摘要 本論文主要提出一種新型雙向指叉式雙頻天線架構。其架構利用一雙向指叉式電容片來製作一雙頻天線，雙向指叉式電容片的兩端被設計來分別控制 2.45GHz和5.5GHz兩個頻段，一般的波長共振模式的天線如 Dipole，Monopole，PIFA都必須和接地面保持一定距離，不然天線效能和輻射場型皆會受到接地面的影響效能上變差，並且在安裝方式也遭受到相當大的限制，天線的安裝位置一般只能受限在主板的四個角落，該新架構的天線能改善上述問題點。 在本文中使用新型雙向指叉式雙頻天線設計出應用於 WLAN(2.45GHz)與 WLAN (5.5GHz)的天線。雙向指叉式雙頻天線結構設計，一開始需先決定雙頻天線WLAN(2.45GHz)與WLAN (5.5GHz)指叉式結構的電容量和雙頻天線淨空區之大小預留，進而安排天線的相關佈局和各自接地端點，如此較能使各頻率維持特性。之後利用雙向指叉天線中的耦合電容量及完成WLAN(2.45GHz)與WLAN(5GHz)之阻抗匹配，以達成雙向指叉式雙頻天線之設計。 而上述之雙向指叉式雙頻天線都已透過模擬與量測之方式，實際驗證出具有良好之特性。 ;Designs of Dual-Band Small Antenna Using Two-Way Inter-Digital Structures for WLAN Applications Abstract In the thesis, a new design of dual-band small antenna using inter-digital structures for WLAN (2.45 and 5.5 GHz) applications is proposed. In the design, two-way inter-digital capacitor chips are used as the main structure of the antenna, in which both ends of the capacitors are designed to control the center frequencies of 2.45 GHz and 5.5 GHz. Generally, the radiation pattern of the proposed antenna is similar to the dipole, monopole, or PIFA with a ground nearby. Therefore, the antenna performance and radiation pattern are affected by the presence of the ground plane, causing some limitation in antenna installation. The antenna is generally deployed in the four corners of the motherboard. Nevertheless, the proposed structure of the antenna can improve the problems mentioned above. The area in the design is sufficient to contain the fork structure of electric capacity and dual-band antenna clearance area. The antenna layout and ground endpoint are arranged, while maintaining the antenna characteristics. With the bidirectional interdigitated coupling capacitance, the impedance matching of the antenna at both (2.45 GHz and 5.5 GHz) bands is achieved to obtain the two-way design of the dual-band antenna. The proposed two-way dual-band inter-digital antenna has been simulated and measured, and good performance has been obtained.
