方向图可重构的叶轮型太赫兹天线的研究与计算

发布时间：2019-06-02 21:11

【摘要】：方向图可重构天线可以根据通信环境的变化实时改变天线的辐射波束方向,既能满足现代通讯高速率、信道多变的要求,又能降低通信平台天线数量,净化电磁环境,是天线领域的前沿课题。传统上实现天线可重构的方式多为加载电子器件或使用机械方法,结构复杂,效率不高。近年来出现的新材料石墨烯具有独特的光电特性和高效的电可调性,且工作频率覆盖太赫兹波段,为实现实时可重构太赫兹天线提供了一条有效途径。本文以单层石墨烯为材料,设计了一种新型的方向图可重构的叶轮型太赫兹天线,并采用矩量法进行了计算和优化。结果表明,该天线可以实现波束360°连续变向并具有适中的增益和很低的后向辐射。本课题的主要工作内容如下:(1)回顾了石墨烯的基本特性,计算了两种基于石墨烯材料的天线:偶极子天线和八木天线。给出了天线的远场辐射特性,并与理想导体天线进行了对比,为石墨烯应用于可重构太赫兹天线的设计提供了理论依据。(2)设计了一种新型的基于石墨烯的叶轮型太赫兹天线,以实现方向图的可重构。天线的主要结构由作为有源振子的石墨烯偶极子天线和沿以其为中心的圆周方向上均匀分布的若干石墨烯薄片所构成。为了考察天线的叶片数量、叶片的化学势分布与天线辐射特性之间的关系,本文仿真计算并优化了 2～9叶天线,总结出如下规律:受化学势调控的石墨烯叶片的阻抗状态决定了天线的主瓣波束方向,背向波束方向的叶片为低阻抗态,起反射作用,迎向波束方向的叶片为高阻抗态,起透射窗口作用。(3)基于上述规律,以45叶天线为例,得到了天线叶片的化学势分布梯形等效函数,并验证了等效函数的有效性,实现了天线辐射方向图360°全向可控连续变向,波束扫描覆盖整个方向角平面。随后,采用化学势分布梯形等效函数方案对45叶天线进行了优化,计算结果表明:天线的主瓣增益可达8.46dB,前后比为31dB,背向辐射得到有效抑制。所采用的梯形等效函数方案同样适用于其它叶片数的叶轮型太赫兹天线的优化。本文所设计的叶轮型太赫兹天线具有结构简单,体积小,360°全向波束扫描,响应速度快等优势,为太赫兹器件之间的无线通信系统的设计提供了一个具有竞争力的可选方案。
[Abstract]:The pattern reconfigurable antenna can change the radiation beam direction of the antenna in real time according to the change of the communication environment, which can not only meet the requirements of high speed and changeable channel of modern communication, but also reduce the number of antennas on the communication platform and purify the electromagnetic environment. It is a frontier topic in the field of antenna. Traditionally, most of the ways to realize antenna reconfiguration are loading electronic devices or using mechanical methods. The structure is complex and the efficiency is not high. In recent years, graphene, a new material, has unique optoelectronic properties and high efficiency electrical adjustability, and the working frequency covers terahertz band, which provides an effective way to realize real-time reconfigurable terahertz antenna. In this paper, a new pattern reconstructable impeller terahertz antenna is designed with single layer graphene as material, and the moment method is used to calculate and optimize it. The results show that the antenna can realize 360 掳continuous beam variation with moderate gain and very low backward radiation. The main contents of this paper are as follows: (1) the basic characteristics of graphene are reviewed, and two kinds of antennas based on graphene materials are calculated: dipole antenna and octagonal antenna. The far field radiation characteristics of the antenna are given and compared with the ideal conductor antenna. It provides a theoretical basis for the application of graphene in the design of reconfigurable terahertz antenna. (2) A new impeller terahertz antenna based on graphene is designed to realize the refactability of pattern. The main structure of the antenna is composed of graphene dipole antenna as active oscillator and several graphene sheets uniformly distributed along the circumferential direction centered on it. In order to investigate the relationship between the number of blades, the chemical potential distribution of the blade and the radiation characteristics of the antenna, the 2 鈮，

本文编号：2491426