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Lumped port

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Hello all,

I have simulated a loop antenna in COMSOL, It works at desired frequency. However, I see a great deal of mismatch in s11 curve. I've simulated the same antenna in CST and it works perfect. Both of them works at 2.4 GHz but in COMSOL: s11 @2.4 GHz is -15dB in CST: s11 @2.4GHz is -35dB I've used discrete port in CST and lumped port (uniform) in COMSOL. Can anybody help me please. I've attached some pictures.

Kind regards,



1 Reply Last Post 9 feb 2018, 13:36 GMT-5
Robert Koslover Certified Consultant

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Posted: 7 years ago 9 feb 2018, 13:36 GMT-5

I don't know anything about CST. But in Comsol, your specification of a 50 Ohm input cable (as I saw in your figure) is probably at least one important issue here, since your loop antenna very likely does not present a 50 Ohm impedance at its connections. I suggest you change the 50 ohm value, re-run it, and see what happens. Do a frequency sweep too. And be sure your mesh is fine enough where it needs to be, and that you have enough computational space around your loop, etc.

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Scientific Applications & Research Associates (SARA) Inc.
www.comsol.com/partners-consultants/certified-consultants/sara
I don't know anything about CST. But in Comsol, your specification of a 50 Ohm input cable (as I saw in your figure) is probably at least one important issue here, since your loop antenna very likely does not present a 50 Ohm impedance at its connections. I suggest you change the 50 ohm value, re-run it, and see what happens. Do a frequency sweep too. And be sure your mesh is fine enough where it needs to be, and that you have enough computational space around your loop, etc.

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