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Title: | 應用相位反轉器於週期洩漏波天線和增強型二維波束成形系統 Application of Phase Inverters to Periodic Leaky-Wave Antennas and an Enhanced 2D Beamforming System |
Authors: | 簡羅斌 Robin Raoul Jacques Jeanty |
Advisor: | 陳仕元 Shih-Yuan Chen |
Keyword: | 頻寬增加,波束成形,巴特勒矩陣,圓極化,緊湊性,雙面平行導線,正向耦合器,洩漏波天線,相位反轉器,相同圓極化旋轉性質, Bandwidth enhancement,Beamforming,Butler matrix,Circular polarization,Compactness,Double-sided parallel striplines,Forward couplers,Leaky-wave antennas,Phase inverters,Same handedness, |
Publication Year : | 2023 |
Degree: | 博士 |
Abstract: | 本論文中,我們聚焦於一個在微波電路中鮮少使用的元件,即相位反轉器,探討它在波束成形應用中的多功能性。其中,我們研究了相位反轉器在波束成形系統中的緊湊性、相移、寬頻和輻射能力。我們提出了實際的分佈式相位反轉器,其與理想的相位反轉器不同處在於一個我們稱之為寄生相位貢獻(PPC)的物理量。我們對該元件進行深入的研究,解釋其設計並強調其全通特性。我們還開發了一種新的建模方法,可從分佈式相位反轉器中提取PPC。此方法中,幾乎所有物理尺寸都可透過解析公式計算出它們的等效集總元件值。
接著,我們以相位反轉器作為輻射單位晶格,開發出有史以來第一款具有相同圓極化旋轉性質的雙向單層週期洩漏波天線。我們提供了其工作機制的詳細分析,包括其等效電路、開放阻帶之消除、輻射機制與模型、以及90度相位差和雙向相同圓極化旋轉性質成因的數學證明。我們也透過實做樣品驗證其全通特性:軸比頻寬為40%,圓極化波束掃描範圍達79度。此外,也提出了其他兩款更容易實現在更高頻率的設計。 最後,我們展示了相位反轉器在巴特勒矩陣中的兩個導波應用:相位反轉器可用於縮短四分之一波長轉換器,進而縮小兩段式分支線耦合器的面積,並可用作+45度相移器的相移單元,以提升頻寬。值得一提的是,我們證明了巴特勒矩陣的傳統交叉線設計限制了矩陣操作頻寬,因其具有仿射傳輸相位。因此,我們提出具有線性相位的新型交叉線設計,可最大化+45度的頻寬。與傳統設計相比,巴特勒矩陣的操作頻寬可因此大幅提升。在整個頻寬範圍內,觀察到的輸出相位不平衡維持在±10度內,振幅不平衡也得以維持。最後,我們整合了基於相位反轉器之寬頻縮小化4×4巴特勒矩陣與基於相位反轉器之週期洩漏波天線做為驗證。整個波束成形系統在縱向平面上呈現頻率相依性波束掃描,在橫向平面上則呈現頻率獨立性掃描。 In this dissertation, we give prominence to an underused component named the phase inverter and highlight its versatility in answering wideband beamforming applications. In particular, we investigate the phase inverter’s compactness, phase shifting, wideband, and radiating capabilities in the context of a beamforming system. We present the “real” distributed phase inverter as deviating from an ideal phase inverter by a quantity termed “parasitic phase contribution (PPC).” An in-depth study of the component is conducted, which explains its design and underlines its all-pass behavior. We also develop a novel modeling approach to extract the PPC from a distributed phase inverter, where almost all physical dimensions are linked to their lumped element equivalents through formulas. Then, the phase inverter is employed as a radiating unit cell to form the first bidirectional circularly polarized periodic leaky-wave antenna with the same handedness ever reported. An extensive analysis of its working mechanism is provided that encompasses an equivalent circuit, the closure of the open stopband, a radiation model, and mathematical derivations of the phase quadrature and the same handedness. We experimentally verify an all-pass behavior, an axial ratio bandwidth of 40%, and a scanning range of 79°. Two other designs are also described that are more prone to scalability to higher frequencies. Finally, we unveil two guided-wave applications of phase inverters in the context of a Butler matrix. The phase inverters are used to shrink the quarter-wavelength transformers of two-section branch-line couplers and used as phase shifting cells for +45° phase shifters following the composite right-/left-handed ”bandwidth enhancement” technique. In particular, we prove that the Butler matrix’s conventional crossover limits the bandwidth enhancement because of its affine transmission phase. Therefore, it is replaced by a novel crossover with a linear phase to maximize the +45° bandwidth. Compared to conventional designs, a significant widening of the Butler matrix’s bandwidth over which the output phase gradients retain a ±10° imbalance is observed. Low magnitude imbalance is also preserved throughout the bandwidth. In the end, for verification, the wideband Butler matrix is combined with a four-element array formed by substrateintegrated waveguide phase-inverter-based periodic leaky-wave antennas. The whole system exhibits a frequency-dependent scanning in the longitudinal plane and a frequency-independent scanning in the transverse plane. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/92051 |
DOI: | 10.6342/NTU202400197 |
Fulltext Rights: | 同意授權(全球公開) |
Appears in Collections: | 電信工程學研究所 |
Files in This Item:
File | Size | Format | |
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ntu-112-1.pdf | 11.25 MB | Adobe PDF | View/Open |
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