環狀天線在近場通訊系統下的設計和應用

Abstract

本論文的內容為針對可應用於ISO14443協定下之近場環狀天線(Loop Antenna)設計的研究與分析，內文試圖結合基礎理論與電磁模擬之驗證，進以尋得最佳的天線結構。 於此論文中，吾人利用了微帶傳輸線的理論來設計環狀天線的主體電感架構。從中可分析物理尺寸(懸空高度,線寬,線距,圈數)對於其對應電感值,品質因子( 值)之影響，再利用微帶線的懸空結構及調整導線的線寬進一步降低了渦旋電流的效應，提升品質因子。本論文更進一步探討實作中容易遇到的渦旋電流與雜散寄生電容效應的問題並提出實際的改善方法。

The main focus of this thesis is on the design of near-field loop antenna under the protocol ISO14443. In order to facilitate the antenna design, theoretical investigations and electromagnetic simulation verifications are given in this study to aid the design.

The theory of microstrip transmission lines is used to aid the design of loop inductors in the antenna structure. How does the physical dimensions (suspended height, line width, line spacings and the number of turns) affects the corresponding inductance and quality factor can then be analyzed. Further use suspended structure and adjust the width of the line reduces the effect of the eddy current and improve the quality factor. Moreover, the thesis gives a discussion on the commonly-met eddy current and stray parasitic capacitance effect and provide feasible solutions to compensate them.