只具串聯匹配電路之新型66%頻寬寬頻帶低雜訊放大器

Abstract

本篇論文以低雜訊放大器為例子,提出一種新型只使用串聯元件而沒有並 聯元件的寬頻帶匹配技術.實頻率法用來處理被要求的負載阻抗.接下來, 以實頻率法綜合處理的初始匹配電路,將以Libra最佳化其特性.(1)理想化 的電感,電容,傳輸線和(2)實際的微帶傳輸線,微帶方型電感,跳線和薄膜 電容,做為匹配網路元件.論文中,使用低雜訊放大器 NEC 42484A 砷化鎵 高速電子移動率電晶體,工作頻率在 1GHz-2GHz 為設計例子.不論一級或 二級低雜訊放大器都將有 1dB 的增益起伏及最大 1.5dB 的雜訊. A novel new broadband matching circuit design technique which uses series matching elements only with no shunt elements is presented using low-noise amplifier(LNA) as illustrating exa- mples. The real frequency method is invoked by applying the desired load impedance data. Followed by the real frequency synthesis of the initial matching circuits the performance of LNAs is optimized by Libra. Both (1) ideal lossless elements such as inductor, capacitor and transmission line and (2) practical elements including microstrip lines, microstrip rectangular inductors, ribbon and thin film capacitors are also used for the matching networks. An octave bandwidth of 1 GHz to 2 GHz of the LNA using NEC 42484A GaAs HEMT is dem- onstrated as theoretic design. The one or two-stage LNA des- igns show transducergain of +/- 1 dB flatness and maximum noise figure of 1.5dB.