- 學位論文
以頻率選擇平面設計雙頻帶反射式陣列
Dualband Reflectarray Using Frequency Selective Surface
摘要
本論文主要利用兩種開槽式頻率選擇平面來分別實現兩款雙頻(10、12 GHz)反射陣列，其中一款為雙線性極化設計、一款為單線性極化。我們先以開槽為單元設計頻率選擇平面，當開槽共振時(10 GHz)，極化方向垂直於開槽之入射波可通過該平面，而對於另一極化之入射波，無論頻率為何均為全反射。此外，若在原本的開槽單元間多加一平行開槽，對於極化方向垂直於開槽之入射波而言，除了原本的通帶頻率(10 GHz)外，將額外產生一傳輸零點(12 GHz)達全反射。我們據此提出兩款雙頻反射陣列設計，均為兩層介質、三層金屬結構，反射陣列之偶極/十字偶極單元置於上層，頻率選擇表面於中間層，底層則為接地金屬面。在頻率選擇表面的通帶(10 GHz)，反射陣列單元之等效基板厚度為兩層疊加，而在全反射頻率(12 GHz)，則偶極/十字偶極單元之等效基板厚度僅為上層板厚，透過這樣的特殊設計，不僅兩個操作頻帶之頻寬相仿，同時可減少耦合效應之影響。我們以十字偶極單元配合單一開槽之頻率選擇表面設計出雙頻雙極化之反射陣列，而以一般偶極單元配合雙開槽頻率選擇表面則可實現雙頻單一線性極化之反射陣列。前者之設計概念與效能已由實驗證實，後者則受限於板厚選擇與單元特性，僅能實作出一折衷版本，但仍符合預期。最後，我們也設計了一款工作於8-GHz之聚焦型反射陣列，與遠場反射陣列將輻射場聚焦至無窮遠處不同，該設計將輻射場聚焦於天線近場區域內之一點，即焦點。該聚焦型反射陣列亦被應用在微波滅病毒實驗中，將病毒樣本置於焦點位置照射一段時間，觀察該樣本之病毒死亡率，經實驗證實使用聚焦型反射陣列可提升病毒死亡率達93%。
並列摘要
Two kinds of dual-band(10、12 GHz) reflectarray using two types of slot-type frequency selective surface are presented in this thesis. The first kind of reflectarray is designed for dual-polarization, and the other one is for single-polarization. At first a slot-type unit cell is used to design Frequency Selective Surface(FSS). When the slot-type FSS is resonant(10 GHz), the incident waves with direction of polarization perpendicular to slot could penetrate the FSS, and the incident waves with direction of polarization parallel to slot could totally reflect from the FSS at any frequency. Moreover, adding a parallel slot between the original one would produce a transmission zero(12 GHz) for the direction of the incident waves perpendicular to the slot. Based on the FSS we proposed, two kinds of dual-band reflectarray are presented both with the structure of two-layer dielectric substrate and three-layer metal, dipole/crossdipole reflectarray element on the top layer, FSS unit cell in the middle layer, the ground plane is at the bottom layer. At the passband of FSS(10 GHz), the effective reflectarray thickness of substrate is equal to the thickness of two layers overlaid, and at the total refletion frequency(12 GHz), the effective reflectarray thickness of substrate is only equal to the top layer of substrate. By this way, not only is the bandwidth of two operating frequency almost the same, but it also reduces the coupling effect. We use crossdipole unit cell with single slot-type FSS to design a dual-band dual-polarization reflectarray, and use dipole unit cell with the dual-slot FSS to design a dual-band single polarization reflectarray. The former is implemented and the performance is confirmed by experiment; due to the selection of thickness of substrate is limited, the latter could be only implemented by a compromise one, but still as expected. Finally, a focusing reflectarray is designed for operating at 8-GHz, which is different from the far-field reflectarray design. The focusing reflectarray concentrates the main beam to the point in the near-field region, called focal point. The focusing reflectarray is applied on virus sanitized by microwaves. The virus sample is placed at the focal point and illuminated by microwaves for a while; the experiment and analysis of the activity of virus revealed that the death rate of virus rises up to 93%
參考文獻
延伸閱讀
- 吳秉學（2017）。波束可調之雙波束反射陣列設計〔碩士論文，國立臺灣大學〕。華藝線上圖書館。https://doi.org/10.6342/NTU201702946
- 齊立平、羅文劭（2014）。利用頻率選擇面製作雙頻操作之高增益天線。資訊電子學刊，6(2)，65-71。https://www.airitilibrary.com/Article/Detail?DocID=P20230213001-N202302230014-00006
- 邱冠智（2014）。應用於無線功率傳輸之陣列雙極化整流天線設計〔碩士論文，國立臺北科技大學〕。華藝線上圖書館。https://doi.org/10.6841/NTUT.2014.00056
- 施宣寧（2007）。Design and Development of Array Type Quartz Crystal Microbalance〔碩士論文，國立臺灣大學〕。華藝線上圖書館。https://doi.org/10.6342/NTU.2007.01040
- Sanches, L. C. F., Mesquita, E., Pavanello, R., & Palermo, L. (2007). Dynamic Stationary Response of Reinforced Plates by the Boundary Element Method. Mathematical Problems in Engineering, 2007(), 620-636. https://doi.org/10.1155/2007/62157