S頻帶高效率及高功率放大器

Abstract

本論文是設計一在S 頻帶上的高效率且高功率放大器，我們實際地做出這個電路，並且量測其結果。此高 效率放大器因低功率損耗所以其體積小，重量輕，適用於可攜式無線電系統。 在設計的過程中，我們使用用一等效模型來模擬電晶體的特性，如此便可借由電腦輔 助設計軟體來模擬此電路。本放大器的設計概廓主要是來自一諧波反動放大器的理念 ，諧波反動放大器是由一組功率電晶體構成，這關鍵在於流經兩電晶體的通路中，二 階諧波可相互抵消，因此造成一種穩定的開關現象，便可提高放大器的效率。最後， 我們設計、製作、測量一個2.2GHz達到百分之五十八功率增加效率和輸出功率2.55瓦 特的微波放大器。

In this thesis, a S band high efficiency and high power amplifier is designed. Fabrication, and measurements of the circuit are also presented. This amplifier has low power consumption, therefore, battery size can be small and light weight and very suitable for portable radio unit. This paper reports on a design routine to design the high efficiency power amplifier. The nonlinear GaAs FET''s device model was created and it provide us with the large-signal information for computer aided design. This amplifier design is from the mechanism of Harmonic Reaction Amplifier (HRA). The HRA is basically constructed with a pair of power FETs. The technical originality lies in a provision of an interconnecting circuit concerning a second-harmonic output component between FETs. This additional circuit realizes an efficient and stable switching-mode operation, which required for the attainment of highly efficient microwave power amplification. This amplifier circuits is constructed with microstrip line. Experimental results at 2.2 GHz are maximum power-added efficiency of 58 % and highest output power of 2.55 W.