本研究探討以一種小型裝置的垂直置放結構的MIMO雙頻天線的操作下之隔離度提升設計， MIMO天線將由兩個不同的天線元件組成，天線的元件為一個具有偶極天線當負載的狹縫(slit)，其中激發槽狹縫將負責低頻帶(2.4GHz) ，偶極負載則負責高頻帶5~6GHz，將兩個同樣的天線元件以極化分集(垂直)的方式置放，藉由天線極化特性可以導致天線之間的互偶量相對減少，並討論幾個不同的設計技巧用以探究將隔離度進一步提升的可能性。 

模擬與實測結果顯示，在共同接地面引進狹長槽孔的垂直置放天線結構，能有效抑制耦合，避免MIMO天線元件的相互干擾；此設計技巧不需額外的主被動元件，亦可減少所需的FR4基板尺寸，且此設計能符合S參數S11<-10dB,S12<-20dB的業界需求，其應用範圍涵蓋IEEE(802.11a/b/g/n/ac)等WLAN頻段。

This thesis is to investigate the MIMO dual-band antenna design for the isolation improvement with two antenna elements perpendicularly placed in a small device. The MIMO antenna consists of two antenna elements, of which each element consists of two antenna components: one is a narrow slit antenna, which is responsible for the radiation at low band (2.4GHz), the other is a dipole antenna, which serve as the load of the previous narrow slit antenna and is responsible for the high-band (5~6GHz). These two antenna elements are perpendicularly placed in order to achieve the polarization diversity, such that the coupling between the antenna elements can be reduced. In this thesis, several different design techniques are explored for the possibility to further enhance the isolation.
Simulated and experimental results show that the introduction of a narrow slit, in the common ground plane of the two planar antenna elements placed perpendicularly, can effectively inhibit the coupling to avoid mutual interference of the MIMO antenna element. This design skill can reduce the FR4 substrate size required, and doesn't need additional active and/or passive components. Also, this antenna design is able to meet the industry demands of S-parameter (|S11|<-10dB, |S12|<-20dB), and its scope of application covers IEEE (802.11a / b / g / n / ac) WLAN band.

目錄
中文摘要....................................................................................................I
英文摘要...................................................................................................II
內文目錄.................................................................................................III
圖表目錄..................................................................................................IV
第一章  序論............................................................................................1
    1.1  簡介...........................................................................................1 1.2  研究目的與動機.......................................................................1
    1.3  論文架構...................................................................................5
第二章  以垂直置放結構提升平面天線的隔離度...............................6
    2.1  提升隔離度方式之簡介...........................................................6
    2.2  天線水平置放結構...................................................................8
    2.3  天線垂直置放結構.................................................................12
    2.3.1天線垂直置放結構—加入狹長孔..........................................19
    2.3.2天線垂直置放結構—具相反金屬接地面.............................31
    2.3.3天線垂直置放結構—加入貫穿孔牆.....................................40
第三章  輻射場型、增益與效率之量測..............................................43
第四章  結論..........................................................................................58
參考文獻..................................................................................................60

圖目錄

圖1.1 WLAN IEEE802.11 演進.............................................................................2
圖1.2 WLAN IEEE802.11支援最大天線數..........................................................3
圖2.1 MIMO多天線架構傳輸方式與數學模型.....................................................6
圖2.2 水平置放MIMO正反面示意圖...................................................................9
圖2.3 水平置放MIMO天線正面尺寸圖...........................................................10
圖2.4 水平置放MIMO天線反面尺寸圖...........................................................10
圖2.5 水平置放MIMO天線間距d之S21參數模擬圖................................11
圖2.6 垂直置放MIMO天線正反面示意圖........................................................13
圖2.7 垂直置放MIMO天線正面尺寸圖...........................................................14
圖2.8 垂直置放MIMO天線反面尺寸圖...........................................................14
圖2.9 垂直置放MIMO天線之S參數模擬圖...............................................15
圖2.10垂直置放MIMO天線2.4GHz電場分布圖.............................................16
圖2.11垂直置放MIMO天線2.5GHz電場分布圖.............................................16
圖2.12垂直置放MIMO天線5GHz電場分布圖.............................................17
圖2.13垂直置放MIMO天線5.5GHz電場分布圖.............................................17
圖2.14垂直置放MIMO天線6GHz電場分布圖.............................................18
圖2.15 帶止濾波器RLC並聯等效電路............................................................22
圖2.16 垂直置放MIMO天線加入狹長孔正反面示意圖................................22
圖2.17 垂直置放MIMO天線加入狹長孔正面尺寸圖....................................23
圖2.18 垂直置放MIMO天線加入狹長孔反面尺寸圖....................................23
圖2.19 垂直置放MIMO天線加入狹長孔之S11參數模擬圖.......................24
圖2.20 垂直置放MIMO天線加入狹長孔之S21參數模擬圖........................24
圖2.21 垂直置放MIMO天線加入狹長孔27.58mm之天線實體圖....................26
圖2.22垂直置放MIMO天線加入狹長孔27.58mm之模擬與實測值........26
圖2.23 垂直置放MIMO天線加入狹長孔2.4GHz電場分布圖....................27
圖2.24 垂直置放MIMO天線加入狹長孔2.5GHz電場分布圖.......................27
圖2.25 垂直置放MIMO天線加入狹長孔5GHz電場分布圖.........................28
圖2.26 垂直置放MIMO天線加入狹長孔5.5GHz電場分布圖......................28
圖2.27 垂直置放MIMO天線加入狹長孔6GHz電場分布圖........................29
圖2.28垂直置放MIMO天線加入狹長孔55.15mm之天線實體圖................29
圖2.29 垂直置放MIMO天線加入狹長孔55.15mm之模擬與實測................30
圖2.30 垂直置放MIMO天線具相反金屬面與狹長孔55.15mm參數模擬圖..32
圖2.31垂直置放MIMO天線-具相反金屬面正反面示意圖......................34
圖2.32 垂直置放MIMO天線-具相反金屬面正面尺寸圖…......................35
圖2.33垂直置放MIMO天線-具相反金屬面反面尺寸圖…......................35
圖2.34 垂直置放MIMO天線-具相反金屬面2.4GHz電場分佈......................36
圖2.35 垂直置放MIMO天線-具相反金屬面2.5GHz電場分佈..........................36
圖2.36 垂直置放MIMO天線-具相反金屬面5GHz電場分佈.............................37
圖2.37垂直置放MIMO天線-具相反金屬面5.5GHz電場分佈..........................37
圖2.38 垂直置放MIMO天線-具相反金屬面6GHz電場分佈.............................38
圖2.39 垂直置放MIMO天線-具相反金屬面之天線實體圖..................................38
圖2.40 垂直置放MIMO天線-具相反金屬接地面之S參數模擬圖.....................39
圖2.41 垂直置放MIMO天線加入狹長孔與貫穿孔正反面示意圖.......................41
圖2.42 垂直置放MIMO天線加入狹長孔與貫穿孔之S參數模擬圖...................41
圖2.43 垂直置放MIMO天線具相反金屬面與貫穿孔正反面示意圖...................42
圖2.44 垂直置放MIMO天線具相反金屬面與貫穿孔之S參數模擬圖..............42
圖3.1 OTA測試環境照.........................................................................................44
圖3.2 垂直置放MIMO天線加入狹長孔的座標平面...........................................44
圖3.3 垂直置放MIMO天線-具相反金屬接地面的座標平面...............................44
圖3.4 垂直置放MIMO天線加入狹長孔XY平面(2.4GHz)場型實測.................45
圖3.5 垂直置放MIMO天線加入狹長孔XY平面(2.5GHz)場型實測.................45
圖3.6 垂直置放MIMO天線加入狹長孔XY平面(5GHz)場型實測…................46
圖3.7 垂直置放MIMO天線加入狹長孔XY平面(5.5GHz)場型實測.............46
圖3.8 垂直置放MIMO天線加入狹長孔XY平面(6GHz)場型實測…..................46
圖3.9 垂直置放MIMO天線加入狹長孔XZ平面(2.4GHz)場型實測.................47
圖3.10 垂直置放MIMO天線加入狹長孔XZ平面(2.5GHz)場型實測.................47
圖3.11 垂直置放MIMO天線加入狹長孔XZ平面(5GHz)場型實測...................48
圖3.12 垂直置放MIMO天線加入狹長孔XZ平面(5.5GHz)場型實測.................48
圖3.13 垂直置放MIMO天線加入狹長孔XZ平面(6GHz)場型實測...................48
圖3.14 垂直置放MIMO天線加入狹長孔YZ平面(2.4GHz)場型實測.................49
圖3.15 垂直置放MIMO天線加入狹長孔YZ平面(2.5GHz)場型實測.................49
圖3.16 垂直置放MIMO天線加入狹長孔YZ平面(5GHz)場型實測.................50
圖3.17 垂直置放MIMO天線加入狹長孔YZ平面(5.5GHz)場型實測.................50
圖3.18 垂直置放MIMO天線加入狹長孔YZ平面(6GHz)場型實測..................50
圖3.19 垂直置放MIMO天線-具相反金屬面XY平面(2.4GHz)場型實測.........51
圖3.20 垂直置放MIMO天線-具相反金屬面XY平面(2.5GHz)場型實測.........51
圖3.21 垂直置放MIMO天線-具相反金屬面XY平面(5GHz)場型實測............52
圖3.22 垂直置放MIMO天線-具相反金屬面XY平面(5.5GHz)場型實測.........52
圖3.23 垂直置放MIMO天線-具相反金屬面XY平面(6GHz)場型實測............52
圖3.24 垂直置放MIMO天線-具相反金屬面XZ平面(2.4GHz)場型實測............53
圖3.25 垂直置放MIMO天線-具相反金屬面XZ平面(2.5GHz)場型實測............53
圖3.26 垂直置放MIMO天線-具相反金屬面XZ平面(5GHz)場型實測............54
圖3.27 垂直置放MIMO天線-具相反金屬面XZ平面(5.5GHz)場型實測............54
圖3.28 垂直置放MIMO天線-具相反金屬面XZ平面(6GHz)場型實測............54
圖3.29 垂直置放MIMO天線-具相反金屬面YZ平面(2.4GHz)場型實測............55
圖3.30 垂直置放MIMO天線-具相反金屬面YZ平面(2.5GHz)場型實測............55
圖3.31 垂直置放MIMO天線-具相反金屬面YZ平面(5GHz)場型實測............56
圖3.32 垂直置放MIMO天線-具相反金屬面YZ平面(5.5GHz)場型實測............56
圖3.33 垂直置放MIMO天線-具相反金屬面YZ平面(6GHz)場型實測............56

表目錄

表2.1 一般提高MIMO天線隔離度之方式...............................................................7
表2.2 水平置放MIMO天線間距d之S21參數值...................................................11
表2.3 垂直置放MIMO天線之S參數值................................................................15
表2.4 垂直置放MIMO天線加入狹長孔之S11參數值.........................................25
表2.5 垂直置放MIMO天線加入狹長孔之S21參數值........................................25
表2.6 垂直置放MIMO天線加入狹長孔27.58mm模擬與實測值.......................26
表2.7 垂直置放MIMO天線加入狹長孔55.15mm模擬與實測值......................30
表2.8 垂直置放MIMO天線-具相反金屬接地面之S參數值...............................32
表2.9 垂直置放MIMO天線加入狹長孔與貫穿孔之S參數值............................39
表2.10 垂直置放MIMO天線-具相反金屬面與貫穿孔之S參數值.......................41
表3.1 垂直置放MIMO天線加入狹長孔之天線增益與效率實測值.....................57
表3.2 垂直置放MIMO天線加入狹長孔之天線增益與效率實測值.....................57

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