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  • 學位論文

無線通訊應用之共面波導饋入開槽天線之設計

Design of Coplanar Waveguide-Fed Slot Antennas for Wireless Applications

指導教授 : 許博文

摘要


本論文提出一系列具有不同阻抗及輻射特性之共面波導饋入開槽天線,其中包含三種開槽天線以及兩種開槽陣列天線,可分別應用於不同的無線通訊系統中。 在開槽天線方面,以共面波導饋入之開槽偶極天線為基礎,論文中介紹了三種新型的開槽天線以滿足不同的系統需求,包含雙頻、寬頻與微小化之設計。首先,在第二章中提出雙頻之放射狀開槽天線,藉由提高中間開槽對的長度,可形成兩個共振頻率,改變開槽間的夾角可調整共振頻率比,其範圍介於1.3與2.1之間,並經實驗佐證,最後將量測得到之資料整理成設計曲線。接著,在第三章中結合共面波導饋入之寬頻領結形開槽天線與延遲開槽線段,並將領結形開槽之左半或右半邊翻轉,得到三個改良型設計,其中最大的工作頻寬可提昇至約為領結形開槽天線的兩倍。最後,在第四章中提出一微小化之電容性折疊式開槽天線,並探討有限大小的接地面對該天線之輸入阻抗的影響,以利縮小天線面積。 在開槽陣列天線方面,第五章中提出終端開路之城垛形開槽陣列天線,將城垛形開槽線之終端以開路取代原本短路的設計,可提高天線的輻射效率及增益,改善遠場輻射場型,同時縮小天線面積,此外,該天線結構簡單,極易設計成一維或二維之陣列天線。第六章中則提出一寬頻之號角形開槽陣列天線,利用號角形開槽本身的寬頻特性,適當地設計輻射單元間的饋入傳輸線網路,即可大幅提昇其工作頻寬及天線增益。

關鍵字

共面波導 開槽天線

並列摘要


In this dissertation, a new category of coplanar waveguide (CPW)-fed slot antennas with various impedance and radiation characteristics, including three slot antennas and two slot array designs, is presented. These antennas can find applications in a variety of wireless communication systems. Based on the CPW-fed slot dipole antenna, three novel designs of CPW-fed slot antennas are proposed to satisfy different system requirements, including the dual-band and wideband operations and the miniaturization. First of all, in Chapter 2, the CPW-fed radial slot antenna is developed for dual-frequency operation. By increasing the length of the central slot pair, an additional lower resonant frequency can be obtained. Various frequency ratios, within the range of about 1.3 to 2.1, of the two resonant frequencies can be achieved by varying the included angle between the radial slots, and they are verified experimentally. Design curves are last plotted according to the measurement results. Secondly, in Chapter 3, the flip-over of one half of the bow-tie slot and the insertion of the delay slotline sections into the CPW-fed bow-tie slot antenna with broadband essence results in three modified designs, of which the maximum operation bandwidth can be increased to be twice that of the original bow-tie slot antenna. In Chapter 4, the CPW-fed capacitive folded-slot antenna and its miniaturization are presented. To facilitate the miniaturization, the effect of the finite size of the ground plane on the input matching condition is discussed and verified experimentally. For the CPW-fed slot array antennas, the open-ended rampart slot array antenna is proposed in Chapter 5. The shunt rampart slotline pairs are terminated in open circuits instead of short ones so as to increase the antenna efficiency and gain, improve the radiation patterns, and simultaneously reduce the antenna size. Furthermore, the antenna structure is simple and can easily be designed in the form of linear or planar arrays. Finally, in Chapter 6, the CPW-fed horn-shaped slot array antenna is presented to possess a wider operation bandwidth, which results mainly from the inherently broadband feature of the radiating horn-shaped slot elements. By properly placing the radiating slots and carefully designing the feeding network, the peak antenna gain of the horn-shaped slot array antenna can be increased enormously without influencing the wideband characteristics.

並列關鍵字

coplanar waveguides slot antennas

參考文獻


[1] C. P. Wen, “Coplanar waveguide: A surface strip transmission line suitable for nonreciprocal gyromagnetic device applications,” IEEE Trans. Microwave Theory Tech., vol. MTT-17, no. 12, pp. 1087-1090, Dec. 1969.
[3] X. Ding, and A. F. Jacob, “CPW-fed slot antenna with wide radiating apertures,” IEE Proc.-Microw. Antennas Propagat., vol. 145, no. 1, pp. 104-108, Feb. 1998.
[4] H.-D. Chen, “Broadband CPW-fed square slot antennas with a widened tuning stub,” IEEE Trans. Antennas Propagat., vol. 51, no. 8, pp. 1982-1986, Aug. 2003.
[5] J.-Y. Chiou, J.-Y. Sze, and K.-L. Wong, “A broad-band CPW-fed strip-loaded square slot antenna,” IEEE Trans. Antennas Propagat., vol. 51, no. 4, pp. 719-721, Apr. 2003.
[6] R. Chair, A. A. Kishk, K.-F. Lee, “Ultrawide-band coplanar waveguide-fed rectangular slot antenna,” IEEE Antennas and Wireless Propagat. Lett., vol. 3, pp. 227-229, 2004.

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