本論文提出可應用於LTE MIMO的金屬機殼手機邊框天線，只運用短邊邊框的有限空間涵蓋多頻操作並達成MIMO操作，此外提出有效降低天線間耦合的設計。第一個設計為LTE/WLAN多天線設計，藉由饋入電路激發金屬短邊邊框，並利用匹配電路增加頻寬，手機上方短邊天線為第一、二、五天線，第一天線為不與長邊邊框相連的倒F形天線可涵蓋824~960/1710~2690 MHz，第二天線為與長側邊框相連之環圈天線可涵蓋GPS頻帶以及1710~2690 MHz，第五天線為與長側邊框相連之倒F形天線可涵蓋WLAN 2.4/5 GHz頻帶，手機下方短邊為第三、四、六天線，其與第一、二、五天線架構相似，但第四天線未涵蓋GPS頻帶，第一以及第三天線在824~960 MHz可應用於2 × 2 LTE MIMO操作，第一、第二、第三以及第四天線在1710~2690 MHz則可應用於4 × 4 LTE MIMO操作，第五及第六天線在WLAN頻帶則可應用於2 × 2 WLAN MIMO操作，並於延伸設計中提出切換整組饋入電路的方式，使低頻切換至703~803 MHz (LTE B28)，並維持多天線系統的操作，但其中發現於1710~2690 MHz頻帶兩天線耦合電流彼此影響，以及兩天線產生輻射場型不足夠獨立，故需達成寬頻解耦合機制改善LTE MIMO系統隔離度，並降低封包相關係數(ECC)。根據第一個設計所遭遇的問題，進而延伸第二個設計為探討有效提升LTE MIMO隔離度及降低封包相關係數方法，由兩個將金屬短邊邊框作為輻射部的倒F形天線組成，第一個天線涵蓋低頻880~960 MHz以及高頻1710~2690 MHz之雙寬頻操作；第二個天線利用耦合饋入結構，涵蓋高頻1710~2690 MHz操作頻寬，並藉由耦合電容結構，以及第二個IFA天線短路部置於兩天線之間，藉由導引接地面表面電流，進而降低兩天線間耦合，可以改善隔離度及封包相關係數(ECC)，達成2 × 2 LTE MIMO操作，最後於下方短邊邊框將本設計應用於4 × 4 LTE MIMO操作，以利提高傳輸速率。

LTE MIMO frame antennas for the metal-casing smartphone are presented. The first design includes six antennas (Ant1 to Ant6) and is for the LTE/WLAN MIMO operation. All the antennas are disposed at the short edges of the smartphone. Ant1, Ant2, and Ant5 are disposed at the top edge of the smartphone. Ant1 provides LTE operation in 824~960/1710~2690 MHz. Ant2 covers 1710~2690 MHz for the LTE operation and 1575~1610 MHz for the GPS operation. Ant5 provides WLAN operation. Ant3, Ant4 and Ant6 are disposed at the bottom edge of the smartphone. Ant3, Ant4 and Ant6 follow the design rule of Ant1, Ant2 and Ant5, but Ant4 does not cover the GPS operation band. Ant1 and Ant3 can be applied in 2 × 2 LTE MIMO operation in 824~960 MHz. Ant1, Ant2, Ant3 and Ant4 can be applied in 4 × 4 LTE MIMO operation in 1710~2690 MHz. Ant5 and Ant6 can be applied in 2 × 2 WLAN MIMO operation. However, it is found that the isolation and ECCs of the 4 × 4 LTE MIMO operation in 1710~2690 MHz need to be improved. To solve this coupling issue in the MIMO antennas design, a second design is devised. Two self-decoupled LTE MIMO Antennas are proposed. The first antenna covers 880~960 MHz in the low band and 1710~2690 MHz in the high band. The second antenna covers 1710~2690 MHz in the high band. The second antenna is an inverted-F antenna (IFA) using a frame section along the short edge of the metal casing as the IFA’s radiation strip. The frame section is gap-coupled to a feed network and also short-circuited to the system ground plane at a position between the two antennas. In this case, the excited surface currents on the ground plane will be directed to the frame section of the second antenna, without entering into the feed ports of the antennas. The coupling between two antennas can thereby be greatly decreased and good independent radiation patterns of the two antennas can be obtained. Therefore, isolation and ECCs for the 2 × 2 LTE MIMO operation can be improved. Moreover, two additional antennas of the same can also be disposed at the opposite short edge to achieve a much higher channel capacity for the 4 × 4 LTE MIMO operation.

論文審定書 i
致謝 ii
中文摘要 iii
英文摘要 iv
目錄 v
圖次 vi
第一章 序論 (Introduction)
1.1 研究動機 1
1.2 文獻導覽 2
1.3 論文各章節提要 2
第二章 LTE/WLAN MIMO多天線設計 (MIMO Antennas for the LTE/WLAN Metal-Casing Smartphone)
2.1 天線結構介紹及技術原理說明 4
2.2 實驗結果與分析 14
2.3 延伸設計與討論 19
2.4 心得與討論 22
第三章 寬頻解耦合LTE MIMO多天線設計 (Wideband Decoupled LTE MIMO Antennas)
3.1雙天線結構介紹及結果分析 23
3.2四天線結構介紹與結果分析 33
3.3心得與討論 37
第四章 結論 (Conclusions) 39
參考文獻 (References) 41
著作表 (Publication List) 44

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