本篇論文提出兩款不同的天線設計，分別應用不同模態分析方法進行天線設
計，透過特徵模態與本徵模態分析的輔助，使得天線設計過程得以簡化，同時滿
足 WLAN 雙頻段的應用需求。
論文中第一款設計為應用特徵模態分析之 Logo 型 WLAN 雙頻槽孔天線，其
結構施作於印刷電路板上。Logo 型 WLAN 雙頻槽孔天線由兩組字母型槽孔組成，
其低頻頻段由 DEL 型字母槽孔產生共振模態；而高頻則透過兩個模態以涵蓋完
整頻段，頻率 5.25 GHz 的共振模態主要為兩個 L 型槽孔同時激發所產生，5.65
GHz 則由第二個 L 型字母槽孔負責產生模態。透過特徵模態理論，分析天線表面
金屬在不同特徵模態下所對應之電場分佈，所得分析結果有利於天線饋入位置的
優化。
第二款天線設計為應用本徵模態分析之 WLAN 雙頻共振腔天線，天線結構
由高頻共振腔天線與低頻貼片天線整合而成，分別提供 WLAN 高低頻段之模態。
透過本徵模態理論，分析共振腔的截止頻率分佈，並依據所得結果決定共振腔尺
寸。同時為改善天線匹配結果，將所提出的金屬 Stub 饋入設計導入至天線結構中，
最後透過腔體頂部的開槽設計，使天線產生輻射；天線的低頻 WLAN 操作頻段，
係透過吾人所提出之貼片天線設計來涵蓋，並透過金屬銅柱整合兩天線的饋入結
構，達到同時激發 WLAN 雙頻之目的。吾人將共振腔天線的結構特性延伸應用，
增加腔體頂部槽孔數量，並透過射頻二極體模擬槽孔關閉的狀態，達到輻射場型
切換的效果。

This thesis proposes two different antenna designs, by applying different mode
analysis methods. With the aid of characteristic mode and eigenmode analyses, the
antenna design process can be simplified, while the dual-band WLAN operation needs
can be met.
The first part is a Logo-type slot antenna design based on characteristic mode
analysis (CMA). The Logo-type slot antenna comprises two letter-shaped slots which
are implemented on a printed circuit board. The low band is supported by the DEL-shape
letter slot. The high band is covered by two resonant modes. One mode at 5.25 GHz is
generated by two L-shaped slots, and the other mode at 5.65 GHz is generated by the
second L-shaped slot. Through the CMA theory, the electrical current distribution of
metal surface can be examined for different characteristic modes. The results can be
forwarded for optimization antenna feeding positions.
The second part is a cavity backed antenna design using the eigenmode solver
approach. The antenna structure comprises a cavity backed antenna and a patch antenna,
which provides dual-band WLAN operation. In order to determine the cavity sizes, the
results of cut-off frequency are applied using the eigenmode solver. The stub feed
structure is employed to improve antenna matching. The WLAN low band is excited by
the patch antenna. The two antennas are integrated by the metal via to provide dual-band
WLAN operation simultaneously. To implement the beam switching feature, the number
of slots cut on the cavity are increased to four. To change the beam direction, the RF
diodes are applied to control the slot opening state.

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