宽频带移动通信基站天线的设计与优化

发布时间：2018-07-14 16:03

【摘要】：在移动通信技术迅猛发展的今天,多种通信标准并存的局面无可避免,用一副基站天线兼容多个通信标准对降低建站成本显然具有重要的意义,因此宽频带基站天线的设计是近年来的一个研究热点。本文提出了一类基于强互耦效应的新型宽频带(57.5%,VSWR1.5)双极化振子天线,它可由同轴线直接馈电,无需采用巴伦做不平衡到平衡的转变,结构简单,十分适合用来组成阵列天线用于移动通信基站中。从外形上看,它与传统的十字形交叉振子颇为相似。但在传统的十字形交叉振子的设计中,为了使两个振子之间获得较高的隔离度,设计时会尽量抑制两振子间的互耦。与此恰恰相反,本文中的天线正是利用了两振子间的强烈互耦而获得了远优于普通十字形交叉振子的工作带宽,而同时该类型天线还具备高隔离度、低交叉极化、输入阻抗可调等优点。本文对该类型天线具有这些优点的原因做了逐条分析,这种分析的方法对其它拥有相似对称结构的天线也是适用的。为了对该类型天线的特性有进一步认识,本文还就一些对天线特性有较大影响的参数进行了分析。结合实际项目需求,本文还分析讨论了基站天线中的方向图优化问题。由于天线的工作频带较宽(1.71GHz—2.69GHz),需要关注的参数众多(3dB波瓣宽度、10dB波瓣宽度、前后比、交叉极化等),同时天线的尺寸应尽可能小,所以天线的优化难度较大。本文中通过采用不同形式、尺寸的反射板来对天线的方向图特性进行优化。在就某一反射板形式,讨论了其部分参数对天线特性影响的变化规律之后,针对这种多目标优化且各目标之间有较强关联的天线优化问题,提出了一优化原则。根据此原则优化得到了最优的反射板参数。为了提高优化效率,在起初的仿真中,模型中采用了简化的天线单元形式;在得到最优的反射板参数后,再将简化的天线单元置换成本文提出的天线单元,最终得到了整体性能良好的基站阵列天线的设计。
[Abstract]:With the rapid development of mobile communication technology, the coexistence of multiple communication standards is inevitable. It is of great significance to reduce the cost of building a station by using a base station antenna compatible with multiple communication standards. So the design of broadband base station antenna is a hot topic in recent years. In this paper, a new type of broadband (57.5 / VSWR1.5) dual-polarization dipole antenna based on strong mutual coupling effect is proposed. It can be fed directly from coaxial line without using Barron to change imbalance to balance, and its structure is simple. It is very suitable to form array antenna for mobile communication base station. In terms of appearance, it is quite similar to the traditional cross-shaped cross-vibrator. However, in the traditional design of crossover oscillators, in order to obtain a higher isolation between the two oscillators, the mutual coupling between the two oscillators will be restrained as much as possible. On the contrary, the antenna in this paper uses the strong mutual coupling between the two dipole to obtain the bandwidth which is much better than the common crossover dipole. At the same time, this type of antenna also has high isolation and low cross-polarization. The input impedance is adjustable and so on. In this paper, the reasons for these advantages of this type of antenna are analyzed one by one. This method is also applicable to other antennas with similar symmetrical structures. In order to further understand the characteristics of this type of antenna, some parameters which have great influence on the antenna characteristics are also analyzed in this paper. Combined with the actual project requirements, this paper also analyzes and discusses the pattern optimization problem in the base station antenna. Due to the wide bandwidth (1.71GHz-2.69GHz) of the antenna, many parameters need to be paid attention to (the width of the 3dB lobe is 10dB, the ratio between the front and back is 10dB, cross-polarization etc.), and the size of the antenna should be as small as possible, so it is difficult to optimize the antenna. In this paper, the pattern characteristics of antenna are optimized by adopting different types and sizes of reflector. After discussing the influence of some parameters on antenna characteristics in a certain reflector form, an optimization principle is proposed for the antenna optimization with multi-objective optimization and strong correlation between each target. According to this principle, the optimal parameters of the reflector are obtained. In order to improve the optimization efficiency, the simplified antenna element form is used in the initial simulation, and the simplified antenna element is replaced by the simplified antenna element after the optimal parameters of the reflector are obtained. Finally, the design of the base station array antenna with good overall performance is obtained.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN929.5

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