摘要
传统单极子天线存在着带宽窄和较低频率下物理长度大等局限，限制了单极子天线的工程应用。设计了一种兼具有宽带和小型化特性的微带单极子天线。该天线采用共形技术，印刷在轻薄柔性基板上并粘贴在介质圆柱表面，以此减小天线截面积；采用二阶Koch分形图案设计辐射单元边界，相比常规矩形单元能够缩小天线尺寸；为了小型化同时扩展天线工作带宽，该天线采取了顶部加栽金属圆盘和四周加栽金属套筒等措施。分析了分形结构、加栽圆盘和套筒、介质圆柱尺寸等参数对天线性能的影响，设计并制作了一只UHF频段的微带单极子天线。数值仿真和测试结果表明该天线的S11〈-10dB的阻抗带宽达到74％（0．82～1．8GHz），而天线高度仅为0．13λ（λ为天线最低工作频率的波长）。
A conventional monopole antenna has limitations in the aspects of narrow bandwidth and long physical length un- der the condition of low frequency, which limits its engineering application. Here, a microstrip monopole antenna which has properties of wideband and miniaturization is proposed. By employing the conformal technology, this antenna is printed on a thin and soft PCB （printed circuit board） and glued on the surface of a dielectric cylinder to reduce its cross-sectional area. The edge of the radiation element is shaped by using a Koch fraetal configuration with the second iteration, and thus the size of the antenna is considerably reduced in comparison with that of the antenna utilizing the commonly-used rectangular radiation element. To enhance the antenna＇s bandwidth under the condition of miniaturization, the antenna loads a metal plate at its top and a metal sleeve around it. The effects of the fractal shape, as well as the dimension of the metal plate, metal sleeve and dielectric cylinder on the performances of the antenna are analyzed, and then a prototype working at UHF （ultra-high frequency） is designed and fabricated. Simulation and measured results show that the ｜S11｜〈-10 dB impedance bandwidth is 74% （0.82-1.8 GHz）, while the electrical height for the antenna is only 0.133., where A is the wavelength of the low bound of the antenna＇s working frequency band.
出处
《现代电子技术》
2013年第5期70-73,76,共5页
Modern Electronics Technique
基金
国家自然科学基金委员会与中国工程物理研究院联合基金[NSAF基金No.U1230112]资助
关键词
宽带
小型化
共形
分形
单极子天线
broadband
miniaturization
conformal
fractal
monopole antenna
