- 學位論文
SMA接頭到微帶線轉接之新穎設計
Novel Design for SMA Connector-to-Microstrip Line Transitions
摘要
本論文主要是改進SMA接頭轉接微帶線的傳輸特性。有鑑於傳統SMA接頭至微帶線之轉接之1-dB通帶僅到15 GHz左右，為了改善其高頻的使用性，文中提出改良式SMA接頭至微帶線的轉接結構。設計的重點是在SMA接頭前端加上一金屬套環結構，作為SMA接頭轉接至微帶線的緩衝區域，減少因電磁場型變化而產生的耗損，再藉由改變基板接地層結構之設計，使有效改善傳輸特性，提升其應用價值。 本論文並對此一設計之傳輸效能作特性評估。首先針對製程中可能產生的誤差進行分析，並將嚴重影響傳輸特性的製程誤差情形找出彌補方法加以改善。之後探討應用於不同微帶線基板、不同傳輸線及不同SMA接頭設計對傳輸特性的影響，證實論文中所提出的設計是有高度的廣泛適用性。 本研究乃採用有限元素法而發展出之高頻結構模擬軟體HFSS來對此設計作模擬，並依照該設計之最佳化參數進行實作，分別利用背對背(Back-to-Back)結構及以TRL校正技術為基礎之量測方法來進行測量，並與模擬結果作比較。根據文中實際量測結果，背對背結構之直接量測的模擬與實作具有高度一致性，而以TRL校正技術為基礎之量測方法可解出單端SMA接頭到微帶線轉接的響應，其1-dB通帶可提升至26 GHz，與傳統設計作比較，頻寬比可大幅增加約73%左右。
並列摘要
The goal of this thesis is mainly to improve the transmission characteristics of the SMA connector-to-microstrip line transitions. The 1-dB passband of the traditional transitions is only up to 15 GHz. This thesis proposes innovative designs for the transitions in order to increase the 1-dB passband. A metallic ring is attached to the conventional SMA connectors. This ring functions as a buffer between the SMA connector and the microstrip line to reduce the insertion loss caused by the sudden change of the electromagnetic fields from one transmission line to another. Additional modifications on the ground plane of the substrate can effectively improve the transmission characteristics of the transitions, and therefore can promote their value for high-frequency applications. The thesis also evaluates the transmission characteristics of the proposed designs for the transitions. Sensitivity study of the proposed transitions subject to fabrication errors is conducted. Solutions are presented for some cases resulting in severe insertion loss. The applications of the proposed designs to various substrates, transmission lines, and SMA connectors are also examined to demonstrate their wide applicability. The finite element method-based simulation tool, HFSS, is employed to conduct the required simulations for the proposed designs. Optimum design parameters are presented to maintain minimum insertion loss within the transmission passband of interest. The back-to-back connected structure of the transitions and the TRL calibration-based measurement technique are selected for the measurements of the proposed designs to validate their simulation results. The measured data of the back-to-back structure of the design are in good agreement with the simulation results. The TRL calibration-based measurement technique is developed to measure the frequency response of a single transition. The experimental results show that the 1-dB passband is improved to 26 GHz, which is a 73% increase compared to the conventional transitions.