小型化准八木天线的仿真与实验研究

Research on simulation and experiment of miniaturized quasi-Yagi antenna

微带准八木天线具有端射的辐射方向图,设计方便,结构简单,其小型化是应用中面临的重要任务。文中针对S波段微带准八木天线的小型化技术开展了仿真和实验研究。首先,研究了基本型的印刷八木天线,在有源振子长度为50 mm和4个引向器的条件下,仿真得到驻波比小于2的频率为2.73 GHz,增益约为4 dBi;然后,在相同的有源振子横向尺寸和引向器个数条件下,采用振子曲折线技术,仿真得到驻波比小于2的频率为2.675 GHz,增益也约为4 dBi;最后,针对相同横向尺寸和引向器个数的曲折线振子,引入介质埋藏技术,对于不同厚度的高介电常数的介质基板覆盖,仿真了准八木天线的端口驻波比和辐射性能的变化情况,在介质基板的相对介电常数为9.8和厚度为8 mm的情况下,仿真得到驻波比小于2的频率为2.2 GHz,增益也约为5 dBi,方向图形状略有变化,对介质埋藏的曲折线振子八木天线进行了加工和测试,测试结果和仿真结果接近。研究结果表明,采用介质埋藏和振子曲折线技术均可以一定程度上缩减准八木天线的横向尺寸,其中介质埋藏技术效果更为明显,二者之间的结合是小型化准八木天线的有效方案,文中的研究为实际工程应用提供了技术参考。

Its endfire radiation pattern,convenient design and simple structure.Its miniaturization is an important task in applications.In this paper,the simulation and experiment research on the miniaturization technology are carried out for S-band microstrip quasi-Yagi antenna.Firstly,the basic printed Yagi antenna is studied to obtain the results that the voltage standing wave ratio(VSWR)is less than 2,frequency is 2.73 GHz and the gain is about 4 dBi under the condition of an active dipole with the transverse length of 50 mm and 4 deflectors.And then,under the condition of the same transverse size of active dipole and the number of directors,the meander line technique is used in the simulation to obtain the results that VSWR is less than 2,frequency is 2.675 GHz and the gain is about 4 dBi.Finally,the dielectric embedding technique is introduced for the quasi-Yagi antenna with the meander line dipole with the same transverse size and the number of deflectors to simulate the change simulation of port VSWR and radiation performance of quasi-Yagi antenna under the condition of the coverage of dielectric substrate with different thickness and high dielectric constant.Under the conditions that the relative dielectric constant of dielectric substrate is 9.8 and its thickness is 8 mm,the simulation results that the VSWR is less than 2,frequency is 2.2 GHz,the gain is about 5 dBi,and the direction pattern changes slightly are obtained.The Yagi antenna with dielectric embedding meander line dipole is processed and tested,and the testing results are close to the simulation results.The research results show that the transverse size of quasi-Yagi antenna can be reduced by dielectric embedding technique and meander line technique to a certain extent,in which the reduction effect of the former one is more obvious.The combination of the two techniques is an effective scheme for miniaturization of quasi-Yagi antenna.The research can provide technical reference for practical engineering applications.