【摘要】：方向圖可重構(gòu)天線可以根據(jù)通信環(huán)境的變化實(shí)時(shí)改變天線的輻射波束方向,既能滿足現(xiàn)代通訊高速率、信道多變的要求,又能降低通信平臺(tái)天線數(shù)量,凈化電磁環(huán)境,是天線領(lǐng)域的前沿課題。傳統(tǒng)上實(shí)現(xiàn)天線可重構(gòu)的方式多為加載電子器件或使用機(jī)械方法,結(jié)構(gòu)復(fù)雜,效率不高。近年來(lái)出現(xiàn)的新材料石墨烯具有獨(dú)特的光電特性和高效的電可調(diào)性,且工作頻率覆蓋太赫茲波段,為實(shí)現(xiàn)實(shí)時(shí)可重構(gòu)太赫茲天線提供了一條有效途徑。本文以單層石墨烯為材料,設(shè)計(jì)了一種新型的方向圖可重構(gòu)的葉輪型太赫茲天線,并采用矩量法進(jìn)行了計(jì)算和優(yōu)化。結(jié)果表明,該天線可以實(shí)現(xiàn)波束360°連續(xù)變向并具有適中的增益和很低的后向輻射。本課題的主要工作內(nèi)容如下:(1)回顧了石墨烯的基本特性,計(jì)算了兩種基于石墨烯材料的天線:偶極子天線和八木天線。給出了天線的遠(yuǎn)場(chǎng)輻射特性,并與理想導(dǎo)體天線進(jìn)行了對(duì)比,為石墨烯應(yīng)用于可重構(gòu)太赫茲天線的設(shè)計(jì)提供了理論依據(jù)。(2)設(shè)計(jì)了一種新型的基于石墨烯的葉輪型太赫茲天線,以實(shí)現(xiàn)方向圖的可重構(gòu)。天線的主要結(jié)構(gòu)由作為有源振子的石墨烯偶極子天線和沿以其為中心的圓周方向上均勻分布的若干石墨烯薄片所構(gòu)成。為了考察天線的葉片數(shù)量、葉片的化學(xué)勢(shì)分布與天線輻射特性之間的關(guān)系,本文仿真計(jì)算并優(yōu)化了 2～9葉天線,總結(jié)出如下規(guī)律:受化學(xué)勢(shì)調(diào)控的石墨烯葉片的阻抗?fàn)顟B(tài)決定了天線的主瓣波束方向,背向波束方向的葉片為低阻抗態(tài),起反射作用,迎向波束方向的葉片為高阻抗態(tài),起透射窗口作用。(3)基于上述規(guī)律,以45葉天線為例,得到了天線葉片的化學(xué)勢(shì)分布梯形等效函數(shù),并驗(yàn)證了等效函數(shù)的有效性,實(shí)現(xiàn)了天線輻射方向圖360°全向可控連續(xù)變向,波束掃描覆蓋整個(gè)方向角平面。隨后,采用化學(xué)勢(shì)分布梯形等效函數(shù)方案對(duì)45葉天線進(jìn)行了優(yōu)化,計(jì)算結(jié)果表明:天線的主瓣增益可達(dá)8.46dB,前后比為31dB,背向輻射得到有效抑制。所采用的梯形等效函數(shù)方案同樣適用于其它葉片數(shù)的葉輪型太赫茲天線的優(yōu)化。本文所設(shè)計(jì)的葉輪型太赫茲天線具有結(jié)構(gòu)簡(jiǎn)單,體積小,360°全向波束掃描,響應(yīng)速度快等優(yōu)勢(shì),為太赫茲器件之間的無(wú)線通信系統(tǒng)的設(shè)計(jì)提供了一個(gè)具有競(jìng)爭(zhēng)力的可選方案。
[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 擄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，

本文編號(hào)：2491426