Microstrip LC resonator

Dear all,

I am trying to design a series LC resonator with a interdigital capacitor in series with a circular planar inductor. When I simulated the S-parameters in the S11 I get the variation of the inductor and on the S22 the response of the Capacitor, and not the behavior of the resonator I would want.

Any idea on what I'm missing? Maybe regarding the matching between elements...

And, are there any special consideration I should be having when mixing these planar L and C elements?

Thanks for your attention. Hope to get some responses.

Post your resonator structure and simulation results to get some ideas about them..