本論文之研究目的在於雙頻多重輸入多重輸出(Multi-Input Multi-Output, MIMO)天線的縮小化設計，主要探討可適用於LTE 700/1800雙頻段，而且符合USB Dongle尺寸規格。在目前大部份文獻上設計的USB Dongle天線中，由於USB Dongle所能容納的天線空間相當小，而且在採用MIMO架構的設計下，兩天線的間距必定會非常接近，使其雙天線間的隔離度會難以提升，所以本研究亦設計一隔離機制來增強天線間的隔離效果。
為了達成上述之天線要求，我們以耦合饋入式的平面倒F型天線(PIFA)作為參考天線，設計以一耦合饋入金屬片，然後增加接地耦合殘段，藉以調整接地耦合殘段使其產生700與1800 MHz之雙頻段共振頻率點。而為使MIMO天線之S21達到可使用標準，本文亦設計一突出接地面之隔離機制，並藉由加上Ω型槽孔的設計提升其隔離效果，使其可以達到-15 dB的表現。最後，所提出之天線占用空間大小整體的基板大小為90×26.5×0.8 〖mm〗^3，而雙天線總共占用的面積僅有16×26.5×0.8 〖mm〗^3，實現使用於LTE 700/1800雙頻段的印刷電路板USB Dongle天線。
為符合現今頻帶應用需求，我們使用類似於前章節的結構，並在突出接地面的部分設計單極槽孔天線，藉以使其產生900 MHz之頻段共振頻率點，並加上增加隔離度之槽孔設計，使其S21達到可使用標準，所提出之天線占用空間大小整體的基板大小為90×34.5×0.8 〖mm〗^3，而雙天線總共占用的面積僅有16×34.5×0.8 〖mm〗^3，實現使用於LTE 700/900/1800三頻段的印刷電路板天線。

This thesis investigates antenna design of a compact Dual-band MIMO antenna for LTE 700/1800 and using in USB Dongle applications. Because of antenna can only occupy a quite small space in the traditional USB Dongle antenna design of the reference. So, placing multiple antenna in a compact wirless communication device, miniaturizing of antenna area becomes very important. Because of using MIMO antenna system, the distance between the two antennas must be very close to the antenna and isolation will be difficult to improve. Therefore we design a isolator to improve isolation of this antenna.
To achieve the requirement mentioned above, we design a PIFA antenna by coupling feed. Then, two resonant frequencice of 700 and 1800 MHz were obtained by a coupling shorting strip. To make the MIMO antenna can be used to achieve the S21 standard, we design a protruded ground plane in central of two antennas. Then, by adding Ω-shaped slot design to enhance its isolation. In the case, the S21 achieves near -15 dB in frequencice of 700 and 1800 MHz for the LTE applications. The antenna portion of 16×26.5×0.8 〖mm〗^3 and overall dimension of 90×26.5×0.8 〖mm〗^3
can be easily applied in USB Dongle.
In order to meet the needs of modern bands applications, we use a structure similar to the previous chapter, and in a prominent part of the ground add a monopole slot antenna to resonant frequencice of 900 MHz, and increase the isolation by the slot design, it can be used to achieve the standard of S21. The antenna portion of 16×34.5×0.8 〖mm〗^3 and overall dimension of 90×34.5×0.8 〖mm〗^3 can be implemented using LTE 700/900/1800 tri-band antenna in the printed circuit board.

目錄
論文審定書 i
致 謝 ii
摘　要 iii
Abstract iv
目　錄 v
圖表目錄 viii
第一章 序　論 1
1.1 研究背景與動機 1
1.2 研究目的與方法 2
1.3 論文大綱 2
第二章 基本天線理論及多重輸入輸出系統介紹 4
2.1　簡述 4
2.1.1 天線阻抗匹配 4
2.1.2 天線效率、指向性和增益 5
2.2　偶極天線 6
2.3　單極天線 7
2.3.1 倒L型天線(inverted-L antenna) 9
2.1.2 倒F型天線(inverted-F antenna) 10
2.3.3 平面倒F型天線(PIFA,planar inverted-F antenna) 11
2.3.4 類PIFA天線 13
2.4　多重輸入輸出系統介紹 14
第三章 使用類PIFA結構設計應用於USB Dongle之雙頻微小化MIMO天線設計 17
3.1　類PIFA天線設計 17
3.2　MIMO天線隔離度設計 24
3.2.1 加上突出接地面設計 24
3.2.2 改變突出接地面L寬度大小比較 26
3.2.3 改變突出接地面與輻射體和饋入金屬片的間距d 27
2.2.4 利用Ω型槽孔增加隔離度達成尺寸縮小化 28
3.3天線模擬與量測討論 30
3.3.1 使用不同量測接頭實測比較 30
3.3.2 天線參數量測 32
第四章 設計應用於LTE 700/900/1800之MIMO天線 36
4.1 天線設計原理 36
4.2 天線隔離度設計 42
4.3 天線實驗與量測 43
第五章 結論 45
參考文獻 46

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