應用於無線網路與無線射頻辨識系統之共平面波導饋入式天線設計

CPW-fed Antenna Designs for Wireless Network and RFID Applications

許慶峰(Ching-Feng Hsu)

國立虎尾科技大學/電機資訊學院/光電與材料科技研究所/碩士(2006年)

摘要

近年來，無線通訊產業蓬勃發展，其中天線元件在無線通訊裝置中扮演重要的角色，設計一個天線具有體積小、結構簡單、製作容易之特性使無線通訊產品具更高度之行動性，是本研究之主要目的。本研究利用共平面波導訊號饋入方式具有僅需單層導體層之特性，來設計出四種可應用於無線網路與無線射頻辨識系統之新型單極天線，且經由模擬與實驗結果分析，調整出適用於各系統對應頻段所需之天線阻抗頻寬、天線輻射場型與天線增益大小等。
本論文中，第一個研究主題為可應用於無線網路之共平面波導饋入式天線設計，提出的兩個天線設計都是利用在天線輻射金屬面加上缺口，使其電流路徑數目增加及長度增長來達到雙頻特性。適當的改變缺口大小可以改善阻抗匹配，使天線阻抗頻寬增加而形成寬頻效果。另一研究主題則以軟性微波基板來設計兩個可折彎式之共平面波導饋入式天線，其中第一個天線設計為利用雙彎臂之輻射金屬微帶線間相互電磁耦合來造成雙頻效果。此天線不僅可以應用於無線區域網路，其可操作頻段亦可適用於無線射頻辨識系統；且實測發現此天線貼於不同曲度之材質上時，天線特性變化並不明顯，非常適合貼附於表面非平坦之通訊裝置上。提出之另一可折彎式共平面波導饋入式天線設計亦可應用於無線射頻辨識系統，此設計利用在長方形金屬導體面上嵌入槽孔的技巧來開發出一個新型的小尺寸天線，天線全尺寸僅為13×15×0.11 mm3，且實驗結果顯示天線以不同曲度彎曲時，天線輻射特性僅產生微小變化，極適合無線射頻辨識系統對天線之小尺寸、軟式可折彎之結構性要求，而具產業利用價值。

並列摘要

Recently, with the increasing development of communication industry the antenna has become an important role for a wireless communication device. Thus, design of an antenna with profits of small size, simple structure, and easy implementation to increase the device’s mobility has become the objective of this research. In this research, by utilizing the coplanar waveguide (CPW) feed skill, four new antenna prototypes have been proposed for applications in the wireless networks and the radio frequency identification (RFID) devices. Corresponding to the device, the required characteristics including impedance bandwidths, radiation patterns, and antenna gains for these antennas can be obtained from numerical simulation and experimental measurement.
The first research topic of this thesis is focused on design of CPW-fed antennas for wireless network applications. Two antennas, of which a notch is embedded to each radiating patch for increasing the number and lengths of the surface current paths and thus to obtain dual-frequency operation, have been proposed. In addition, by properly adjusting the notch size the impedance matching condition and bandwidth can be improved. Another research topic is focused on designs of two flexible CPW-fed antennas for use in a wireless local area network (WLAN) or a RFID system. The first antenna design comprises two meandered striplines for dual-band operation from the electromagnetic coupling effect between them. This proposed antenna is suitable for dual-band WLAN application. For the second proposed flexible antenna design, it is a CPW-fed slotted patch antenna with a very compact size of only 13×15×0.11 mm3 and is suitable for RFID application. The experimental results show that the two antennas both have good antenna characteristics and without significant change when they are folded in various curvatures for attaching on a non-smooth device surface.

參考文獻

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