圓極化器中高次模對軸比的影響

小弟現(xiàn)在在仿真一個圓波導(dǎo)中的螺釘圓極化器，但是圓波導(dǎo)的電尺寸較大，高次模TM01、TE21、TE01和TM11模都可以傳輸。我現(xiàn)在就是不知道怎么考察或計算這些高次模對圓極化器軸比的影響（我從論文上看到的軸比計算公式好像是只針對主模的）...
PS：1、從仿真結(jié)果看，由主模激勵起的高次模傳輸系數(shù)S2(n),1(1)都在-25dB以下，是不是就可以不用考慮由主模激勵起的高次模對軸比的影響啦？
2、由于圓波導(dǎo)電尺寸較大，如果激勵端口本來就有高次模，怎么考察或計算這些高次模對軸比的影響呢？
小弟才疏學(xué)淺，望各位大俠給點建議吧，小弟感激不盡

first one
the fact is not familiar with what you said,-25db is the level of cross-polarization. if theexcitation is the main mode, the purpose you addressed is correct. those evanescent mode will vanish in a certain distance which is yield to the vector of wave. if the distance is large than the distance which is in your project, it should be considered.
second one
you can port a high mode, and get the frequency response. due to the proportion of different modes's energy, the final respone can be handled.

Thank you very much for your explaination!!!