本論文主要提出一種新型雙指叉式電容天線架構。其架構利用兩片分開的指叉式電容片來製作一雙頻天線，兩片的指叉式電容片被設計來分別控制 GPS和WLAN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指叉式電容天線設計出應用於 GPS(1.575GHz)與 WLAN (2.45GHz)的天線。雙指叉天線結構設計，一開始需先決定雙頻天線GPS(1.575GHz)與WLAN (2.45GHz)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，以降低雙天線間的相互干擾，如此較能使各頻率維持特性。之後利用雙指叉天線中的第二層線路分別調整GPS(1.575GHz)與WLAN(2.45GHz)之阻抗匹配，以達成雙頻指叉式天線之設計。而上述之雙指叉式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。In the thesis, we will propose a new design of dual inter-digital capacitive antenna. Two separate inter-digital capacitor chips are used to create the main structure of a dual-band antenna. Both capacitors are applied to control the GPS and WLAN two bands. Generally, the antennas, such as a dipole, monopole, and PIFA must be kept a certain distance from the ground, because the antenna performance and radiation pattern are affected by the ground plane. Often the antenna is deployed in the four corners of the motherboard. The proposed structure of the antenna can improve the problems mentioned above. The proposed dual inter-digital capacitive antenna is designed for GPS (1.575GHz) and WLAN (2.45GHz) applications. At first, the area of the dual-band antenna is determined to contain the fork structure of electric capacity and dual-band antenna clearance area. Then the antenna layout and ground endpoint are arranged to reduce the mutual interference between two antennas, while maintaining the antenna characteristics. The second layer line of the dual fork antenna is used to adjust the impedance matching of GPS (1.575GHz) and WLAN (2.45GHz). The proposed dual inter-digital capacitive antenna has been simulated and measured, and good performance has been obtained.
