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Rectangular input port phase shift possible bug (microwave heating)

Posted 05.04.2013, 06:19 GMT-4 RF & Microwave Engineering Version 4.3a 2 Replies

Luca De Stefano
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Hi all,

I'm working with the microwave heating module to simulate the heating of a load with highly non-linear material properties (varying with temperature).

I have two input ports both set on ON.

Since using coaxial ports the model doesn't converge, I am using rectangular ports and it works (very slow but it works).

The problems start when i try to phase shift the 2 input ports; when I modify the phase of one port (the internal variable name is 'Thetap') and I compute, Comsol suddenly crashes and closes.

Is it a bug? Am I doing something wrong?

(if you want to try and see yourself you can draw a cavity with two rectangular ports and vary the phase on one of the two, it's very fast and simple)

Thanks!

Luca
2 Replies Last Post 05.04.2013, 06:35 GMT-4
Edgar J. Kaiser Certified Consultant
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Posted: 1 decade ago 05.04.2013, 06:31 GMT-4

Hi,

I recently did some work that involved two uniform lumped ports with a phase shift in the RF module. This worked without problems.

There was one thing that surprised me though: The phase imput field didn't accept a parameter. It only worked with an explicit number. If I used a parameter it was treated as zero.

Cheers
Edgar

--
Edgar J. Kaiser
www.emphys.com
Hi, I recently did some work that involved two uniform lumped ports with a phase shift in the RF module. This worked without problems. There was one thing that surprised me though: The phase imput field didn't accept a parameter. It only worked with an explicit number. If I used a parameter it was treated as zero. Cheers Edgar -- Edgar J. Kaiser http://www.emphys.com
Luca De Stefano
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Posted: 1 decade ago 05.04.2013, 06:35 GMT-4

Hi,

I recently did some work that involved two uniform lumped ports with a phase shift in the RF module. This worked without problems.

There was one thing that surprised me though: The phase imput field didn't accept a parameter. It only worked with an explicit number. If I used a parameter it was treated as zero.

Cheers
Edgar

--
Edgar J. Kaiser
www.emphys.com


Thanks for the answer, for me it worked with coaxial ports, apparently the problem concerns only rectangular ports..

The problem is that with rect ports my simulation finds a solution, with coaxial ports it doesn't.. maybe i could try lumped ports, but i think it would go too far from my real model..

Thanks

Luca
[QUOTE] Hi, I recently did some work that involved two uniform lumped ports with a phase shift in the RF module. This worked without problems. There was one thing that surprised me though: The phase imput field didn't accept a parameter. It only worked with an explicit number. If I used a parameter it was treated as zero. Cheers Edgar -- Edgar J. Kaiser http://www.emphys.com [/QUOTE] Thanks for the answer, for me it worked with coaxial ports, apparently the problem concerns only rectangular ports.. The problem is that with rect ports my simulation finds a solution, with coaxial ports it doesn't.. maybe i could try lumped ports, but i think it would go too far from my real model.. Thanks Luca

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