一种新型宽频带高增益对称振子天线

Novel Dipole with Wide Bandwidth and High Gain

提出了一种基于多谐振的具有稳定波束指向的宽频高增益对称振子天线,该天线包含一对切尖的宽振子,位于振子顶部的两片圆盘,一块矩形金属底板,同轴馈电结构,与之并列的巴伦变换以及用于连接内导体与振子另一臂的金属导体。其中切尖宽振子自身具有较宽带宽,圆盘在顶部作为寄生辐射单元,产生额外谐振并充当引向器,方形金属板在天线底部作为反射器,巴伦转换结构使天线方向图更对称。仿真结果显示,该天线在VSWR<2的条件下,可以达到0.85GHz^1.97GHz(79%)的带宽,带内具有稳定的波束指向,H面最大波束指向保持0°,E面波束指向在-5°~0°之间,增益9.5d B±1.5d B,E面和H面具有对称的方向图,半功率波瓣宽度为83°~102°,前后比大于15.7d B。

A high gain wideband dipole consisting of multi-resonators with stable beam direction is presented. This antenna is composed of a cut wide dipole with two discs on it, a rectangular metal plate, coaxial feed structure with balun parallel to it, rectangular metal strip connected to inner conductor of coaxial cable and the other arm of the dipole. The discs act as parasitic radiators to generate two additional resonant frequencies and directors which guide energy to propagate forward. The rectangular metal plate works as ground, and balun makes pattern more symmetrical. According to the simulation, a wide impedance bandwidth of 79% （VSWR 〈 2） from the frequency of 0.85GHz to 1.97GHz is achieved. The antenna has symmetrical radiation patterns and stable beam directions, which stay 0°in H plane and vary from -5°to 0° in E plane. High gain （9.5dB ± 1.5dB） is achieved over the entire operating frequency band. Half-power beamwidth is 93° ＋ 10° , and front-toback ratio is better than 15.7dB.