摘要：
本文為瞭解磁旋行波放大器的寬頻與高功率特性之後，並知道在磁旋行波放大器中會有絕對不穩定的產生。因為絕對不穩定會原地長起來，而影響放大器上游的入射波的波源，所以本文計算的方法為先去算可能存在的絕對不穩定對操作電壓與外加磁場的起振電流，指出在不同操作電壓與外加磁場下的穩定操作區（即為絕對不穩定之起振電流不起振的電壓與磁場操作範圍）。之後在穩定操作區去計算磁旋行波放大器的飽和功率、飽和增益、飽和3dB頻寬與飽和效率，計算磁旋行波放大器的飽和功率與飽和3dB頻寬可以藉著改變磁場與電壓提升到多高。計算結果顯示，操作電壓在90kV附近可以達到飽和高功率的放大器，但是此時的飽和3dB頻寬卻很窄。另外亦算出在操作電壓低一點的範圍，雖然飽和3dB頻寬會比較寬，但是飽和功率卻很低。最後計算磁旋行波放大器再加上調變磁場，同樣調變磁場的範圍也必須是可以抑制絕對不穩定的。最後計算出的結果顯示，當操作電壓在100kV磁場在1.012Bzg01時，可以得到一個高功率的磁旋行波放大器，飽和功率為168.2kW，飽和效率33.6%、飽和增益57.7dB、飽和3dB頻寬2.2GHz(2.4%)。另外當操作電壓在50kV磁場在0.996Bzg01時，可以得到一個寬頻的磁旋行波放大器，飽和功率為70.0kW，飽和效率28.0%、飽和增益69.9dB、飽和3dB頻寬7.2GHz(7.9%)。所以如果需求的為一個寬頻的放大器，但是對功率的要求不一定要很高，可以把操作電壓降低，然後再去適當選擇一的外加磁場即可得到3dB頻寬很寬的磁旋行波放大器。

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