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Lumped Port Microstrip antenna set up
Posted 11 mars 2013, 16:05 UTC−4 RF & Microwave Engineering Version 4.3, Version 4.3b 5 Replies
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i am completely new to COMSOL and i am struggling with a few basic things for my uni project. I followed the tutorial for the inset microstrip antenna provided. I must have done this ten times now and it works fine. I tried to transfer the same procedures over to my design, a circular polarised microstrip antenna but i am having a few problems. My end goal is to find the S parameters and impedance so i can design a quarter wave transformer to go on the end to match the antenna. The design is really simple, i have attached it at the bottom if anyone wants to take a look.
Anyways the mesh seems to be an issue
I have one mesh covering the inner sphere (i think this is a gaussian surface or something to calculate electric fields but it doesn't say. The tutorial used a free tetrahedral mesh and creates a further 2 sizes. One for the microstrip line edges, or at least that's what the turorial seemed to do so i selected my edges too and one cover the ground, substrate and patch... i dont know if this is right because i aint got a clue where the ground is on the turoial one given as the patch is inside the substrate.....
anyways, i get a few errors,
Edge is much shorter than the specified minimum element size.
Face is (or has a narrow region that is) much smaller than the specified minimum element size.
Question 1
previously i never had to specify a minimum element, i thought it would just do this for me.... how do i choose an appropriate minimum element???
Question 2
on the tutorial for the lumped port domains, he chooses the microstrip line edge which is to be excited, i have done this but when i compute the study i receive the following message
error in automatic sequence lumped port .....
any ideas??
and thanks for your help.
Lee.
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Hello Lee Edwards
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I'm also beginner in Comsol, i'm designing a rectangular patch antenna, and i'm also using the the inset microstrip antenna model provided, sorry I dont have answers to your questions yet, but i need some help :
Theoretically, the microtrip antenna have 3 major parts : the ground, the substrate and finally the metallic patch, but in this model i found only the subsrate !! Why ? I don't understand :(
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The ground plane and patch are modelled as planar surfaces i.e with no thickness so only the face of the patch is selected.
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because i want to study the effect on the microstrip antenna if I vary the conductivity of the patch, have you please any idea how can i do this ?
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With regards to your reply (I know its old) but how can we change the material of the patch to be different to that of the substrate. Presently all the model examples presented by COMSOL simulate the patch and the substrate with the same material. I want to simulate the patch made of copper on a silicon substrate.
PLease help
Thanks