多頻同軸探針饋入式無線USB收發器天線設計

Design of Multi-Band Coaxial Probe-fed Antennas for Wireless USB Dongle

陳永倫(Yung-Lun Chen)

指導教授 ： 劉文忠

國立虎尾科技大學/工程學院/航空與電子科技研究所/碩士(2011年)

摘要

因應通用串列匯流排(USB)裝置便利於資訊設備端使用，本論文針對此裝置設計一系列天線結構，以提升其無線化。因USB天線被要求體積小、結構簡單，且頻寬上必須涵蓋雙頻帶或多頻帶操作之需求。設計上於是採用同軸探針饋入方式，利用接地面來增加電流路徑長度，達到降低操作頻率及縮小天線尺寸之目的。
　　本研究成果包括(1)非對稱摺疊式天線設計：此天線由摺疊的輻射體與長方形接地面結合，整體尺寸僅為10 × 37 mm2，可激發出兩個頻率位於2.39 及5.57 GHz並具有良好阻抗匹配之共振模態。所得之雙阻抗頻寬分別為270及840 MHz，可應用於2.4/5.2/5.8 GHz之無線區域網路。研究中並分析調整輻射體結構參數對低、高頻共振模態之影響；(2)雙彎臂式天線設計：整體尺寸僅為10 × 37 mm2，且可分別於3.15及4.3 GHz激發出共振模態，所得阻抗頻寬可達1.98 GHz。在本設計中，除量測天線元件之電磁特性外，並將天線連接於筆記型電腦上，以分析電腦裝置對此天線在頻寬及場型等特性上之效應，進而驗證此天線之實際應用價值；(3)矩形槽孔式天線設計：完成設計之天線整體尺寸約為15 × 37 mm2。研究中並發現在適當位置與調整槽孔長度，可激發出三個頻率位於3.42、4.67、5.34 GHz之共振模態，阻抗頻寬則可達10.51 GHz，並可提供抑制5 GHz無線區域網路頻帶操作之功能。

關鍵字

USB ； 同軸探針饋入 ； 筆電 ； 多頻 ； WLAN

並列摘要

It is convenient to use Universal Serial Bus (USB) device with Information Technology (IT) equipment. In the research, the device is designed for a series of antennas to enhance the device’s wireless function. Such antennas are required to have a compact size, a simple structure, and a potential function in dual or multiband operation to cover the possible operating bands. In the device, coaxial probe-fed and ground plane are used to increase the length of current path, which can reduce the operating frequency and the antenna size.
　　The research includes three types of antenna designs. The first type is asymmetric fold including the folded strip radiator with rectangle ground, and its overall size is only 10 × 37 mm2. It generates two resonances at 2.39 GHz and 5.57 GHz. It also has good impedance matching of these two resonance modes. The dual impedance bandwidth with 270 and 840 MHz could be applied to 2.4/5.2/5.8 GHz Wireless Local Area Networks (WLAN). In the study, the researcher also analyzes the influence of its adjusting structure parameters for lower and higher frequency bands. The second type is double-curved arms, and its overall size is only 10 × 37 mm2. This kind of antenna could generate resonant mode excitation in 3.15 and 4.3 GHz respectively, which can help increase impedance bandwidth up to 1.98 GHz. It can be used to measure the electromagnetic characteristic of antenna elements, and it can be connected to a laptop with antenna to analyze the effect of bandwidth and patterns, which can verify the proposed the practical value of the antenna design. The last type is rectangle slot, and its overall size of the complete design is about 15 × 37 mm2. The result of the research proves that putting the slot in an appropriate place and adjusting its length could generate the frequency resonances with 3.42, 4.67, and 5.34 GHz, which can help increase the impedance bandwidths up to 10.51 GHz, and offer the function of inhibiting a 5-GHz-WLAN frequency band.

並列關鍵字

USB ； Coaxial Probe-fed ； laptop ； multi-band ； WLAN

參考文獻

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