超宽带Vivaldi天线的设计及分析

Design and Analysis of Ultra-Wideband Vivaldi Antenna

针对机载、弹载等平台的空间有限,设计了一种双指数渐变结构的超宽带Vivaldi天线。天线由微带渐变线馈电,通过矩形共面带线阻抗变换器将小型的超宽带巴伦与天线集成,从而获得2~18GHz的带宽。仿真结果表明:在2~18GHz的工作频段内,天线的回波损耗小于-10dB,天线增益最高可达到10.5dB以上,实测结果与仿真结果基本吻合。将所设计的Vivaldi天线放置于一金属腔体内,对金属腔体对天线性能的影响进行了研究与分析。仿真结果表明:将天线单元放置于金属腔体后,辐射方向相对于原来的辐射方向发生了一定程度的偏转,但随着频率增高,偏转角度逐渐减小。

For the space of airborne and missile-borne platforms is limited,an ultra-wideband Vivaldi antenna with double exponential tapered structure is designed.The antenna is fed by the microstrip tapered line,and the small ultra-wideband balun is integrated with the antenna through the rectangular coplanar stripline impedance converter to get the bandwidth of 2-18 GHz.The simulation results show that the antenna return loss is less than-10 dB in the working frequency band of 2-18 GHz,and the antenna gain can be up to 10.5 dB or more and maintain a good flatness over the entire frequency band.The measured result is basically consistent with the simulation result.Then the designed Vivaldi antenna is placed in a metal cavity,and the influence of the metal cavity on the antenna performance is studied and analyzed.The simulation results show that,when the antenna element is placed in the metal cavity,the radiation direction is deflected to a certain degree relative to the original radiation direction.But as the frequency increases,the deflection angle gradually decreases.