I want to get the input impedance which look in form port 1 at different frequencies, but I can only get the results that close to zero, I think this is due to the capacitance, but I don't know how to simulate in a right way.
I will be very grateful if you can help me！
Rather than simulating, are you able to calculate the reactance of a capacitor? If yes, you must know that it is 1/(2.pi.f.C) and that given the above values, it makes all capacitors to have an impedance value below unity, therefore virtually shorting the central node to ground. Moreover, the above capacitance values do not appear realistic for the simulated frequency, at least in a resonant circuit.
Thank you very much for your answer!
This is indeed the case. The S11 curve obtained by the circuit simulation is not normal. If I don't understand it correctly, my capacitor is not the right size. So if you need to build a normal resonant circuit, how much capacitor do I need?
Thank you again for your help!
I would expect to see all them in series or parallel with minor variants (ie. added parasitics), or at least the components representing the ones selected for the fundamental frequency. Why don't you first specify what you need?
The S11 curve obtained by the circuit simulation is not normal. If I don't understand it correctly, my capacitor is not the right size. So if you need to build a normal resonant circuit, how much capacitor do I need?
My capacitor is too big, so I didn't notice the troughs in the S11 because it is at a very small frequence,
Now I reduce my cap to pF and I get the S11 at 4.25MHz.
Thank you very much!