Plot field of microstrip

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GeneYang

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Hi Gurus, I try to have intuitive understanding of the field distribution in a simple microstrip. As the picture, it can't be simplied as a microtrip, and two wave ports capsulate its endings. The "solution frequency" is at 10GHz. The S21 is normal as almost 0dB from 0 to 10GHz.

But the field is obvious un-even. At port1 it is yellow indicating intense field. At port2 it is deep blue indicating weak field. I can't reconcile it with the S21. I expect even distributed field from port1 to port2.

Can anyone enlighten me?

 

What value have you plotted? This looks like current density in an OPEN ended line.
 

What value have you plotted? This looks like current density in an OPEN ended line.

I chose Quantity as Mag_E, and In Volume as Substrate. The distribution pattern changes if I change frequency value in Intrinsic Variable, so that I wonder it is like standing wave. But I am using wave port without Renormalization. So I think there shouldn't be reflection leading to standing wave.
 

Now I figured out why. Mag_E is real time amplitude at a specified phase, which means it will exhibit the waveform in the space. After using ComplexMag_E, the standing wave pattern disappears.

But it is not the ending. I changed the model to create standing wave by setting wave port impedance different from the microstrip. S21 exhibits clearly filter effect, but ComplexMag_E is still even level along the micro strip.

I am confused.


 

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