加袖双Koch分形天线的研究

构建了一种形式新颖的加袖双Koch分形天线。运用矩量法，研究了天线谐振特性随不同几何参数如弯折角、袖间距以及袖长度等的变化规律，并将遗传算法引入到适合于移动通信GSM和DCS系统的双带单极子天线的设计。研究结果表明，双Koch分形天线比单Koch分形天线具有更低的谐振频率，而且随着弯折角的增加而降低。加袖后的分形天线可有效地改善天线的高频端特性，袖长和袖间距对高频特性有较强的调节作用。
关 键 词 分形天线; Koch曲线; 弯折角; 谐振特性; 优化设计; 遗传算法

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.