摘要
本論文為超高功率磁旋行波管放大器之理論探討，磁旋行波管放大器的操作原理是基於對流不穩定(convective instability)，當輸入的波一邊向前傳遞一邊和電子束交互作用，使得波的振幅隨著軸前進而增大，而有了放大的效果。然而，波導管中的絕對不穩定(absolute instability)不需要輸入訊號，當管內雜訊以返波內部回饋機制(internal feedback) ，即在原地將雜訊放大，而影響放大器的入射波的波源。因此，抑制磁旋放大器中的絕對不穩定，增加穩定操作電流，為設計超高功率磁旋行波管放大器之首要問題。
為了抑制磁旋放大器中的絕對不穩定，我們延續過去的分佈式損耗(distributed loss)的方法，大幅增高管壁損耗以及利用輸出端線圈電流(output coil)製造高梯度磁場。除此之外，我們探討各參數對於絕對不穩定的影響，來抑制在W-band頻段TE01模式的磁旋放大器中的絕對不穩定，以增加操作電流來增高輸出功率，並提高橫截面速度對軸向速度的比值alpha，提升電子和電磁波之交互作用，提升效率。最後，此設計之計算結果達到飽和輸出功率488kW，效率45dB，增益48.8%的超高功率磁旋行波管放大器。

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