WLAN极化双工天线的设计

发布时间：2018-05-08 04:38

本文选题：微带天线 + 双极化　；参考：《大连海事大学》2017年硕士论文

【摘要】：同时同频全双工(CCFD)通信具有节约频谱资源,提高频带利用率等优点,因此近年来引起了人们的广泛关注。在CCFD系统中,极化双工天线是一个关键器件,因此,研究具有高隔离度和宽频带特性的高性能极化双工天线具有理论价值和实际意义。极化双工要求天线具有双极化特性,现如今,双极化天线的实现方式有很多,其中,微带贴片天线具有结构简单、体积小、重量轻、能与载体共形、便于与微波有源器件和电路集成等优点,而且利用同一个贴片可以收、发两个互不干扰的正交极化电磁波,因此,本文采用微带贴片天线结构设计应用于WLAN系统的极化双工天线。本文首先设计了一款工作在2.4GHz WLAN频段的高隔离度双极化微带贴片天线。该天线为积叠式微带贴片结构,通过两层辐射贴片引入两个相邻的谐振频率,进而展宽天线的频带。馈电方式采用混合馈电,水平极化端口为微带线侧馈,垂直极化端口为缝隙耦合馈电,耦合缝隙采用的是耦合效率较高的H型缝隙。由于微带天线采用了混合馈电方式,两条微带馈线分别置于开缝接地板的两侧,屏蔽了相互之间的干扰,提高了端口间的隔离度。在此基础上,以此天线作为单元天线,采用错位倒相馈电组成了 2×2天线阵,优化了端口间的隔离度,同时有效抑制了主瓣内的交叉极化电平。本文利用3个一分二等分Wilkinson功分器通过级联方式设计了一款一分四等分功分器,并引入180°移相器,以达到倒相馈电的目的。然后,本文又设计了一款工作在5.2GHz和5.8GHz WLAN频段的宽频带双极化天线。该天线采用了方形环缝隙结构,总体形状为阶梯形矩形。环缝的相邻的两臂通过微带线馈电,以产生两个相互正交的电磁场,而另外两臂的引入则使得天线结构对称,并减少了交叉极化。通过优化槽臂和馈线尺寸,实现了要求的阻抗匹配和隔离度。本文采用理论设计和仿真软件优化设计相结合的方法对双极化天线及阵列进行设计,并根据设计结果对天线进行了加工与测试。测试结果显示,本文设计的双极化天线及天线阵基本达到设计要求。
[Abstract]:At the same time, CCFDs have the advantages of saving spectrum resources and improving the efficiency of frequency band, so they have attracted more and more attention in recent years. Polarization duplex antenna is a key device in CCFD system. Therefore, it is of theoretical and practical significance to study high performance polarization duplex antenna with high isolation and broadband characteristics. Polarization duplex requires dual polarization characteristic of antenna. Nowadays, there are many ways to realize dual polarization antenna. Among them, microstrip patch antenna has simple structure, small size, light weight, and conformal with carrier. It is easy to integrate with microwave active devices and circuits, and the same patch can be used to receive and transmit two orthogonal polarized electromagnetic waves that do not interfere with each other. In this paper, the microstrip patch antenna structure is used to design the polarized duplex antenna used in WLAN system. In this paper, we first design a high isolation dual polarization microstrip patch antenna working in the 2.4GHz WLAN band. The antenna is a stacked microstrip patch structure. Two adjacent resonant frequencies are introduced through the two-layer radiation patch to widen the frequency band of the antenna. The feed mode is mixed feed, horizontal polarization port is microstrip line side feed, vertical polarization port is slot coupling feed, coupling gap is H type slot with high coupling efficiency. Because the microstrip antenna adopts the mixed feed mode, the two microstrip feeders are placed on the two sides of the slotted floor respectively, which shield the interference between each other and improve the isolation between the ports. On this basis, the antenna is used as a unit antenna, and a 2 脳 2 antenna array is formed by using a staggered inverse-phase feed, which optimizes the isolation between ports and effectively restrains the cross-polarization level in the main lobe. In this paper, a four-divider is designed by cascading three Wilkinson splitters, and a 180 掳phase shifter is introduced to achieve the purpose of inverting the phase feed. Then, a broadband dual-polarization antenna working in the 5.2GHz and 5.8GHz WLAN bands is designed. The antenna adopts a square ring slot structure and its overall shape is a stepped rectangle. The adjacent arms of the annulus are fed through the microstrip line to generate two mutually orthogonal electromagnetic fields, while the introduction of the other two arms makes the antenna structure symmetrical and reduces cross-polarization. By optimizing the size of grooves and feeders, the required impedance matching and isolation are realized. In this paper, the dual polarization antenna and array are designed by combining theoretical design and simulation software optimization design, and the antenna is machined and tested according to the design results. The test results show that the dual polarization antenna and antenna array designed in this paper basically meet the design requirements.
【学位授予单位】：大连海事大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN822

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