基于S波段的微带天线的研究与设计

【作者】 何俊；

【导师】 唐广；

【作者基本信息】 电子科技大学 ， 电路与系统， 2012， 硕士

【摘要】 随着无线通信技术的快速发展,射频微波电路接收与发射环节中必不可少的微带天线成为了重要的研究课题。本文研究并设计了几种应用于S波段的微带天线,并论述了曲折线结构理论,以及其应用于天线小型化的效果。本文主要介绍了应用于S波段的三类微带天线：鞭状天线、倒F天线、以及环状天线。其中重点讨论了曲折线结构的加载对各种微带天线特性的影响以及小型化的效果,并与未加载的同类型天线进行了对比分析。曲折线结构是本文讨论的重点。加载曲折线结构对天线尺寸的缩减起到了很好的效果,并且对天线的有效带宽以及其他特性影响较小。加载曲折线结构后的鞭状天线尺寸相比加载前减小了约15%；将其加载到倒F天线也起到了相同的作用,天线的水平臂长度减小了约25%；由于环状天线结构对称,天线占用PCB面积适中(121-256mm2),其中加载三段曲折线结构的方环天线(121mm2)尺寸略大于之前设计的曲折型倒F天线(111.36mm2)。加载曲折线结构会使天线的有效带宽有所下降,但可以通过调整天线结构来弥补。通过仿真设计还注意到环状天线的有效带宽最大,鞭状天线次之,倒F天线最小。其中曲折型方环天线达到了900MHz左右的有效带宽,而倒F天线只有92MHz。虽然环状天线尺寸上略大于倒F天线,但是环状天线的输入阻抗随频率变化较平稳,因此有效带宽相对较宽,为实际制版留下了余量。仿真的三类天线在全向性与天线辐射特性上均满足设计要求。本文完成了上述各种微带天线的仿真与实际测量。最后,通过对试制天线的输入电压驻波比与实际应用中接收信号强度的测试,进一步验证了仿真分析的正确性,对于测试结果中存在的偏差进行了分析。更多还原

【Abstract】 With the rapid progress in the wireless communication technology developing, the microstrip antenna, as a vital part in the RF and microwave circuits for the reception and launch, has become an important subject for researching. This paper studies and designs several of the microstrip antennas in the S-band, and discusses the theory of the meander line, and its effect on antennas’ miniaturization.This paper describes three types of microstrip antennas which working in S-band, the printed whip antenna, the inverted-F antenna, and the loop antenna. In this paper, the effect on antennas’ characteristic and minimizing their size by loading the mender lines were discussed, and the comparative analysis of the same antenna with or without this structure was given.The discussion about the meander line is the central part of this paper. Loading the meander lines plays a favorable effect on the reduction of antennas’ size, and brings a little impact on the effective bandwidth and the antenna characteristics. The size of the printed whip antenna with meander lines is reduced by15%comparing with the printed whip antenna. This structure also plays a similar role when utilizing it in the inverted-F antenna and the antenna’s horizontal length is reduced by about25%. The loop antennas have symmetrical structure, the areas of PCB occupied by the antennas are reasonable (121-256mm2).The area of the square loop antenna with three meander lines structure (121mm2) slightly larger than the compact inverted-F antenna’s (111.36mm2). Loading the meander lines makes the effective bandwidth ofthe antennas drop, but adjusting antennas’ structure will make up for their reducing.Through the simulation and design, the following were noticed. The loop antennas have the widest effective bandwidth; the whip antennas take the middle place, followed by the inverted-F antennas. The effective bandwidth of the square loop antenna with the meander lines is about900MHz, and the inverted F antenna is only92MHz. Although the loop antennas’ size slightly larger than the inverted-F antennas’, the loop antennas’ input impedance are stable when the frequency changes in the application’s band, so the effective bandwidth is relatively wide, leaving a margin for the fabrication. There were simulations and measurements for these microstrip antennas that mentioned above. Finally, the trial antennas were taken the input voltage standing wave ratio test and the practical application of the received signal power strength test and the results validated the correctness of the simulation analysis, the cause of deviations was discussed.更多还原