fractal antenna with sleeves is presented, and dependences of its resonant parameters on the indentation angles, the half cone angles, the sleeve space and the sleeve height are investigated by using the method of moment. Based on these discussions, a double-band unipole antenna for application of GSM/DCS is designed by using the genetic algorithm. All the analyses show that dual-Koch fractal antenna has much lower resonant frequency than single-koch fractal antenna, and the resonant frequency decreases with increase of the indentation angle. The sleeves can effectively improve the performance of the fractal antenna at high resonant frequency. That is, its space and its height have excellent ability to tune at high resonant frequency.