【摘要】：變換光學(xué)理論的蓬勃發(fā)展,使得人們想要人為操縱光線傳播的夢(mèng)想成為現(xiàn)實(shí)。作為變換光學(xué)理論的核心方法——坐標(biāo)變換法被逐漸地應(yīng)用于電磁器件的研究,隱身衣就是其中一個(gè)典型的例子。隨后有學(xué)者認(rèn)為,坐標(biāo)變換法可以為共形天線的研究提供新的理論指導(dǎo)。但是,目前的研究多是基于理想電磁源的等效,如何從理想電磁源過(guò)渡為實(shí)際天線的研究,是一個(gè)頗具挑戰(zhàn)的難題。 本文基于變換光學(xué)理論,用坐標(biāo)變換的方法和邊界條件推導(dǎo)了天線饋電端口的切向饋電場(chǎng)的坐標(biāo)變換公式。然后用了四種不同的天線模型來(lái)驗(yàn)證該公式的正確性,從而證明了基于變換光學(xué)方法的共形天線的研究的可行性。論文的主要研究工作和創(chuàng)新點(diǎn)可分為以下幾個(gè)部分： 1.根據(jù)變換空間中等效理想電磁源的坐標(biāo)變換公式,用邊界條件和格林函數(shù)的方法,分別推導(dǎo)了線天線在饋電處切向饋電場(chǎng)的坐標(biāo)變換公式和面天線在饋電端口處切向平面上的饋電場(chǎng)的坐標(biāo)變換公式。推導(dǎo)結(jié)果顯示,只需在天線的饋電處的切向饋電場(chǎng)遵循原本線電流或者面電流的變換方法,即可實(shí)現(xiàn)在坐標(biāo)變換前后天線的輻射場(chǎng)保持一致的特性。該公式的提出,實(shí)現(xiàn)了從理想電磁源的共形變換到天線的等效共形變換的過(guò)渡。 2.通過(guò)理想二維情況下的線天線模型的提出,將天線的饋電公式用于二維理想線天線pinwheel模型,通過(guò)電磁仿真軟件COMSOL對(duì)該模型進(jìn)行仿真和結(jié)果分析,得出了天線在坐標(biāo)變換前后輻射特性等效的結(jié)論,從而驗(yàn)證了天線饋電公式的正確性。 3.本文進(jìn)一步提出了三維情況下的實(shí)際線天線模型,首先提出了球面偶極子天線模型,仿真得到變換后的天線的輻射場(chǎng)與原始偶極子天線的一致。然后又用埋藏式單極子天線模型來(lái)仿真驗(yàn)證變換前后天線的輻射等效性,并提出了一種簡(jiǎn)便的天線設(shè)計(jì)的方法。這兩個(gè)模型不僅驗(yàn)證了線天線饋電方程的正確性,而且可以將理論聯(lián)系實(shí)際,為實(shí)際工作中線天線的共形設(shè)計(jì)提供了理論上的可行性。 4.由于微帶貼片天線在共形設(shè)計(jì)中的普遍應(yīng)用,文中提出了平面微帶貼片天線球面化的模型,仿真并驗(yàn)證了面天線切向饋電口面上饋電場(chǎng)的坐標(biāo)變換公式的正確性。從仿真結(jié)果來(lái)看,天線實(shí)現(xiàn)了等效共形變換。由于在實(shí)際應(yīng)用中,微帶貼片天線的共形研究較多,因此,該模型的仿真在諸多研究方法中增添了一種更為簡(jiǎn)單和有效的方法。
[Abstract]:With the rapid development of transformational optics, the dream of manipulating the propagation of light becomes a reality. As the core method of transform optics theory, coordinate transformation method has been gradually applied to the study of electromagnetic devices. Stealth clothing is one of the typical examples. Subsequently, some scholars believe that coordinate transformation method can provide new theoretical guidance for the study of conformal antenna. However, the current research is mostly based on the equivalent of the ideal electromagnetic source. How to transition from the ideal electromagnetic source to the actual antenna is a challenging problem. Based on the theory of transformation optics, the coordinate transformation formula of the tangential feed field of the antenna feed port is derived by using the method of coordinate transformation and boundary conditions. Then four different antenna models are used to verify the correctness of the formula, which proves the feasibility of the research of conformal antenna based on transform optics. The main research work and innovation points can be divided into the following parts: 1. According to the coordinate transformation formula of the equivalent ideal electromagnetic source in the transformation space, the boundary condition and the Green's function method are used. The coordinate transformation formulas of the tangential feed field at the feed point and the coordinate transformation formula of the feed field on the tangential plane of the plane antenna at the feed port are derived respectively. The derivation results show that the radiation field of the antenna before and after coordinate transformation can be kept consistent as long as the tangential feed field at the antenna follows the original line current or surface current transformation method. The formula can realize the transition from the common deformation of the ideal electromagnetic source to the equivalent conformal transformation of the antenna. 2. The feed formula of the antenna is applied to the pinwheel model of the two-dimensional ideal wire antenna through the proposed linear antenna model under the ideal two-dimensional condition. The simulation and result analysis of the model are carried out by the electromagnetic simulation software COMSOL. The equivalent radiation characteristics of the antenna before and after coordinate transformation are obtained, and the correctness of the antenna feed formula is verified. 3. In this paper, the actual antenna model in 3D is proposed. Firstly, the spherical dipole antenna model is proposed. The radiation field of the transformed antenna is consistent with that of the original dipole antenna. Then the radiation equivalence of the antenna before and after the transformation is verified by the buried monopole antenna model, and a simple antenna design method is proposed. These two models not only verify the correctness of the wire antenna feed equation, but also combine the theory with practice, and provide the theoretical feasibility for the conformal design of the line antenna in practice. 4. Due to the general application of microstrip patch antenna in conformal design, a spherical model of planar microstrip patch antenna is proposed, and the correctness of the coordinate transformation formula of the feed field on the tangential feed surface of the plane antenna is verified by simulation. From the simulation results, the equivalent conformal transformation is realized. Because the conformal research of microstrip patch antenna is much more in practical application, the simulation of the model has added a simpler and more effective method in many research methods.
【學(xué)位授予單位】：北京交通大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：TN820

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本文編號(hào)：2412918