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Novel Composite Right/Left-Handed Metamaterial-Based Leaky-Wave Transmission-Lines.

机译：基于新型右手/左手超材料的泄漏波传输线。

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摘要

The focus of this dissertation is on the design procedure as well as analysis of a very interesting category of metamaterial-based structures namely composite right/left-handed (CRLH) Leaky-wave (LW) transmission-lines (TL). As a result several unique CRLH-TLs are designed and presented. Each of the discussed CRLH LW-TLs has exceptional and beneficial characteristics, which is only realizable due to their composite right/left-handed nature and dispersion characteristics. The operation mechanism of CRLH-TL is explained in the first chapter by the overview of the theory behind the CRLH concept. The dispersion diagram of a CRLH unit-cell shows that the phase constant (beta) is a non-linear function of frequency with a beta = 0 point at a non-zero frequency. Furthermore, a CRLH-TL supports left-handed slow-wave (guided-wave) and fast-wave (leaky-wave) modes, where the phase velocity and the group velocity are anti-parallel and phase advanced is achievable, as well as right-handed slow-wave and fast-wave modes, where the two velocities are parallel and phase delay can be observed.;The subject of the second chapter is conformal CRLH LW-TLs. The effect of conformation of a planar uniform CRLH LW-TL on a convex and a concave surface are investigated. It is shown when the CRLH LW-TL is operating in the fast-wave region the conformation affects its radiation characteristics and the radiation pattern becomes wider in both convex and concave cases. A dispersion engineering method is introduced to modify the conformal structure such that it provides comparable performance to that of the planar version in terms of radiation characteristics. Then taking advantage of the proposed modification method a multifunctional electronically controlled conformal CRLH LW-TL is introduced in a later part of this chapter. Varactor diodes are introduced in the unit-cells to electronically control its guided and radiation characteristics. This CRLH-TL has the ability to operate partially in the slow-wave mode and partially in the fast-wave mode by applying proper biasing voltages to the different sections of the TL. Therefore, it has a unique radiation aperture selectivity function which results in controlling the radiation angle and beamwidth at a fixed frequency. In addition this electronically controlled conformal CRLH LW-TL has the capability to compensate for the conformation effect and refocus the radiation beam by adjusting the biasing voltages properly.;The subject of the third chapter is CRLH LW-TLs with different polarization states and properties. First, a via-free coupled CRLH LW-TL that behaves as a conventional CRLH LW-TL under differential-mode excitation but with radiation polarization orthogonal to that of the conventional CRLH LW-TL. But when common-mode excitation is applied, the TL only supports right-handed guided- and leaky-waves and the left-handed waves are cutoff. Next, a dual polarized coupled CRLH LW-TL is a discussed which is a modification of the first type by inserting vias at the center of the left-handed stub of each unit-cell along the symmetry plane to provide a physical short-circuit to the ground. This structure behaves as a conventional CRLH LW-TL under both common- and differential-mode excitations but with orthogonal polarizations when operating in the fast-wave mode. The following section of this chapter is on a two port CRLH LW-TL that has the capability of switching between two orthogonal polarizations while operating in the fast-wave region. This switchable functionality is achievable based on the configuration of the unit-cells in use for the proposed structure. Each unit-cell consists of two orthogonal CRLH portions and two orthogonal microstrip sections. Each microstrip section is in parallel to one of the CRLH portions. The active propagation path of the unit-cell includes only one CRLH and one microstrip portion. Depending on the chosen propagation path of the CRLH portion followed by the microstrip section or vice versa, two orthogonal radiating field polarizations can be obtained. At last a circularly polarized (CP) CRLH LW-TL is presented in this chapter. This CRLH LW-TL consists of two conventional CRLH LW-TL oriented orthogonal to each other which are connected to a quadrature hybrid coupler for a 90° phase difference feeding purpose. This structure maintains its CP characteristic while performing continuous frequency beam scanning from backward direction to forward direction including broadside radiation in the fast-wave mode.;The subject of the fourth chapter is a dual-band (DB) CRLH-TL. In this chapter the concept of a simple DB-CRLH-TL which is based on combination of a conventional CRLH unit-cell with two microstrip sections is discussed. The equations required for analysis/synthesis of such structure is derived and presented. Using the DB-CRLH concept, two types of DB-CRLH LW-TLs are demonstrated. First is a straight DB-CRLH LW-TL and it has a dual-band radiation beam steering feature when operating in the fast-wave mode. For this case the polarization of the radiated waves are the same for both frequency bands. The second type is a zigzag-shaped DB-CRLH LW-TL. This structure also has the capability of backfire to endfire beam steering including broadside radiation in two different frequency bands. But interestingly in this case during the fast-wave mode operation the radiated waves from the first frequency band have orthogonal polarizations in compare to those from the second frequency band.
机译：本文的重点是设计过程，以及对非常有趣的基于超材料的结构类别的分析，即复合右手/左手（CRLH）漏波（LW）传输线（TL）。结果，设计并提出了几种独特的CRLH-TL。所讨论的每个CRLH LW-TL具有出色的有益特性，这仅是由于其综合的右手/左手特性和分散特性才可实现。在第一章中，通过概述CRLH概念背后的理论来解释CRLH-TL的运行机制。 CRLH晶胞的色散图显示，相位常数（β）是频率的非线性函数，在非零频率处β= 0点。此外，CRLH-TL支持左手慢波（导波）和快波（漏波）模式，其中相速度和群速度是反平行的，并且可以实现相位超前，以及右旋慢波和快波模式，两个速度是平行的，可以观察到相位延迟。第二章的主题是共形CRLH LW-TL。研究了平面均匀CRLH LW-TL在凸面和凹面的构象影响。如图所示，当CRLH LW-TL在快波区域中工作时，构象会影响其辐射特性，并且在凸凹情况下辐射图都会变宽。引入了一种色散工程方法来修改共形结构，使其在辐射特性方面可提供与平面版本相当的性能。然后，利用提出的修改方法，在本章的后面部分介绍了一种多功能电子控制的保形CRLH LW-TL。变容二极管被引入到单元电池中，以电子方式控制其导引和辐射特性。通过向TL的不同部分施加适当的偏置电压，此CRLH-TL能够部分地在慢波模式下和部分在快波模式下运行。因此，它具有独特的辐射孔径选择性功能，可在固定频率下控制辐射角度和束宽。此外，这种电控共形CRLH LW-TL具有补偿构象效应并通过适当调节偏置电压来重新聚焦辐射束的能力。第三章的主题是具有不同偏振态和性质的CRLH LW-TL。首先，无通孔耦合CRLH LW-TL在差模激励下的性能与常规CRLH LW-TL相同，但辐射极化与常规CRLH LW-TL正交。但是，当应用共模激励时，TL仅支持右旋导波和漏波，而左旋波被截断。接下来，讨论双极化耦合的CRLH LW-TL，这是对第一类型的修改，方法是沿对称平面在每个单元电池左手边的中心插入过孔，以提供物理短路。地面。该结构在共模和差模激励下均表现为常规CRLH LW-TL，但在快速波模式下工作时具有正交极化。本章的以下部分介绍两端口CRLH LW-TL，它具有在快速波区域中工作时在两个正交极化之间切换的能力。基于用于所提出的结构的单位单元的配置，可以实现这种可切换功能。每个单位单元由两个正交的CRLH部分和两个正交的微带部分组成。每个微带段与CRLH部分之一平行。单位单元的有效传播路径仅包括一个CRLH和一个微带部分。取决于选择的CRLH部分的传播路径，然后是微带部分，反之亦然，可以获得两个正交的辐射场极化。最后，本章介绍了圆极化（CP）CRLH LW-TL。该CRLH LW-TL由两个相互垂直的常规CRLH LW-TL组成，两个CRLH LW-TL连接到正交混合耦合器，用于90°相差馈电。这种结构在快速波模式下进行从后向前的连续频率扫描时，包括从宽边辐射在内，都可以保持其CP特性。第四章的主题是双频（CBD）CRLH-TL。在本章中，将讨论基于常规CRLH单元电池与两个微带段的组合的简单DB-CRLH-TL的概念。推导并提出了这种结构的分析/合成所需的方程。使用DB-CRLH概念，演示了两种类型的DB-CRLH LW-TL。首先是直型DB-CRLH LW-TL，在快速波模式下运行时，它具有双频辐射束控制功能。在这种情况下，两个频带的辐射波的极化都相同。第二种是锯齿形的DB-CRLH LW-TL。这种结构还具有逆火能力，可以对射束进行转向，包括在两个不同频段的宽边辐射。但是有趣的是，在这种情况下，在快速波模式操作期间，与来自第二频带的辐射相比，来自第一频带的辐射波具有正交极化。

著录项

  • 作者

    Hashemi, Mohammed Reza Mahmoodi.;

  • 作者单位

    University of California, Los Angeles.;

  • 授予单位 University of California, Los Angeles.;
  • 学科 Engineering Electronics and Electrical.;Physics Electricity and Magnetism.
  • 学位 Ph.D.
  • 年度 2011
  • 页码 193 p.
  • 总页数 193
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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