Some TEM / Q TEM modes were not considered at port 1, 求解答
Some TEM / Q TEM modes were not considered at port 1.This may lead to an inaccurate energy blance.
求高手解答.....
這段英語是什么意思,樓主先翻譯一下?
彷彿說部分的TEM/QTEM模式?jīng)]有考慮在波端口,有可能導致不精準的能量平衡.
試著將波端口大小更改但是訊息仍在...
求解器設置的端口模式?是使用的標準波導么?上CST文件吧
Construction:StripLine
Frequency:020GHz
Transient Solver
Accuracy 30dB
Waveguide port Type: Differential port
Waveguide port size : width 5*w
為什么要改端口大???有什么理論可以支持這種做法嗎?
什么是differential port的波導端口?樓主你是想說Multipin Waveguide Port嗎?如果是,樓主如何確定已經(jīng)完整的設置了端口可能存在的傳輸模式?
所以要增加Number of modes?
高次模出現(xiàn)?
工作頻率20GHz ,PCB介電常數(shù)=4 ,波長=7.5mm,
導線寬度<(7.5mm/(2*sqrt(4)))<<<導線寬度設置=0.5mm
與地高度<(7.5mm/(2*sqrt(4)))<<<與地高度=1mm
導線寬度與地高度都在範圍內(nèi)猜想應該能保持TEM
Some (Q)TEM modes are not considered at port "xxx". This may lead to an inaccurate energy balance.
It is important that the number of defined potential sets equals the number of degenerated QTEM or TEM modes in the waveguide. If not a large part of the field may propagate in the unconsidered mode patterns. The waveguide port boundary still treats these fields internally but they will not contribute to the scattering matrix and may therefore lead to an inaccurate energy balance.
這是CST在模擬時出現(xiàn)的警告&建議說明,但是怎麼改善我還摸不著頭緒
對于multipin waveguide port,如果設置的potential沒有“照顧”到所有可能的QTEM或者TEM傳輸模式,那么那部分的傳輸模式的能量不會反映在S參數(shù)中,這有可能導致不準確的energy balance。
以上是可能性,不是必然性,有可能S參數(shù)的數(shù)值沒有明顯的變化。
解決方法就是要提前知道在設置的頻段之內(nèi)微波器件有可能的傳播模式并且設置對應的potential。如果是在不知道,可以先設置普通waveguide port,手動增加mode,看看都存在什么樣的傳輸模式。