无线通信系统中多频带低剖面天线的研究

发布时间：2018-03-17 08:09

本文选题：低剖面　切入点：多频段　出处：《西安电子科技大学》2014年博士论文　论文类型：学位论文

【摘要】：随着无线通信技术的迅速发展,通信系统对于设备的性能与体积提出了更高的要求。这不仅仅需要电子设备能同时工作在多个频带,满足多通信系统的需求,也要求其处理信息的能力更加智能化。小型化设备的设计更体现了人性化的追求,便于设备的使用与推广。作为无线通信系统的最前端设备,天线的各种性能要求也越来越高。因此,天线的多频段工作和低剖面设计将成为主要的设计目标。本论文结合无线通信系统的具体需求,以实现天线的多频段与低剖面特性为设计目标,对双频带低剖面的全向天线、多频段的定向天线以及紧凑型多天线系统进行了深入的研究与分析。作者的主要工作与成果可以概括为以下几点:1.对多频段低剖面的全向天线进行了研究。针对全向天线的低剖面要求,提出了一种基于零阶谐振的双频低剖面微带单极子天线。天线以圆形贴片为基础,在其周围排列蘑菇型结构的短路贴片。应用蘑菇型结构形成零阶谐振,使其可以谐振在亚波长频段;同时利用圆形贴片和圆形环的TM02模式,使其具有类似单极子的辐射方向图。整个天线的设计都在普通的介质基板上,从而具有非常低的剖面(大约0.02λ)。双频微带单极子天线工作在两个频段,其垂直面方向图的前向位置具有一个较深的零陷,而水平面方向图则保持着全向辐射的特性。2.对多频段低剖面的定向天线进行了研究。针对不同的应用场景,提出了三种多频段低剖面的定向天线。首先利用EBG结构特性,其在理论上等效于理想磁导体,实现了基于双频带EBG反射板的低剖面定向天线;再者,在传统长方形贴片天线的基础上,将具有SRR缝隙的导体片平行放置在贴片与地板之间,从而实现天线的多频段工作特性。并利用SRR的不同性质,设计了双频和三频的低剖面定向天线;最后,提出了一种基于短路贴片与方形贴片构成的低剖面天线。天线采用阶梯阻抗的微带线进行耦合馈电,并利用U型反射板增加前向辐射。馈电处的耦合电容与短路探针的电感相互抵消,因此增加了高频段的带宽。双频带低剖面天线的阻抗相对带宽在低频段为1.6%,而在高频段可以达到60%。3.对紧凑型的多天线系统进行了研究。针对LTE通信系统对多天线的需求,设计了紧凑型的全向MIMO天线与定向MIMO天线。全向MIMO天线由改进的非对称双锥天线和多个印制对称振子组成,其中垂直极化天线单元可以工作在两个频段,而水平极化单元工作在高频频段。水平极化单元嵌套在垂直极化单元两个圆锥之间,从而整个天线系统结构较为紧凑。二者的隔离度大于25dB,满足了MIMO系统的要求。这种新颖的天线单独使用垂直极化单元时便可以应用在GSM900,CDMA800以及WCDMA等通信系统,而且同时利用垂直极化和水平极化单元就可以应用在LTE的系统中。定向MIMO天线由两个孔径耦合的短路贴片天线组成。天线通过H型缝隙馈电,天线单元之间的间距仅为4mm。通过修改短路面的形状,改变了地板上电流的耦合,从而利用缺陷短路面技术来提高天线系统隔离。
[Abstract]:With the rapid development of wireless communication technology, communication system has put forward higher requirements for the performance and size of equipment. This requires not only the electronic equipment can work in multiple frequency bands at the same time, meet the requirement of communication system, also requires the ability to process information more intelligent design. Equipment miniaturization also reflects the humanization the pursuit of ease of use and promotion of equipment. As the front-end equipment of the wireless communication system, antenna performance requirements are increasingly high. Therefore, the multi band antenna and low profile design will become the subject of a major design goal. This paper combined with the specific needs of the wireless communication system with multi band and low profile the characteristics of the antenna is realized as the design target of omni-directional antenna for dual band low profile antenna, directional multi band and compact multiple antenna system is studied and analyzed deeply. The author's main To work and achievements can be summarized as follows: 1. the multi band low profile antenna is studied. According to the requirements of low profile antenna, a dual band low profile microstrip monopole antenna based on zeroth order resonance antenna. Based on the circular patch, arrangement of mushroom shaped structure in short patch the application of mushroom type structure is formed around zero order resonance, so that it can be in the resonant sub wavelength band; at the same time using the circular patch and the circular ring of the TM02 model, which has similar monopole radiation diagram. The design of antenna are common on the dielectric substrate, which has a very low profile (about 0.02 lambda). Microstrip monopole antenna operating in two frequency bands, the vertical direction map forward position has a deep nulls, and the horizontal pattern while maintaining the characteristics of.2. omnidirectional radiation of multi frequency low profile The directional antenna is studied. According to different application scenarios, puts forward three kinds of directional antenna multi band low profile. We use EBG structure characteristics, its theory is equivalent to perfect magnetic conductor, to achieve a low profile dual band directional antenna reflector based on EBG; moreover, based on the traditional rectangular patch antenna on the conductor piece with SRR slot placed in parallel between the patch and the floor, so as to realize the characteristics of multi band antenna. And the use of different SRR, low profile dual and tri band directional antenna design; finally, proposed a low profile antenna with a shorted patch antenna based on the square patch. The microstrip stepped impedance of coupled feed, and the use of U type reflection plate increases the forward radiation. The feed coupling capacitance and short circuit inductance probe offset each other, thus increasing the frequency bandwidth. The relative impedance bandwidth of dual band low profile antenna at low frequency was 1.6%, while in high frequency can reach 60%.3. of compact antenna system is studied. According to the requirement of multi antenna LTE communication system, a compact MIMO omnidirectional antenna and directional antenna design. MIMO omnidirectional MIMO antennas by asymmetric double cone the improved antenna and a plurality of printed dipole components, wherein the vertical polarized antenna unit can work in two frequency bands, and the horizontal polarization unit operates in high frequency band. The horizontal polarization unit nested between vertical polarization unit two cone, thus the antenna system has compact structure. Two the isolation of more than 25dB, to meet the the requirements of MIMO system. This novel antenna unit is used alone in vertical polarization can be used in GSM900, CDMA800 and WCDMA communication system, and at the same time using vertical polarization and horizontal pole The unit can be applied in the LTE system. MIMO directional antenna consists of two short patch antenna aperture coupling. Antenna through H slot feeding, distance between antenna elements by modifying the shape of short road is only 4mm., change the floor current coupling, in order to use the technology to improve the defect of the short road isolated antenna system.

【学位授予单位】：西安电子科技大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TN823.27;TN92

【共引文献】