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The lumped element is an inductor not a capacitor.

The lumped element is an inductor not a capacitor.

Hi Edgar, so my coil produces the 2.96uH capacitance and the lumped element is a capacitor(I might have mistakenly changed it when I was deleting the mesh). However, if you set it to a capacitor of about 47pF you still do not get resonance at 13.56MHz but at around 800MHz. Something is still wrong?

You should post your model together with the mesh sequence and the study and solver sequence you used. You don't need to delete the mesh sequence, only delete the mesh. Same with study and solver and dataset. You don't need to delete them, only delete the solution.

You should post your model together with the mesh sequence and the study and solver sequence you used. You don't need to delete the mesh sequence, only delete the mesh. Same with study and solver and dataset. You don't need to delete them, only delete the solution.

Hi Mr. Kaiser, here is the file once again with the mesh and study.

So I did a long sweep from 10MHz to 1GHz to get the resonance frequency and that is how I managed to get a resonant frequency at 800MHz. However, I need my lumped element capacitance to work ?

Kelvin,

you need to remove the coil domain from the emw physics, otherwise the impedance bc doesn't work. You also don't need to mesh the coil domain, only its boundary.

And you won't be even close to 50 Ohm impedance at the port in resonance. I think this kind of RFID antenna is typicall driven in series resonance?

Cheers Edgar

Kelvin,

you need to remove the coil domain from the emw physics, otherwise the impedance bc doesn't work. You also don't need to mesh the coil domain, only its boundary.

And you won't be even close to 50 Ohm impedance at the port in resonance. I think this kind of RFID antenna is typicall driven in series resonance?

Cheers Edgar

Hey Edgar, So I followed your mesh and boundary advice. However I still do not get resonance. You mentioned driving the antenna in series resonance. Does this mean that the capacitor lumped element is wrongly placed?

Hi...in my case I have not checked the maths yet it won't work at any rate. The harmony between the L and C isn't right. At that recurrence it will be hard to get a capacitor of that size that doesn't act like an inductor. The capacitor ought to be in the scope of 100pF to 1nF and the inductors should then be made to suite.

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Kelvin,

you built a parallel LC circuit that shows high impedance at resonance. In a real circuit you typically prefer low impedance, e.g. for a transistor driver. In this case you would have the coil and the capacitor in a series circuit.