應用於區域網路之多輸入多輸出迴圈槽孔複合式天線設計

Abstract

本文提出一種應用於無線區域網路(WLAN)之雙頻多輸入多輸出迴圈槽孔複合式天線，此天線之輻射機制源於兩種諧振結構之結合：金屬迴圈結構與槽孔結構，以此兩種結構結合而成之天線滿足無線區域網路24億赫茲(24 ~ 24.85億赫茲)與50億赫茲(51.5 ~ 58.5億赫茲)之操作頻寬，並以中和線技術針對天線之間的隔離度進行改善。本文所提出之天線實現於一全金屬背蓋之超薄型平板電腦，此平板電腦尺寸為 214 x 183 x 6 立方毫米，天線置於金屬背蓋之上且緊鄰液晶螢幕，此天線尺寸僅有60 x 7.5 x 4.5立方毫米。 根據量測結果，若以 -10分貝為天線操作頻寬之定義，則在無線區域網路所需之兩個頻帶分別有 1.3億赫茲與 11億赫茲之操作頻寬，而天線間的隔離度在兩頻帶內分別被改善至 -16分貝與 -23分貝，此天線在天線增益與天線效率方面解有良好了輻射表現，此外，包含包絡相關係數與通道容量之天線分集評估也在文中有進一步的探討。

A novel compact dual-band loop-slot combination MIMO antenna for wireless local area network (WLAN) applications is proposed. The radiation mechanism is based on two types of resonant structure, metal loop and slot line, combined into a single antenna to achieve WLAN 2.4 (2.4 ~ 2.484 GHz) and 5 GHz (5.15 ~ 5.85 GHz) operation. The decoupling element is based on the neutralization line technique. The proposed antenna is implemented in an ultra-thin tablet computer of dimensions 241 x 183 x 6 mm3 with a fully metallic cover on the bottom. The size of the proposed antenna is only 60 x 7.5 x 4.5 mm3 with a metal bottom cover below and a LCD panel nearby. The scattering coefficient measured from the antenna demonstrates that the operation bandwidth is 130 and 1100 MHz using a -10 dB definition and the isolation is improved -16 and -23 dB in WLAN 2.4 and 5 GHz bands, respectively. The good radiation performance as antenna gain and antenna efficiency is also achieved. In addition, antenna diversity assessments including the envelope correlation coefficient and the channel capacity are also studied in this thesis.