做输入功率扫描是为什么会增益会波动

好问题。
也和小编一样想知道答案。
我测试到的很多线性放大器有这样的特点。
称作Gain expand。
好像是和增益补偿电路有关系。
期望高手能够帮忙。

many FET power transistors have this character. The possible reason is Vgs is shifting when the PA is powered up to P1dB. You can measure this change with a multimeter (my experience is Vgs will be changed to more than 100%, and the shifting range is related with matching circuit design). The change of Vgs changed gain. The physical reason of gain expansion however I am not very clear.
such expansion is more prominent in high power FETs than low power FETs; for example , 40W FET is more easy to exhibit gain expansion than 10W FETs

谢谢了哈