近年來極化可調式天線受到相當大的關注，因為它能利用於許多應用上，像是極化掃描、頻率可重複使用以及感測系統。
本文提出了一個新穎的平面式及單層極化可切換天線，所提出的天線設計極化可切換至垂直極化或水平極化。
    本論文所提出的天線可以印刷於印刷電路板上並且利用CPW到ACPS結構來饋送天線，此天線利用偏壓電路來控制二極體做線性極化切換並透過ACPS耦合到CPW來產生CPW的奇模態，而CPW的奇偶模態對提出的天線能分別產生垂直極化或水平極化。
    利用所提出的天線與文獻中的可切換槽孔天線相比較會發現我們所提出的天線具有相對小型的尺寸，並且具有天線結構與天線性能不會隨著接地平面的尺寸改變而改變的優點。此外可以容易調整兩個正交極化的諧振頻率。這個設計可以實現於電路板的邊緣，使其更適合用於實際應用。
 
	
   這在我們所提出的天線的垂直極化與水平極化的中心頻率皆為2.4 GHz,另外垂直極化與水平極化的-10 dB反射系數頻寬皆達到4.56 %以上，此外還測量了天線參數，例如:反射系數、天線兩個輸入端的隔離度、天線的增益及輻射場型圖，並利用實測來驗證所提出的設計。

Polarization reconfigurable antennas have received considerable interest since they are useful for many applications such as polarization diversity, frequency reuse, and sensor systems. In this paper, a novel polarization switchable semi-loop antenna is presented. Polarization of the proposed antenna design can be switched to vertical polarization or horizontal polarization. 
The proposed antenna can be printed on a printed circuit board and utilized a CPW fed to ACPS structure to feed our antenna. This antenna design has a bias circuit to control two PIN diodes. When diode 1 is in the ON state and diode 2 is in the OFF state it is used to produce even mode of the CPW, and another one is when diode 1 is in the OFF state and diode 2 is in the ON state, which is coupled to CPW using ACPS, produces odd mode of the CPW. By exciting even mode or odd mode of the CPW, the proposed antenna can generate vertical polarization or horizontal polarization, respectively. 
Compared to the polarization switchable slot antennas found in the literature, the proposed design has a relatively compact size and has the advantages that the antenna mechanism and antenna performance will not be changed as the size of the ground plane changed. Also, resonant frequencies of the two orthogonal polarization can be easily adjusted. This design can be realized at the edge of the circuit board, making it more suitable for practical applications. 
The center frequency of the vertical polarization and horizontal polarization are both 2.4 GHz and the −10 dB reflection coefficient bandwidth of the vertical polarization and horizontal polarization both are   over than 4.56 %, respectively. Antenna parameters such as reflection coefficient, isolation between two input ports, antenna gain, and radiation patterns are also measured to validate the proposed design.

目錄
中文摘要	I
英文摘要	III
目錄	V
圖目錄	VII
表目錄	XI
第一章 序論	1
1.1 簡介	1
1.2 研究目的	1
1.3 極化切換之方式	3
1.4論文架構	7
第二章 天線理論介紹	8
2.1概述	8
2.2 單極天線	9
2.2.1 映像原理	9
2.2.2 單極天線原理	10
2.3天線極化種類與理論基礎	13
第三章 半環形線性極化可切換式天線	22
3.1簡介	22
3.2半環形極化可切換之天線設計	22
3.3半環形極化可切換天線設計之調整輻射場型之方式	33
第四章 平面式單層線性極化可切換天線	47
4.1簡介	47
4.2 ACPS傳輸線之設計	47
4.3 加入ACPS激發水平極化之設計	49
4.4 平面式單層線性極化切換天線之設計	51
第五章 結論	62
參考文獻	64












 
圖目錄
圖2. 1 映像電流源與映像磁流源圖	10
圖2. 2  1/2波長偶極天線與單極天線電流分佈圖	12
圖2. 3  1/4波長單極天線E平面輻射場型圖	13
圖2. 4 電磁波之E場、H場分佈圖。	14
圖2. 5 線性極化波示意圖	16
圖2. 6右手極化波示意圖；(a)圓形極化波，(b)橢圓極化波	19
圖2. 7左手極化波示意圖；(a)圓形極化波，(b)橢圓極化波	21
圖3. 1半環型天線結構示意圖(a)正面(b)背面	23
圖3. 2調整參數W	24
圖3. 3調整參數L	25
圖3. 4調整參數d	25
圖3. 5半環型天線之S11與S22	26
圖3. 6半環型天線之隔離度	27
圖3. 7半環型天線實體圖(a)正面(b)背面	27
圖3. 8 實測與模擬之S參數圖	28
圖3. 9 電流分佈圖(a)垂直極化(b)水平極化	29
圖3. 10電流分佈向量圖(a)垂直極化(b)水平極化	29
圖3. 11(a) 垂直極化之增益圖	30
圖3. 11(b) 水平極化之增益圖	30
圖3. 12(a) X-Z面的E-theta與E-phi天線輻射場型圖	31
圖3. 12(b) Y-Z的E-theta與E-phi天線輻射場型圖	32
圖3. 13(a) X-Z面的E-theta與E-phi天線輻射場型圖	32
圖3.13(b) Y-Z面的E-theta與E-phi天線輻射場型圖	33
圖3. 14 半環型天線結構示意圖(a)正面(b)背面	34
圖3. 15 天線S參數	35
圖3. 16 天線之隔離度	35
圖3. 17 (a) X-Z面的E-theta與E-phi天線輻射場型圖	36
圖3. 17 (b) Y-Z面的E-theta與E-phi天線輻射場型圖	36
圖3. 18 (a) X-Z面的E-theta與E-phi天線輻射場型圖	37
圖3. 18 (b) Y-Z面的E-theta與E-phi天線輻射場型圖	37
圖3. 19電流分佈圖(a)垂直極化(b)水平極化	38
圖3. 20 (a) 垂直極化之增益圖	38
圖3. 20 (b) 水平極化之增益圖	39
圖3. 21半環型天線結構示意圖(a)正面(b)背面	40
圖3. 22天線之S參數圖	40
圖3. 23天線之隔離度	41
圖3. 24天線之實體圖	41
圖3. 25天線實測與模擬之S參數圖	42
圖3. 26 (a) X-Z面的E-theta與E-phi天線輻射場型圖	43
圖3. 26 (b) Y-Z面的E-theta與E-phi天線輻射場型圖	43
圖3. 27 (a) X-Z面的E-theta與E-phi天線輻射場型圖	44
圖3. 27 (b) Y-Z面的E-theta與E-phi天線輻射場型圖	44
圖3. 28 2.41 GHz電流分佈圖(a)垂直極化(b)水平極化	45
圖3. 29 (a) 垂直極化之增益圖	46
圖3. 29 (b) 水平極化之增益圖	46
圖4. 1 ACPS傳輸線之結構圖	48
圖4. 2 ACPS傳輸線之S21及S31	48
圖4. 3結構圖	50
圖4. 4 天線之返回損耗	50
圖4. 5 電流分佈圖	51
圖4. 6 天線設計結構示意圖	53
圖4. 7天線結構示意圖(a)垂直極化(b)水平極化	53
圖4. 8調整參數W	54
圖4. 9調整參數L	55
圖4. 10調整D2二極體之位置	55
圖4. 11垂直極化與水平極化之S參數	56
圖4. 12天線實體圖	57
圖4. 13天線實測與模擬結果	57
圖4. 14電流分佈圖(a)垂直極化(b)水平極化	58
圖4. 15電流分佈圖(a)垂直極化(b)水平極化	58
圖4. 16 (a) X-Z面的E-theta與E-phi天線輻射場型圖	59
圖4. 16 (b) Y-Z面的E-theta與E-phi天線輻射場型圖	59
圖4. 17 (a) X-Z面的E-theta與E-phi天線輻射場型圖	60
圖4. 17 (b) Y-Z面的E-theta與E-phi天線輻射場型圖	60
圖4. 18 (a) 垂直極化之增益圖	61
圖4. 18 (b) 水平極化之增益圖	61

 
表目錄
表3. 1天線各個參數最佳值	23

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