本論文進行了兩項與天線分集相關的研究。第一部分我們提出了兩個天線的量測系統；首先是天線分集量測系統，由於無線通訊裝置越來越常見，但是裝置的主要使用地區是集中在具有多重路徑散射的環境中，為了抑制多重路徑通道的衰減，通常會使用MIMO和天線分集技巧來克服此干擾，因此天線分集的效能越來越重要，所以本研究提出了一種天線分集的量測系統，用以測量天線分集效能。另一個量測系統則是二維平面掃描式天線遠場量測場；在此系統中，我們將二維掃描平台自動化並同步控制網路分析儀進行取樣，在結合訊號處理演算法後，可產生待測天線的輻射場型。該量測系統可應用在毫米波頻段天線的量測。
第二部分提出了一款應用在無線區域網路頻段無線存取基地台的四天線系統。此系統採用四支相同雙頻段的晶片天線，晶片天線的尺寸大小僅有8.5 × 3 × 1.6 mm3，天線之結構主要包含一條饋入帶線、淨空區以及晶片天線上的迴紋針槽縫。將晶片天線放置於測試板的四個角落來模擬WLAN基地台，藉由四支天線擺放位置的不同，達到空間分集與場型分集的效果。模擬與量測之結果顯示高頻具有良好的隔離度，但在低頻天線間的隔離度較差；為了抑制低頻天線間的耦合，我們在接地面上插入兩條槽縫，破壞地板上的電流分佈。增加解耦合系統後的反射係數可符合IEEE 802.11的標準，而兩操作頻段的天線耦合都有獲得抑制；原型天線以本研究所提出的天線分集量測系統量測，結果顯示該天線系統可以應用在無線區域網路裝置且能提供天線分集的效果。

Two topics relevant to antenna diversity are studied in this thesis. In the first part, two antenna measurement systems are developed. One is a antenna diversity measurement system. Wireless communication devices are usually used in the multi path-rich environment. In order to suppress the multipath fading, MIMO and antenna diversity technology are commonly used methods. Hence an antenna diversity measurement system is devised to measure the diversity performance. The other antenna measurement system is a two dimensional planar scanner that is capable of measuring far-field antenna patterns in the mmWave range. The two dimensional planar scanner operation is automated in conjunction with network analyzers. By implementing post signal processing algorithms, the antenna’s radiation patterns can be derived.
An antenna arrangement made of four similar compact dual-band chip antennas is proposed for uses on WLAN access point devices. The antennas are placed at corners of a small printed circuit board that emulates a WLAN base station. The antenna comprises a feeding line, a clearance region and a chip with a slotted patch. The volume occupied by the antenna chip is 8.5 × 3 × 1.6 mm3 only. Antenna diversity is achieved with a combination of spatial and pattern diversities. In order to suppress the antenna’s coupling, two slits are added to in the ground plane to disturb the current distribution. Reflection coefficient of the decoupled system is comply with the IEEE 802.11 standard, and the isolation in both band is reduced. The antenna diversity performance was measured by the antenna diversity measurement system, the results indicated the proposed antenna configurations can be applied to WLAN devices with the MIMO feature.

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