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How to excite a Microstrip?

Posted Apr 8, 2014, 4:33 a.m. EDT Low-Frequency Electromagnetics, MEMS & Nanotechnology, RF & Microwave Engineering, MEMS & Piezoelectric Devices Version 4.4 4 Replies

Alex J
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Dear community,

i am currently designing a microwave resonator consisting of microstrips.

Does anyone know how to put an excitation just along one strip, as in a coax cable without outer conductor?

I havent found that in any complete model.
The port and lumped port can only apply fields or voltages between two adjacent parts of my geometry, if i got it correctly.

Thank you a lot in advance
4 Replies Last Post Apr 14, 2014, 8:43 a.m. EDT
Edgar J. Kaiser Certified Consultant
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Posted: 1 decade ago Apr 8, 2014, 4:58 a.m. EDT
Hi Alex,

a coaxial cable with stripped off outer conductor can be seen like being excited by a lumped port between the end of the shield and the center wire.
Maybe you have to explain your requirements a little clearer, e.g. with a sketch

Cheers
Edgar

--
Edgar J. Kaiser
emPhys Physical Technology
www.emphys.com
Hi Alex, a coaxial cable with stripped off outer conductor can be seen like being excited by a lumped port between the end of the shield and the center wire. Maybe you have to explain your requirements a little clearer, e.g. with a sketch Cheers Edgar -- Edgar J. Kaiser emPhys Physical Technology http://www.emphys.com
Alex J
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Posted: 1 decade ago Apr 8, 2014, 7:40 a.m. EDT
Thanks for your fast response!

If i just remove the outer conductor, I think there will be impedance matching troubles.

There are devices called coaxial to microstrip connector, but since there isnt something like that in comsol, I will try using an AC voltage as drawn in the PNG.

Is there a way to connect my resonator to the external circuit? There is no real 'port', the resonator is a thin layer of copper forming an omega.

Best regards
Alex
Thanks for your fast response! If i just remove the outer conductor, I think there will be impedance matching troubles. There are devices called coaxial to microstrip connector, but since there isnt something like that in comsol, I will try using an AC voltage as drawn in the PNG. Is there a way to connect my resonator to the external circuit? There is no real 'port', the resonator is a thin layer of copper forming an omega. Best regards Alex
Edgar J. Kaiser Certified Consultant
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Posted: 1 decade ago Apr 8, 2014, 9:28 a.m. EDT

How do you realize ground in your model? A microstrip has a ground plane under the strip.

--
Edgar J. Kaiser
emPhys Physical Technology
www.emphys.com
How do you realize ground in your model? A microstrip has a ground plane under the strip. -- Edgar J. Kaiser emPhys Physical Technology http://www.emphys.com
Alex J
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Posted: 1 decade ago Apr 14, 2014, 8:43 a.m. EDT
Hi,

as everytime after asking questions, I got some insights and ideas, so my model advanced, I attached it.

I wanted to make a microstrip similar to the goubau line, without ground plane, but then decided to realize the ground by another strip.

Could you please give me a hint how to improve my meshing? Solver warns me of low minimum element quality but i dont see any other possibility to sensibly resolve my structure.

Is there an option to find the resonance frequency instead of searching the maximum of
(Pport_1-Pelement_1)/Pport_1?

I would be again really glad if u could help me

cheers
Alex
Hi, as everytime after asking questions, I got some insights and ideas, so my model advanced, I attached it. I wanted to make a microstrip similar to the goubau line, without ground plane, but then decided to realize the ground by another strip. Could you please give me a hint how to improve my meshing? Solver warns me of low minimum element quality but i dont see any other possibility to sensibly resolve my structure. Is there an option to find the resonance frequency instead of searching the maximum of (Pport_1-Pelement_1)/Pport_1? I would be again really glad if u could help me cheers Alex

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