Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.

S21, RF attenuation between two cross-sections

Please login with a confirmed email address before reporting spam

Hello,

I am trying to simulate a circular wave guide below cut-off to be used as an attenuator. I started with just a cylinder whose boundaries were PECs and each end defined as a port. The S21 followed exponential decay as expected

Now I am exciting the TE11 mode with two parallel wires using a lumped port voltage between them. After simulation I can view the field profile and it is the desired mode. However I would like to know S21 between a short distance after the end of the wires to the end port.

Apparently comsol does not let you define internal boundaries so I am not sure how to do it. I have included a screen shot of my geometry.

Thank you.


1 Reply Last Post 2016年2月23日 GMT-5 09:55

Please login with a confirmed email address before reporting spam

Posted: 9 years ago 2016年2月23日 GMT-5 09:55
I have tried making a cross-sectional work plane and circle with the same radius as the cylinder, and defining that as a port, and enabling the slit condition. Also i tried defining that as a lumped port with h=0. And I tried calling the the pack plate a port but that failed because of the wires going through it. So no luck with any approach and I cant think what else to do. If anyone has any suggestions for defining ports at arbitrary locations or work arounds to find S21 please reply.
I have tried making a cross-sectional work plane and circle with the same radius as the cylinder, and defining that as a port, and enabling the slit condition. Also i tried defining that as a lumped port with h=0. And I tried calling the the pack plate a port but that failed because of the wires going through it. So no luck with any approach and I cant think what else to do. If anyone has any suggestions for defining ports at arbitrary locations or work arounds to find S21 please reply.

Note that while COMSOL employees may participate in the discussion forum, COMSOL® software users who are on-subscription should submit their questions via the Support Center for a more comprehensive response from the Technical Support team.